The clinical utility of FRAX to discriminate fracture status in men and women with chronic kidney disease

We assessed the ability of the World Health Organization's fracture risk assessment tool (FRAX), bone mineral density (BMD), and age to discriminate fracture status in adults with pre-dialysis chronic kidney disease (CKD). In adults with CKD, FRAX was able to discriminate fracture status but performed no better than BMD alone. Patients with CKD are at increased risk for fracture but the best method to assess fracture risk is not known. We assessed the ability of the World Health Organization's FRAX, compared with BMD at the femoral neck (FN), and age to discriminate fracture status (prevalent clinical nonspine and/or morphometric vertebral) in men and women, 18 years and older with pre-dialysis CKD. Results are presented as area under receiver operator characteristic curves (AUC) with 95 % confidence intervals (CI). We enrolled 353 subjects; mean age was 65 +/- 14 years; weight was 79 +/- 18 kg, and estimated glomerular filtration rate was 28 ml/min/1.73 m(2). About one third of the subjects had a prevalent clinical nonspine and/or morphometric vertebral fracture. FRAX was able to discriminate among those with prevalent clinical nonspine fractures (AUC, 0.72; 95 % CI, 0.65-0.78), morphometric vertebral fractures (AUC, 0.66; 95 % CI, 0.59-0.73), and any fracture (AUC, 0.71; 95 % CI, 0.65-0.77). The discriminative ability of BMD at the FN alone was similar to FRAX for morphometric vertebral and any fractures; FRAX performed better than BMD for prevalent clinical nonspine fractures (AUC for BMD alone, 0.66; 95 % CI, 0.60-0.73). Compared to FRAX, the AUC for age alone was lower for all fracture types. Among men and women with CKD, FRAX is able to discriminate fracture status but performs no better than BMD alone.