Automatic reporting of estimated glomerular filtration rate in Australia turns 13: re-examining the impact

eGFR automated reporting has been associated with improved early detection and management of chronic kidney disease

Chronic kidney disease (CKD) affects 1.7 million Australian adults, of whom less than 10% are aware they have this condition.1 CKD is associated with comorbidity, reduced quality and quantity of life and vast financial cost. Yet, the trajectory of CKD can be controlled by early detection in at-risk individuals and through the implementation of best-practice management — steps typically undertaken in primary care.2

To improve the identification of asymptomatic CKD, in 2005, the Australasian Creatinine Consensus Working Group recommended that all Australasian laboratories automatically report the estimated glomerular filtration rate (eGFR) each time serum creatinine was ordered in an adult.3 This position statement and subsequent modifications4,5 were accompanied by a multifaceted health professional and consumer education strategy under the guidance of the Primary Care Education Advisory Committee for Kidney Health Australia.

In the 13 years since the introduction of the eGFR reporting initiative, there is accumulating evidence of improved detection of CKD and clinical outcomes. This has been evident particularly in patient subgroups most at risk of underdetection when serum creatinine is the sole marker of kidney function (eg, older patients, females, Indigenous peoples, and those with low body mass index). A prospective audit of renal services in Queensland showed a 40% increase in monthly referral rates and a greater absolute number of “appropriately referred” patients with CKD in the 12 months after the implementation of automated eGFR reporting and the concomitant education program.6 An analysis of the data from the Australia and New Zealand Dialysis and Transplant Registry also indicated that introduction of eGFR automatic reporting was associated with a statistically significant and clinically important reduction in the proportion of patients, particularly older and Indigenous Australians, who were referred late to specialists for commencement of renal replacement therapy (RRT), from 25.8% to 21.8%.7 International experiences similarly showed significant and sustained increases in the number of referrals to nephrology services following implementation of automatic eGFR reporting, particularly in the older female population.8

Automatic reporting of eGFR also created significant momentum in establishing a CKD consumer vocabulary, which has improved the personalised and integrated care sought after by patients with CKD,9 and has facilitated public awareness opportunities aimed at improving CKD early detection. The incidence of new patients commencing RRT in Australia has plateaued since 2010, following an approximate five-fold progressive increase in incidence rates during the preceding 30 years.10 An ongoing focus on early detection and management will hopefully have an impact on future RRT rates.

Balanced against these observed benefits are concerns shared by clinicians and consumers regarding the overdiagnosis of CKD and the creation of “worried well” individuals. This has been particularly relevant to older patients with eGFR values just below 60 mL/min/1.73 m², which may represent physiological ageing. However, large epidemiological studies have convincingly demonstrated that age does not modify the relationship between eGFR and clinical outcomes, such that older individuals with mildly reduced kidney function remain at significantly increased risk of adverse renal and cardiovascular outcomes, similar to that of younger individuals.

There remain uncertainties regarding the applicability of eGFR in certain circumstances, including children, pregnancy, drug dosing and diverse racial groups. A number of customised race-specific eGFR formulae have been developed. However, a previous large, multinational cohort study suggested that the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation for eGFR is broadly applicable across a range of racial and ethnic groups living in Western countries.11 Furthermore, a study of adult Indigenous Australians found that the CKD-EPI (without the African American correction factor) equation provided an unbiased and accurate estimate of glomerular filtration rate in this at-risk group.12

The use of eGFR for informing drug-dosing decisions instead of Cockcroft–Gault estimates of creatinine clearance remains controversial. However, the Cockcroft–Gault formula has not been revalidated with the standardised creatinine assays now used throughout Australia. A large pharmacokinetic simulation study comparing the use of eGFR, estimates of creatinine clearance and measured glomerular filtration rate found that using either the Modification of Diet in Renal Disease Study equation or the Cockcroft–Gault equation made little difference in the administered drug dose for the majority of patients and for most drugs tested.13

In summary, after 13 years of eGFR automated reporting in Australia, the available evidence suggests that this national, coordinated public health initiative, in conjunction with sustained education, has been associated with clinically important improvements in public awareness, early detection, management and appropriate referral of people with CKD. Although data on the impact of eGFR reporting on patient outcomes remain limited, it is heartening that late referral and incidence rates of patients starting RRT for end-stage kidney disease in Australia have plateaued in the post-eGFR era. Nevertheless, eGFR reporting is one small part of a broad array of assessments and interventions aimed at stemming the tide of CKD. This disease remains a major burden to our health care system and community, and we need to continue to develop evidence-based strategies to improve its management in primary care.