The Association between Vitamin D Deficiency and the Risk of Mortality after Hip Fractures: A Systematic Review and Meta-Analysis.

Prevalence of hip fractures is on the rise and is associated with high mortality, especially in aging patients. Vitamin D is routinely recommended for bone health in general population. Our study explores the potential association between low levels (≤20 ng/mL) of vitamin D and mortality in hip fracture patients. Systematic search was done for studies that were published from inception until May 10, 2023, and that report a possible correlation between low vitamin D levels and mortality in patients with hip fractures. A random-effects model was used to assess the effects of normal vitamin D levels on mortality, subgroup analyses were conducted to assess the link between low levels of vitamin D and geographic location of the study and its impact on the recovery process. In 575 identified studies, 18 met the inclusion criteria. A strong connection between low serum levels of vitamin D (<20 ng/mL) and mortality (hazard ratio (HR): 2.29, p<0.001). Further analysis indicated that insufficient (20 to 30 ng/mL) and sufficient (>30 ng/mL) levels of vitamin D levels did not have a significant association with the mortality (HR: 1.10, p=0.12), and (HR: 1.04, p=0.50). As shown by subgroup analysis vitamin D deficiency significantly correlated with mortality in studies conducted in Europe (HR: 2.4). Our results clearly demonstrate that vitamin D deficiency is associated with higher risk of mortality in hip fracture patients. Additional analyses demonstrate that insufficient and sufficient levels of vitamin D were not significantly associated with mortality outcomes in hip fracture patients.