PhD student University of Manitoba Winnipeg, Canada
Background: People with HIV (PWH) are at an increased risk of venous thromboembolism (VTE). Among PWH, marijuana use is common. Marijuana has been shown to display both procoagulant and anticoagulant effects on the blood, however its effect on VTE in PWH has not been evaluated.
Objectives: We aimed to assess whether there is an association between marijuana use and incident VTE among PWH.
Methods: We conducted a cohort study using data from the Centers for AIDS Research Network of Integrated Clinical Systems (CNICS), a US-based, multisite cohort of PWH. Marijuana use was obtained from a clinical assessment of patient reported outcomes on substance use collected as part of care using the modified Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) instrument. VTEs were assessed using multiple ascertainment criteria and then centrally adjudicated by at least 2 expert physician reviewers. Only first VTEs were included among PWH who have had more than one. Cox models were used to determine the association of incident VTE with marijuana use. Models were adjusted for age, sex, race/ethnicity, cigarette smoking, alcohol use, substance use (cocaine and methamphetamine), CD4 cell count, HIV viral load, diabetes, hypertension, dyslipidemia, chronic kidney disease (CKD [eGFR < 30]), Hepatitis C (HCV), and Hepatitis B (HBV) co-infection.
Results: Among 12,515 PWH in care between 2009 and 2019 at 6 CNICS sites across the US, 213 (1.7%) experienced a VTE. Mean follow up was 4.5 years, mean age was 44 years, 17% were female, 45% were white, and 32% reported current marijuana use in the past 3 months. Around 18% had dyslipidemia, 16% had HCV co-infection, 9% had diabetes, and 1% had CKD. The mean CD4 count was 532 cells/mm3 and 19% had a viral load >400 copies/mL. In adjusted models, former (adjusted hazard ratio [aHR] 0.83, 95% CI 0.57-1.20) and current (aHR 0.78, 95% CI 0.51-1.13) marijuana use were not associated with a significant increase in VTE incidence compared to never users. Furthermore, no association was observed between frequency of marijuana use and risk of incident VTE, suggesting there is no dose-dependent increase in VTE risk.
Conclusions: Among PWH there seems to be no evidence of increased VTE risk with the use of marijuana, and so VTE risk mitigation does not need to specifically consider marijuana use.
