The Relationship Between Vitamin D Status and the Clinical Severity of COVID-19 Infection: A Retrospective Single-Center Analysis

Abstract

Background and objectiveSome studies have suggested a potential protective role of vitamin D in coronavirus disease 2019 patients, and this has led to a debate on the topic in the medical community. However, the reported data on the number of hospitalized patients who were vitamin D-deficient is not convincing. In light of this, the aim of the present study was to explore if vitamin D deficiency is correlated with severity and mortality rates of COVID-19 infection in hospitalized COVID-19 patients at a tertiary care hospital in Greece. MethodsWe conducted a single-center retrospective study involving 71 patients hospitalized with COVID-19 from August to October 2020. Serum 25-hydroxyvitamin D (25(OH)D) level was assessed in all patients within 48 hours of hospital admission. Serum 25(OH)D level ≤20 ng/ml was defined as a deficiency, while that >20 ng/ml as repletion. The primary outcomes of the infection were classified as partial/complete recovery and mortality during hospitalization. The secondary outcomes were blood markers of inflammation and thrombosis. ResultsAmong the 71 COVID-19-positive patients [mean age: 63 years, range: 20-97; male (n=47; 66.2%): female (n=24; 33.8%)] who were enrolled in the study, 46 (64.8%) patients had 25(OH)D levels ≤20 ng/ml and 25 (35.2%) had a level >20 ng/ml. According to the patients' medical history, 55 patients (77.5%) had comorbidities. It appears that vitamin D deficiency (<20 ng/ml) significantly correlated with elevated biochemical markers such as procalcitonin and troponin (p<0.001). Moreover, male gender, advanced age (>60 years), and comorbidities were positively associated with more severe COVID-19 infection (elevated inflammation markers, radiographic findings on X-rays, and increased length of hospital stay). ConclusionThese preliminary findings show that vitamin D status among the patients was not related to the severity of COVID-19 infection.

The bounds of meta-analytics and an alternative method

“…A meta-analysis is performed in sequential steps. As exemplified by research aiming to establish the impact of vitamin D on protecting patients from coronavirus disease 2019 (COVID-19) [ 3 - 23 ], the steps include focusing on establishing research questions, formulating the population, conducting a literature search for published results, selecting published studies of appropriate quality, and evaluating whether the summary measures in studies are comparable, whether the model to integrate the studies should involve fixed or random effects, and whether the heterogeneity among the study populations is acceptable in order for the findings of the meta-analysis to yield meaningful insights into the issue at hand.…”