Perioperative risk factors in patients with a femoral neck fracture - influence of 25-hydroxyvitamin D and C-reactive protein on postoperative medical complications and 1-year mortality

Background: This study examined the association of 25-hydroxyvitamin D (25(OH)D) and C-reactive protein (CRP) with postoperative medical complications and one year mortality of elderly patients sustaining a low-energy cervical hip fracture scheduled for surgery. We hypothesized that vitamin D deficiency and CRP in these patients might be associated with an increased 1-year mortality. Methods: The prospective single-center cohort study included 209 patients with a low-energy medial femoral neck fracture; 164 women aged over 50 years and 45 men aged over 60 years. Referring to 1-year mortality and postoperative medical complications multiple logistic regression analysis including 10 co-variables (age, sex, BMI, ASA, creatinine, CRP, leukocytes hemoglobin, 25(OH) D, vitamin D supplementation at follow-up) was performed. Results: Vitamin D deficiency was prevalent in 87 % of all patients. In patients with severe (< 10 ng/ml) and moderate (10-20 ng/ml) vitamin D deficiency one year mortality was 29 % and 13 %, respectively, compared to 9 % in patients with > 20 ng/ml 25(OH) D levels (p = 0.027). Patients with a mild (CRP 10-39.9 mg/l) or active inflammatory response (CRP = 40 mg/l) showed a higher one year mortality of 33 % and 40 % compared to 16 % in patients with no (CRP < 10 mg/l) inflammatory response (p = 0.002). Multiple logistic regression analysis identified CRP (OR 1.01, 95 % CI 1.00-1.02; p = 0.007), but not 25(OH) D (OR 0.97, 95 % CI 0.89-1.05; p = 0.425) as an independent predictor for one year mortality. 20 % of patients suffered in-hospital postoperative medical complications (i.e. pneumonia, thromboembolic events, etc.). 25(OH) D (OR 0.89, 95 % CI 0.81-0.97; p = 0.010), but not CRP (OR 1.01, 95 % CI 1.00-1.02; p = 0.139), was identified as an independent risk factor. Conclusion: In elderly patients with low-energy cervical hip fracture, 25(OH)D is independently associated with postoperative medical complications and CRP is an independent predictor of one year mortality.