Ejection fraction in patients with heart failure and preserved ejection fraction is greater than in healthy controls: A meta-analysis

• Ejection fraction data in HFPEF and healthy controls, at rest, was sought.
• Ejection fraction in HFPEF is greater than that in healthy controls.
• Ejection fraction in HFPEF declines with age, however less than it does in healthy controls.
• A “greater-than-normal” ejection fraction in HFPEF may represent an adaptive physiologic mechanism.

BackgroundEjection fraction (EF) slightly declines with age in healthy control (HC) subjects. Yet, studies of heart failure with preserved ejection fraction (HFPEF) often report EF values which are surprisingly greater than those reported for HC of the same age. The goals of this study were to: (1) compare the EF, at rest, in subjects with HFPEF versus HC, and (2) compare how EF varies with age in HFPEF and HC.MethodsA systematic review and meta-analysis of the literature was performed. Studies were identified in the PUBMED and EMBASE databases until August 2013. A study reporting EF at rest in HFPEF and HC was included regardless of the aim of the primary study. In most of the primary studies (25 of 28 studies, 89%) EF was not a primary endpoint. A summary measure was the standardized mean difference (SMD) of the EF in HFPEF vs. HC.ResultsTwenty eight studies (1529 HFPEF and 1068 HC subjects) were included. SMD was 0.71 (95% CI: 0.31, 1.12, P < 0.001) demonstrating a greater EF in HFPEF. Effect size of HFPEF on EF was moderate. A meta-regression showed a statistically non-significant trend of increased SMD with older age.ConclusionsThis analysis showed that EF in HFPEF is on average “greater-than-normal”. This phenomenon may be related to an underlying adaptive mechanism occurring in HFPEF. Further research is needed.