Fragility fractures and imminent fracture risk in Hong Kong: one of the cities with longest life expectancies.

Introduction: Imminent fracture risk, or fractures within 2 years of an initial fracture, is a pressing issue worldwide. Hong Kong is a city with one of the longest life expectancies. The concern of fragility fractures and the imminent risk of a subsequent fracture is becoming a top priority. The objective of this study was to present the epidemiology of incident fragility fractures of all public acute hospitals and the imminent risk of a subsequent fracture in Hong Kong.

Methodology: This was a retrospective population-based analysis. Patient records from all acute hospitals in Hong Kong from 1 January 2004 to 31 December 2018 were retrieved for patients ≥ 50 years of age with hip, distal radius, or proximal humerus fractures. Secondary fractures and falls were identified in the subsequent 5 years. Post hoc analysis in recent 2013-2018 period was performed. Overall survival (re-fracture incidence) on age subgroups using Kaplan survival analysis and variables was compared using the log-rank test. Cox proportional hazard regressions, obtaining the hazard ratios (HR) and their respective 95% confidence intervals (CI), were used.

Results: There is an overall increasing trend of fragility fractures (hip, distal radius, proximal humerus) from 5596 in 2004 to 8465 in 2018. The average cumulative imminent risk of fractures from recent 5 years is 3.87% at 1 year and 6.50% at 2 years. 49.5% of the patients with a secondary fracture occurred within 2 years since the initial major fragility fracture. Post hoc analysis in recent 2013-2018 period (N = 7039) showed male patients were 1.21 times more likely to have further fractures with time (HR = 1.21 (1.02, 1.45), p = 0.03) compared with female patients. Patients over age 95 were 2.01 times higher than patients of age under 75 to have further fracture over time.

Conclusions: Following an initial fracture, prompt treatment strategies should be adopted to avoid imminent risk of fractures. This window of opportunity in the first 2 years is a golden period to treat osteoporosis and prevent falls. Our post hoc analysis has shown that male patients and patients older than 95 are at even higher risk. Clinicians and allied healthcare professionals should be alert on these patients.