Performance of FRAX in older adults with frailty: the Framingham Heart Study

We compared the performance of FRAX according to frailty status in 3554 individuals from the Framingham Study. During 10-year follow-up, 6.9% and 3.0% of participants with and without frailty experienced MOF. Discrimination profiles were lower in participants with frailty compared to those without, but they improved when FRAX included BMD.

INTRODUCTION

Frailty increases fracture risk. FRAX was developed to predict fractures but never validated in individuals with frailty. We aimed to compare the predictive performance of FRAX (v4.3) in individuals with and without frailty.

METHODS

We conducted a cohort study using the Framingham Heart Study. Frailty was defined by the Fried phenotype. Major osteoporotic fractures (MOF) were ascertained from medical records during 10-year follow-up. To evaluate discrimination and calibration of FRAX, we calculated the area-under-the-receiver-operating characteristics curves (AUC) using logistic regression models and observed-to-predicted fracture probabilities. Analyses were stratified by frailty status.

RESULTS

Frailty was present in 550/3554 (15.5%) of participants. Participants with frailty were older (81.1 vs. 67.6 years), female (68.6% vs. 55.1%), and had greater mean FRAX scores (MOF: 15.9% vs. 10.1%) than participants without frailty. During follow-up, 38 participants with frailty (6.9%) and 91 without (3.0%) had MOFs. The AUC for FRAX (without BMD) was lower in participants with frailty (0.584; 95% CI 0.504-0.663) compared to those without (0.695; 95% CI 0.649-0.741); p value = 0.02. Among participants with frailty, the AUC improved when FRAX included BMD (AUC 0.658, p value < 0.01). FRAX overestimated MOF risk, with larger overestimations in individuals without frailty. Performance of FRAX for hip fracture was similar.

CONCLUSION

FRAX may have been less able to identify frail individuals at risk for fracture, as compared with individuals without frailty, unless information on BMD is available. This suggests that BMD captures features important for fracture prediction in frail persons. Future fracture prediction models should be developed among persons with frailty.

Osteoporosis Medications Prevent Subsequent Fracture in Frail Older Adults

Frailty is common in older adults with fractures. Osteoporosis medications reduce subsequent fracture, but limited data exist on medication efficacy in frail individuals. Our objective was to determine whether medications reduce the risk of subsequent fracture in frail, older adults. A retrospective cohort of Medicare fee-for-service beneficiaries was conducted (2014-2016). We included adults aged ≥65 years who were hospitalized with fractures without osteoporosis treatment. Pre-fracture frailty was defined using claims-based frailty index (≥0.2 = frail). Exposure to any osteoporosis treatment (oral or intravenous bisphosphonates, denosumab, and teriparatide) was ascertained using Part B and D claims and categorized according to the cumulative duration of exposure: none, 1-90 days, and >90 days. Subsequent fractures were ascertained from Part A or B claims. Cause-specific hazard models with time-varying exposure were fit to examine the association between treatment and fracture outcomes, controlling for relevant covariates. Among 29,904 patients hospitalized with fractures, 15,345 (51.3%) were frail, and 2148 (7.2%) received osteoporosis treatment (median treatment duration 183.0 days). Patients who received treatment were younger (80.2 versus 82.2 years), female (86.5% versus 73.0%), and less frail (0.20 versus 0.22) than patients without treatment. During follow-up, 5079 (17.0%) patients experienced a subsequent fracture. Treatment with osteoporosis medications for >90 days compared with no treatment reduced the risk of fracture (hazard ratio [HR] = 0.82; 95% confidence interval [CI] 0.68-1.00) overall. Results were similar in frail (HR = 0.85; 95% CI 0.65-1.12) and non-frail (HR = 0.80; 95% CI 0.61-1.04) patients but not significant. In conclusion, osteoporosis treatment >90 days was associated with similar trends in reduced risk of subsequent fracture in frail and non-frail persons. Treatment rates were very low, particularly among the frail. When weighing treatment options in frail older adults with hospitalized fractures, clinicians should be aware that drug therapy does not appear to lose its efficacy. © 2022 American Society for Bone and Mineral Research (ASBMR).