25-hydroxyvitamin D levels in the early healing of osteoporotic hip fracture and their relationship with clinical outcome

Introduction: vitamin D is involved in recovery after an osteoporotic hip fracture (OHF). Previous studies have reported decreased serum vitamin D levels during fracture healing. Objectives: our aim was to evaluate: a) serum 25-hydroxyvitamin D3 (25OHD3) levels in patients with OHF at hospital admission and 8 days post-admission, and b) the relationship between 25OHD levels and clinical outcomes. Methods: a prospective study including 66 patients aged over 65 years hospitalized for OHF. We gathered data on baseline demographic characteristics, medical history, Mini Mental State (MMS) assessment, Activities of Daily Living (ADL) results, nutritional assessment, and type of fracture and surgery. Laboratory results were collected on bone biomarkers, albumin, 25OHD3, and IL6. Clinical outcomes included length of stay, complications, and mortality. In the statistical analysis, a t-test was used for continuous variables and a chi-square test for qualitative variables. Linear regression models were used for the multivariate analysis, adjusted for covariates. Results: our study population had low serum vitamin D levels at admission, with a mean [(standard error of the mean (SEM)] of 12.04 (1.03) ng/mL. Both 25OHD3 and interleukin 6 (IL-6) levels significantly declined (p < 0.001) during the early post-fracture phase. A greater decline in 25OHD3 levels was significantly associated with longer hospital stay (p = 0.042, multivariate analysis). Serum 25OHD3 levels were also associated with cognitive status as assessed using the MMS exam. Conclusions: 25OHD3 levels were reduced in OHF patients at admission, and significantly decreased during the first 8 days post-admission. 25OHD3 levels were associated with MMS-assessed cognitive status. A greater decline in serum 25OHD3 was associated with a longer hospital stay.