A high C-reactive protein level and poor performance status are associated with delayed sputum conversion in elderly patients with pulmonary tuberculosis in Japan.

Abstract

Although the aging population had been increasing in many countries, the factors associated with sputum conversion in elderly patients with pulmonary tuberculosis have not been fully elucidated. We aimed to identify the predictors of delayed sputum conversion and to assess the impact of non-conversion on mortality during tuberculosis treatment in elderly patients. Elderly patients (>65 years) admitted at our hospital in Japan for sputum smear-positive pulmonary tuberculosis were included. The risk factors for sputum non-conversion after 2 months of treatment were determined using multiple logistic regression. Cox hazard regression was used to assess the influence of non-conversion on mortality. We included 185 patients, with median age of 82 years (IQR, 79-88 years). The median time to conversion was 47 (95% CI 43-51) days, and 62 (34%) were identified as non-converters. Multivariate analysis showed that high pretreatment smear grade, high C-reactive protein level and poor performance status were associated with non-conversion. Non-conversion did not contribute to death during treatment. In elderly patients, inflammation level and physical activity level, along with initial smear grade may have a significant impact on delayed sputum conversion. Non-conversion after two months of treatment might not be related with mortality.