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

Background:
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.

Methods:
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)

Results:
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.

Conclusion:
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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