Description
The National Heart, Lung, and Blood Institute (NHLBI) and NIH Office of Dietary Supplements (ODS) convened a working group on June 6 and 7, 2013. Members were asked to: 1) assess the evidence base for dietary and nutritional guidance for heart failure (HF) patients; 2) identify critical evidence gaps regarding the efficacy and clinical utility of dietary interventions for meeting nutritional needs, mitigating symptoms, and potentially arresting or reversing HF progression; and 3) consider how to develop new knowledge in the field and approaches for translation that will optimally use existing or new evidence, including novel study designs and methodological approaches. An important aspect of this working group was the dialogue among experts representing cardiology, nephrology, nutrition science, biostatistics and clinical trials, and basic science. In addition to NHLBI and ODS, representatives from NIDDK, NIA, and NINR participated. These stakeholders considered needs, opportunities, and obstacles regarding medical nutrition therapy (MNT) and HF management. The working group is responsive to NHLBI Strategic Plan Goals 1, 2, and 3. Recent meta-analyses, including an IOM report entitled Sodium Intake in Populations: Assessment of Evidence, conclude that current nutrition guidelines recommending sodium restriction, the most commonly prescribed dietary modification in HF, are poorly evidenced and may cause harm, adding urgency to the deliberations and recommendations from the working group.
HF remains a major public health burden. However, compared with the situation for cardiovascular risk factor management, there is little well-founded evidence regarding the efficacy, safety, and clinical impact of dietary modifications for patients with various HF phenotypes. The importance of diet and nutrition to promote health and prevent or control disease is well established. The obesity epidemic has fueled keen interest and focused investigations to develop nutritional guidelines to prevent cardiovascular disease, especially hypertension, metabolic syndrome, and atherosclerosis in the general population. In contrast, assessment tools and determining nutritional needs for the patient with HF lack high caliber evidence regarding safety, efficacy, and clinical impact of dietary modifications. The stronger evidence and focus on disease prevention and health promotion with diet modifications like DASH cannot be easily applied or extrapolated for disease management, especially HF, because of critical knowledge gaps and potential harm.
Chronic HF often presents as a multisystem disease with important co-morbidities such as anemia, insulin resistance or diabetes, autonomic dysregulation, and impaired renal function. Intestinal dysfunction with impaired motility and circulation and disturbed intestinal barrier and flora may lead to a chronic inflammatory state and nutrient malabsorption. In advanced cases, catabolic/anabolic imbalance is associated with cardiac cachexia, a difficult to treat condition which itself carries a poor prognosis. Finally, psychosocial symptoms associated with HF, such as depression and impaired cognition, can result in poor self-care, which can include lack of adherence to recommended dietary, physical activity, and medication regimens. Nutritional status concerns for patients with HF increase with disease severity. Nevertheless, except for salt restriction, which has become controversial, clinicians give little attention to diet as a potential intervention to improve outcomes, both for lack of evidence on efficacy and lack of conviction that adherence will be adequate.
The following themes emerged from discussion. Optimal management in HF must include nutrition therapy based on sound evidence. The need for research to establish evidence for nutritional guidance is compelling and immediate. Given the enormous public heath burden and high health care utilization and costs of HF on one hand and the potential for improved outcomes with dietary modification on the other, there is a strong consensus calling for commitment from the research community to resolve evidence gaps for nutrition therapy in HF now. Needs and opportunities for fundamental and clinical studies to address a number of novel promising strategies and to elucidate mechanisms of protein wasting which if answered would increase impact of diet modification were also identified. NHLBI, other institutes and partners with shared interest should consider trans-NIH approaches to enhance nutrition research leveraging existing resources. Strategies to promote multicenter, investigator initiated studies are also needed.