Association between early weight variation and treatment outcomes among extensively drug-resistant tuberculosis patients in Pakistan: a multicenter retrospective cohort study

Tuberculosis (TB) is commonly associated with significant weight loss, and weight gain during treatment is often considered an indicator of treatment response. However, evidence regarding the association between weight change and treatment outcomes among patients with extensively drug-resistant TB (XDR-TB) remains limited. This study aimed to evaluate the relationship between weight change during treatment and treatment outcomes among XDR-TB patients in Pakistan. A multicenter retrospective cohort study was conducted using data from XDR-TB patients treated at 27 Programmatic Management of Drug-Resistant TB units across Pakistan between May 2010 and June 2019. Patient data were extracted from the Electronic Nominal Recording and Reporting System of the National Tuberculosis Control Program. Weight change was assessed at 2, 4, and 6 months of treatment and categorized as no weight gain, weight gain <4 kg, and ≥4 kg. Logistic regression analysis was performed to determine the association between weight gain and favorable treatment outcomes. A total of 255 XDR-TB patients were included in the final analysis. Among them, 54.9% were male, and the majority (52.2%) belonged to the 21-40 year age group. Overall, favorable treatment outcomes were observed in 54.9% of patients. In multivariate analysis, weight gain at the fourth month of treatment showed a statistically significant negative association with favorable treatment outcomes for both weight gain <4 kg (OR 0.343, p=0.039) and ≥4 kg (OR 0.370, p=0.020). No statistically significant association was observed between weight gain at two or six months and treatment outcomes. These findings suggest that weight gain during treatment may not be a reliable predictor of favorable treatment outcomes among XDR-TB patients, and additional clinical and microbiological indicators should be considered when monitoring treatment response.