(135) The Impact of COVID-19 Pandemic on Alcohol Dependence Treatment in Portugal: a Retrospective Cohort Study

Background: The COVID-19 pandemic imposed relevant risks to marginalized people, particularly those with substance abuse disorders. Despite the positive outcomes of alcohol dependence treatment, a low rate of patients remains on treatment.

Objectives: To estimate the impact of the COVID-19 pandemic on persistence to alcohol dependence treatment in Portugal.

Methods: This is a retrospective, multicentre, cohort study of patients taking acamprosate, disulfiram, nalmephen or naltrexone in the Portuguese community pharmacies. Data of Patients’ medicines sales, age and gender was retrieved for the period between January 2019 and March 2022 from the community pharmacy software. Persistence to treatment was calculated for the two groups: Group 1 - patients initiating treatment between January 2019 and February 2020 (one year before the start of the COVID-19 pandemic); Group 2: patients initiating treatment between March 2020 and March 2022 (COVID-19 pandemic period). All participants were followed-up from their first medicine purchase, which was defined as the date without prior purchase of the same medicine in the previous 90 days. A patient was classified as non-persistent to treatment if missed prescription refill (treatment interruption) for more than 90 days from exhausting the previous prescription. Kaplan-Meier survival analysis was used to estimate patients’ persistence to treatment. Univariable and multivariable Cox regression models were used to compare groups and analyze the impact of COVID-19 on patients’ persistence to treatment.

Results: We assessed data from 13,058 patients. Patients’ average age per group varied between 47.7 (SD = 13.0) years (naltrexone) and 53.5 (SD=11.9) years (acamprosate). In all medicines, the majority of the patients on treatment were men. The COVID-19 pandemic was significantly associated with an increased risk of non-persistence to treatment with disulfiram (HR=1.10; 95% CI=1.01-1.19, p=0.032), nalmephen (HR=1.40; 95% CI=1.18-1.66, p=0.001) and naltrexone (HR=1.20; 95%CI=1.11-1.30, p< 0.001). Regarding acamprosate, the pandemic was associated with an increased risk of patients’ non-persistence to this medicine during the first 90 days of follow-up (HR=1.08; 95%CI=1.00-1.16, p=0.044). However, after 90 days of treatment, the opposite effect was observed (HR=0.74; 95%CI=0.65-0.85, p< 0.001). An increased risk of non-persistence was observed in males for all medicines.

Conclusions: Results suggest that COVID-19 negatively affected patients’ persistence to alcohol dependence treatment. Different healthcare strategies to improve treatment persistence may be needed in case of a future pandemic.