Does Nutritional Support Improve Treatment Outcomes among Undernourished Tuberculosis Patients?
Maurice Wanyonyi *
Department of Mathematics and Statistics, University of Embu, Kenya and Research and Development, African Institute for Capacity Development, Nairobi, Kenya.
John Kiluyi Wafula
Department of Assets, Office of Auditor General, Nairobi, Kenya.
Jonathan Ndolo Mbithi
Department of Mathematics and Statistics, University of Embu, Kenya.
*Author to whom correspondence should be addressed.
Abstract
Undernutrition is common among patients with tuberculosis (TB) and is associated with poor treatment outcomes. Although the World Health Organization recommends nutritional support, evidence from routine programme settings in sub-Saharan Africa remains limited. We conducted a retrospective cohort study of undernourished adults (body mass index [BMI] < 18.5 kg/m2) with drug-susceptible TB in Embu County, Kenya, from 2017 to 2024. The exposure of interest was food-based nutritional support, including ready-to-use therapeutic foods (RUTF), fortified blended foods (FBF), or nutritional counselling (NC). The primary outcome was a favourable treatment outcome (defined as cure or treatment completion). We estimated associations using multivariable logistic regression, propensity score matching (1:1 matching with a caliper of 0.2 standard deviations), and inverse probability of treatment weighting (IPTW). Among 2,138 patients (mean age 38.9 years; 82.7% male), 1,761 (82.4%) received nutritional support. In multivariable analysis, nutritional support was not associated with a favourable outcome (adjusted odds ratio [AOR] = 1.08, 95% confidence interval [CI]: 0.69–1.66; p = 0.724). Propensity score matching yielded 371 matched pairs with a matched odds ratio of 1.14 (95% CI: 0.73–1.77; p = 0.574). IPTW analysis produced a weighted odds ratio of 1.17 (95% CI: 0.77–1.74; p = 0.519). There was no evidence of effect modification by severity of undernutrition (p for interaction = 0.974). Subgroup analyses by HIV status, patient type, and sputum smear positivity similarly showed no significant associations. In routine TB care in Kenya, food-based nutritional support was not associated with improved treatment outcomes among undernourished patients. These findings suggest that current supplementation strategies may be insufficient in this setting. Future research should evaluate higher-calorie, longer-duration, and better-monitored nutritional interventions. Strengthening nutritional assessment and counselling remains important, but routine food supplementation as currently implemented may not improve TB treatment outcomes.
Keywords: Tuberculosis, undernutrition, nutritional support, treatment outcome, propensity score matching, inverse probability of treatment weighting, retrospective cohort, body mass index, Kenya, programme data