Impact of low cardiac function and diabetes mellitus on survival and causes of death following coronary artery surgery

TL;DR

The study finds that low heart function and diabetes worsen survival after heart surgery and increase specific causes of death.

Contribution

The study identifies distinct survival outcomes and causes of death associated with low cardiac function and diabetes after CABG.

Findings

Patients with EF ≤ 35% and diabetes had the worst 10-year survival (53.5%) after CABG.

Diabetes was linked to higher risk of death from cancer and pneumonia.

Low ejection fraction was strongly associated with death from heart failure.

Abstract

To determine the differential impact of low cardiac function (ejection fraction [EF] ≤ 35%) and diabetes mellitus (DM) on survival and to identify causes of death after coronary artery bypass grafting (CABG).

Overall, 1036 patients who underwent isolated CABG between 2009 and 2022 were divided into four groups based on EF and DM. Kaplan–Meier analysis was performed to calculate each group’s estimated survival. Inter-group multivariate Cox regression was performed with the reference group showing EF > 35% and DM (−). Additional Cox regressions were performed to investigate the associations of EF ≤ 35% and DM (+) with death from heart failure, myocardial infarction, cancer, pneumonia, cerebrovascular disease and renal failure.

Off-pump techniques were used in 980 patients (95%). Patient population and estimated 10-year postoperative survival were as follows: EF > 35% DM (−), 430, 75.1%; EF > 35% DM (+), 456, 66.3%; EF ≤ 35% DM (−), 73, 62.5%; and EF ≤ 35% DM (+), 77, 53.5%. Hazard ratios (HRs) (P values) for the three groups were as follows: EF > 35% DM (+), 1.53 (0.006); EF ≤ 35% DM (−), 1.84 (0.017); and EF ≤ 35% DM (+), 2.23 (0.001). For death from heart failure, HR (P value) for EF ≤ 35% versus EF > 35% was 3.62 (0.012). For deaths from cancer and pneumonia, HRs (P values) for DM (+) versus DM (−) were 1.73 (0.097), and 2.72 (0.046), respectively.

EF ≤ 35% and DM (+) are associated with worse post-CABG survival. Each is associated with specific causes of death.

Coronary artery bypass grafting (CABG) provides better mid- to long-term survival than other treatments, depending on the underlying disease.

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