Post-fracture Prescribed Calcium and Vitamin D Supplements Alone Or, in Females, with Concomitant Anti-osteoporotic Drugs is Associated with Lower Mortality in Elderly Hip Fracture Patients: a Prospective Analysis

Background: Several studies have shown excess mortality among hip fracture patients compared with the normal population of the same age. Finnish guidelines for medical treatment of hip fracture patients recommend anti-osteoporosis medication and the daily concomitant use of prescribed calcium and vitamin D supplements. However, whether post-fracture use of calcium and vitamin D supplements is associated with survival in such patients has not been evaluated.

Objective: To study the association between survival in hip fracture patients and patients' sex and age, pre-fracture vitamin D status, American Society of Anesthesiologists - Physical Status (ASA-PS) class, type of fracture and post-fracture use of prescribed calcium plus vitamin D and anti-osteoporotic medication.

Methods: The study population was 221 hip fracture patients primarily treated in acute care for a new hip fracture in 2003-4 in two Finnish hospitals. After a median of 27.5 months from the fracture, a questionnaire was sent to all patients who were still alive at the time (n = 137). The patients were queried about their use of prescribed calcium plus vitamin D supplementation and of anti-osteoporotic drugs. The follow-up time for use of anti-osteoporotic medication and prescribed calcium and vitamin D was 19.5-36 months (median 27.5 months). Data on the use of prescribed calcium plus vitamin D supplementation and anti-osteoporotic drugs were checked against information on reimbursement of drug prescriptions held by the Finnish Social Insurance Institution. A total of 4 years' (48 months') survival data for all patients in the study population was also obtained, with the dates of patient deaths being checked against Official National and Regional population statistics. Patient survival was analysed using both the Bayesian multivariate analysis and the life table method.

Results: In the multivariate analysis, the combination of variables that best explained post-fracture survival was as follows: age <80 years; ASA-PS class 1-2 (ASA-PS class 1 and 2 data were combined in calculations); post-fracture use of prescribed calcium plus vitamin D supplements concomitantly with anti-osteoporotic drugs; post-fracture use of prescribed calcium plus vitamin D supplements; post-fracture use of anti-osteoporotic drugs only; and type of fracture (femoral neck or subtrochanteric). This model correctly predicted 74% of cases. At 36 months, we observed a 36% reduction in deaths in females who used prescribed calcium plus vitamin D supplementation and a corresponding 43% reduction in males. Survival of females who used anti-osteoporotic drugs concomitantly was even greater (43% reduction in deaths) over the entire follow-up period. Excess mortality was highest in females and males who used neither anti-osteoporotic drugs nor prescribed calcium and vitamin D.

Conclusion: Our results indicate a potential relationship between reduced mortality and post-fracture use of prescribed calcium plus vitamin D supplementation and, in females, concomitant use of anti-osteoporotic drugs. However, further investigations are needed to understand the reason for the reduction in the risk of death. Population-based, randomized, placebo-controlled trials with total mortality as the main endpoint should be conducted to verify our results.