Response to treatment and low serum vitamin D levels in North Indian patients with treatment-naive category I and multi-drug resistant pulmonary tuberculosis

Abstract

Background: Tuberculosis (TB) is a bacterial infection that usually affects the lungs, although it can also affect other parts of the body. Vitamin D deficiency and response to treatment have been demonstrated in patients with active TB in several studies, but not in MDR-TB patients, which is a new observation in the present study.

Objective: To study the time to initial sputum culture conversion and to associate baseline vitamin D levels and response to treatment in patients with PTB Cat I and MDR-TB.

Methods: A total of 897 North Indian participants were recruited and divided into three groups: treatment-naïve PTB Cat I, MDR-TB, and healthy controls. Serum biochemistry, including 25-hydroxyvitamin D and calcium, was measured in all participants with PTB, Cat I, and MDR-TB.

Results: PTB Cat I patients had high bacillary load grading at baseline compared to 2^nd month followed by 6^th month of treatment. More severe chest radiographic features, such as cavitation and the presence of bilateral disease at baseline. Mean sputum smear conversion times were 0.95 ± 0.7 months and culture conversion to negative occurred at a mean time of 0.8 ± 0.7 in PTB Cat I patients compared to MDR-TB patients on average sputum smear and time of 2.4 ± 3 months. Significantly lower mean serum 25-hyroxyvitamin D concentration was found in the 6^th month than in the 2^nd month and baseline in PTB Cat I.

Conclusion: Low serum vitamin D deficiency was observed in both groups during treatment and is one of the important factors responsible for susceptibility to TB in both groups; however, its significance is uncertain. Patients with continuous positive sputum for multidrug-resistant tuberculosis (MDR-TB) had a worse prognosis than those with sputum bacteriology conversion. Two months into a treatment regimen, sputum smear conversions may be a useful indicator of an MDR-TB patient's prognosis.

Keywords: Cat I pulmonary tuberculosis; Multi-drug resistant tuberculosis; smear and culture conversion; treatment response; vitamin D.

Figure 1.

Association of serum vitamin D levels with response to treatment [sputum AFB smear (A) and culture (B)] in patients with MDR-TB. (A) Scatter plot is shown between serum vitamin D levels (ng/ml) on the X-axis and sputum smear conversion time (in months) on the Y-axis with correlation coefficient (r) and significance of correlation (p). (B) (B) Scatter plot of serum vitamin D levels (ng/ml) on the X-axis and sputum culture conversion time (in months) on the Y-axis with correlation coefficient (r) and significance of correlation (p).

Figure 2.

Association of serum vitamin D levels with response to treatment [sputum AFB smear (A) and culture (B)] in patients with PTB cat I. (A) Scatter plot of serum vitamin D levels (ng/ml) on the X-axis and sputum smear conversion time (in months) on the Y-axis with correlation coefficient (r) and significance of correlation (p). (B) Scatter plot of serum vitamin D levels (ng/ml) on the X-axis and sputum culture conversion time (in months) on the Y-axis with correlation coefficient (r) and significance of correlation (p).

Figure 3.

Correlation between serum vitamin D and iPTH levels in MDR-TB, PTB cat I patients and healthy controls. A scatter plot is shown between serum iPTH levels (pg/ml) on the X-axis and serum vitamin D levels (ng/ml)) on the Y-axis with correlation coefficient (r) and significance of correlation (p).

Figure 4.

Correlation between serum vitamin D and ionized calcium levels in MDR-TB, PTB cat I patients and healthy controls. A scatter plot is shown between serum ionized calcium (mg/dl) in the X-axis and serum vitamin D levels (ng/ml)) in the Y-axis with correlation coefficient (r) and significance of correlation (p).

Figure 5.

Correlation between serum vitamin D and serum total calcium levels in MDR-TB, PTB cat I patients and healthy controls. Scatter plots are shown between serum total calcium (mg/dl) on the X-axis and serum vitamin D levels (ng/ml)) on the Y-axis with correlation coefficient (r) and significance of correlation (p).

Figure 6.

Seasonal variations of serum vitamin D levels levels (ng/ml) in PTB cat I patients at three time points. The bar Graph represents seasonal variations in months (X-axis) of serum vitamin D levels (Y-axis).