In heart failure with left ventricular ejection fraction reduction <40% (HFrEF) the increased mortality in patients with underlying ischaemic heart disease (IHD) compared to multi-aetiological non-ischaemic HFrEF is established. The prognostic difference over time in comparison with dilated cardiomyopathy (DCM) is less clear.
To evaluate the difference in mortality between IHD and DCM in HFrEF, overall, in specific subgroups and over time.
By applying multivariable Cox regression analyses on Swedish Heart Failure Registry data from the years 2000 to 2012 (including 51,060 patients), the incidence of mortality in 8,982 patients with non-valvular clinical IHD-HFrEF was compared to 2,220 patients with DCM-HFrEF overall and for subgrouping variables of age category, sex and EF group (<30% and 30-39%), adjusted for additional 23 baseline variables.
The overall mortality was higher in IHD-HFrEF with the crude mortality of 42.1% and the event rate 15.4 (95% confidence interval [CI]: 14.9 - 15.9) per 100 person years compared with 19.4% and 5.5 (95% CI: 5.0-6.1) in DCM-HFrEF. The probability of survival in IHD-HFrEF was lower than in DCM-HFrEF (Figure). After multivariable adjustment the risk for mortality in IHD-HFrEF remained increased with a hazard ratio (HR) of 1.34 (95% CI: 1.18-1.50). The adjusted HR was higher in all groups of age <80 years and in both sexes, with a significantly higher risk in women than in men (HR 1.85 vs 1.22, p for interaction = 0.002). Overall, HR was increased regardless of EF group but analyses by both age group and EF group revealed significantly increased mortality in EF <30% only for age groups <80 years. No significant temporal trend was seen between IHD-HFrEF and DCM-HFrEF.
In patients with heart failure and reduced ejection fraction, ischaemic heart disease compared to dilated cardiomyopathy was associated with increased mortality in all age groups below 80 years of age, throughout the 13-year study period.