Heart failure: Dietary intervention to reduce sodium intake does not reduce clinical events

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For the past century people with weak hearts have been told to lower their salt intake, but until now there has been little scientific evidence behind the recommendation.

The largest randomized clinical trial to look at sodium reduction and heart failure reported results simultaneously in The Lancet and at the American College of Cardiology’s 71st Annual Scientific Session over the weekend, and the findings were mixed.

Though reducing salt intake did not lead to fewer emergency visits, hospitalizations or deaths for patients with heart failure, the researchers did find an improvement in symptoms such as swelling, fatigue and coughing, as well as better overall quality of life.


Findings

Between March 24, 2014, and Dec 9, 2020, 806 patients were randomly assigned to a low sodium diet (n=397) or usual care (n=409). Median age was 67 years (IQR 58–74) and 268 (33%) were women and 538 (66%) were men. Between baseline and 12 months, the median sodium intake decreased from 2286 mg/day (IQR 1653–3005) to 1658 mg/day (1301–2189) in the low sodium group and from 2119 mg/day (1673–2804) to 2073 mg/day (1541–2900) in the usual care group.

By 12 months, events comprising the primary outcome had occurred in 60 (15%) of 397 patients in the low sodium diet group and 70 (17%) of 409 in the usual care group (hazard ratio [HR] 0·89 [95% CI 0·63–1·26]; p=0·53). All-cause death occurred in 22 (6%) patients in the low sodium diet group and 17 (4%) in the usual care group (HR 1·38 [0·73–2·60]; p=0·32), cardiovascular-related hospitalisation occurred in 40 (10%) patients in the low sodium diet group and 51 (12%) patients in the usual care group (HR 0·82 [0·54–1·24]; p=0·36), and cardiovascular-related emergency department visits occurred in 17 (4%) patients in the low sodium diet group and 15 (4%) patients in the usual care group (HR 1·21 [0·60–2·41]; p=0·60). No safety events related to the study treatment were reported in either group.

Interpretation

In ambulatory patients with heart failure, a dietary intervention to reduce sodium intake did not reduce clinical events.


“We can no longer put a blanket recommendation across all patients and say that limiting sodium intake is going to reduce your chances of either dying or being in hospital, but I can say comfortably that it could improve people’s quality of life overall,” said lead author Justin Ezekowitz, professor in the University of Alberta’s Faculty of Medicine & Dentistry and co-director of the Canadian VIGOUR Centre.

The researchers followed 806 patients at 26 medical centers in Canada, the United States, Columbia, Chile, Mexico and New Zealand. All were suffering from heart failure, a condition in which the heart becomes too weak to pump blood effectively. Half of the study participants were randomly assigned to receive usual care, while the rest received nutritional counseling on how to reduce their dietary salt intake.

Patients in the nutritional counseling arm of the trial were given dietitian-designed menu suggestions using foods from their own region and were encouraged to cook at home without adding salt and to avoid high-salt ingredients. Most dietary sodium is hidden in processed foods or restaurant meals rather than being shaken at the table, Ezekowitz noted.

“The broad rule that I’ve learned from dietitians is that anything in a bag, a box or a can generally has more salt in it than you would think,” said Ezekowitz, who is also a cardiologist at the Mazankowski Alberta Heart Institute and director of the U of A’s Cardiovascular Research Institute,

The target sodium intake was 1,500 milligrams per day—or the equivalent of about two-thirds of a teaspoon of salt—which is the Health Canada recommended limit for most Canadians whether they have heart failure or not.

Before the study, patients consumed an average of 2,217 mg per day, or just under one teaspoon. After one year of study, the usual care group consumed an average of 2,072 mg of sodium daily, while those who received nutritional guidance consumed 1,658 mg per day, a reduction of a bit less than a quarter teaspoon equivalent.

The researchers compared rates of death from any cause, cardiovascular hospitalization and cardiovascular emergency department visits in the two study groups but found no statistically significant difference.

They did find consistent improvements for the low-sodium group using three different quality of life assessment tools, as well as the New York Heart Association heart failure classification, a measure of heart failure severity.

Ezekowitz said that he will continue to advise heart failure patients to cut back on salt, but now he will be clearer about the expected benefits. He urges clinicians to recognize that dietary changes can be a useful intervention for some of their patients.

The team will do further research to isolate a marker in the blood of patients who benefited most from the low-sodium diet, with the aim of being able to give more targeted individual diet prescriptions in the future. The researchers will also follow up the trial patients at 24 months and five years to determine whether further benefits are achieved over the long term.


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The potential role of the DASH diet in heart failure management. Assessment of patients with heart failure (HF) stages (A–D) is followed by comprehensive clinical care management, which includes an individual-level DASH diet recommendation. Once successfully adopted and adhered to, the DASH diet can improve patients’ physical and functional capacities through reductions in blood pressure, body weight, and LDL cholesterol concentration and improvements in cardiac function, arterial compliance, exercise capacity, and quality of life. The positive effects of the DASH diet implemented as part of a comprehensive care plan for risk reduction and disease management and monitoring can contribute to improved health outcomes.

Heart failure (HF) is a major health care burden increasing in prevalence over time. Effective, evidence-based interventions for HF prevention and management are needed to improve patient longevity, symptom control, and quality of life. Dietary Approaches to Stop Hypertension (DASH) diet interventions can have a positive impact for HF patients. H

owever, the absence of a consensus for comprehensive dietary guidelines and for pragmatic evidence limits the ability of health care providers to implement clinical recommendations. The refinement of medical nutrition therapy through precision nutrition approaches has the potential to reduce the burden of HF, improve clinical care, and meet the needs of diverse patients.

The aim of this review is to summarize current evidence related to HF dietary recommendations including DASH diet nutritional interventions and to develop initial recommendations for DASH diet implementation in outpatient HF management.

Current Cardiovascular Disease Risk Reduction Recommendations

Diet patterns that support good health emphasize the consumption of fruits, vegetables, whole grains, lean protein sources, legumes, dairy, nuts, and healthy fats, while limiting intake of energy-dense sugars and processed foods. The DASH diet has been shown to be efficacious for CVD risk reduction and is a healthy diet pattern endorsed in the USDA Dietary Guidelines for Americans, 2020–2025 [14,15].

While other dietary patterns are included in these guidelines, the composition of comprehensive diet practices such as Mediterranean and vegetarian diets have been variably defined in the literature, making their systematic evaluation more challenging. The DASH diet is one of several included in the American Heart Association/American College of Cardiology (AHA/ACC) recommendations for diet patterns that can help adults who need to lower low-density lipoprotein cholesterol (LDL-C) and blood pressure (BP); the DASH diet is especially noted for the extensive evidence to that effect [16].

The US Preventive Services Task Force 2020 recommendations include behavioral counseling interventions to promote a healthy diet and physical activity for all adults with CVD risk based on evidence of moderate net benefit [17]. Globally, the European Society of Cardiology guidelines recommend that HF patients receive education on fluids to avoid excessive fluid intake and dehydration and on a healthy diet to prevent malnutrition, avoid consuming >5 g of salt daily, and healthy body weight maintenance [18].

Though several expert panels have endorsed a multifaceted lifestyle approach combining diet, exercise, and pharmacological therapy in order to promote improved HF outcomes (Figure 1), widespread implementation of these sensible and effective measures has been elusive.

Dietary Approaches for Heart Failure Management
Sodium and Fluid Restriction

Nutrition care is integral to comprehensive HF management. The current primary dietary approaches for HF management are sodium and fluid restriction, but individualization to patient needs is essential as multiple variables need to be considered in advanced HF [19,20]. Various levels of sodium restriction may be recommended in clinical practice, despite limited rationale for these levels. In the 1997–1999 DASH–Sodium trial, three sodium levels were set for diets based on the typical US sodium consumption (3450 mg/d), the recommended upper limit of sodium intake at the time of the study (2300 mg/d), and potentially optimal sodium intake levels (1500 mg/d) [21].

When combining a low sodium intake of 1500 mg/d with the DASH diet compared to a 3450 mg/d high sodium intake from a control diet, BP was lowered 7.1 mmHg for those without hypertension and 11.5 mmHg in participants with hypertension, though BP reductions were observed with lower sodium intake independent of diet type [22]. Limiting sodium intake to 1.5 g/d requires consumption of reduced sodium and no salt added versions of most foods with restricted salt use with food preparation.

Additionally, potential barriers to achieving low sodium adherence of 1.5 g/d include awareness and availability of reduced sodium food options, familiarity with alternative flavoring options when preparing foods, and food palatability and preferences. Sodium intake of 2.3 g/d is more achievable than lower sodium levels with regular foods, avoidance of highly salted processed foods, limiting use of table salt, and modestly seasoning with salt while cooking. Even when reduced sodium intake is achieved, however, not all individuals experience BP changes in response to sodium intake, indicating people can be salt-sensitive or salt-resistant [23].

Factors to consider when personalizing sodium recommendations for HF patients include HF stage and symptoms, LVEF, diagnosis of HFpEF vs. HFrEF, concurrent medications affecting cardiac function and urinary output, comorbidities, patient body size, and baseline diet. While excessive sodium and fluid intake seen in the setting of non-compliance are common causes of HF exacerbation and hospitalizations, overly strict recommendations can have adverse nutritional and physiologic consequences. Excessive sodium and fluid restrictions increase the perception of thirst [24].

Severe sodium restriction may result in reduced palatability and intake overall, thus increasing the risk of nutritional inadequacies and deficiencies [20,25]. In contrast to strict low sodium recommendations, modest sodium may contribute to cardiac performance in compensated HF, and the level recommended should be based on clinical evaluation of the patient [26]. A recent systematic review evaluating dietary interventions consisting of 1.5–3 g of daily sodium intake did not find robust or conclusive support of efficacy for a particular dietary sodium recommendation [25]. Professional society guidelines typically endorse a 2–3 g/d sodium intake depending on HF stage based on fair or level C strength of scientific evidence and is a recommendation consistent with public health recommendations for chronic disease prevention [20,27].

For fluid restriction, the ACC/AHA HF guidelines suggest fluid restriction of 1.5 to 2 L/day in patients with HF class D or severe hyponatremia [27]; the recommendations are based on expert opinion due to the limited evidence on the benefits of such recommendations [28,29]. Beyond this, the cardiology societies do not provide comprehensive dietary recommendations or guidelines. There is room for additional scientific evidence regarding the efficacy and effectiveness of optimal diet pattern and composition recommendations in HF patients and best practice approaches to provide individualized care to improve clinical outcomes.

reference link : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8708696/


More information: Justin A Ezekowitz et al, Reduction of dietary sodium to less than 100 mmol in heart failure (SODIUM-HF): an international, open-label, randomised, controlled trial, The Lancet (2022). DOI: 10.1016/S0140-6736(22)00369-5

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