Relationship between alcohol consumption, whether linked to other substance use or not, and antiretroviral treatment adherence in HIV+ patients.

Hazardous alcohol consumption is a common diagnosis among people living with HIV infection. The relationship between alcohol consumption and poor adherence to antiretroviral therapy has been highlighted in different studies, yet few of them performed a parallel analysis of other substance use. In Spain, alcohol consumption is frequently associated with other substance use, mainly cannabis and cocaine. The aim of this study is to assess the influence of hazardous alcohol consumption both combined with other substances (cocaine, heroin, methadone and/or cannabis) or alone on antiretroviral therapy adherence in our social environment. We performed an observational case-control study including 119 HIV+ individuals. We recruited 40 non-adherent patients, defined by less than 90% compliance according to hospital pharmacy refill data, and corroborated by the Simplified Medication Adherence Questionnaire (SMAQ) and referring professional's opinion. Control cases (n=79) were defined as those patients with similar characteristics but considered adherent according to the same parameters. Data collection took place between May 2013 and September 2015. Statistical analysis was performed using a binary logistic regression model. Our results indicate that alcohol consumption decreases adherence to antiretroviral therapy. The use of methadone represents a statistically significant increased risk of poor adherence. No significant differences were found between adherent and non-adherent groups regarding cocaine, heroin or cannabis use in this study. In summary, the detection of substance use and especially alcohol consumption in HIV+ patients can improve the effectiveness of antiretroviral therapy by identifying and treating at-risk individuals for a poor therapeutic adherence.