The Fracture Risk Assessment Tool (FRAX®) predicts fracture risk in patients with chronic kidney disease

The Fracture Risk Assessment Tool (FRAX®) was developed to predict fracture risk in the general population, but its applicability to patients with chronic kidney disease (CKD) is unknown. Using the Manitoba Bone Mineral Density (BMD) Database, we identified adults not receiving dialysis with available serum creatinine measurements and bone densitometry within 1 year. Estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. Incident major osteoporotic fractures and hip fractures were ascertained from population-based health care databases. The performance of FRAX, derived without and with BMD, was studied in relation to CKD stage. Among 10,099 subjects (mean age 64 ± 13 years, 13.0% male), 2,154 had eGFR 30-60 mL/min/1.73 m2 (CKD stage 3) and 590 had eGFR <30 mL/min/1.73 m2 (CKD stages 4-5). During a 5-year observation period, 772 individuals experienced a major osteoporotic fracture and 226 had a hip fracture. FRAX predicted risk for major osteoporotic fracture and hip fracture in all eGFR strata. For every standard deviation increase in FRAX score derived with BMD, the hazard ratio (HR) for hip fracture was 4.54 (95% confidence interval [CI] 3.57-5.77) in individuals with eGFR ≥ 60 mL/min/1.73m2, 4.52 (95% CI 3.15-6.49) in individuals with eGFR 30-60 mL/min/1.73m2, and 3.10 (95% CI 1.80-5.33) in individuals with eGFR <30 mL/min/1.73m2. The relationship between FRAX and major osteoporotic fracture was stronger in those with CKD compared to those with preserved eGFR. These findings support the use of FRAX to risk stratify patients with non-dialysis CKD for major osteoporotic fractures and hip fractures.