Relationship between 25-hydroxyvitamin D levels and treatment course of pulmonary tuberculosis

Low serum vitamin D level is associated with a high risk of developing active tuberculosis (TB). We investigated the relationships between serum vitamin D levels and clinical course of TB after standard chemotherapy in hospitalized non-HIV patients with TB.

Hospitalized patients with TB were recruited between February 2008 and July 2010. Confirmatory tests were performed using sputum smear and culture positivity tests for Mycobacterium tuberculosis. Drug sensitivity testing was performed for all the subjects and those not showing drug resistances for the first-line anti-TB drugs were included in the study. These patients were treated with the standard first-line anti-TB drugs. Serum 25-hydroxyvitamin D [25(OH)D] levels were measured on admission, and the relationships between 25(OH)D and clinical characteristics (laboratory data on admission and treatment outcomes) were examined. We defined vitamin D deficiency as a condition where serum level of 25(OH)D was lower than 20 ng/ml.

A total of 38 patients were included in the study. Mean (± SD) 25(OH)D levels were 13.7 ± 5.9 ng/ml. The prevalence of vitamin D deficiency was 87%. In 23 patients treated with the standard first-line 4-drug regimen (Age < 80 years) serum 25(OH)D levels showed significant negative correlation with time taken to obtain 3 consecutive negative sputum smears or TB bacteria cultures. This relationship suggests that low serum vitamin D level may not only increase the risk of developing active TB but may also be related to the poor treatment outcomes in these patients.

Low serum vitamin D level is a good predictor of prolonged clinical course in patients with active pulmonary TB.