# Comparative Study on the Effect of Vitamin D Deficiency on Platelet Indices in COVID‐19 and Hepatitis C Patients; an Observational Comparative Study

## TL;DR

This study compares vitamin D deficiency and platelet changes in patients with COVID-19 and Hepatitis C, finding stronger effects in the former.

## Contribution

The study provides new evidence linking vitamin D deficiency with increased platelet activation and inflammation in COVID-19 compared to HCV.

## Key findings

- COVID-19 patients had significantly lower vitamin D levels and lower platelet counts than HCV patients.
- Vitamin D deficiency was associated with higher platelet activation and inflammatory markers in both groups.
- Platelet and inflammatory changes were more pronounced in vitamin D-deficient COVID-19 patients.

## Abstract

Despite growing interest in the role of vitamin D in various infectious diseases, limited evidence exists regarding its association with platelet (PLT) parameters in patients with COVID‐19 and Hepatitis C Virus (HCV) infection. This study aims to assess the relationship between serum vitamin D levels and PLT indices in patients with COVID‐19 and chronic HCV.

The study included 113 patients with confirmed COVID‐19 and 97 patients with chronic HCV infection. All participants were classified into two subgroups based on their vitamin D status (deficient vs. non‐deficient). The chi‐square test (χ2) or Fisher exact test was used to compare the results between the two groups.

Patients with COVID‐19 had significantly lower levels of vitamin D compared with HCV patients (p < 0.001). PLT counts were lower in the COVID‐19 group, and MPV, PDW, and inflammatory markers (PLR, MPR, and MLR) were significantly higher. Also, a significant negative correlation was observed between vitamin D levels and MPV in both groups (p < 0.001). In patients with vitamin D deficiency, PLT and inflammatory changes were more pronounced in COVID‐19 than in HCV.

The results of this study showed that COVID‐19 patients had lower vitamin D levels, lower PLT counts, and higher indices of platelet activation compared with HCV patients. These changes are associated with the severity of the inflammatory response in COVID‐19 and could be part of the mechanisms that cause thrombotic complications in this disease.