Association of BMI Category Change with TB Treatment Mortality in HIV-Positive Smear-Negative and Extrapulmonary TB Patients in Myanmar and Zimbabwe

Lenka Benova,Katherine Fielding,Bern-Thomas Nyang'Wa,Marcio Silveira Da Fonseca,Philipp Du Cros,Jane Greig,Esther Carrillo Casas

doi:10.1371/journal.pone.0035948

Abstract

ObjectiveThe HIV epidemic has increased the proportion of patients with smear-negative and extrapulmonary tuberculosis (TB) diagnoses, with related higher rates of poor TB treatment outcomes. Unlike in smear-positive pulmonary TB, no interim markers of TB treatment progress are systematically used to identify individuals most at risk of mortality. The objective of this study was to assess the association of body mass index (BMI) change at 1 month (±15 days) from TB treatment start with mortality among HIV-positive individuals with smear-negative and extrapulmonary TB.Methods and FindingsA retrospective cohort study of adult HIV-positive new TB patients in Médecins Sans Frontières (MSF) treatment programmes in Myanmar and Zimbabwe was conducted using Cox proportional hazards regression to estimate the association between BMI category change and mortality. A cohort of 1090 TB patients (605 smear-negative and 485 extrapulmonary) was followed during TB treatment with mortality rate of 28.9 per 100 person-years. In multivariable analyses, remaining severely underweight or moving to a lower BMI category increased mortality (adjusted hazard ratio 4.05, 95% confidence interval 2.77–5.91, p<0.001) compared with remaining in the same or moving to a higher BMI category.ConclusionsWe found a strong association between BMI category change during the first month of TB treatment and mortality. BMI category change could be used to identify individuals most at risk of mortality during TB treatment among smear-negative and extrapulmonary patients.

Highlights

We found a strong association between body mass index (BMI) category change during the first month of TB treatment and mortality
In 2010, approximately 8.8 million incident cases of tuberculosis (TB) occurred, 1.45 million people died from the disease and 24% of those who died were co-infected with the human immunodeficiency virus (HIV) [1]
63% of 5,930 adult HIV-positive TB patients with information on clinical presentation enrolled in TB treatment by Medecins Sans Frontieres (MSF) in six countries between January 2006 and September 2008 were smear-negative or extrapulmonary [12]

Summary

Introduction

In 2010, approximately 8.8 million incident cases of tuberculosis (TB) occurred, 1.45 million people died from the disease and 24% of those who died were co-infected with the human immunodeficiency virus (HIV) [1]. 63% of 5,930 adult HIV-positive TB patients with information on clinical presentation enrolled in TB treatment by Medecins Sans Frontieres (MSF) in six countries between January 2006 and September 2008 were smear-negative or extrapulmonary [12]. These patients are at higher risk of TB treatment default and mortality, partly as a result of delayed diagnosis and treatment [7,13,14]. Both Zimbabwe and Myanmar are in the WHO ‘high TB burden’ category and most notified new TB cases in both countries (51% and 66%, respectively) are either smear-negative or extrapulmonary [15,16]

Methods

Results

Conclusion