Inter-rater agreement for detection of potentially inappropriate medication according to explicit and implicit STOPP criteria

The Screening Tool of Older Person's Prescriptions (STOPP) is used to detect potentially inappropriate medication. Version 2 includes 80 criteria, whereof two can be considered implicit as their detection primarily relies on the assessor's expertise: (A1) drugs without indication and (A2) drug treatment beyond recommended duration. To explore the inter-rater agreement for detection of explicit and implicit criteria, data on consecutive primary care patients from a previous study (n = 302, 65–99 years of age) were used, including independent assessments of the 78 explicit criteria (23 556 assessments) and the two implicit criteria (604 assessments) by two specialist physicians. Overall, 123 (0.5%) explicit and 10 (2%) implicit criteria were fulfilled according to both physicians. The positive agreement for a criterion being fulfilled was 56% for explicit and 16% for implicit criteria, with kappa values of 0.56 and 0.09. Discordant detection of furosemide and proton pump inhibitors was common using explicit and implicit criteria.