Substance use is independently associated with pneumonia severity in persons living with the human immunodeficiency virus (HIV).

Background: Pneumonia is common in persons living with the human immunodeficiency virus (HIV) (PLWH). Alcohol, cocaine, and marijuana impact pneumonia pathogenesis. We hypothesized that substance use was independently associated with pneumonia severity in PLWH and modified the effect of alcohol on pneumonia severity. Methods: Retrospective data analysis of PLWH admitted with a diagnosis of pneumonia was conducted. Alcohol use disorder was defined by the Alcohol Use Disorders Identification Test score ≥14. Drug use was quantified by self-report. Pneumonia severity was defined by the pneumonia severity index (PSI). Multivariable linear regression was used to test independent associations with pneumonia severity and effect modification by sex. Results: Of 196 PLWH, the mean age was 44 (SD = 9) years and the majority were men (71%). Ten percent ( n =  19) of subjects met criteria for an alcohol use disorder (AUD). In subjects reporting alcohol use, 25% reported concomitant crack/cocaine use and 16% reported marijuana use. PSI scores were higher with lifetime use of crack/cocaine (mean PSI: 63.1 vs. 57.3, P  = .06) and/or injection drug use (68.4 vs. 54.9, P  = .04). PSI scores were lower with active marijuana use (51.5 vs. 62.2, P  = .01). There was no significant difference in clinical outcomes. Sex modified the effect of drug use on PSI, with greater PSI scores in women with an AUD (β = 58.1, 95% confidence interval [CI]: 46.7 to 69.5, P  < .01), whereas active marijuana use mitigated the effect of AUD on PSI in men (β = -12.7, 95% CI: -18.8 to -6.6, P  < .01). Conclusions: Active alcohol and/or crack/cocaine use was associated with increased pneumonia severity in PLWH, with less severe pneumonia with marijuana use. Alcohol and marijuana effects on pneumonia severity differed by sex, with increased PSI in women and decreased PSI in men with concomitant marijuana and AUD.