Can routine data from prisoners' files be used to estimate prevalence rates of illicit drug use among prisoners?

Abstract The paper examines whether routine data from prisoners' files is a useful basis to estimate prevalence rates of illicit drug use among prisoners.Medico-legal files of 190 younger (20-49 years) and 190 older (50-75 years) male prisoners from 13 prisons in Switzerland were analysed. Indications of illicit drug use were extracted based on recorded legal measures, notes from health care professionals, diagnoses related to the use of illicit substances, prescribed medications, other treatment indicators, and results from mandatory drug tests in prison.Estimated lifetime prevalence of illicit drug use based on those indicators is 50.0% for younger and 24.2% for older prisoners. Current cannabis use is an estimated 10.0% and current cocaine, opioids, or other drug use 4.7% for younger prisoners. Among older prisoners, prevalence of current cannabis use is an estimated 3.2% and of other drug use 0.5%.The paper concludes that analysing routine data is a reasonable alternative to surveys if prisoners' files are kept more complete and concise and if data is collected for no other purpose than to benefit prisoners' health.