Red cell distribution width (RDW) values are associated with risk for fracture in older men, particularly those with anemia, according to study results published in the Journal of Bone and Mineral Research.
RDW is associated with many adverse age-related health outcomes. Using data from participants in the Osteoporotic Fractures in Men (MrOS) study, researchers aimed to identify whether RDW is also associated with incident fracture risk.
Fasting blood sample data were available for 3635 men (mean age, 79.1 years), who composed the study population. Complete blood counts were measured, for which RDW is a routine parameter. Hemoglobin levels were also measured and used to identify individuals with anemia (hemoglobin concentration <13.0 g/dL). The occurrence of fractures and falls was assessed at 4-month intervals.
Over the course of follow-up (median duration, 8.1 years), 164 men experienced hip fracture. The risk for fracture increased with higher RDW values, and men with the highest RDW values (≥15.1%) were at a 2.3-fold greater risk (95% CI, 1.1-4.7; P <.05) for hip fractures than those with the lowest values (≤13.0%). A significant interaction was found between anemia and RDW (P =.006), so individuals were subsequently stratified by anemia status. The risk for hip fracture in men with anemia was greater than in those without (hazard ratio [HR], 2.6; 95% CI, 1.9-3.6), but risk for fracture still increased along with RDW values in men without anemia (P =.02).
At least 1 clinical fracture occurred 701 men during the follow-up period. Risk for falls (P <.001) and clinical fracture (P =.01) both increased with higher RDW values. The highest RDW values were associated with a 1.8-fold increased risk (95% CI, 1.3-2.5) for clinical fractures compared with the lowest values. No interaction was observed between anemia and RDW values in analyses of risk for clinical fracture or falls.
The researchers noted that the MrOS cohort is made up of predominantly older white men, which may limit the generalizability of results to other groups.
“As RDW and hemoglobin are part of [the complete blood count] that is most commonly performed in health screening and medical care, the vast majority of adults will have RDW and hemoglobin values in their medical records,” the study authors noted. “Therefore, future research is needed to determine the clinical utility of these simple [measures] in fracture prediction.”
Kim KM, Lui LY, Cauley JA, et al. Red cell distribution width is a risk factor for hip fracture in elderly men without anemia [published online January 28, 2020]. J Bone Miner Res. doi:10.1002/jbmr.3963