Estimating the Number of Heroin Users in Metropolitan France Using Treatment Centers Data: An Exploratory Analysis

Background: An updated prevalence estimate for heroin users in France is lacking. Accurate figures are needed to estimate the potential need for treatment. Method: This research relies on a capture-recapture framework and, for the first time, makes use of individual data collected by a standardized survey conducted within treatment centers. Taking the hierarchical structure of data collection into consideration, a multilevel Zelterman regression model was used, thus enabling estimates at national level. Results: The number of heroin users was estimated to be 76,000, 95% CI = 68,000; 85,000] in 2009 (prevalence of 1.9‰ 1.7–2.1]), 101,000 in 2011, 95% CI = 66,000–137,000] (prevalence of 2.5‰ 1.6–3.4]), and 107,000 in 2013, 95% CI = 85,000–124,000] (prevalence of 2.6‰ 2.1–3.1]), with a 4:1 ratio of male:female. Less than one heroin users out of three was seen in treatment centers in 2013. Conclusions: The rise in the number of heroin users is related to an increasing availability of heroin, increasing use in more remote areas, and providers targeting new types of users. The figures, however, should be completed with alternative estimates and enhance the need for a perennial monitoring.