Introduction: Role of vitamin D status in osteoporotic fractures remains controversial; its effect on outcomes poorly defined.
Objectives: To assess in older hip fracture (HF) patients temporal trends in vitamin D status at admission and in-hospital mortality over a 20-year period (1999-2019).
Methods: Data on sociodemographic, clinical and laboratory parameters, including admitting 25-hydroxyvitamin D [25(OH)D] levels, and outcomes were collected prospectively from 3719 consecutive HF patients (mean age 82.8±8.1[SD] years; 76.4% females; 53.4% with cervical HF). Patients were stratified according to 25(OH)D levels: vitamin D deficiency (<25 nmol/L), moderate (25-50 nmol/L) and mild insufficiency (50-75 nmol/L). Trends were assessed in five 4-year periods using Poisson regression; models were adjusted for age, gender and various pre-fracture chronic conditions.
Results: Over 20 years, mean 25(OH)D levels increased by 68.4% (from 37.0 nmol/L in 1999-2002 to 62.3 nmol/L in 2015-2018), while post-operative in-hospital mortality rates decreased by 23.9% (from 6.7% to 5.1%, respectively). Every 4-year the prevalence of vitamin D deficiency decreased (age and gender adjusted) on average by 40% (incidence rate ratio [IRR] 0.60, 95% confidence interval [CI] 0.55-0.64, p<0.001), prevalence of moderate vitamin D insufficiency decreased by 27% (IRR 0.73, 95%CI, 0.69-0.76, p<0.001) and the mortality rate declined by 14% (IRR 0.86, 95%CI, p=0.031). Regression analysis demonstrated significant inverse relationship between low admission 25(OH)D levels and fatal outcome. Adjustment for pre-existing conditions including dementia, cardiovascular, lung, Parkinson’s disease and diabetes (prevalence of each increased or unchanged), chronic kidney disease (decreased) and HF type did not appreciably explain declining mortality rates. Only vitamin D deficiency, elevated PTH levels (>6.8 pmol/L) along with advanced age and male gender were significantly associated with in-hospital death in multivariate regression analysis.
Conclusions: Over the last decades, in HF patients the prevalence of altered vitamin status and mortality rates are decreasing. Vitamin D deficiency is a significant independent determinant of fatal outcome. Further research is suggested to evaluate the effect of vitamin D supplementing on outcomes.