Synergism between diabetes and human immunodeficiency virus in increasing the risk of tuberculosis

SETTING Community health screenings in KwaZulu-Natal Province, South Africa. OBJECTIVE To study the synergism between diabetes mellitus (DM) and human immunodeficiency virus (HIV) infection in increasing the risk of tuberculosis (TB). DESIGN In this cross-sectional study, we analyzed data from two community health projects, one at congregate settings, and one at household settings (n = 7708), in a rural resource-limited region where integrated communicable and non-communicable disease screening services were offered. Odds ratios (ORs) for demographic factors, socio-economic factors, DM status, and HIV positivity were calculated using multivariate analysis, and the statistical interaction between HIV and DM was tested. The primary outcome was the presence of TB symptoms. RESULTS Among 7708 individuals, age >65 years (OR 1.72, 95%CI 1.47-2.02), HIV infection (OR 1.66, 95%CI 1.40-1.97) and DM (OR 1.36, 95%CI 1.11-1.67) were independently associated with increased odds of TB symptoms. Receiving monthly grants (OR 0.78, 95%CI 0.66-0.91), access to a toilet (OR 0.54, 95%CI 0.35-0.83), and access to solar or electric energy (OR 0.86, 95%CI 0.77-0.97) reduced the odds. There was evidence of significant interaction between DM and HIV on the multiplicative scale. CONCLUSION DM and HIV synergistically increased the odds of TB symptoms according to these retrospective data. Future studies should prospectively evaluate synergism between HIV and DM in increasing the risk of active TB.