SAMMSU cohort study confirms: Opioid Agonist Therapy (OAT) is effective. Care needs are becoming more complex.

The analysis of the national SAMMSU cohort (2014–2024), published on January 6, 2026, provides for the first time a comprehensive overview of the health status of more than 1,500 patients receiving opioid agonist therapy (OAT) in Switzerland. A large proportion of the participating patients were treated at Arud.

Key findings:

The OAT population is aging significantly (median age now approximately 51 years).
Chronic physical conditions such as hypertension, diabetes, COPD, and osteoporosis occur earlier and more frequently than in the general population.
Mental health disorders and the concurrent use of multiple medications are very common.
OAT is effective: illegal substance use and intravenous drug use clearly decrease over time.
Health risks are shifting away from acute substance-related harms toward complex, chronic, and multiple physical comorbidities.
IMPORTANT: OAT services need to evolve from a purely addiction-focused approach towards comprehensive, long-term, and integrated care.

A big thank you to our patients
A large proportion of the study participants are Arud patients. Their contribution has been essential in shaping this national data base and in making visible the real-world challenges that patients receiving OAT are facing today.

Background of the study
A cohort study follows a clearly defined group of individuals over an extended period of time in order to observe how health status, diseases and care needs develop.

«OAT» (Opioid Agonist Therapy) is a pharmacological treatment for opioid dependence that is combined with medical, psychological, and social care.

«SAMMSU» stands for Swiss Association for the Medical Management in Substance Users and refers to a nationwide cohort drawn from specialized treatment centers across Switzerland.

Authors from the Arud team
Philip Bruggmann, Co-Medical Director of Internal Medicine
Oliver Senn, Specialist in Internal Medicine, Board Member

Study cooperation partners
Institute of Primary Care, University Hospital Zurich, University of Zurich

Clinic for Infectious Diseases and Infection Prevention, Cantonal Hospital Aarau

Fondazione Epatocentro Ticino / Ingrado Addiction Services, Lugano

Independent research activity, Basel

Swiss Hepatitis, Zurich

Addiction Support Foundation, St. Gallen

Private practice, Lausanne / HepC Virtual Clinic, Lausanne

Clinic for Infectious Diseases, University Hospital Bern, University of Bern

Les Toises, Sion

Here you can access the full SAMMSU cohort study publication

For more research projects by Arud, click here