Very high alcohol use is associated with latent tuberculosis infection (LTBI) among adults living with HIV in Uganda, according to data published in Clinical Infectious Diseases.
The risk of tuberculosis (TB) is significantly higher in people living with HIV and associations between alcohol use; the development of TB has been linked to alcohol-induced immunosuppression and increased transmission due to social marginalization and drift. This higher risk includes both primary TB and reactivation TB from latent infection. Despite these findings, the relative contribution of alcohol use to the risk for TB infection acquisition in people living with HIV is, according to researchers, not well understood.
To investigate the relationship between hazardous levels of alcohol use and LTBI in individuals with HIV investigators compared tuberculin skin test positivity across medium, high, and very-high alcohol use levels. Eligible participants had positive point-of-care urine dipstick ethyl glucuronide tests (cutoff ≥ 300 ng/mL) and endorsed hazardous drinking within the previous 3 months, defined by Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) score. Levels of drinking were classified as: medium (AUDIT-C score, 4-5 men and 3-5 women), high (score, 6-7), very high (score, 8-12). LTBI, was defined as a positive tuberculin skin test, which was an induration of ≥ 5 mm without symptoms of TB disease.
Among the 617 participants, the median AUDIT-C score was 6 and drinking levels were medium in 41%, high in 31%, and very high in 28% of participants. In a multivariable analysis, very high use was associated with LTBI (adjusted odds ratio, 1.61; 95% CI, 1.03-2.50). The prevalence of LTBI, measured by positive tuberculin skin test, was 35%, though heterogeneity was noted on the basis of clinic site, ranging from 22% to 44%. LTBI prevalence was highest with very-high level use (77 of 170, 45%) relative to high-level (62 of 191, 33%) and medium-level use (78 of 256, 31%).
The study did have several limitations including the fact that CD4 counts were not captured or accounted for in the multivariable model. Individuals with lower CD4 counts are more likely to be anergic on tuberculin skin testing, resulting in false-negatives. The study also did not include low-level or non-drinkers as comparison groups and alcohol use was based on self-reports and therefore subject to and social desirability bias. Finally, data on socioeconomic status or comorbidities that may influence LTBI risk and differ by alcohol use level were not available.
Study strengths included, the use of an ethyl glucuronide to confirm hazardous alcohol use and the quantifying of levels of alcohol use which allowed for more granular examination of hazardous drinking on LTBI. Also, the inclusion of rural and urban sites augmented the diversity of the study population and generalizability of results.
According to investigators, very-high alcohol use was associated with LTBI compared with medium-level use in this cross-sectional study of individuals with HIV. Furthermore, these results suggested that increased risks for TB disease associated with heavy drinking compared with non-drinkers, “may be partly attributable to higher rates of LTBI with hazardous alcohol use, especially very-high level use.” However, investigators could not specifically identify the mechanisms behind the association between higher levels of alcohol use and LTBI they observed.
Puryear SB, Fatch R, Beesiga B, et al. Higher levels of alcohol use are associated with latent tuberculosis infection in adults living with HIV [published online May 6 2020]. Clin Infect Dis. doi:10.1093/cid/ciaa527