Can frailty in conjunction with FRAX identify additional women at risk of fracture - a longitudinal cohort study of community dwelling older women

Abstract

Abstract Background Fracture risk assessment is still far from perfect within the geriatric population. The overall aim of this study is to better identify older women at risk for fractures, using a quantitative measure of frailty in conjunction with the web-based Fracture Risk Assessment Tool (FRAX®). Methods This study was performed in the Osteoporosis Risk Assessment (OPRA) cohort of n = 1023, 75-year-old women followed for 10-years. A frailty index (FI) of ‘deficits in health’ was created, and FRAX 10-year probability for major osteoporotic and hip fractures was calculated and bone mineral density measured. Incident fractures were continuously registered for 10-years. Receiver Operating Characteristic (ROC) curves were used to compare FI, FRAX and the combination FI + FRAX as instruments for risk prediction. Discriminative ability was estimated by comparing Area Under the Curve (AUC). In addition, using guidelines from the Swedish Osteoporosis Foundation, a category of low risk women who would not have been recommended for pharmacological treatment (non-treatment group) was identified, categorized by frailty status and for relative risk analysis, hazard ratios (HR) and 95% confidence intervals were calculated using Cox proportional hazard regressions. Results For hip fracture, FRAX and frailty performed almost equally (HIP AUC 10y: 0.566 vs. 0.567, p = 0.015 and p = 0.013). Next, FI was used in conjunction with FRAX; proving marginally better than either score alone (AUC 10y: 0.584, p = 0.002). Comparable results were observed for osteoporotic fracture. In the non-treatment group (564 women), being frail was associated with higher 10y hip fracture risk (HR 2.01 (1.13–3.57)), although failing to reach statistical significance for osteoporotic fracture (HR 1.40 (0.97–2.01). The utility of measuring frailty was also demonstrated when using T-score as an index of bone density to define fracture risk. Among n = 678 non-osteoporotic women, frailty added to the 10-year fracture risk (Hip; HR 2.22 (1.35–3.71); Osteoporotic fracture; HR 1.57 (1.15–2.14)). Conclusions While the addition of frailty to FRAX marginally improved fracture prediction, applying a frailty measurement to a group of ‘low risk’ women, identified a set of individuals with high actual hip fracture risk that would not be prioritized for pharmacological treatment. Further cost-benefit analysis studies are needed to formally test potential benefit.