Different Profiles of Body Mass Index Evolutions Among Patients with Multidrug-Resistant Tuberculosis: A Retrospective Cohort Study

Background: Despite the predictor role of the body weight variation on multidrug-resistant tuberculosis (MDR-TB) treatment outcome, little data are available to corroborate this finding. We aimed to study the course of weight in patients with MDR-TB, to identify subgroups of weight evolutions, and to determine factors that influence these evolutions. Methods: Patients treated with a shorter MDR-TB treatment regimen between June 07, 2016 and June 22, 2018 from three major drug-resistance TB centres in Guinea, who had rifampicin resistance, and who were cured or died were analysed. Patients were seen monthly until the end of treatment. Clinical outcome was the Body Mass Index (BMI). We used a linear mixed model to analyze the course of BMI and a latent class mixed model to identify subgroup of BMI evolutions. Findings: Of 232 patients treated for MDR-TB during the study period, only 165 (71%) patients who were cured or died were analysed. These patients had a total of 1387 visits, with a median of 5 visits (interquartile range, 3 - 8 visits). Monthly BMI increase was 0·24 (SE 0·02) per kg/m2. Factors that associated with faster BMI progression were cured to MDR-TB treatment (0·24 [SE 0·09] per kg/m2; p = 0·0205), and the absence of lung cavities on X-ray (0·18 [0·06] per kg/m2; p = 0·0068). Two subgroups of BMI evolution were identified: "Rapid BMI (n = 121; 85%) and "Slow BMI evolution (n = 22; 15%). Patients in the slow increasing BMI group were mostly female (68%) without history of TB treatment (41%) with most severe clinical condition at baseline, characterized by a higher frequency of symptoms including HIV infection (59%), depression (18%), dyspnea (68%), nausea (23%), poor adherence to MDR-TB treatment (64%), lower platelets count, and higher liver SGOT count. These patients had also a longer time to-initial culture conversion delay (log-rank test: p = 0·0087). Interpretation: The available data provide quantitative information on BMI progression of patients with MDR-TB treated with a shorter regimen, and allowed the identification of the subgroup of patients with different BMI evolutions. Furthermore, they emphasize the usefulness of BMI as biomarker to monitor MDR-TB treatment outcome, and allow more efficient use of resources and patient management. Funding Statement: The authors stated: "None" Declaration of Interests: The authors declare no competing interests in relation with this work. Ethics Approval Statement: The study was approved by the National Ethics Committee for Heath Research (NECHR) attached to the Ministry of Health (Conakry, Guinea).