Low Body Mass Index at Treatment Initiation and Rifampicin-Resistant Tuberculosis Treatment Outcomes: An Individual Participant Data Meta-Analysis

Underweight individuals (body mass index <18.5 kg/m(2)) at initiation of rifampicin-resistant tuberculosis treatment have significantly higher odds of unfavorable outcomes compared with individuals who are not underweight. The 24-month mortality risk was approximately 10% higher among underweight individuals, regardless of human immunodeficiency virus status. 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/m(2)) 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%) were living with 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 patients not living with HIV, 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 living 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.