Home-based cardiac rehabilitation decreases red cell distribution width in chronic heart failure

Objective Red cell distribution width (RDW) is a measure of variation in the volume of circulating erythrocytes and has recently emerged as a powerful prognostic marker in heart failure. We studied the effect of 5-month, home-based cardiac rehabilitation on RDW. Methods and results Sixty-two patients (age: median 67 years, IQR 63-74) with chronic heart failure caused by reduced left ventricular systolic function were enrolled. Exercise time and physical activity levels out of the hospital were determined by a single-axial accelerometer. Baseline RDW values were: median 13.6, IQR 12.8-14.4%, with 13 patients (21.0%) showing values above the upper normal limit. RDW values were decreased significantly after training in the 13 patients with elevated baseline RDW values (P < 0.01), but not in the remaining 49 patients with normal baseline RDW values. There was a highly significant correlation between baseline RDW and changes in RDW after exercise training (P = 0.0001, r(2) = 0.628, n = 62). The time spent for moderate (> 3 METs) exercise was: median 9.0, IQR 3.0-18.8 minutes per day. Conclusions Relatively low intensity, home-based cardiac rehabilitation was associated with decreased RDW in heart failure patients with abnormal RDW.