[Two-year follow-up of an opioid-user cohort treated with high-dose buprenorphine (Subutex)]

Care for opioid users changed greatly in France in 1996 when general practitioners (GP) were allowed to prescribe high-dose sublingual buprenorphine (Subutex((R))) for maintenance treatment of major opioid dependence. In order to evaluate treatment benefits, a prospective epidemiological 2-year follow-up was initiated in May 1996 with the participation of 105 French GPs.

A cohort of outpatient opioid users who started high-dose sublingual buprenorphine maintenance therapy at study onset or who had recently started were included in a prospective epidemiological study by GPs involved in management of drug abusers. Patients were followed for 2 years with collection of standardized information at 1, 3, 6, 12, and 24 months. The main evaluation criteria were follow-up by the same GP throughout the study and retention in the care system 2 years later. For patients who fulfilled these criteria, secondary end points were analyzed: information about buprenophine prescription, social status, and hepatitis B and C and HIV seroconversions.

The 101 GPs included 919 patients and 909 were analyzed 2 years later. At study onset, a majority of the patients (70.6%) were taking an ongoing maintenance treatment, 10.5% had previously received such a treatment and the treatment was initiated for 18.8%. At the end of the study, 508 patients (55.9%) were still being followed by the same GP and 101 (11.1%) were followed by another healthcare provider (another GP, hospital or specialized center). No information about the care giver was available for 82 patients (9%). Among the other patients, 123 (13.5%) were lost to follow-up, 24 (2.6%) had moved, 23 (2.6%) were incarcerated, 11 (1.2%) had successfully discontinued drug usage and 7 (0.8%) had died. Other reasons for unsuccessful follow-up by the same GP were mainly (for 6 patients each): relapse, switch to methadone, no medical information, non-compliance with scheduled controls. Among the patients followed by the same GP, declaration of heroin and drug intake significantly decreased (p<0.001), and social status (GAF scale) and TMSP evaluation significantly improved (p<0.001). The social situation (housing condition and work) also improved significantly (p<0.001). The rate of buprenorphine treatment was 84% with longer and less fractionated prescriptions. The HBV, HBC and HIV seroconversion rates were low in this high-risk population (2.7%, 4.1% and 0.8% respectively).

This two-year follow-up of 909 opioid users showed that nearly 70% of the patient remained within the healthcare system, mainly with the same GP or more rarely with another practitioner. Among the 508 patients still followed by the same GP, maintenance treatment with high-dose buprenorphine was observed in more than 80% of the patients. These patients had a significantly improved social status, a significant decrease in drug intake and a significant improvement in their social adaptation and severity of drug abuse.