(087) Association of Substance Use Disorder and Risk of COVID-19-related Outcomes Among Adults in Hong Kong

Background: Substance use disorders (SUD) are associated with an increased risk of worse COVID-19-related outcomes, and previous studies have shown disparities in race and SUD category. However, the findings are inconsistent, and there is a limited comprehensive analysis of a broader range of COVID-19-related outcomes in Asians.

Objectives: To examine associations between different SUD categories and risks of COVID-19-related outcomes among adults in Hong Kong.

Methods: This population-based cohort study was conducted to evaluate the risks of COVID-19-related outcomes in people with or without SUD, using territory-wide electronic health records in Hong Kong. Individuals aged ≥18 years who did not test positive for COVID-19 on or before January 1, 2022, were included. The exposure was having a diagnosis of SUD on or before January 1, 2022, and further divided into three SUD categories, including Tobacco Use Disorder (TUD), Alcohol Use Disorder (AUD), and Drug Use Disorder (DUD). People with multiple categories of SUD diagnosis were excluded. Each individual with SUD was randomly matched with participants without SUD before the end of the study, based on baseline characteristics, up to a 1:10 ratio. Individuals were followed for up to 8 months until August 31, 2022. Inverse probability treatment weighting was applied to further balance measured confounders between exposed and unexposed groups. Cox proportional hazard regression models were used to compare the risk of each COVID-19-related outcome (COVID-19 infection, COVID-19-related hospitalisation and mortality) between the two groups for each SUD category.

Results: Of 4,078,019 adults who did not test positive for COVID-19 on or before January 1, 2022, 49,665 individuals with SUD, were identified (TUD: 32,430; AUD: 8,321; DUD: 6,896), while 2,018 people with multiple categories of SUD diagnosis were excluded. 476,464 individuals without SUD (matched for TUD: 324,300; for AUD: 83,204; for DUD: 68,960) were matched to the exposed group with similar characteristics. Compared to people without SUD, people with AUD or DUD were associated with significantly higher risks of COVID-19-related mortality (AUD: adjusted hazard ratio [aHR], 1.73; 95% CI, 1.02-2.95; DUD: aHR, 2.58; 95% CI, 1.17-5.69), and people with DUD were associated with a significantly higher risk of COVID-19-related hospitalisation (aHR, 1.60; 95% CI, 1.27-2.02).

Conclusions: The findings suggest that among adults in Hong Kong, DUD was associated with an increased risk of COVID-19-related hospitalisation and mortality, while AUD was associated with an increased risk of COVID-19-related mortality.