RESUMO
Introduction: Patients with delayed intensive phase sputum conversion have a higher risk of multidrug resistant-tuberculosis (MDR-TB) and poorer treatment outcomes. Both, host (immune response and comorbidity) and pathogen factors play important roles in determining sputum conversion after treatment initiation. Impaired host immune response, especially the cellular components, as defined by the increased pre-treatment level of neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR) and other additional factors, were associated with severe active TB. Purpose: To evaluate whether impaired immune responses (high pre-treatment level of NLR and MLR) and other factors associate with delayed sputum conversion at the end of the intensive phase treatment. Patients and Methods: This was a case-control study from 2016 to 2020, which retrospectively analyzed the pre-treatment level of NLR, MLR and other factors among patients with new cases of pulmonary tuberculosis (PTB). Results: A total of 62 patients (31 cases and 31 control). The cut-off value of high pretreatment level of NLR and MLR was 5.065 and 0.585, respectively. Bivariate analysis showed that pretreatment NLR ≥5.065 (OR 8.23, CI 95% 2.48-27.32, p < 0.001), MLR ≥0.585 (OR 10.18, 95% CI 3.13-33.18, p < 0.001) and BMI <18.5 (OR 2.91, 95% CI 1.03-8.20, p = 0.041) were associated with an increased risk of delayed sputum conversion. Multivariate analysis, however, showed that pretreatment NLR ≥5.065 was not significantly associated with delayed sputum conversion (AOR 3.370, 95% CI 0.71-15.91, p value 0.125). A high pretreatment of MLR (AOR 30.802, 95% CI 3.22-287.55, p value 0.003) and lower BMI (AOR 10.942, 95% CI 1.121-98.563, p value 0.033) were significantly associated with an increased risk of delayed intensive phase sputum conversion. Conclusion: High MLR pretreatment and a low BMI were significantly associated with an increased risk of delayed sputum conversion at the end of the PTB intensive phase treatment. High NLR pretreatment, smoking, diabetes, and HIV were not associated with sputum conversion.