Red cell distribution width (RDW), a measure of the amount of variability in the size of red blood cells, is routinely assessed in blood counts and may accurately predict risk for hip fracture, according to study results presented at the American Society for Bone and Mineral Research 2019 Annual Meeting, held September 20 to 23 in Orlando, Florida.
Previous studies have reported that increased RDW may predict mortality, cardiovascular disease, and many aging-related diseases. The goal of the current study was to assess whether this measure can aid in identifying patients at high risk for hip fracture.
The study cohort included 3635 men (aged 71-99 years) participating in the Osteoporotic Fractures in Men Study with available femoral neck bone mineral density (BMD) data. The RDW levels were classified into percentiles (<10, 10-25, 26-75, 76-90, or >90) and the risk for hip fracture was assessed by percentile RDW. Furthermore, the researchers used receiver operating characteristic curves to assess the accuracy of RDW plus age or RDW plus age and BMD in identifying men who would have incident hip fracture.
Over an average follow-up of 8.1 years, the researchers identified 164 hip fractures. Higher percentile RDW was found to be a strong predictor of hip fracture, with a hazard ratio of 2.8 (95% CI, 1.3-5.9) for high (top 10 percentile; ≥15.7%) vs low RDW level (lowest 10 percentile; ≤13.0%). There was no correlation between femoral neck BMD and RDW (r=0.02).
The accuracy of a combination of RDW plus age for fracture prediction was similar to that of the osteoporosis risk assessment score FRAX. The combination of RDW with age and BMD (area under the curve, 0.76; 95% CI, 0.73-0.80) predicted hip fracture more accurately than FRAX plus BMD (area under the curve, 0.71; 95% CI, 0.67-0.74; P <.001).
“RDW is a simple, universal, and powerful measure to identify those at high risk of hip fracture,” concluded the researchers.
Kim KM, Lui LY, Cauley J, et al. Red cell distribution (RDW), a widely available simple measure of cell aging, strongly predicts hip fracture. Presented at: American Society for Bone and Mineral Research 2019 Annual Meeting; September 20-23, 2019; Orlando, FL. Abstract 1069.