Functional Capacity, Functional Performance, and Symptoms in People With Heart Failure: An Integrative Review

Heart failure (HF) is a clinical syndrome that has a negative effect on functional status, a multidimensional concept characterizing one's ability to provide for the necessities of life. Symptoms might be associated with different aspects of functional status in HF. However, the terms functional capacity and performance have been misused interchangeably, and no previous review has focused on the extent to which symptoms contribute to functional capacity and performance among people with HF.

The aim of this study was to comprehensively review and synthesize the existing literature on the relationship between symptoms, functional capacity, and functional performance in people with HF.

We conducted an integrated review of observational studies in which authors examined the relationship between at least 1 symptom and at least 1 aspect of functional capacity or performance in people with HF 18 years or older. The Joanna Briggs Institute's critical appraisal tools were used to analyze the quality of studies.

We included 23 studies with 7219 participants and an age range of 40 to 86 years. Fifteen symptom measures were used to measure dyspnea, fatigue, pain, insomnia symptoms, depressive symptoms, and anxiety symptoms. Three functional capacity measures were assessed in 9 studies, and 7 functional performance measures were assessed in 17 studies. As often measured with the Six-Minute Walk Test, functional capacity was inversely associated with pain/discomfort, insomnia symptoms, and psychological symptoms. Functional performance, often measured by the New York Heart Association functional class and Medical Outcome Scale Short Form 36, was associated with sleep difficulties, fatigue, depressive symptoms, and anxiety. Four studies combined functional capacity and performance measures to elicit functional status. Depressive symptoms, fatigue, pain, and insomnia symptoms are associated with decreased functional performance and capacity.

Commonly, symptoms experienced in HF are associated with declining functional status. However, this finding depends on the measures or metrics used to assess symptoms, functional capacity, and performance. The observed dissimilarities in the relationship between symptoms and functional capacity and performance highlight the conceptual distinctions, suggesting that authors of future studies should judiciously select appropriate dimensions and measures of functional status based on the study's purposes, design, and available resource.