Baseline Neutrophil-to-Lymphocyte Ratio, Monocyte-to-Lymphocyte Ratio, and Systemic Immune-Inflammation Index Predict Second-Month Sputum Conversion and Treatment Outcomes in Drug-Resistant Tuberculosis: A Retrospective Cohort Study

Drug-resistant tuberculosis (DR-TB) remains a major public health challenge, highlighting the need for accessible prognostic biomarkers. This study evaluated the associations of baseline neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and systemic immune-inflammation index (SII) with second-month sputum conversion and treatment outcomes. A retrospective cohort study included 36 adults who initiated DR-TB treatment at Nene Mallomo Hospital, Indonesia, between January 2023 and June 2026. Baseline inflammatory biomarkers were calculated from pretreatment complete blood count results. Statistical analyses included the Mann–Whitney U test, receiver operating characteristic (ROC) curve analysis, and logistic regression. Sputum conversion was evaluated in 31 patients, while the mortality analysis included 24 patients. Baseline NLR was significantly higher among patients with delayed or absent sputum conversion than among those who achieved early conversion (p = 0.048), whereas differences in MLR and SII were not statistically significant. All three biomarkers were significantly elevated among patients who died compared with those who survived. NLR demonstrated the highest observed discriminatory ability for mortality (area under the curve [AUC] = 0.836), followed by MLR (AUC = 0.813) and SII (AUC = 0.766). These findings suggest that elevated systemic inflammatory markers were associated with unfavorable treatment outcomes. However, the small sample size and wide confidence intervals limited the precision and generalizability of the results. Baseline NLR may serve as a potential marker for early risk stratification, although its independent prognostic value remains unconfirmed. Larger prospective multicenter studies are warranted to validate these findings, establish clinically relevant cutoff values, and assess the predictive performance of these biomarkers across diverse DR-TB populations