HbA_1c Associated With HF With Recovered Ejection Fraction in Type 2 Diabetes

Patients with type 2 diabetes mellitus (T2DM) who develop heart failure (HF), especially HF with ischemic etiology, are less likely to have subsequent partial or complete recovery of ejection fraction (HFrecEF) if they have uncontrolled hemoglobin A_1c (HbA_1c). These findings were published in the International Journal of Cardiology.

Researchers in China aimed to evaluate the relationship between the occurrence of HFrecEF and glycemic control among patients hospitalized with HF with reduced left ventricular (LV)EF (HFrEF) and comorbid T2DM.

They conducted a retrospective cohort study in Shanghai Ruijin Hospital, Shanghai, China, that included 557 consecutive patients with T2DM hospitalized between January 2011 and December 2019 with HFrEF. There were 463 patients in the analysis after exclusion criteria, including heart transplantation, malignant tumor, renal failure requiring hemodialysis, and patients lacking HbA_1c measurements at admission, were applied. Patients were classified as having HFrecEF (second EF measurement of >40% and absolute EF improvement of ≥10%) or persistent HFrEF based on a follow-up echocardiogram at approximately 12 months.

Patients were divided into 3 cohorts based on HbA_1c level tertiles and researchers noted those with higher levels also had higher fasting glucose and triglyceride levels and more frequent ischemic etiology. The cohorts were similar for other demographics and characteristics (sex, age, blood pressure, cholesterol and N-terminal pro b-type natriuretic peptide levels, renal function, smoking, BMI, and history of hypertension).

At the 12-month follow-up, researchers found that 44.5% of patients developed HFrecEF. These patients had significantly lower HbA_1c levels (6.5% [IQR, 5.8%-7.2%]) compared with patients with persistent HFrEF (6.7% [IQR, 6.1%-7.8%]; P =.003). Only patients in the ischemic subgroup had lower HbA_1c levels with HFrecEF vs patients with persistent HFrEF (6.5% [IQR, 5.8%-7.6%] vs 6.8% [IQR, 6.1%-8.0%]; P =.018) rather than patients with nonischemic etiology (6.5% [IQR, 5.9%-7.0%] vs 6.6% [IQR, 6.1%-7.4%]; P =.172).

The researchers noted that EF recovered from 33.3%±5.8% to 42.8%±10.5% in the overall population at 12 months (P <.001). They found a stepwise decrease in LVEF recovery across the 3 HbA_1c tertiles (11.33%±10.66% vs 9.57%±9.91% vs 7.81%±9.32%; P =.008).

The researchers discovered an inverse correlation between HbA_1c levels and changes in EF at follow-up. Every 1% HcA_1c increase resulted in a 17.4% lower likelihood of HFrecEF (odds ratio [OR], 0.826; 95% CI, 0.701-0.968) after multivariate adjustment. They observed that patients with poor glycemic control (HbA_1c, >7.1%) had a 52.0% decreased likelihood of HFrecEF (OR, 0.480; 95% CI, 0.281-0.811) compared with patients with good glycemic control (HbA_1c ≤6.2%).

Study limitations include the retrospective observational design and that the data are from a single center. There was also selection bias and the sample size was underpowered.

 “…uncontrolled HbA_1c levels are associated with compromised development of HFrecEF in T2DM patients with HF, especially in those with an ischemic etiology,” the study authors wrote.