Volume 191 - Issue 6
Quality of drug interaction alerts in prescribing and dispensing software
Authors: Michelle Sweidan, James F Reeve, Jo-anne E Brien, Pradeep Jayasuriya, Jennifer H Martin and Graeme M Vernon
Med J Aust 2009; 191 (6): 358-359. || doi: 10.5694/j.1326-5377.2009.tb02832.x
Published online: 21 September 2009
Published online: 21 September 2009
In reply: Cheong notes that the terms “sensitivity” and “specificity” have a slightly different meaning in our study compared with the usual definitions. This was intentional, and the definitions we used are clearly described in our article.1
Our definitions for sensitivity and specificity were based on two important practical considerations. First, an electronic prescribing system should alert the clinician to potentially clinically significant drug interactions (“true positives” by our definition); and second, a system should not inundate clinicians with alerts containing irrelevant or unhelpful information about minor or clinically unimportant interactions (“false positives” by our definition). We know that these latter alerts can cause “alert fatigue” and are a subject of complaint for doctors and pharmacists. We are not aware of there being any problem with prescribing systems producing alerts for pairs of drugs that do not interact at all; hence, we did not investigate this group.
Tan questions whether the low specificity we found for the MIMS DrugAlert database may have been due to inappropriate severity level settings. Although it might seem appealing to reduce the number of alerts by allowing users to “switch off” drug interaction alerts that are classified as low severity, there are difficulties in doing this because of a lack of evidence for the application of severity ratings to drug interactions. Severity ratings are subjective — studies have shown there is little consensus on such ratings between major reference sources.2,3 This is not surprising, given that there is little evidence available on adverse clinical outcomes resulting from drug interactions, and also because the clinical outcome is context-dependent according to variables such as patient characteristics and drug dosage. We believe that, rather than relying on software vendors or users to switch off some alerts, drug interaction knowledgebases should include only potentially clinically significant interactions.
We tested all systems at the lowest severity setting (if available) for consistency, and to maximise detection of drug interaction alerts. For minor interactions, the rating was based on both presence of the alert and quality of the information — if a minor interaction was either not detected or was detected and provided appropriate information indicating it was minor, then it was a “pass”.
References
- Sweidan M, Reeve JF, Brien JE, et al. Quality of drug interaction alerts in prescribing and dispensing software. Med J Aust 2009; 190: 251-254. 0_CBBJDBIG
- Abarca J, Malone DC, Armstrong EP, et al. Concordance of severity ratings provided in four drug interaction compendia. J Am Pharm Assoc (2003) 2004; 44: 136-141. 0_pgfId-1863066
- Vitry AI. Comparative assessment of four drug interaction compendia. Br J Clin Pharmacol 2007; 63: 709-714. 0_CBBECHDI