Correlation of severity of chronic obstructive pulmonary disease with serum vitamin-D level

The global scenario of illness is shifting from infectious diseases to non-communicable diseases, with chronic conditions such as heart diseases, stroke and Chronic Obstructive Pulmonary Disease (COPD) now being chief causes of death globally and more than 90% of deaths due to COPD occur in low and midline income countries.[1] Low serum vitamin D level is associated with various lung diseases and decreased lung function.[2].

This study was designed to study the serum vitamin D level and its correlation with severity of COPD as assessed by spirometry, COPD assessment test (CAT) and exercise capacity and BMI of COPD patients.

Observational cross sectional study conducted on patients of COPD attending the outpatient department.

One hundred sixty consecutive patients of COPD attending the outpatient Department were included in the study. Pack years, CAT score, 6 minute walk distance, post bronchodilator spirometry values and BMI was recorded along with complete history and physical examination.

Data analysis was done using IBM SPSS 23 software. Descriptive statistics, Independent sample t test, ANOVA and Pearson correlation were applied.

A significant positive correlation was found between FeV1% of predicted and serum Vitamin D level(r = 0.291; P < 0.001). A negative correlation was found between serum Vitamin D level and severity of COPD as assessed by CAT score (r = -0.355; P < 0.001). Also, a significant positive correlation was found between vitamin D levels and exercise capacity as assessed by 6 minute walk test (6MsWT) (r = 0.648; P < 0.001).

COPD patients with more severe disease tend to have lower serum Vitamin D levels. As it is an immunomodulator affecting various inflammatory pathways, it is imperative that we give due consideration to Vitamin D levels in managing patients of COPD.