Longitudinal body weight and sputum conversion in patients with tuberculosis, Southwest Ethiopia: a retrospective follow-up study

OBJECTIVES: To describe the association between change in body weight and sputum smear conversion and to identify factors linked with body weight and sputum smear conversion in Jimma University Specialized Hospital, Southwest Ethiopia. DESIGN: A retrospective follow-up study. SETTING: Teaching hospital in Southwest Ethiopia. PARTICIPANTS: A total of 450 patients with tuberculosis (TB) were included in the follow-up between 2011 and 2013. MAIN OUTCOME MEASURES: The association between body weight and sputum conversion was measured using joint modelling. RESULTS: The association between change in body weight and change in sputum conversion was −0.698 (p<0.001). A strong inverse association between change in body weight and change in sputum conversion was observed. The study variables sex, age, type of TB, HIV status, dose of anti-TB drug and length of enrolment to TB treatment were significantly associated with change in body weight of patients with TB. The study variables age, type of TB, dose of anti-TB drug and length of enrolment were significantly associated with change in sputum status of patients with TB. CONCLUSIONS: Among patients with TB who were on anti-TB treatment, increase in body weight and positive sputum status were inversely related over time. TB prevention and control strategies should give emphasis on factors such as female sex, older age, non-pulmonary positive type of TB, HIV-positive, lower dose of anti-TB drug and length of enrolment to TB treatment during monitoring of trends in body weight and sputum status.