Glycated Hemoglobin Variability Is Associated With Adverse Outcomes in Patients With Heart Failure Irrespective of Diabetic Status

Background The effect of glycated hemoglobin (HbA1c) variability on adverse outcomes in patients with heart failure (HF) is unclear. We aim to investigate the predictive value of HbA1c variability on the risks of all‐cause death and HF rehospitalization in patients with HF irrespective of their diabetic status. Methods and Results Using a previously validated territory‐wide clinical data registry, HbA1c variability was assessed by average successive variability (ASV) or SD of all HbA1c measurements after HF diagnosis. Multivariable Cox proportional hazards models were used to estimate the adjusted hazard ratio (HR) and its corresponding 95% CI. A total of 65 950 patients with HF were included in the study. Over a median follow‐up of 6.7 (interquartile range, 4.0–10.6) years, 34 508 patients died and 52 446 required HF rehospitalization. Every unit increment of variability in HbA1c was significantly associated with higher HF rehospitalization (HR ASV, 1.20 [95% CI, 1.18–1.23]) and all‐cause death (HR ASV, 1.50 [95% CI, 1.47–1.53]). Diabetes significantly modified the association between HbA1c variability and outcomes (Pinteraction