Low bone mineral density and fractures in stages 3-5 CKD: an updated systematic review and meta-analysis

The utility of bone mineral density (BMD) testing in chronic kidney disease (CKD) is not known. We performed a meta-analysis of studies reporting on BMD and fracture in CKD. All but one study was cross-sectional. BMD was lower in those with CKD and fractures compared to those without fractures. CKD is associated with an increased risk of fracture. The utility of dual energy X-ray absorptiometry (DXA) to assess fracture risk in CKD is unknown. We performed an updated meta-analysis and systematic review of published studies that reported on the association between DXA and fracture (morphometric spine or clinical nonspine) in predialysis and dialysis CKD. We identified 2,894 potential publications, retrieved 292 for detailed review, and included 13. All but one study was cross-sectional and three reported on the ability of DXA to discriminate fracture status in predialysis CKD. Results were pooled using a random effects model and statistical heterogeneity was assessed using the I (2) statistic. BMD was statistically significantly lower at the femoral neck, lumbar spine, the 1/3 and ultradistal radius in subjects with fractures compared to those without regardless of dialysis status. For example, femoral neck BMD was 0.06 g/cm(2) lower in dialysis subjects and 0.102 g/cm(2) lower in predialysis subjects with fractures compared to those without. Lumbar spine BMD was 0.05 g/cm(2) lower in dialysis subjects and 0.108 g/cm(2) lower in predialysis subjects with fractures compared to those without. Our meta-analysis was limited to studies with small numbers of subjects and even smaller numbers of fractures. All of the studies were observational and only one was prospective. There was statistical heterogeneity at the lumbar spine, 1/3 and ultradistal radius. Our findings suggest that BMD can discriminate fracture status in predialysis and dialysis CKD. Larger, prospective studies are needed.