Biochemical role of Vitamin D and Impact of anti-tuberculosis treatment on haematological parameters in newly diagnosed pulmonary and abdominal tuberculosis patients: A systematic review

Abstract

TB is a major health issue to this date and affects numerous low- and middle-income populations, where the prevalence of the disease is still high. One of the established vitamins being correlated to TB pathogenesis is Vitamin D which is famous for the immune system and bone health. Vitamin D together with its metabolites, may one day be used to manage the TB disease. There are also haematologic manifestations of TB and its management, which further challenge the care of affected patients. Objective: To know the biochemical role of vitamin D in TB patients and to review the changes in haematological parameters due to anti-tubercular treatment in newly diagnosed pulmonary as well as abdominal tuberculosis patients. Methodology: An extensive search was made from PubMed, MEDLINE, Scopus, Web of Science, and the Cochrane Library for articles complied between January 2016 and December 2021. These comprised; patients being newly diagnosed with pulmonary and/or abdominal Tuberculosis who had not begun anti-Tuberculosis therapy; patients with Vitamin D status or supplementation; and patients with abnormal haematological parameters who should have their parameters evaluated before and after initiation of anti-Tuberculosis therapy. Data extraction was done by two authors separately and, in case of disagreement, the third author made the final decision. The methodological quality of the studies included in this meta-analysis was evaluated based on the Cochrane ‘Risk of Bias’ tool for RCTs, and the Newcastle–Ottawa Scale for cohort and case–control studies. Results: The review focused on a number of fifteen studies that focused on the baseline Vitamin D levels of TB patients and that observed a common trend of Vitamin D deficiency where the mean levels were seen to be as low as 11. 1 to 15. 9 ng/mL. In the study demographic, the patients who had TB, 72–86% of them were Vitamin D deficient. Additionally, 12 studies evaluated haematological parameters, showing significant post-treatment improvements: haemoglobin levels were higher from 11. 3 ± 1. 9 g/dL to 13. 1 ± 1. 9 g/dL, WBC counts decreased from 9.4 ± 3.1 ×10â¹/L to 7.2 ± 2.1 ×10â¹/L, and platelet counts reduced from 360 ± 75 ×10³/µL to 285 ± 65 ×10³/µL. A positive correlation between Vitamin D sufficiency and higher baseline haemoglobin levels was observed. Conclusion: The correlation identified for vitamin D and haemoglobin is positive, indicating vitamin D could have an independent role in boosting hemological improvement during anti-TB therapy. The authors underlined more specific issues to be considered in the approach to TB, such as assessment of Vitamin D deficiency and further investigation of the therapeutic effect of Vitamin D supplementation in TB patients