Epidemiology of Left Ventricular Systolic Dysfunction and Heart Failure in the Framingham Study: An Echocardiographic Study Over 3 Decades

Abstract

Objectives: The purpose of this study was to describe the temporal trends in prevalence of left ventricular systolic dysfunction (LVSD) in individuals without and with heart failure (HF) in the community over a 3-decade period of observation.

Background: Temporal trends in the prevalence and management of major risk factors may affect the epidemiology of HF.

Methods: We compared the frequency, correlates, and prognosis of LVSD (left ventricular ejection fraction [LVEF] <50%) among Framingham Study participants without and with clinical HF in 3 decades (1985 to 1994, 1995 to 2004, and 2005 to 2014).

Results: Among participants without HF (12,857 person-observations, mean age 53 years, 56% women), the prevalence of LVSD on echocardiography decreased (3.38% in 1985 to 1994 vs. 2.2% in 2005 to 2014; p < 0.0001), whereas mean LVEF increased (65% vs. 68%; p < 0.001). The elevated risk associated with LVSD (∼2- to 4-fold risk of HF or death) remained unchanged over time. Among participants with new-onset HF (n = 894, mean age 75 years, 52% women), the frequency of heart failure with preserved ejection fraction (HFpEF) increased (preserved LVEF ≥50%: 41.0% in 1985 to 1994 vs. 56.17% in 2005 to 2014; p < 0.001) and heart failure with reduced ejection fraction (HFrEF) decreased (reduced LVEF <40%: 44.10% vs. 31.06%; p = 0.002), whereas heart failure with midrange LVEF remained unchanged (LVEF 40% to <50%: 14.90% vs. 12.77%; p = 0.66). Cardiovascular mortality associated with HFrEF declined across decades (hazard ratio: 0.61; 95% confidence interval: 0.39 to 0.97), but remained unchanged for heart failure with midrange LVEF and HFpEF. Approximately 47% of the observed increase in LVEF among those without HF and 75% of the rising proportion of HFpEF across decades was attributable to trends in risk factors, especially a decline in the prevalence of coronary heart disease among those with HF.

Conclusions: The profile of HF in the community has changed in recent decades, with a lower prevalence of LVSD and an increased frequency of HFpEF, presumably due to concomitant risk factor trends.

Keywords: echocardiography; ejection fraction; epidemiology; heart failure.

Figure 1. Distribution of left ventricular ejection fraction by decade in participants free of heart failure (Panels A–C) and in those with heart failure (Panel D)

Panel D displays a smoothed probability density function (Y axis) for values of left ventricular ejection fraction (X axis) by decade in participants free of heart failure (dotted lines) juxtaposed next to those with heart failure (solid lines) for comparison. Data for decade 1985–1994 are indicated in blue, those for decade 1995–2004 in red and for decade 1005–2014 in green. SAS proc sgplot was used to generate the kernel density plots for the EF distribution by time period for the HF and non-HF samples.

Figure 2. Kaplan Meier curves for survival of participants with HFrEF, HFmrEF and HFpEF in the three decades and pooled across decades

The horizontal line indicates median survival, and the vertical lines show median survival time for participants with new–onset HF for each subtype of HF.