Maintenance therapy and 3-year outcome of opioid-dependent prisoners: a prospective study in France (2003-06)

To describe the profile of imprisoned opioid-dependent patients, prescriptions of maintenance therapy at imprisonment and 3-year outcome in terms of re-incarceration and mortality. Prospective, observational study (France, 2003-06). Health units of 47 remand prisons. A total of 507 opioid-dependent patients included within the first week of imprisonment between June 2003 and September 2004, inclusive. Physicians collected socio-demographic data, penal history, history of addiction, maintenance therapy and psychoactive agent use, general health status and comorbidities. Prescriptions at imprisonment were recorded by the prison pharmacist. Re-incarceration data were retrieved from the National Register of Inmates, survival data and causes of death from the National Registers of vital status and death causes. Prison maintenance therapy was delivered at imprisonment to 394/507 (77.7%) patients. These patients had poorer health status, heavier opioid use and prison history and were less socially integrated than the remaining 113 patients. Over 3 years, 238/478 patients were re-incarcerated [51.3 re-incarcerations per 100 patient-years, 95% confidence interval (CI) 46.4-56.2]. Factors associated independently with re-incarceration were prior imprisonment and benzodiazepine use. After adjustment for confounders, maintenance therapy was not associated with a reduced rate of re-incarceration (adjusted relative risk 1.28, 95% CI 0.89-1.85). The all-cause mortality rate was eight per 1000 patient-years (n = 10, 95% CI 4-13). Prescription of maintenance therapy has increased sharply in French prisons since its introduction in the mid-1990s. However, the risk of re-imprisonment or death remains high among opioid-dependent prisoners. Substantial efforts are needed to implement more effective preventive policies.