Association of baseline HALP and PIV/AISI with 2-month sputum culture conversion in newly diagnosed culture-positive pulmonary tuberculosis: a prospective single-center cohort study

Baseline blood composites that summarize nutritional reserve and systemic inflammation may help identify pulmonary tuberculosis patients less likely to achieve early microbiologic response, but prospective evidence remains limited. We conducted a prospective single-center cohort study enrolling adults with newly diagnosed, culture-positive, rifampicin-susceptible pulmonary tuberculosis who started first-line treatment between January 2023 and October 2025. Pretreatment HALP and PIV/AISI were calculated from the closest complete blood count plus albumin sample within 72 h before the first dose. The primary endpoint was 2-month sputum culture conversion in the day 42–70 window. Separate multivariable logistic models evaluated the independent association of ln-transformed, standardized HALP and PIV/AISI, with secondary assessment of incremental model performance. A post hoc end-of-treatment cure analysis used Firth penalized logistic regression. Among 317 analyzed participants, 249 achieved 2-month culture conversion and 68 did not. Higher HALP independently predicted conversion (adjusted OR 1.58, 95% CI 1.15–2.17; p =0.004), whereas higher PIV/AISI predicted lower odds of conversion (adjusted OR 0.64, 95% CI 0.46–0.90; p =0.010). HALP improved the apparent C-statistic from 0.739 to 0.813 and the optimism-corrected C-statistic from 0.723 to 0.809. Findings remained directionally consistent in prespecified sensitivity/supportive analyses, including the stricter culture-conversion endpoint and an exploratory day-90 time-to-conversion analysis. In the post hoc end-of-treatment analysis, 278 of 317 participants met the WHO definition of cure; associations remained directionally consistent for HALP (Firth-adjusted OR 1.42, 95% CI 1.05–1.92) and PIV/AISI (Firth-adjusted OR 0.72, 95% CI 0.53–0.98). In this prospective single-center cohort, higher baseline HALP and lower baseline PIV/AISI were independently associated with sputum culture conversion during intensive-phase treatment, with HALP showing slightly better incremental model performance. These low-cost biomarkers may complement baseline risk stratification, but external validation is required before routine implementation.