Background: The impact of low body mass index (BMI) at initiation of rifampicin-resistant tuberculosis (RR-TB) treatment on outcomes is uncertain. We evaluated the association between BMI at RR-TB treatment initiation and end-of-treatment outcomes.
Methods: We performed an individual participant data meta-analysis of adults aged ≥18 years with RR-TB whose BMI was documented at treatment initiation. We compared odds of any unfavorable treatment outcome, mortality, or failure/recurrence between patients who were underweight (BMI <18.5 kg/m2) and not underweight. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated using logistic regression, with matching on demographic, clinical, and treatment-related factors. We evaluated effect modification by human immunodeficiency virus (HIV) status and other variables using likelihood ratio tests. We also estimated cumulative incidence of mortality during treatment stratified by HIV.
Results: Overall, 5148 patients were included; 1702 (33%) were underweight at treatment initiation. The median (interquartile range) age was 37 years (29 to 47), and 455 (9%) had HIV. Compared with nonunderweight patients, the aOR among underweight patients was 1.7 (95% CI, 1.4-1.9) for any unfavorable outcome, 3.1 (2.4-3.9) for death, and 1.6 (1.2-2.0) for failure/recurrence. Significant effect modification was found for World Health Organization region of treatment. Among HIV-negative patients, 24-month mortality was 14.8% (95% CI, 12.7%-17.3%) for underweight and 5.6% (4.5%-7.0%) for not underweight patients. Among patients with HIV, corresponding values were 33.0% (25.6%-42.6%) and 20.9% (14.1%-27.6%).
Conclusions: Low BMI at treatment initiation for RR-TB is associated with increased odds of unfavorable treatment outcome, particularly mortality.
Keywords: body mass index; drug resistance; malnutrition; tuberculosis.
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