Bone Mineral Density and Fracture Risk in Older Individuals with CKD

Abstract

Kidney Disease Improving Global Outcomes guidelines recommend against bone mineral density (BMD) screening in CKD patients with mineral bone disease, due to a lack of association of BMD with fractures in cross-sectional studies in CKD. We assessed whether BMD is associated with fractures in participants with and without CKD in the Health, Aging, and Body Composition study, a prospective study of well functioning older individuals. Hip BMD was measured by dual-energy x-ray absorptiometry. Osteoporosis was defined as a femoral neck BMD (FNBMD) T score below -2.5 and CKD as an estimated GFR <60 ml/min per 1.73 m(2). The association of BMD with incident nonspine, fragility fractures to study year 11 was analyzed using Cox proportional hazards analyses, adjusting for age, race, sex, body mass index, hyperparathyroidism, low vitamin D level, and CKD. Interaction terms were used to assess whether the association of BMD with fracture differed in those with and without CKD. There were 384 incident fractures in 2754 individuals (mean age 73.6 years). Lower FNBMD was associated with greater fracture, regardless of CKD status. After adjustment, the hazard ratios (95% confidence intervals) were 2.74 (1.99, 3.77) and 2.15 (1.80, 2.57) per lower SD FNBMD for those with and without CKD, respectively (interaction P=0.68), and 2.10 (1.23, 3.59) and 1.63 (1.18, 2.23) among those with osteoporosis in patients with and without CKD, respectively (interaction P=0.75). BMD provides information on risk for fracture in older individuals with or without moderate CKD.