1318. Examining Multimorbidity as a Moderating Effect on the Relationship Between Substance Use and Viral Suppression Among People Living with HIV

Background Substance use and multimorbidity (≥2 chronic conditions) are highly prevalent among people living with HIV (PLWH). However, their impact on achieving viral suppression are not well understood. The purpose of this study was to examine the relationship between substance use and viral suppression and the potential moderating effect of multimorbidity. Methods A retrospective cohort study was conducted at an academic Ryan White Funded clinic in central Kentucky. Individuals were included if they were diagnosed with HIV, seeking care between 2010 and 2014, had at least one year of follow-up, and did not have a chronic condition at the time they entered care. The primary independent variable was substance use which included alcohol, nicotine use, and/or illicit drug use; the moderating variable was multimorbidity (0, 1, ≥2 chronic conditions); and outcome was viral suppression (≤50 copies/mL). A logistic regression model was developed to examine the interaction between substance use and multimorbidity on achieving viral load suppression. The model controlled for medication adherence, insurance status, age, and CD4+ cell counts. Results A total of 941 individuals were included in the study, with an average age of 43.9 ± 11.7 years. Approximately 67.0% reported substance use; 54% had ≥2 chronic conditions diagnosed. The three most prevalent conditions diagnosed were hypertension (34.6%), mental health (33.9%), and diabetes (21.5%) Approximately 61.0% of substance users had ≥2 conditions. Those with viral suppression were less likely to be substance users, but were more likely to have ≥2 conditions compared with their counterparts. There was a significant interaction between substance use and multimorbidity (P = 0.037). Stratified by multimorbidity, substance use was associated with unsuppressed viral loads; among those with ≥2 chronic conditions substance users had lower odds of achieving viral suppression compared with nonusers (OR=0.24; 95% CI=0.10–0.55). Conclusion Substance use may impede the opportunity for PLWH to achieve viral suppression, increasing their risk of transmission and progression of disease. More research is needed to understand the role substance use plays in impacting viral load, specifically among those with multiple chronic conditions