Nutrition and Early Extrapulmonary Tuberculosis Response

This single-study briefing examines nutritional status within a prospective observational study of treatment response among patients with microbiologically confirmed extrapulmonary tuberculosis. The investigators studied patients at Chandrikaben Rashmikant Gardi Hospital, a tertiary care teaching hospital in Ujjain, Madhya Pradesh, India, serving a mixed urban and rural population and functioning as a tuberculosis referral centre, including for complex extrapulmonary presentations. The setting matters because the reported associations arise from a hospital-based, referral population rather than from an unselected population with tuberculosis. [pmid:42970549]

Evidence

The study enrolled 532 patients with extrapulmonary tuberculosis confirmed by the Xpert MTB/RIF assay. It was conducted prospectively between 2018 and 2024 and collected baseline demographic, clinical, and laboratory information. The stated objectives were to evaluate early clinical response to therapy and identify factors associated with rifampicin resistance. Confirmation by molecular testing defined the study population; the findings therefore concern microbiologically confirmed extrapulmonary tuberculosis rather than all patients evaluated for possible extrapulmonary disease. [pmid:42970549]

For the treatment-response analysis, the investigators assessed clinical response at 8 weeks using standardized criteria among patients with rifampicin-sensitive disease. They used standardized data-collection tools and predefined outcome criteria, then applied multivariable logistic regression to identify factors associated with slow clinical response and with rifampicin resistance. This approach provides both a direct comparison of responder groups and an adjusted association analysis, but the available results do not provide effect estimates for the individual independent associations. [pmid:42970549]

Among the 496 patients with rifampicin-sensitive extrapulmonary tuberculosis included in the response analysis, 113 (22.8%) had slow clinical response at 8 weeks. The comparison table divided this analytic population into 113 slow clinical responders and 383 responders. Thus, the outcome was an early standardized clinical-response classification, not a direct measure of nutritional intervention, sustained cure, or patient-reported nutritional recovery. The denominator and group definitions are important when interpreting the nutritional comparison reported in the same table. [pmid:42970549]

Underweight, defined in the table as body mass index below 18.5 kg/m², was recorded in 54 of 113 slow clinical responders (47.8%) and 107 of 383 responders (27.9%), with p <0.001. This is the study’s clearest directly reported nutrition-related group comparison. It describes a higher recorded prevalence of underweight among patients classified as slow responders at 8 weeks than among those classified as responders within the rifampicin-sensitive analytic group. It does not describe changes in body mass index during treatment. [pmid:42970549]

In multivariable logistic regression, slow clinical response was independently associated with malnutrition, diabetes mellitus, HIV co-infection, chronic obstructive pulmonary disease, prolonged symptom duration, and non-lymph node disease, particularly abdominal and genitourinary tuberculosis. Rural residence and lower educational status also showed independent association, as did elevated erythrocyte sedimentation rate and C-reactive protein. These results place malnutrition within a broader pattern of host-related, socioeconomic, inflammatory, and disease-related characteristics associated with the measured early response outcome. [pmid:42970549]

The study also reported that rifampicin resistance was more common among slow clinical responders than among responders and identified previous tuberculosis, HIV infection, male sex, and disseminated disease as independent correlates of rifampicin resistance. This overlap is relevant to interpretation because slow response in this cohort was not presented as a nutrition-only pattern. The study assessed both treatment response and rifampicin resistance, while it did not assess the efficacy or clinical benefit of nutritional treatment. [pmid:42970549]

Analysis — Observed nutritional pattern

The observed pattern is consistent with the study’s prospective hospital-based design and its selection of patients with Xpert MTB/RIF-confirmed extrapulmonary tuberculosis. Underweight was more frequent in the slow-response group, and malnutrition remained independently associated with slow clinical response in the reported multivariable analysis. At the same time, the same outcome was associated with comorbidities, symptom duration, disease site, socioeconomic characteristics, and inflammatory markers. Nutritional status therefore cannot be interpreted in isolation from the clinical and selection profile captured by the study. The responder comparison was restricted to patients with rifampicin-sensitive disease, whereas rifampicin resistance was analyzed as a related but distinct outcome. Statistical significance in the underweight comparison indicates the reported group difference under the study analysis; it does not by itself establish the clinical importance of that difference. Because this was an observational analysis, the results describe associations rather than causal effects of malnutrition or underweight on clinical response. [pmid:42970549]

Limitations

The observational design cannot establish causation. Although data collection and follow-up were prospective, differences between slow responders and responders may reflect measured and unmeasured differences in disease severity, comorbid conditions, social characteristics, diagnostic timing, or other features of the referral population. The tertiary-care setting, which receives complex extrapulmonary tuberculosis cases, also creates potential selection bias and limits direct generalization beyond patients represented there. [pmid:42970549]

The main nutrition-related quantitative result was a baseline underweight comparison, while the broader regression result used the term malnutrition. The available material does not specify how malnutrition was operationalized for that adjusted analysis, and it does not provide the corresponding adjusted effect size, confidence interval, or model details. The available description acknowledges that the study had several limitations but does not detail them. These gaps should be treated as limits of the available extraction, not as evidence that the study did not report such information elsewhere. [pmid:42970549]

The outcome was standardized clinical response at 8 weeks in a microbiologically confirmed extrapulmonary tuberculosis cohort, not a universal measure of all tuberculosis outcomes. Comparisons were made between slow responders and responders within the rifampicin-sensitive response-analysis population, so they do not establish the same pattern for rifampicin-resistant disease or for other tuberculosis populations. The study did not evaluate nutritional intervention efficacy or patient benefit from nutritional treatment. [pmid:42970549]