Medical comorbidities over time in people who use drugs (PWUD) on long-term opioid assisted treatment (OAT)

Author: Dario Willi, David Strittmatter, Peer Brandt, Hansjakob Furrer, Eveline Hofman, Maria Christine Thurnheer

Theme: Clinical Research Year: 2023

Improved survival of PWUD on OAT may lead to an increase in medical conditions in an ageing population. To assess medical co-morbidities of PWUD on long-term OAT over time, we performed a sequential cross sectional cohort study in a single Swiss OAT center, specialized in Diacetylmorphine assisted treatment.

Sequential single-center cross-sectional cohort study, collecting information in 2009, 2012 and 2019 on demographics, medical diagnosis (ICD 10 code), type of OAT, illicit drug use and alcohol consumption using a standardized CRF. A sub-cohort of patients present in all three surveys was further analyzed (descriptive statistics and logistic regression model, STATA 16)

Of 200 individuals assessed in 2009, 103 were followed in 2012 and 2019 (140 (69%) male, median age in 2019 49 years (IQR 41-54y), median stay since last admission 10.25 years (IQR 4.6-14.3y).
HIV infection rates increased from 12/103 (2009) to 13/103 (2019), 11/12 (2009) and 12/13 (2019) patients were on antiretroviral treatment.
The rate of HCV-antibody positive patients with undetectable HCV RNA increased from 32/82 (39.0%) in 2009 to 75/83 (90.4%) in 2019 (50/83 (60.2%) after treatment and 25/83 (30.1%) after spontaneous clearance).
There was a marked increase of patients with multiple medical comorbidities: In 2009 27/103 (26.2%) suffered from 1 condition and 10 (9.7%) patients had 2 or more medical comorbidities. In 2019, 26/103 (25.2%) had at least 1 medical diagnosis and 39/103 (37.9%) had 2 or more comorbidities. Older age (OR 1.5, p=0.031, 95%CI 1.04-2.19) and depression (OR 3.7, p=0.001, CI 1.75-7.9) were associated with increased odds for 2 or more medical comorbidities.

While harm-reduction including OAT and medical advances in HCV treatment improve survival of long-term PWUD, this ageing population faces an increasing burden of medical comorbidities. Recognizing this trend should incite comprehensive strategies to improve medical care in this population.

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