RELATIONSHIP BETWEEN SEVERE VITAMIN D DEFICIENCY AND FREQUENCY OF COPD EXACERBATIONS: A RETROSPECTIVE COHORT STUDY AT A TERTIARY CARE CENTER IN NORTH INDIA

Abstract

Chronic Obstructive Pulmonary Disease (COPD) is a significant and escalating public health concern in India, contributing substantially to disability-adjusted life years (DALYs), particularly within large, environmentally challenged states such as Uttar Pradesh.¹ Acute Exacerbations of COPD (AECOPDs) are critical events that accelerate lung function decline, drive morbidity, and account for a large proportion of healthcare expenditure.² Vitamin D (25-hydroxyvitamin D) is recognized for its crucial, non-skeletal functions in regulating host immunity and systemic inflammation, which are key defense mechanisms against respiratory infections and exacerbation triggers.³ Hypovitaminosis D is endemic across the Indian subcontinent, affecting an estimated 70% to 100% of the general population.¹ Recent international cohort data suggest a high risk of severe exacerbations is concentrated specifically within the subpopulation experiencing severe vitamin D deficiency (SVDD, defined as <10 ng/mL).⁴ Local quantification of this risk in North India is crucial for developing regionally relevant clinical protocols.
Objectives: The primary aims of this study were:

1. To determine the prevalence of categorized 25(OH)D statuses (Severe VDD, Deficiency, Insufficiency, and Sufficiency) within a local COPD cohort at the Career Institute of Medical Science & Hospital;


2. To quantify the independent association between SVDD (<10 ng/mL) and the frequency of AECOPDs requiring hospitalization over a subsequent 06-month follow-up period.

Methodology: This retrospective, single-center observational cohort study involved the review of electronic health records (EHR) for N=530 adult patients diagnosed with spirometrically confirmed COPD. Data were abstracted from records spanning 2020–2024 at the Career Institute of Medical Science & Hospital, Ghailla-Lucknow. Patients were categorized based on their baseline 25(OH)D levels, with Sufficiency (>30 ng/mL) serving as the reference group.⁴ The primary outcome was the count of AECOPDs requiring hospital admission in the 12 months following baseline assessment. Multivariate Cox Proportional Hazards Regression analysis was performed to estimate the adjusted Hazard Ratio (HR) for SVDD, controlling for established exacerbation risk factors including age, BMI, and GOLD E classification.⁶ Statistical analysis utilized IBM SPSS Statistics, Version 26.0 and R statistical software.
Results: A profound deficiency was observed: 67.9% of the cohort had VDD (<20 ng/mL), with 30.2% specifically falling into the Severe VDD category (<10 ng/mL). The Severe VDD group reported a mean of 2.6 \pm 1.1 AECOPD hospitalizations per year, compared to 0.9\pm 0.5 in the Sufficiency group. Multivariate Cox regression analysis demonstrated that Severe VDD (<10 ng/mL) was an independent, statistically significant predictor of severe exacerbation risk (Adjusted HR: 2.85; 95% CI: 1.60–5.09; P < 0.001). The risk associated with Deficiency (10–20 ng/mL) did not reach statistical significance (HR: 1.55, P=0.114).
Conclusion: Severe vitamin D deficiency is highly prevalent in this North Indian COPD cohort and constitutes a powerful, independent risk factor for frequent, severe exacerbations requiring hospital admission. These findings highlight the importance of routine 25(OH)D assessment and targeted nutritional intervention as an essential component of comprehensive COPD management in regions facing endemic VDD