Volume 175 Issue 1

MJA 2001; 175: 15-18 For editorial comment, see Hugh & Hugh Abstract - Methods - Results - Discussion - Acknowledgements - References - Authors' details - - More articles on Surgery Abstract Objective: To measure and describe changes in the incidence of appendicectomy in the population of Western Australia (WA) for 1981-1997. Design: Population-based incidence study using hospital discharge data. Setting: All hospitals in WA (1981-1997). Patients: All patients who underwent an appendicectomy in WA hospitals. Main outcome measures: Changes in the incidence of appendicectomy procedures over time; age-standardised rates and age-sex profiles of four appendicectomy subgroups: (1) acute emergency admission, (2) other emergency admission, (3) incidental appendicectomy and (4) other appendicectomy. Results: From 1981 to 1997, there were 59 749 appendicectomies in WA hospitals. The age-standardised rate of appendicectomy declined by 63% in metropolitan females, by 44% in non-metropolitan females, by 41% in metropolitan males and by 21% in non-metropolitan males. The rate of decline was significantly greater in females and in metropolitan patients. From 1988 to 1997, acute emergency admission for appendicectomy was the most common admission status and was more common in males than females (122 v 103 per 100 000 person-years) and in non-metropolitan areas. The rate of incidental appendicectomy was higher among females than males (20 v 7 per 100 000 person-years). From 1988 to 1997, recorded diagnosis coding for appendicitis became more specific, with a marked reduction in the use of the "unspecified" appendicitis code. Conclusions: The overall incidence of appendicectomy has declined markedly in WA and includes a decline in the practice of incidental appendicectomy. The trend was greatest in the metropolitan hospitals. Appendicectomy is one of the most common surgical procedures in adults and children.1-3 Increases in the incidence of appendicitis were reported during the early part of the 20th century, but a decline has been reported since about 1930.4-6 Significant advances in diagnostic and surgical technology may have influenced treatment options for patients and surgical outcomes.3 Linked hospital discharge data from Oxford (UK), 1970-1986, reported by Primatesta and Goldacre, showed falls in acute appendicitis and the prophylactic and incidental use of appendicectomy, but no decline in conditions that mimic the disease.7 The authors raised the concern that appendicectomy without acute appendicitis was much more common in women than men, questioning the appropriateness of the use of the procedure.7 Our study used data from the Quality of Surgical Care Project8 stored in the WA Health Services Linked Database (WA Linked Database)9 to assess trends in appendicectomy in Western Australia (WA) for 1981-1997. Methods The WA Linked Database provided hospital morbidity data for all patients who underwent appendicectomy for 1981-1997. Hospital morbidity records with a separation date before 1988 were selected using the ICPM procedure code 5-470,10 while ICD-9-CM procedure codes 47.0 and 47.1 were used for patients separated in 1988-1997.11 Data for incidental appendicectomy were evaluated only for the period 1988-1997, as there was no specific incidental appendicectomy procedure code before 1988. To allow comparison with the Oxford study,7 patients who underwent appendicectomy were classified into four subgroups based on procedure and diagnosis codes in conjunction with admission status (Box 1). Western Australia occupies the western third of the Australian continent. It is sparsely populated, except for the southwest corner of the State and some coastal settlements to the north. Seventy-three per cent of the total population of 1.9 million reside in the capital city of Perth. We used postcode data to classify patients as residing in Perth (metropolitan) or non-metropolitan areas, following the Health Zone classification system of the Health Department of Western Australia. We estimated annual rates of appendicectomy procedures per 100 000 person-years (PY) by the direct method,12 age standardised to the WA population.13 Population estimates were obtained from the Australian Bureau of Statistics.14 Men and women were analysed separately. We analysed descriptive statistics with the statistical program SPSS,15 and time trends in rates of admission by Poisson regression models using the SAS procedure GENMOD.16 These models included terms for "locality" (metropolitan/non-metropolitan), "time", "age-group" and "sex", and associated rate ratios are reported. Depending on goodness of fit, "time" was modelled either as a single term for linear trend or categorically. In our modelling, we also assessed whether trend effects differed by sex and/or locality by using appropriate higher-order interaction terms. Results Trends in appendicectomy rates, 1981-1997 Of the 59 749 appendicectomies performed in WA in 1981-1997, 33 352 (55.8%) were performed on female patients and 26 397 (44.2%) on males. There was a marked decline in the rate of appendicectomy during the study period (Box 2). The age-standardised rate declined by 63% (from 386 to 144 per 100 000 PY) in metropolitan females, by 44% (from 393 to 221 per 100 000 PY) in non-metropolitan females, by 41% (from 240 to 142 per 100 000 PY) in metropolitan males and by 21% (from 258 to 204 per 100 000 PY) in non-metropolitan males. The decline was more marked in females than males and was also greater in the metropolitan area. The adjusted rate ratio (RR) in metropolitan females fell by 6.2% per year (RR, 0.938; 95% CI, 0.933-0.943), compared with 3.2% per year (RR, 0.968; 95% CI, 0.959-0.976) in non-metropolitan females. For metropolitan males, the adjusted rate ratio declined by 3.9% per year (RR, 0.961; 95%CI, 0.955-0.967), compared with the 1.6% per year decline (RR, 0.984; 95% CI, 0.976-0.993) in non-metropolitan males. Trends in admission classification, 1988-1997 Of the 30 934 appendicectomies performed in WA during 1988-1997, 18 961 (61.3%) were acute emergency admissions, 3820 (12.3%) were other emergency admissions, 2192 (7.1%) were incidental procedures and 5961 (19.3%) were recorded as other appendicectomy admissions. The age-sex profiles for each group are presented in Box 3. Acute emergency admission appendicectomy was more common in males than females (122.2 v 102.9 per 100 000 PY). The highest rates were in males aged 10-14 years (300 per 100 000 PY) and females aged 15-19 years (289 per 100 000 PY). There was an asymptotic decrease in rates of acute emergency appendicectomy after the 20-24-years age group in both sexes. Rates were higher in non-metropolitan areas for males (149 v 111 per 100 000 PY) and females (131 v 93 per 100 000 PY). The difference between metropolitan and non-metropolitan areas remained significant after adjustment for age, sex and year of separation (RR, 1.37; 95% CI, 1.30-1.45). There was a modest increase in the rate ratio of 1.5% per year over time (95% CI, 0.6%-2.4%) for patients in this group, with no difference between metropolitan and non-metropolitan areas in the rate of acute emergency admissions. Rates of other emergency appendicectomies were higher in females than males (31 v 15 per 100 000 PY). In females, the rates were highest in those aged 15-19 years (108 per 100 000 PY) and declined sharply after the 20-24-years age group. Rates were higher in non-metropolitan areas for both females (44 v 26 per 100 000 PY) and males (21 v 13 per 100 000 PY) and this effect remained after adjustment for age, sex and year of separation (RR, 1.66; 95% CI, 1.53-1.80). The age-sex profile of incidental appendicectomies showed a very different pattern. The rate of incidental appendicectomy was higher in females than males (20 v 7 per 100 000 PY). The age profiles were also different, with a sharp, bell-shaped pattern of increase and decrease in women between the ages of 15 and 49 years, with the highest rate occurring in women aged 35-39 years (37 per 100 000 PY). Rates were higher in non-metropolitan areas, with this difference considerably more pronounced in females (29 v 17 per 100 000 PY) than in males (8 v 6 per 100 000 PY). There was a marked decline in the rate of incidental appendicectomies over time among females (Box 4), with a significantly more pronounced trend in metropolitan than non-metropolitan areas (P < 0.001). The primary surgical procedures with which incidental appendicectomies were performed varied by sex. Incidental appendicectomies in females were most frequent during admissions for operations of the uterus (57%) and ovary (24%), and for operations on the intestines (52%), and hernia and abdomen (20%) in males. Rates of other appendicectomy were higher in females than males (50 v 22 per 100 000 PY). The highest rate occurred in females aged 15-19 years (139 per 100 000 PY). Rates in this group were higher in non-metropolitan areas for both females (55 v 48 per 100 000 PY) and males (26 v 20 per 100 000 PY). This locality effect was significant after adjustment for age, sex and year of separation (RR, 1.19; 95% CI, 1.09-1.29). There was a strong linear decrease in the incidence of other appendicectomies, with the rate ratio declining 14.4% per year (95% CI, 13.2%-15.5%). This rate of decline was significantly greater for males (17.2%) than females (13.1%; P = 0.002). Changes in recorded diagnosis, 1988-1997 Changes in the diagnostic profiles of appendicectomy records, excluding incidental appendicectomies, are shown in Box 5. There was a 10-fold reduction in the use of the unspecified appendicitis diagnosis code, with an increase in the use of acute appendicitis diagnosis codes. To assess whether the increased use of acute appendicitis codes was more likely to reflect changes in recording practices rather than in true disease incidence, trends in appendicectomy rates were examined in males aged 10-24 years, as this group predominantly reflected acute emergency admissions. From 1981 to 1997, age-specific rates of appendicectomy in young males declined by 42% (from 692 to 399 per 100 000 PY) in those aged 10-14 years, by 45% (from 629 to 346 per 100 000 PY) in those aged 15-19 years and by 33% (from 373 to 251 per 100 000 PY) in those aged 20-24 years. Discussion The incidence rate of appendicectomy in WA hospitals declined markedly from 1981 to 1997, consistent with trends reported from other industrialised countries.5,6 The age-sex profiles of the four different classifications of appendicectomy defined in our study were similar to those found in the Oxford Record Linkage Study.7 These profiles were unaffected by the different procedure classifications employed, namely ICD-9-CM in our study and the Office of Population Censuses and Surveys Operations Codes in the Oxford study. Improvements in diagnostic technology during the past decade have resulted in a much greater use of compression ultrasonography, laparoscopic examination and scoring systems to verify acute appendicitis in patients with abdominal pain.17,18 These technical improvements may have contributed to the decline in appendicectomy and an improvement in coding practice. Further research is warranted here given a recent finding of no significant benefits from ultrasonography compared with clinical diagnosis alone, other than reduced time to operation.19 Our study found changes in the specificity of coding of recorded diagnoses of appendicitis from 1988 to 1997. In 1988, most diagnoses of appendicitis were recorded using the non-specific code 541.x. By 1997, relatively few diagnoses of appendicitis were assigned this code. There was an increase in the number of diagnoses coded as acute appendicitis either with peritonitis (540.0 or 540.1) or without peritonitis (540.9). This change could be taken to indicate that the incidence of acute appendicitis increased in WA during 1988-1997. However, our data show a fall in the number of appendicectomies in WA since 1981 and a fall among males aged 10-24 years, the group most likely to be admitted with acute appendicitis. A more likely explanation is that there was an improvement over time in the accuracy of coding in WA hospitals. There is now concern about the continued practice of incidental appendicectomy.20 While the physiological role of the appendix is unclear, it may have surgical potential in reconstructive urology and the management of faecal incontinence. The frequency of emergency (acute and other) appendicectomy peaks in the 15-19-years age group, the frequency of incidental appendicectomy peaks in the 35-39-years age group in women and at around 70 years in men. A retrospective review and meta-analysis of incidental appendicectomy by Snyder and Selanders supported incidental removal of the appendix in young patients (< 35 years), suggested that the patient's clinical condition should determine incidental removal between 35-50 years, and could not justify incidental appendicectomy in patients older than 50 years.21 To address the concerns that incidental appendicectomy is unjustified, further comparison of the risk of appendicectomy and the risk of complications (especially adhesion formation) for different age groups is needed. The decline in incidental appendicectomy has also seen a convergence of appendicectomy trends for males and females, which most likely reflects a change in attitude by surgeons. The rate of incidental appendicectomy was about five times higher in females than males in 1988, but had reduced to twice the magnitude by 1997. There was no indication of a parallel decline in other abdominal procedures to account for the decline in appendicectomy rates, although the increased use of laparoscopic procedures may have contributed to the decline in incidental appendicectomy. The decline in the incidence of appendicectomy in WA from 1981 to 1997 is consistent with trends in other industrialised countries and most likely reflects a change in attitude to the use of the procedure, coupled with improvements in diagnostic technology. The trend was most notable in young women in the metropolitan area. There was a fivefold decline in incidental appendicectomy in women in both the metropolitan and non-metropolitan areas. Incidental appendicectomy was more common in women in non-metropolitan areas, which raises questions about differences in practice between the metropolitan and non-metropolitan areas. While the decline in the rates of incidental appendicectomy reflects a change in clinical practice, the question still remains whether incidental appendicectomy is justified to prevent future appendicitis, and does the risk of additional problems and complications outweigh the potential benefit. Acknowledgements We thank the National Health and Medical Research Council for the funds that supported this study, and Dr John Bass and the Extramural Unit of the Western Australian Health Services Research Linked Database Project for the linkage of patient records. Mr Neil Donnelly was on secondment from the Needs Assessment and Health Outcomes Unit, Central Sydney Area Health Service, Sydney, NSW, Australia. References Pearl RH, Hale DA, Molloy M, et al. Pediatric appendectomy. J Pediatric Surg 1995; 30: 173-181. Reid RI, Dobbs BR, Frizelle FA. Risk factors for post-appendectomy intra-abdominal abscess. Aust N Z J Surg 1999; 69: 373-374. Wilcox RT, Traverso LW. Have the evaluation and treatment of acute appendicitis changed with new technology? Surg Clin North Am 1997; 77: 1355-1369. Raguveer-Saran MK, Keddie NC. The falling incidence of appendicitis. Br J Surg 1980; 67: 681. Bisset AF. Appendicectomy in Scotland: a 20-year epidemiological comparison. J Public Health Med 1997; 19: 213-218. Blomqvist P, Ljung H, Nyren O, Ekbom A. Appendectomy in Sweden 1989-1993 assessed by the Inpatient Registry. J Clin Epidemiol 1998; 51: 859-865. Primatesta P, Goldacre MJ. Appendectomy for acute appendicitis and for other conditions: an epidemiological study. Int J Epidemiol 1994; 23: 155-160. Semmens JB, Lawrence-Brown MMD, Fletcher DR, et al. The Quality of Surgical Care Project: a model to evaluate surgical outcomes in Western Australia using population-based record linkage. Aust N Z J Surg 1998; 68: 397-403. Holman CDJ, Bass AJ, Rouse IL, Hobbs MST. Population-based linkage of health records in Western Australia: development of a health services research linked database. Aust N Z J Public Health 1999; 23: 453-459. International classification of procedures in medicine. Geneva: World Health Organization, 1978. The official NCC Australian version of ICD-9-CM. Tabular list (annotated) and index of procedures. Sydney: National Coding Centre, Faculty of Health Sciences, University of Sydney, 1995. Rothman KJ. Modern epidemiology. Boston/Toronto: Little, Brown and Company, 1986. Muir C, Waterhouse J, Mack T, et al. Cancer incidence in five continents, Vol. V. Lyon: IARC Scientific Publications, International Agency for Research on Cancer, 1987. Australian Bureau of Statistics. Estimated resident population by age and sex in statistical local areas, Western Australia (Catalogue no. 3203.5). Canberra: ABS, 1995. SPSS for Windows, release 5.0 [computer program]. Chicago, Ill: SPSS Inc., 1992. SAS version 6.12 [computer program]. Cary, NC: SAS Institute, 1997. Calder JDF, Gajraj H. Recent advances in the diagnosis and treatment of acute appendicitis. Br J Hosp Med 1995; 54: 129-133. Beasley SW. Can we improve the diagnosis of acute appendicitis? [editorial]. BMJ 2000; 321: 907-908. Douglas CD, McPherson NE, Davidson PM, Gani JS. Randomised controlled trial of ultrasonography in diagnosis of acute appendicitis, incorporating the Alvarado score. BMJ 2000; 321: 1-6. Wheeler RA, Malone PS. Use of appendix in reconstructive surgery: a case against incidental appendicectomy. Br J Surg 1991; 78: 1283-1285. Snyder TE, Selanders JR. Incidental appendicectomy — yes or no? A retrospective case study and review of the literature. Infec Dis Obstet Gynecol 1998; 6: 30-37. (Received 20 Sep 2000, accepted 20 Mar 2001) Authors' details Needs Assessment and Health Outcomes Unit, Central Sydney Area Health Service, Sydney, NSW. Neil J Donnelly, BSc (Hons), MPH, Statistician. Centre for Health Services Research, Department of Public Health, The University of Western Australia, Nedlands, WA. James B Semmens, MSc, PhD, Research Fellow, Quality of Surgical Care Project. C D'Arcy J Holman, MB BS, MPH, PhD, Director. University Department of Surgery, Fremantle Hospital, Fremantle, WA. David R Fletcher, MB BS, MD, FRACS, Professor. Reprints will not be available from the authors. Correspondence: Dr James B Semmens, Quality of Surgical Care Project, Centre for Health Services Research, Department of Public Health, The University of Western Australia, Nedlands, WA, 6907. Make a comment 1: Four appendicectomy subgroups Definitions based on ICD-9-CM diagnosis and procedure codes in conjunction with recorded admission type status: Acute emergency admission appendicectomy Diagnosis code for acute appendicitis with or without rupture (540.0, 540.1 or 540.9) + procedure code for appendicectomy (47.0) or Diagnosis code for unspecified appendicitis (541.0 or 541.9) + procedure code for appendicectomy (47.0) + emergency admission type status. Other emergency admission appendicectomy Patients who were clinically hard to define: patients treated with appendicectomy where the diagnosis did not include either acute or unspecified appendicitis (540.x or 541.x) but who were admitted as an emergency case (procedure code for appendicectomy (47.0) + emergency admission type status + any diagnosis codes not including 540.0, 540.1, 540.9, 541.0 or 541.9). Incidental appendicectomy Incidental or prophylactic excision of a normal appendix during abdominal operations (procedure code 47.1). Other appendicectomy All patients with a procedure code for appendicectomy (47.0) not included in subgroups 1 and 2. Back to text Age-standardised total annual incidence rates for appendicectomy in men and women in the metropolitan and non-metropolitan areas of Western Australia for the period 1981-1997. Back to text A: Acute emergency appendicectomy in males and females, Western Australia, 1988-1997. B: Other emergency appendicectomy in males and females, Western Australia, 1988-1997. C: Incidental appendicectomy in males and females, Western Australia, 1988-1997. D: Other appendicectomy in males and females, Western Australia, 1988-1997. Back to text Age-standardised total annual incidence rates for incidental appendicectomy in males and females in the metropolitan and non-metropolitan areas of Western Australia for the period 1988-1997. Back to text 5: Diagnostic profiles of appendicectomy records excluding incidental appendicectomy in Western Australia, 1988-1997 Acute rupture (540.0, 540.1) Acute non-rupture (540.9) Unspecified appendicitis (541.x) Other appendix (542.x, 543.x) Abdominal pain (789.x) Other 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 157 230 215 316 318 311 388 386 469 527 943 988 922 1084 1265 1478 1396 1364 1559 1563 1436 1138 1016 658 448 369 225 195 167 157 102 169 179 219 306 289 296 263 201 213 273 228 248 282 341 378 297 243 206 161 153 167 211 258 246 277 233 207 183 225 Coding numbers used in this table are from ICD-9-CM.11 Back to text

Neil J Donnelly · James B Semmens · David R Fletcher

Indigenous health Regional variation in the incidence of end-stage renal disease in Indigenous Australians Alan Cass, Joan Cunningham, Zhiqiang Wang and Wendy Hoy MJA 2001; 175: 24-27 Abstract - Methods - Results - Discussion - Acknowledgements - References - Authors' details - - More articles on Aboriginal health Abstract Objective: To evaluate regional variation in the incidence of end-stage renal disease (ESRD) in Indigenous Australians, and to examine the proximity to ESRD treatment facilities of Indigenous patients. Design: Secondary data review, with collection of primary data regarding patients' place of residence before beginning ESRD treatment. Participants: Indigenous ESRD patients who commenced treatment in Australia during 1993-1998. Methods: We obtained data from the Australian and New Zealand Dialysis and Transplant Registry regarding 719 Indigenous patients who started ESRD treatment between 1 January 1993 and 31 December 1998. We obtained primary data from the treating renal units to determine the place of residence before beginning renal replacement therapy. We calculated the average annual incidence of ESRD for each of the 36 Aboriginal and Torres Strait Islander Commission regions using population estimates based on the 1996 Census, and calculated standardised incidence ratios with 95% confidence intervals for each region. We compared the number of cases with the treatment facilities available in each region. Main outcome measure: Regional standardised ESRD incidence for Indigenous Australians referenced to the total resident population of Australia. Results: Standardised ESRD incidence among Indigenous Australians is highest in remote regions, where it is up to 30 times the national incidence for all Australians. In urban regions the standardised incidence is much lower, but remains significantly higher than the national incidence. Forty-eight per cent of Indigenous ESRD patients come from regions without dialysis or transplant facilities and 16.3% from regions with only satellite dialysis facilities. Conclusions: There is marked regional variation in the incidence of ESRD among Indigenous Australians. Because of the location of treatment centres, there is inequitable access to ESRD treatment services for a significant proportion of Indigenous patients. In Australia, geographical differences in morbidity and mortality have been demonstrated.1-4 In general, people living in rural and remote areas have higher death and hospital separation rates, which have been attributed to differences in socioeconomic status,1,3-5 access to health services,2,6,7 ethnicity4 and racial discrimination.8 Indigenous Australians constitute a disproportionate number of new patients commencing end-stage renal disease (ESRD) treatment:9 in 1997, the incidence rate (adjusted for age and sex) for Indigenous Australians beginning ESRD treatment was nearly nine times that of non-Indigenous Australians.10 Although epidemics of renal disease among Indigenous Australians in defined areas11 have been documented, there have been no systematic reports of the regional patterns of ESRD incidence in Australia. In this study we have attempted to determine these patterns and to examine the accessibility of ESRD treatment facilities for Indigenous people. Methods Databases The Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) maintains a database of patients treated by maintenance dialysis or renal transplantation in Australia. All renal units that provide ESRD treatment in Australia participate in the Registry. Postcode of residence at the start of treatment is collected for all new patients entered into the ANZDATA Registry. ANZDATA maintains a list of hospital renal transplant services, tertiary referral units and satellite dialysis units. Satellite units are defined as dialysis facilities, generally staffed by specialist nurses, that are geographically separate from hospital nephrology services. Data validity Postcode of residence at the start of treatment is an imperfect indicator of the usual place of residence before starting treatment. In remote areas of Australia a single postcode may apply to many communities across a vast area. Furthermore, patients may be required to relocate to a major regional centre to access dialysis services; thus, their postcode at the start of treatment may not reflect their previous usual place of residence. To determine the usefulness of postcode data, we reviewed 104 Indigenous patients who commenced ESRD treatment from 1993 to 1998 at Royal Darwin Hospital, Northern Territory. For these patients the previous usual place of residence was known. Fifty-one patients (49%) had postcodes in the Darwin region, but only nine of these 51 patients previously lived in this region. The other 42 had relocated to Darwin to commence dialysis and were from communities across the "Top End", extending from the Torres Strait in Queensland to Geraldton in Western Australia. As a result of this audit, we decided to collect primary data from each treating renal unit regarding the previous place of usual residence of their Indigenous patients. Indigenous identification was based upon self-identification and discussion with the treating physician. There is often significant concern about the quality of Indigenous identification in morbidity, mortality and demographic data sets. However, we believe that racial identification in the ANZDATA registry is good. A survey form is completed every six months for all patients on maintenance dialysis or with functioning renal transplants. In this survey, question five is about "Racial origin" and includes a prompt regarding Indigenous status. ESRD patients have regular contact with renal services from the time of diagnosis, through intensive maintenance therapy until death. There is heightened awareness of renal disease in Indigenous Australians and multiple opportunities exist to reconfirm data accuracy. Patients From 1 January 1993 to 31 December 1998, 719 Indigenous patients started treatment for ESRD in Australia. We determined the previous place of usual residence for 680 (94.6%). For 38 patients (5.3%) we used the postcode at entry as an indicator of previous place of usual residence. No geographical data were obtainable for one patient. Geography We used the 36 Aboriginal and Torres Strait Islander Commission (ATSIC) regions (Boxes 1 and 2) as our geographic units for analysis. These are legally prescribed administrative areas and the smallest geographical areas for which accurate resident population estimates for the Indigenous population are available.12 We assigned the place of usual residence for Indigenous patients to the appropriate ATSIC regions. We assigned the 38 patients for whom we could not obtain exact information on previous place of residence to ATSIC regions according to their postcode at the time of beginning ESRD treatment. Statistical analysis Using population estimates based on the 1996 Census, we calculated the average annual incidence of ESRD in the 36 ATSIC regions. We used ABS estimates of the Indigenous population, derived using Census information on place of usual residence. These estimates are adjusted for net Census undercount and non-response to the Census question about Indigenous status.13 We used indirect standardisation to calculate an age- and sex-standardised incidence ratio with 95% confidence intervals for each region. Rates for the total Australian resident population were used as the reference (standardised incidence ratio equals incidence in the Indigenous population divided by incidence in the total Australian population, after adjusting for differences in the age and sex composition of both populations). Statistical analysis was performed using Stata.14 Ethical approval We obtained ANZDATA approval to analyse geographic data for Indigenous patients starting treatment for ESRD between 1 January 1993 and 31 December 1998. We also obtained approval for the study from the joint institutional ethics committee of Royal Darwin Hospital and the Menzies School of Health Research. The head of each renal unit gave written consent for us to access potentially identifying patient data in order to determine the previous place of usual residence for Indigenous ESRD patients. Results Mapping reveals significant variation in the incidence of ESRD among Indigenous Australians. The areas of highest incidence (up to 1300 cases per million per year) were the remote regions of Tennant Creek, Aputula and Jabiru in the Northern Territory, Warburton and Kalgoorlie in Western Australia, and Ceduna in South Australia (Box 1). The areas of lowest incidence (less than 100 per million per year) were the regions of Rockhampton and Brisbane in Queensland, Sydney and Queanbeyan in NSW/ACT, Wangaratta (which includes much of eastern Victoria) and Hobart (which encompasses all of Tasmania) (Box 1). The standardised incidence ratio for ESRD (compared with the total national population incidence) ranged from less than two in Rockhampton, Sydney, Queanbeyan and Wangaratta to more than 25 in Aputula, Kalgoorlie and Tennant Creek (Box 2). There were no ESRD patients identified as Indigenous in Tasmania in the six-year period. Tertiary renal services, particularly transplant services, are located within significant population centres such as capital cities. Three hundred and forty-five (48.0%) of the 719 Indigenous ESRD patients lived in ATSIC regions without ESRD treatment facilities (Box 2). A further 117 (16.3%) lived in regions with only satellite dialysis facilities (Box 2). Most Indigenous patients must travel hundreds of kilometres to access transplant services, which are located in Perth, Adelaide, Melbourne, Sydney, Newcastle and Brisbane. Discussion In this study we have demonstrated a large gradient in Indigenous ESRD incidence from urban to remote regions and highlighted inequitable access for remote patients to treatment facilities. However, even in urban regions, the Indigenous ESRD incidence was high after age and sex standardisation. Poor Indigenous health outcomes are not confined to the most disadvantaged or most remote regions, but exist across the Indigenous population. The quality of Indigenous identification is a potential concern in our study. ANZDATA relies upon self-identification and discussion with the treating physician. Self-identification is the method used by the Australian Bureau of Statistics in census collections and is generally used in health-related data collection. We believe that the quality of identification in our study is high owing to the ongoing intensive interaction of ESRD patients with medical and nursing staff, Indigenous status being a prominent question in the six-monthly survey form, and the strong awareness of Indigenous ESRD among nephrologists. The most likely error would be the failure to identify all urban Indigenous ESRD patients. This would result in an underestimate of the true Indigenous ESRD incidence in urban areas and an overestimate of the gradient from urban to remote Indigenous ESRD incidence. Yet, as this gradient is so large, representing an almost 20-fold variation in standardised ESRD incidence, it can not be entirely explained by problems with Indigenous identification. The very high standardised incidence ratios for Indigenous people in remote areas would not change. These results have significant implications for the delivery of services to Indigenous people with ESRD. Satellite facilities opened in the Jabiru region in 1999 and the Katherine region in 2000 (after the patients in this study commenced treatment). Of the 16 regions with the highest Indigenous ESRD incidence, at the beginning of 2001 only Kalgoorlie, Jabiru (Tiwi Islands), Geraldton, Katherine and South Hedland had satellite dialysis units. A satellite unit is scheduled to open soon in Broome and recommendations have been accepted to establish a satellite haemodialysis service in the Torres Strait as part of the recent Queensland Renal Strategy.15 We recognise the significant difficulties related to the establishment and maintenance of renal treatment facilities in remote locations. These include high construction costs, poor reliability of electricity and water supply, variable water quality, difficulties in training and retaining specialised nursing staff, infrequent access to medical staff and provision of housing for patients returning to live in their local community. Despite these difficulties, treatment facilities have been established in some of the most remote communities in Australia. Even with the availability of satellite units, initiation of ESRD treatment usually requires a prolonged stay in a major urban centre. During this stay, vascular or peritoneal access for dialysis is created, the patient starts and is stabilised on treatment and learns skills required for self-care in order to return to a remote satellite dialysis unit. We should develop more innovative methods of patient education, training for self-care and delivery of treatment to allow patients to remain within their communities whenever possible. Improving prevention and treatment services in high-incidence areas should be a priority. Indigenous people living in remote communities demand more equitable access to dialysis services,16 regardless of practical problems related to the establishment of remote treatment facilities. The need to relocate to distant urban areas to access treatment affects the patient, patient's family and community. A recent study of ESRD among Aboriginal people of central Australia concluded: "This level of illness and death [due to ESRD] represents Aboriginal family trauma and loss on a shocking scale, described without exaggeration as sorrows nearly every year [because] the young and the old are dying". 17 Acknowledgements The data reported here have been supplied by the Australia and New Zealand Dialysis and Transplant Registry. The interpretation of these data is the responsibility of the authors and should not be seen as an official policy or interpretation of the Australia and New Zealand Dialysis and Transplant Registry. Dr Alan Cass receives postgraduate research scholarship funding from the Colonial Foundation. Dr Joan Cunningham is supported by a fellowship from the Menzies Foundation. We thank Dr Mark Thomas, Dr Paul Snelling, Dr Meshak Kirubakaran, Dr Tim Furlong, Dr Peter de Jersey and the heads of renal units for providing information regarding the place of usual residence for their patients. References Glover J, Harris K, Tennant S. A social health atlas of Australia. 2nd ed. Adelaide: Public Health Information Development Unit, University of Adelaide, 1999. Sexton PT, Sexton TL. Excess coronary mortality among Australian men and women living outside the capital city statistical divisions. Med J Aust 2000; 172: 370-374 [see comments Med J Aust 2000; 172: 360-361]. National Health Strategy. Enough to make you sick: how income and environment affect health, Research Paper No. 1. Melbourne: National Health Strategy Unit, 1992. Taylor R, Chey T, Bauman A, Webster I. Socio-economic, migrant and geographic differentials in coronary heart disease occurrence in New South Wales. Aust N Z J Public Health 1999; 23: 20-26. Turrell G, Mathers CD. Socioeconomic status and health in Australia. Med J Aust 2000; 172: 434-438. Heller RF. Mortality from cardiovascular disease is too high outside capital cities [editorial]. Med J Aust 2000; 172: 360-361. McLaren B. Renal failure in Arnhem Land: missed opportunities for prevention and treatment. Aust J Rural Health 1996; 4: 61-66. Lowe M, Kerridge IH, Mitchell KR. 'These sorts of people don't do very well': race and allocation of health care resources. J Med Ethics 1995; 21: 356-360. Disney A, Russ G, Walker R, et al, editors. ANZDATA Registry Report 1999. Adelaide: Australia and New Zealand Dialysis and Transplant Registry, 1999. Cass A, McDonald SP, Wang Z. Australians with renal disease: a new national survey [letter]. Med J Aust 1999; 171: 444. Spencer JL, Silva DT, Snelling P, Hoy WE. An epidemic of renal failure among Australian Aboriginals. Med J Aust 1998; 168: 537-541 [see comments Med J Aust 1998; 168: 532-533 and Med J Aust 1999; 170: 191-192]. Australian Bureau of Statistics. Population issues, Indigenous Australians. Canberra: Australian Bureau of Statistics, 1999. Australian Bureau of Statistics. Experimental estimates of the Aboriginal and Torres Strait Islander population. Canberra: Australian Bureau of Statistics, 1998. Stata version 6 [computer software]. College Station, TX: Stata Corporation, 1999. Schmidt B. Northern zone renal services plan 2000-2010, 2000. Devitt J, McMasters A. On the machine: Aboriginal stories about kidney troubles. Alice Springs: IAD Press, 1998. Devitt J, McMasters A. Living on medicine: a cultural study of end-stage renal disease among Aboriginal people. Alice Springs: IAD Press, 1998. (Received 13 Sep 2000, accepted 22 Mar 2001) Authors' details Menzies School of Health Research, Casuarina, NT. Alan Cass, GradDipClinEpi, FRACP, PhD Student and Nephrologist. Joan Cunningham, ScD, Epidemiologist and Menzies Fellow. Zhiqiang Wang, PhD, Biostatistician. Wendy Hoy, MB BS, FRACP, Head of Renal Unit. No reprints will be available from the authors. Correspondence: Dr Alan Cass, Menzies School of Health Research, PO Box 41096, Casuarina, NT, 0811. Make a comment Map numbers refer to Aboriginal and Torres Strait Islander Commission regions as specified in Box 2 Back to text 2: End-stage renal disease among Indigenous Australians from 1993 to 1998 ATSIC region (map references) Treatment facilities† Patients (number) Standardised incidence ratio* (95% CI) Tennant Creek (35) 30 31.05 (20.96 - 44.33) Kalgoorlie (27) S 23 27.75 (17.60 - 41.64) Aputula (33) 58 25.03 (19.01 - 32.36) Warburton (23) 20 22.77 (13.91 - 35.17) Ceduna (18) 10 22.48 (10.78 - 41.34) Jabiru (31) 45 21.87 (15.95 - 29.26) Geraldton (28) S 25 18.20 (11.78 - 26.86) Mount Isa (11) 33 17.74 (12.21 - 24.91) Kununurra (22) 22 16.85 (10.56 - 25.51) Katherine (32) 30 15.64 (10.56 - 22.33) Torres Strait (15) 28 14.99 (9.96 - 21.66) South Hedland (25) S 18 14.75 (8.74 - 23.30) Derby (26) 16 13.40 (7.66 - 21.76) Nhulunbuy (34) 21 11.74 (7.27 - 17.94) Cooktown (12) 21 11.61 (7.19 - 17.75) Broome (21) 11 11.47 (5.73 - 20.53) Port Augusta (19) S 17 10.45 (6.09 - 16.74) Bourke (2) S 21 10.16 (6.29 - 15.53) Townsville (16) T, S 35 9.41 (6.55 - 13.08) Cairns (10) T, S 35 8.71 (6.07 - 12.12) Alice Springs (30) T, S 11 8.55 (4.27 - 15.30) Narrogin (24) S 13 8.20 (4.37 - 14.02) Darwin (36) T, S 17 7.02 (4.09 - 11.24) Perth (20) Tx, T, S 29 6.70 (4.48 - 9.61) Adelaide (17) Tx, T, S 15 4.62 (2.58 - 7.61) Tamworth (5) T, S 12 4.18 (2.16 - 7.30) Roma (14) T, S 8 3.70 (1.60 - 7.28) Coffs Harbour (3) Tx, T, S 24 3.68 (2.36 - 5.47) Ballarat (8) Tx, T, S 10 3.42 (1.64 - 6.28) Wagga Wagga (6) T, S 14 2.98 (1.63 - 5.00) Brisbane (9) Tx, T, S 17 2.51 (1.46 - 4.02) Rockhampton (13) T, S 5 1.78 (0.58 - 4.16) Sydney (4) Tx, T, S 16 1.77 (1.01 - 2.88) Queanbeyan (1) T, S 4 1.75 (0.48 - 4.48) Wangaratta (7) Tx, T, S 4 1.39 (0.38 - 3.55) Hobart (29) T, S 0 0.00 (0.00 - 1.03) * Indirectly standardised to the rates for the total Australian resident population. †Tx = transplant service, T = tertiary renal unit, S = satellite dialysis unit. Geographical data were unobtainable for one patient. Back to text

Alan Cass · Joan Cunningham · Zhiqiang Wang · Wendy Hoy

Cannabis has been advocated as a treatment for nausea, vomiting, wasting, pain and muscle spasm in cancer, HIV/AIDS, and neurological disorders. Such uses are prohibited by law; cannabinoid drugs are not registered for medical use in Australia and a smoked plant product is unlikely to be registered. A New South Wales Working Party has recommended granting exemption from prosecution to patients who are medically certified to have specified medical conditions. This proposal deserves to be considered by other State and Territory governments. Wayne D Hall, Louisa J Degenhardt and David Currow MJA 2001; 175: 39-40 In August 1999, the New South Wales Premier convened a Working Party on the Use of Cannabis for Medical Purposes1 to advise on whether cannabis and cannabinoid drugs had any medical uses and, if so, to suggest how these substances could be made available for medical use without decriminalising cannabis for non-medical use. The Working Party's report was tabled in Parliament on 1 November 2000. Its recommendations were endorsed in principle by the Premier and are currently being considered by the NSW government. We believe that they deserve wider consideration. The Working Party reviewed the scientific evidence on the safety and efficacy of the medical uses of the crude cannabis plant (which is usually smoked) and of cannabinoid drugs (pharmaceutically pure substances found in the cannabis plant, such as tetrahydrocannabinol [THC], or synthetic drugs that act on the same receptors in the brain as THC).2 It agreed with the United States Institute of Medicine2 and the UK House of Lords Standing Committee on Science and Technology3 that THC can be useful in treating nausea, vomiting and appetite loss in patients with HIV and in cancer patients undergoing chemotherapy.1 It noted the suggestive evidence from animal studies and clinical case series that THC may relieve painful muscle spasms in neurological disorders and chronic pain that has not responded to conventional analgesics.2 It recommended further research on the therapeutic use of cannabis and cannabinoid drugs in these conditions. These recommendations do not address the needs of those currently using cannabis for medical purposes, as THC is not registered for medical use in Australia. THC is registered in the US, and a synthetic cannabinoid, nabilone, is registered in the United Kingdom to treat nausea caused by cancer chemotherapy and HIV-related wasting. These drugs could be registered in Australia if a pharmaceutical company applied. No company has done so to date. Smoked cannabis can not be medically prescribed in Australia, as it does not satisfy the requirements for registration as a "therapeutic good" under the Therapeutic Goods Act 1989 (Cwth). Smoking is an unsafe and unreliable way to deliver a drug that may be used daily to treat a chronic illness.1 The risks are much lower if cannabis is smoked for a limited time (eg, to treat nausea during a course of cancer chemotherapy, or to intermittently stimulate appetite in patients with HIV/AIDS or terminal cancer).1 The best chance for establishing the medical use of cannabinoids lies in the development, testing and registration of new synthetic cannabinoid drugs. This is likely to take considerable time.2 The next-best option is to find ways of administering THC that are more efficient than the oral route and do not involve smoking a crude cannabis plant product.2 However, existing technologies (eg, transpulmonary delivery systems used for opioid drugs) are not readily adapted for delivering THC, which is not water soluble.4 In the meantime, under existing NSW law (and in other States/Territories except South Australia, the Australian Capital Territory and the Northern Territory), patients who smoke cannabis for medical reasons face criminal prosecution if detected by the police. The Working Party's view was that the law should not compound the predicament of seriously ill patients. Accordingly, it recommended that a limited exemption from criminal prosecution should be given to specific classes of patients who wished to use cannabis for medical purposes. The exemption would be an interim measure until pharmaceutical cannabinoids were registered, and the effects of this exemption would be evaluated after a two-year trial period. The exemption would be limited to patients who had been certified by an approved medical practitioner to have HIV-related or cancer-related wasting, nausea caused by cancer chemotherapy, muscle spasm in neurological disorders or spinal cord injury, or pain unrelieved by conventional analgesics. Certification would have to be obtained before medical cannabis use. This would allow the practitioner to counsel the patient about alternative treatments and the risks of smoking cannabis, and to review their health regularly. The patient would have to renew the certificate after six months. To allow patients to avoid resorting to the black market, the Working Party recommended that these patients be allowed to grow a small number of cannabis plants for their own use. In the case of seriously ill and debilitated patients, a carer would be allowed to grow the plants on behalf of the certified patient. How many patients are likely to use such provisions? According to estimates derived from data supplied by the New South Wales Cancer Council, around 12 000 patients suffer from nausea during cancer chemotherapy or cancer-related wasting in any year.5 Another 2000 suffer from HIV-related wasting and neurological disorders and 4500 from chronic pain unrelieved by conventional treatments in New South Wales in any year. The total estimate of about 19 000 (Box) is likely to be an upper limit on the number of medical cannabis users, as the symptoms of many of these patients will be managed with existing treatments and others may not want to use cannabis.5 The size of the current cannabis black market makes it unlikely that cannabis grown for medical purposes will be diverted to the black market. The number of people who would be permitted under these recommendations to use cannabis for medical purposes is less than 2.5% of the 820 000 New South Wales adults estimated to have used cannabis for non-medical purposes in 1998.7 It is also unlikely that allowing exemptions for medical uses of cannabis will be seen as condoning the non-medical use of cannabis. In the US, survey evidence (and passage of citizen-initiated referenda)2 show majority support for medical uses of cannabis, yet there is strong support for the continued prohibition of non-medical cannabis use.8 We believe that the Working Party's recommendations balance the needs of patients with community concern about non-medical cannabis use in a way that deserves to be considered by all State and Territory governments. Ultimately, patients with certain illnesses will be able to use pharmaceutical cannabinoids or other drugs, but, in the meantime, the Working Party's recommendations will allow these patients to use cannabis for medical reasons without changing the legal prohibition on non-medical use of cannabis, and without expanding the black market for cannabis products. References Report of the Working Party on the Use of Cannabis for Medical Purposes. Volume I: Executive summary; Volume II: Main report. Sydney: NSW Government, 2000. Available at <http://www.druginfo.nsw.gov.au/druginfo/reports/medical_cannabis.html>. Institute of Medicine (United States). Marijuana and medicine: assessing the science base. Washington: National Academy Press, 1999. House of Lords Select Committee on Science and Technology (United Kingdom). Cannabis: the scientific and medical evidence. London: The Stationery Office, 1998. Mather L. Delivery systems for medical cannabis. Appendix D in the Report of the Working Party on the Use of Cannabis for Medical Purposes. Volume II: Main report. Sydney: NSW Government, 2000. Available at <http://www.druginfo.nsw.gov.au/druginfo/reports/medical_cannabis.html>. Hall W, Degenhardt L. Estimated number of potential medical users of cannabis. Sydney: National Drug and Alcohol Research Centre, 2000. Available at <http://www.med.unsw.edu.au/ndarc/>. Blyth FM, March LM, Brnabic AJM, et al. Chronic pain in Australia: a prevalence study. Pain 2001; 89: 127-134. National Drug Strategy household survey: first results. Canberra: Australian Institute of Health and Welfare, 1999. (Drug Statistics Series; AIHW catalogue no. PHE 15.) Johnston L, O'Malley P, Bachman J. National survey results on drug use from the monitoring the future study, 1975-1999. Rockville, MD: National Institute on Drug Abuse, 2000. Authors' details The National Drug and Alcohol Research Centre, University of New South Wales, Sydney, NSW. Wayne D Hall, PhD, Executive Director, and Chair, Working Party on the Use of Cannabis for Medical Purposes; Louisa J Degenhardt, BA(Hons), Research Assistant, and Research Officer, Working Party on the Use of Cannabis for Medical Purposes. Flinders University, Adelaide, SA. David Currow, MPH, FRACP, Professor of Palliative Care, and Member, Working Party on the Use of Cannabis for Medical Purposes. Reprints: Dr W D Hall, The National Drug and Alcohol Research Centre, University of New South Wales, Sydney, NSW 2052. w.hallATunsw.edu.au Make a comment Estimated number of potential medical users of cannabis It is difficult to estimate the potential number of people in New South Wales who suffer from conditions that might be alleviated by cannabis or cannibinoids for several reasons: we are uncertain about the prevalence of these diseases; we do not know what proportion of these patients have the symptoms which cannabis has been claimed to relieve; and we do not know the proportion of these patients whose symptoms are unrelieved by existing treatments. Cancer-related wasting: In 1997, 11 594 people died of cancer in NSW (NSW Central Cancer Registry, 2000). If we assume that almost all of these persons suffered from cancer-related wasting, then about 11 000 people might have benefited from cannabis use to improve appetite. This does not take into account people who experienced cancer-related wasting but who did not die. Severe nausea from chemotherapy: Cancers vary in type, severity of symptoms and therapeutic regimen, so it is difficult to provide an accurate estimate of the number who may receive cancer chemotherapy that causes severe nausea and vomiting. Platinum-based chemotherapy is the most emetogenic form of chemotherapy, and is used in the treatment of ovarian cancer, testicular cancer, soft tissue sarcoma, 20% of head and neck cancers, 33% of distal oesophagus cancers, and about 10% of non-small-cell lung cancers. Based on 1997 estimates of these cancers, about 1000 people might have experienced severe nausea from platinum-based chemotherapy. HIV-related wasting: According to the Australian Research Centre in Sex, Health and Society at La Trobe University (Vic.), there were 2289 people with clinical AIDS in 1999, and 55% of them lived in NSW. A survey of 924 AIDS patients conducted by La Trobe University suggested that a third of people with HIV/AIDS experience weight loss. If these figures are applied to the estimate in NSW, then there would be around 400 people with HIV/AIDS in NSW in any one year who would be potential medical consumers of cannabis or cannabinoids. Muscle spasticity: According to the Multiple Sclerosis Society of Australia, patients with the disease known to the society represent 0.3% of the Australian adult population: about 11 000 people in NSW. To take account of patients not known to the society and to include people with less common neurological disorders whose symptoms may be alleviated by cannabis or cannabinoids (eg, patients with spinal cord injuries), we double this estimate, to 20 000. There are no Australian data on the prevalence of muscle spasticity among these patients. If we assume 10% prevalence, then about 2000 people with neurological conditions might benefit from cannabis or cannabinoids. Chronic pain: In any year, 11% of males and 13.5% of females have chronic pain that interferes with daily activities.6 Of these, 2.9% will have seen a pain specialist and 20% of them will have incomplete pain relief (Dr F M Blyth, Pain Management and Reseach Centre, University of Sydney, personal communication). In NSW, this amounts to 4500 people. Therefore, about 18 900 people in any year might benefit from the medical use of cannabis or cannabinoids. To this should be added the unknown number of persons with acute and chronic pain that is unrelieved by existing treatment. Back to text

Wayne D Hall · Louisa J Degenhardt · David Currow