Fracture prediction from self-reported falls in routine clinical practice: a registry-based cohort study

A Summary A simple question construct regarding number of falls in the previous year, ascertained by a single question, was strongly associated with incident fractures in routine clinical practice using a population-based dual-energy X-ray absorptiometry (DXA) registry. Introduction There is conflicting evidence from research cohorts that falls independently increase fracture risk. We examined the independent effects of falls on subsequent fractures in a large clinical registry of bone mineral density (BMD) results for the Province of Manitoba, Canada that has been systematically collecting self-reported falls information since September 1, 2012. Methods The study population consisted of 24,943 women and men aged 40 years and older (mean age 65.5 +/- 10.2 years) with fracture probability assessment (FRAX), self-reported falls for the previous year (categorized as none, 1, 2, or >= 3) and fracture outcomes. Adjusted hazard ratios (HR) with 95 confidence intervals (CI) for time to fracture were estimated using Cox proportional hazards models. Results During mean observation time of 2.7 +/- 1.0 years, 863 (3.5%) sustained one or more major osteoporotic fractures (MOF), 212 (0.8%) sustained a hip fracture, and 1210 (4.9%) sustained any incident fracture. Compared with no falls in the previous year (referent), there was a gradient of increasing risk for fracture with increasing number of falls (all P < 0.001). Results showed minimal attenuation with covariate adjustment. When adjusted for baseline fracture probability (FRAX score with BMD) the HR for MOF increased from 1.49 (95% CI 1.25-1.78) for one fall to 1.74 (1.33-2.27) for two falls to 2.62 (2.06-3.34) for >= 3 falls. HRs were similar for any incident fracture and slightly greater for prediction of hip fracture, reaching 3.41 (95% CI 2.19-5.31) for >= 3 previous falls. Conclusions Self-report number of falls in the previous year is strongly associated with incident fracture risk in the routine clinical practice setting, and this risk is independent of age, sex, BMD, and baseline fracture probability. Moreover, there is dose-response with multiple falls (up to a maximum of 3) conferring greater risk than a single fall.