Undernutrition Linked to Increased Mortality in Multidrug-Resistant TB

Patients with multidrug-resistant tuberculosis with a body mass index of less than 18.5kg/m2 had a 2.8-times higher odds of death.

Increased mortality and longer time to sputum culture conversion among individuals with multidrug-resistant tuberculosis (MDR-TB) is significantly associated with undernutrition, according to a systematic review and meta-analysis published in the International Journal of Infectious Diseases.

Reviewers sought to assess the effect of undernutrition on treatment outcomes and sputum culture conversion among individuals with MDR-TB. The primary study endpoints were unsuccessful treatment outcomes (ie, a composite of loss to follow-up, treatment failure, and death) and all-cause mortality. The secondary endpoint was sputum culture conversion, defined as the transition from a positive culture to 2 consecutive negative cultures at least 30 days apart.

The investigators conducted a review and random-effect meta-analysis, searching the Embase, Scopus, Medline, and Web of Science databases for studies estimating the effects of undernutrition on treatment outcomes and sputum culture conversion. Effect estimates were summarized with odds ratios (ORs) for treatment outcomes and with hazard ratios (HRs) for sputum culture conversion.

The review included cross-sectional, case-control, and cohort studies found in peer-reviewed and grey literature, excluding abstracts, conference papers, and studies that were not in English. Also excluded were studies of adults with DS-TB or exclusively with children or pregnant women. Risk of bias was assessed independently by 2 reviewers using a modified Newcastle-Ottawa Assessment scale.

Reviewers included 63 studies with a total of 31,583 participants with MDR-TB (all at least 15 years of age with bacteriologically confirmed MDR/rifampicin-resistant-TB). Reviewers defined undernutrition as body mass index (BMI) less than 18.5kg/m2; individuals with BMI from 18.5 to 24.9kg/m2 were used as the comparator. Among included studies, 15 were high quality, 45 were moderate quality, and 3 were low quality. No significant publication bias was identified among the included studies.

Undernutrition was significantly associated with a higher mortality rate, poorer treatment outcomes, and longer time to sputum culture conversion among people with MDR-TB.

Meta-analysis showed that undernutrition was significantly associated with unsuccessful treatment outcomes (OR, 1.8; 95% CI, 1.5-2.1; I2=70%), a longer time to sputum culture conversion (HR, 0.7; 95% CI, 0.6-0.9; I2=67.1%), and a higher rate of mortality (OR, 2.8; 95% CI, 2.1-3.6; I2=21%).

Overall, 9 studies indicated that patients with a BMI of less than 18.5kg/m2 had a 2.8-times higher odds of death vs comparators. Among the 40 studies assessing the association between undernutrition and unsuccessful treatment outcomes that were suitable for meta-analysis, 22 studies reported an association and 18 studies reported no association. The effect of undernutrition on sputum culture conversion was evaluated in 11 cohort studies, 5 of which were not suited to meta-analysis.

Significant study limitations include the use of studies published in English only and the fact that most included studies used secondary data.

Reviewers concluded that “Undernutrition was significantly associated with a higher mortality rate, poorer treatment outcomes, and longer time to sputum culture conversion among people with MDR-TB.” These findings “suggest the need for urgent expansion of access to nutritional support to improve the nutritional status of people living with MDR-TB, notably at the early stage of treatment,” said study authors.

References:

Wagnew F, Alene KA, Kelly M, Gray D. The effect of undernutrition on sputum culture conversion and treatment outcomes among people with multidrug-resistant tuberculosis: A systematic review and meta-analysis. Int J Infect Dis. Published online December 6, 2022. doi:10.1016/j.ijid.2022.11.043