Non-cardiac factors for prediction of response to cardiac resynchronization therapy: The value of baseline, and of serial changes, in red cell distribution width

Background Increased red blood cell distribution width (RDW) has been associated with poor outcome after cardiac resynchronization therapy (CRT). However, whether baseline RDW, and its serial changes after CRT implant, have incremental prognostic value is unknown. Methods and results In 148 consecutive patients (age, 68±9years; 122 men) undergoing CRT, RDW was assessed before and 3months after implant. Patients were categorized according to baseline RDW (≤14.5% vs >14.5%); and as "stable", "decreased", "increased", relative to post-implant changes. Primary end-point was a composite of death/HF hospitalization during follow-up (median 21months). A reduction in left ventricular (LV) end-systolic volume by ≥15% at 6-month identified LV reverse remodeling. By multivariable logistic regression analysis "increased" (OR:0.22, 95%CI: 0.07-0.69, P =0.010) and "stable-high" RDW at follow-up (OR: 0.39, 95%CI: 0.17–0.89, P =0.027) showed a lower likelihood to develop LV reverse remodeling, while baseline RDW was no longer predictive of LV remodeling. During follow-up, there were 57 events. Baseline RDW>14.5% (HR: 2.24, 95%CI: 1.05–4.77, P =0.036), "increased" (HR: 2.55, 95% CI: 1.09–5.97, P =0.030) and "stable-high" RDW (HR: 2.95, 95% CI: 1.45–5.99, P =0.003) independently predicted outcome after adjusting for functional improvement after CRT, radial dyssynchrony, BNP, creatinine clearance, and left atrial volume index. However, integrated discrimination improvement and net reclassification improvement were not statistically significant when both baseline RDW and its changes were added to a base predictive model. Conclusion Increased and stable-high values of RDW were independently associated with both LV reverse remodeling and outcome after CRT; however, RDW did not show any incremental predictive value.