Undertreatment of osteoporosis following hip fracture: a retrospective, observational study in Singapore

Undertreatment of osteoporosis after hip fracture increases the risk of death, disability, recurrent osteoporotic fractures, and financial burden. Only half were compliant with osteoporosis medications. Elderly patients were less persistent and compliant to treatment. Denosumab was associated with a higher proportion of days covered by osteoporosis medications than oral bisphosphonates. Purpose The aim of this study was to identify factors that contributed to the initiation of osteoporosis medications following hip fracture as well as the compliance and persistence to osteoporosis medications. Methods Clinical data of 532 patients older than 50 years old admitted for surgical fixation of hip fractures were reviewed. Three hundred forty-seven had sufficient data for analysis after excluding patients with non-fragility fractures. Prescription for any osteoporosis medication in the year following hip fracture as well as compliance to treatment was evaluated. Results Only 40.3% of patients were prescribed with osteoporosis medication within 1 year post-hip fracture. Females (p =0.020) performing dual-energy x-ray absorptiometry scan (p <0.001) and 25 hydroxyvitamin D levels testing post-hip fracture (p <0.027) were independent determinants of increased likelihood of being prescribed with osteoporosis medication. Patients with proportion of days covered (PDC) >= 0.8 (or 80% of days covered in a year) were defined as compliant. Overall, only 49.7% of the patients were compliant with osteoporosis medications. Elderly patients aged 70-79 years (p =0.002) and males (p =0.017) were less persistent with osteoporosis treatment when compared with patients aged < 69 years and females. The compliance was poorer in patients aged 70-79 years (p= 0.026) as compared with those under 69 years of age. Statistically significant difference (p =0.032) was observed between mean PDC of oral bisphosphonates (0.66) and denosumab (0.83). Only 39.3% of patients were persistent with treatment at 1 year. Conclusion Our findings demonstrate the urgent need to increase awareness through a structured protocol of osteoporosis treatment. A multi-disciplinary Fracture Liaison Service should be set up to ensure compliance to osteoporosis medication post-hip fracture.