Letter by Fung et al regarding article, "Frailty and clinical outcomes in heart failure : a systematic review and meta-analysis"

We read with interest an article titled "Frailty and Clinical Outcomes in Heart Failure: A Systematic Review and Meta-analysis" by Zhang et al published in the Journal. The article raises concerns in terms of its quality, methodology, and the degree to which it has inaccurately summarized the literature on frailty and heart failure (HF), which may cause readers to misinterpret the results. HF is a complex syndrome with often insidious disease onset, development and progression, interspersed decompensation episodes in the advanced stages, periods of stabilization following appropriate treatment, an unpredictable trajectory, marked differences in outcomes between inpatients and outpatients, and variable responses to interventional therapies. Discernible phases and acuity of the disorder with or without intervention(s) should not be combined and grouped under the umbrella term "heart failure." Moreover, we wish to highlight concerns we have with the approach taken.