Subclinical left ventricular dysfunction carries excess mortality in patients with diabetes

Background

Diabetes mellitus (DM) predisposes individuals to subclinical myocardial dysfunction and heart failure. However, the prevalence and prognostic impact of asymptomatic left ventricular systolic (aLVSD) and diastolic dysfunction (aLVDD) in Asian patients without overt cardiovascular disease remain incompletely defined.

Aims

To determine the prevalence, predictors, and long-term mortality impact of asymptomatic left ventricular dysfunction (aLVD) in individuals with and without type 2 diabetes.

Methods

We analyzed 40,254 adults undergoing comprehensive echocardiography at a tertiary medical centre (2006–2015). Patients with established cardiovascular disease or heart failure were excluded. aLVSD was defined as LVEF <50%. aLVDD was defined as LVEF ≥50% with ≥3 abnormal diastolic parameters (septal e′ <7 cm/s, E/e′ >15, left atrial diameter >40 mm, or tricuspid regurgitation velocity >2.8 m/s). All-cause mortality was ascertained via linkage to the National Death Registry. Multivariable Cox models adjusted for demographic and clinical covariates.

Results

Among 40,254 participants (mean age 59 years; 46% male), 16.5% had diabetes. The prevalence of aLVSD and aLVDD was 3.6% and 8.7%, respectively. During a median follow-up duration of 7.6 years, the fully adjusted analyses showed aLVSD was independently associated with both mortality and heart failure hospitalization. In the overall cohort, hazard ratios (HR, 95% CI) for mortality were 1.55 (1.36–1.77) for aLVSD and 1.09 (0.97–1.21) for aLVDD. For heart failure hospitalization, corresponding HRs were 2.39 (1.93–2.96) for aLVSD and 1.13 (0.92–1.37) for aLVDD.

When stratified by diabetes status, both aLVSD and aLVDD were independently associated with adverse outcomes in individuals with and without diabetes. Compared with subjects without diabetes neither aLVD, in diabetics patients, aLVSD was associated with a 75% higher mortality risk (HR 1.75, 95% CI 1.41–2.18) and nearly threefold higher heart failure hospitalization risk (HR 2.86, 95% CI 2.03–4.03). In diabetic patients with aLVDD, corresponding hazard ratios were 1.37 (95% CI 1.16–1.62) and 1.58 (95% CI 1.17–2.12), respectively. Diabetes alone was independently associated with increased risk even in the absence of ventricular dysfunction.

Conclusions

Asymptomatic left ventricular systolic dysfunction is a strong and consistent predictor of both mortality and heart failure hospitalization in individuals without overt cardiovascular disease. Diabetes confers additional risk, with the highest event rates observed in individuals with concomitant diabetes and systolic or diastolic dysfunction. These findings highlight the prognostic importance of detecting subclinical ventricular impairment in both diabetic and non-diabetic populations.Survival curve