Application of the waiting time distribution in a nationwide screening of real-world dermatology drug utilization for aberrant use patterns.

Abstract

Inappropriate use of medicines may have critical consequences from individual, public health, and economic perspectives. Discovering wrongful medicine use may require intentional surveillance or screening. The objectives of this study were to: (i) apply and evaluate the waiting time distribution (WTD) method as a screening tool for identifying aberrant drug use and (ii) evaluate the nationwide use of Dermatology drugs in Denmark for signals of aberrant drug use. Dermatology drug use data from the Danish nationwide healthcare registries from 2018 to 2020 were used to produce WTDs that were analyzed for drug use patterns. The method provides estimates of the prevalence and incidence and enables estimation of mean treatment duration, drug relapse, and unexpected drug prescribing. The study included 2 027 889 individual drug users and analyzed 6 141 449 prescriptions. The analysis included approximately 100 dermatology drugs and drug categories and produced 56 WTD drug curves. The WTD patterns and epidemiological estimates confirmed that most drugs are used as intended and revealed few unexpected patterns for further investigation. Three unexpected findings were identified concerning (i) short-term use that would entail suboptimal clinical efficiency for minoxidil, (ii) sub-optimal use of topical tacrolimus, and (iii) potential undesirable increase in short-course doxycycline treatments. In Denmark, dermatology drugs are predominantly used as expected, with few unexpected use patterns identified. Targeted specific follow-up on the identified signals is necessary for conclusions about inappropriate use. The findings suggest that the WTD method is applicable for screening for aberrant drug use.