Dietary Interventions in Heart Failure with Preserved Ejection Fraction (HFpEF): a systematic scoping review and meta-analysis

Type of funding sources: Public Institution(s). Main funding source(s): Evelyn Trust.

Pharmacotherapies have improved outcomes for patients with Heart Failure with reduced Ejection Fraction (HFrEF), but less so for patients with HFpEF. Limited treatments results in substantial burden at personal, clinical and economic levels. Diet has been implicated in the pathogenesis and prognosis of HFpEF, as such, dietary manipulation has the potential to be a useful management strategy.

The aim of the scoping review was to establish which nutritional interventions have so far been tested in patients with HFpEF and establish how the dietary manipulation was achieved. The aim of the meta-analysis was to quantify the effects of interventions tested to determine whether there is evidence to support specific dietary recommendations in patients with HFpEF.

Key word searches were performed in five bibliographic databases to identify randomised or controlled studies of dietary interventions conducted in HFpEF or mixed heart failure (HF) samples. Study characteristics were summarised according to PICO (population, intervention, comparator, outcome) categories and intervention complexity was assessed. Studies included in the meta-analysis were appraised for bias and the quality of the body of evidence was assessed via the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) framework.

Twenty-five different interventions reported across 31 papers were identified. Only ten (40%) were conducted exclusively in HFpEF subjects. Studies employing highly tailored prescribed methods were most common (n=12, 48%). Dietary supplementation (n=10, 40%) and dietary pattern manipulations (n=3, 12%) were less represented. Seventeen studies were considered for meta-analysis; all but one were judged to be at high risk of bias. There was moderate quality evidence that caloric restriction led to clinically meaningful improvements in blood pressure and body weight. There was moderate quality evidence carbohydrate restriction resulted in meaningful reductions in blood pressure. There was very low quality evidence protein supplementation improved blood pressure and body weight and moderate quality evidence for clinically meaningful improvements in function.

Very few dietary interventions have been tested in HFpEF specifically. Most interventions tested were complex at the patient level, which may not be suitable for the older, multi-morbid patients who typify HFpEF. Results of meta-analyses performed were not of sufficient quality to make generalised conclusions. Some interventions delivered clinically meaningful changes that may be important to patients, therefore, clinicians could draw on these findings to inform personalised care plans and treatment goals.