Theme: Epidemiology & Public Health Research Year: 2024
Background: Of the 22-27,000 people with opioid dependency in Switzerland, about 80% receive opioid agonist therapy (OAT). Diacetylmorphine/heroin prescription (1,800 patients) is restricted to 23 institutions in 14/26 cantons, while other opioids (≈16,000 patients) can be prescribed by any physician (in ≈60% a general practitioner (GP)). OAT in the SAMMSU-cohort was described and compared to data from the National OAT Statistics (NOS).
Methods: The SAMMSU-cohort is an open cohort with yearly follow-up, enrolling >18-year-old patients with current or previous OAT in eight different centers throughout Switzerland since 2014. By 02/01/2024, 1,390 patients have been enrolled (76% male, median age: 44 years, 75% ever intravenous drug use, 61% HCV-antibody-positive, 10% HIV-antibody-positive). Since 02/2021, data on OAT-prescriber and OAT-provider are collected, while data on OAT-drug are available since the beginning.
Results: At their last follow-up, 91.7% (1,274/1,390) patients were on OAT: 23.7% diacetylmorphine/heroin, 39.1% methadone, 31.3% slow-release morphine, 8.3% buprenorphine and 4.4% levomethadone (n=1,261). Excluding diacetylmorphine/heroin patients to compare SAMMSU with NOS data, the percentages were: 48.6% versus 54.6% methadone (p<0.001), 34.2% versus 29.1% slow-release morphine (p<0.001), 10.9% versus 8.6% buprenorphine (p=0.015), and 5.1% versus 4.4% levomethadone (p=0.323) [SAMMSU: n=962; NOS: n=15,854].
In non-diacetylmorphine/heroin-SAMMSU-patients, the OAT-prescriber was in 73.3% an institution, in 25.1% a GP and in 1.6% a psychiatrist (n=550), and the OAT-provider in 72.2% an institution, in 26.5% a pharmacy and in 1.3% a practice (n=544). In the NOS, the OAT-provider distribution was: 33.4% institution, 51.2% pharmacy and 13.9% practice (n=15,800, p<0.001 for all comparisons).
Conclusion: In the SAMMSU-cohort, patients with an institution as OAT-provider (centralized setting) are overrepresented, while patients with a pharmacy or practice as OAT-provider are underrepresented. Accordingly, diacetylmorphine/heroin as OAT-drug is over- and methadone underrepresented. To increase representativity, recruitment in decentralized settings (pharmacy, GP) must be increased, which is of course more challenging than in institutions.
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