Impact of vitamin D deficiency on mortality in patients with hip fracture: A meta-analysis

Background: Vitamin D deficiency has been linked to numerous health issues, including an increased risk of hip fractures. This meta-analysis aimed to investigate the relationship between vitamin D deficiency and mortality in patients with hip fracture. To assess the impact of different levels of vitamin D deficiency on mortality in patients with hip fractures and examine the influence of potential confounding factors.Methods: A systematic search of PubMed, EMBASE, Scopus, and Cochrane Collaboration Library was conducted, resulting in nine eligible cohort studies (n = 4409). Patients with hip fractures were categorized based on their vitamin D levels as severe, moderate, or insufficient. Mortality was the primary outcome measure in this study. Subgroup analyses were performed according to the follow-up time. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using a random-effects model in Review Manager 5.4.Results: Nine studies, with a pool of 4409 patients, were included. Vitamin D insufficiency was significantly associated with increased mortality (OR 1.24, 95% CI 1.05-1.46; I-2 = 4%). Severe deficiency also led to a significant increase in mortality (OR 2.08, 95% CI 1.09-3.97; I-2 = 42%), whereas moderate deficiency did not show a significant effect (OR 1.06, 95% CI 0.79-1.44; I-2 = 0%). Subgroup analysis revealed significant associations between vitamin D insufficiency and increased mortality at 1-year (OR 1.37, 95% CI 1.06-1.77) and 2-year follow-ups (OR 1.78, 95% CI 1.01-3.15). After adjusting for potential confounders, no significant increase in the mortality rate was observed.Conclusions: This meta-analysis suggests that vitamin D insufficiency and severe deficiency are associated with increased mortality in patients with hip fracture. However, after adjusting for confounding factors, this association was not statistically significant. Further research is necessary to understand the role of vitamin D deficiency in this population.