Evaluation of serum 25-hydroxyvitamin D levels in calcific rheumatic mitral stenosis- A cross sectional study.

BACKGROUND AND AIM OF THE STUDY: Rheumatic mitral stenosis (RMS) is an autoimmune, progressive destructive valve disease occurring as a sequele of streptococcal infection. Epidemiological studies support an association of vitamin D deficiency with initial susceptibility and severity of autoimmune diseases. The aim of the present study was to assess serum level of 25 hydroxyvitamin D in subjects of RMS and assess if any correlation exists with serum levels of vitamin D and severity of disease along with calcification assessed semi-quantitatively by echocardiography by applying Wilkins score.

METHOD: Fifty five patients of RMS without any calcification of the valves (Group A) assessed by echocardiography along with fifty five patients of RMS with mild to moderately calcified valves (Group B, Wilkins calcium score 1 or 2) and 55 patients with severely calcified valves (Group C, Wilkins calcium score 3 or 4) were enrolled for the study. All subjects underwent clinical, echocardiographic, and biochemical evaluation. The total Wilkins score, Wilkins calcium score along with serum level of 25 hydroxyvitamin D was evaluated in all the patients.

RESULTS: The median serum level of 25 hydroxyvitamin D was significantly lower in Group B (20.4ng/ml, p<0.001) and group C (11.4ng/ml, p<0.001) compared to Group A patients (27.9ng/ml). Similarly serum level of 25 hydroxyvitamin D in Group C patients were significantly less than Group B patients (p<0.001). A significant inverse correlation was identified between serum level of 25 hydroxyvitamin D and total Wilkins score (r=-0.65, p<0.001) as well as Wilkins calcium score (r=-0.69, p<0.001). But no correlation was identified between 25 hydroxyvitamin D levels and other echocardiographic parameters of RMS.

CONCLUSION: Our study showed a significantly lower level of 25 hydroxyvitamin D in subjects of RMS with severely damaged and calcified valves as compared to those with less severely damaged non-calcified valves and it correlated with both Wilkins score and Wilkins calcification score. Thus a link may exist between vitamin D deficiency (an immunomodulator) and severity of autoimmune injury on the valves.