Bodyweight gain to predict treatment outcome in patients with pulmonary tuberculosis in Peru

Tuberculosis control programmes of two health care centres in the central rainforest of Peru.

To evaluate if bodyweight gain (BWG) predicts treatment outcome in patients with pulmonary tuberculosis (PTB).

Retrospective cohort study of adults with PTB diagnosed between 1995 and 2004. BWG was assessed after month 1 of treatment, after the initial phase and at the end of treatment. Patients were stratified into two BWG categories, < or = 5% and >5%. Failures and relapses were grouped together as unsuccessful treatment outcome.

A total of 650 patients were included: 7.2% (n = 47) had an unsuccessful outcome. Unsuccessful outcome was associated with BWG < or = 5% at the end of treatment (RR 2.05, 95%CI 1.10-3.80), but not at the completion of month 1 (RR 0.99, 95%CI 0.52-1.88) or at completion of the initial phase (RR 1.46, 95%CI 0.82-2.57). Median BWG at completion of the initial phase was higher in cured patients (P = 0.007). BWG < or = 5% at end of treatment (RR 2.35, 95%CI 1.17-4.72), initial sputum smear 2+ (RR 2.48, 95%CI 1.14-5.31) and positive smear microscopy at month 2 (RR 4.0, 95%CI 1.30-12.31) were independent predictors of unsuccessful treatment outcome.

BWG < or = 5% at the end of treatment, high bacterial load and lack of sputum conversion correlate with unsuccessful treatment outcome in this setting. New discriminative cut-offs for BWG are proposed.