Abstract
Objective: To assess the relationship between serum vitamin D concentrations and the severity of community-acquired pneumonia (CAP) in a defined patient population over a specific timeframe.
Methodology: This prospective cohort study was conducted in the Department of Medicine at PAF Hospital, Islamabad, from March 2023 to March 2024. Pneumonia severity was assessed using the CURB-65 (confusion, uraemia, respiratory rate, blood pressure, age ≥ 65 years) score. Serum vitamin D levels were measured and classified as deficient, insufficient, or sufficient. The relationship between pneumonia severity and serum vitamin D levels was analysed using SPSS version 26, considering a p≤0.05 as statistically significant.
Results: A total of 158 patients with CAP were enrolled. The mean serum vitamin D concentration was 26.90±24.74 ng/ml. The CURB-65 score revealed that 89% of male and 82.5% of female patients with severe pneumonia had associated comorbidities. Additionally, 75% of male patients aged over 55 presented with severe pneumonia (p=0.009). A significant positive correlation was found between deficient serum vitamin D levels and pneumonia severity (p<0.001; OR=1.20; CI=1.09–1.33), while higher vitamin D levels showed a significant inverse correlation with CURB-65 scores (p=0.007; OR=0.96; CI=0.93–0.98). The risk of severe illness was highest among patients with pre-existing conditions (p<0.001; OR=8.005).
Conclusion: Increasing vitamin D deficiency was associated with greater severity of CAP, particularly in older patients and those with comorbidities.

Key words: Community-acquired pneumonia, Vitamin D, CURB- 65, Risk factor.