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Hydration may slow cardiac decline and reduce heart failure risk – NIH study

Staying well-hydrated may may slow down decline in cardiac function and decrease prevalence of heart failure, according to researchers at the National Institutes of Health (NIH), in the European Heart Journal.

While fluid guidelines vary based on the body’s needs, the researchers recommended a daily fluid intake of 6-8 cups (1.5- 2.1 litres) for women and 8-12 cups (2-3 litres) for men.

Heart failure, a chronic condition that develops when the heart does not pump enough blood for the body’s needs, affects more than 6.2m Americans, a little more than 2% of the population. It is also more common among adults aged 65 and older.

“Similar to reducing salt intake, drinking enough water and staying hydrated are ways to support our hearts and may help reduce long-term risks for heart disease,” said Natalia Dmitrieva, PhD, the lead study author and a researcher in the Laboratory of Cardiovascular Regenerative Medicine at the National Heart, Lung, and Blood Institute (NHLBI), part of NIH.

After conducting preclinical research that suggested connections between dehydration and cardiac fibrosis, a hardening of the heart muscles, Dmitrieva and researchers looked for similar associations in large-scale population studies. To start, they analysed data from more than 15,000 adults, aged 45-66, who enrolled in the Atherosclerosis Risk in Communities (ARIC) study between 1987-1989 and shared information from medical visits over a 25-year period.

In selecting participants for their retrospective review, the scientists focused on those whose hydration levels were within a normal range and who did not have diabetes, obesity, or heart failure at the start of the study. Approximately 11,814 adults were included in the final analysis, and, of those, the researchers found that 1,366 (11.56%) later developed heart failure.

To assess potential links with hydration, the team assessed the hydration status of the participants using several clinical measures. Looking at levels of serum sodium, which increases as the body’s fluid levels decrease, was especially useful in helping to identify participants with an increased risk for developing heart failure. It also helped identify older adults with an increased risk for developing both heart failure and left ventricular hypertrophy, an enlargement and thickening of the heart.

For example, adults with serum sodium levels starting at 143 milliequivalents per litre (mEq/L) – a normal range is 135-146 mEq/L – in midlife had a 39% associated increased risk for developing heart failure compared with adults with lower levels.

And for every 1 mEq/L increase in serum sodium within the normal range of 135-146 mEq/L, the likelihood of a participant developing heart failure increased by 5%.

In a cohort of about 5,000 adults aged 70-90, those with serum sodium levels of 142.5-143 mEq/L at middle age were 62% more likely to develop left ventricular hypertrophy. Serum sodium levels starting at 143 mEq/L correlated with a 102% increased risk for left ventricular hypertrophy and a 54% increased risk for heart failure.

Based on these data, the authors conclude serum sodium levels above 142 mEq/L in middle age are associated with increased risks for developing left ventricular hypertrophy and heart failure later in life.

A randomised, controlled trial will be necessary to confirm these preliminary findings, the researchers said. However, these early associations suggest good hydration may help prevent or slow the progression of changes within the heart that can lead to heart failure.

“Serum sodium and fluid intake can easily be assessed in clinical exams and help doctors identify patients who may benefit from learning about ways to stay hydrated,” said Dr Manfred Boehm, who leads the Laboratory of Cardiovascular Regenerative Medicine.

Fluids are essential for a range of bodily functions, including helping the heart pump blood efficiently, supporting blood vessel function, and orchestrating circulation. Yet many people take in far less than they need, the researchers said. While fluid guidelines vary based on the body’s needs, the researchers recommended a daily fluid intake of 6-8 cups (1.5- 2.1 litres) for women and 8-12 cups (2-3 litres) for men.

Study details
Middle age serum sodium levels in the upper part of normal range and risk of heart failure

Natalia Dmitrieva, Delong Liu, Colin Wu, Manfred Boehm.

Published in the European Heart Journal on 29 March 2022

Abstract

Aims
With increasing prevalence of heart failure (HF) owing to the ageing population, identification of modifiable risk factors is important. In a mouse model, chronic hypohydration induced by lifelong water restriction promotes cardiac fibrosis. Hypohydration elevates serum sodium. Here, we evaluate the association of serum sodium at middle age as a measure of hydration habits with risk to develop HF.

Methods and results
We analysed data from Atherosclerosis Risk in Communities study with middle age enrolment (45–66 years) and 25 years of follow-up. Participants without water balance dysregulation were selected: serum sodium within normal range (135–146 mmol/L), not diabetic, not obese and free of HF at baseline (N = 11 814). In time-to-event analysis, HF risk was increased by 39% if middle age serum sodium exceeded 143 mmol/L corresponding to 1% body weight water deficit [hazard ratio 1.39, 95% confidence interval (CI) 1.14–1.70]. In a retrospective case-control analysis performed on 70- to 90-year-old attendees of Visit 5 (N = 4961), serum sodium of 142.5–143 mmol/L was associated with 62% increase in odds of left ventricular hypertrophy (LVH) diagnosis [odds ratio (OR) 1.62, 95% CI 1.03–2.55]. Serum sodium above 143 mmol/L was associated with 107% increase in odds of LVH (OR 2.07, 95% CI 1.30–3.28) and 54% increase in odds of HF (OR 1.54, 95% CI 1.06–2.23). As a result, prevalence of HF and LVH was increased among 70- to 90-year-old participants with higher middle age serum sodium.

Conclusion
Middle age serum sodium above 142 mmol is a risk factor for LVH and HF. Maintaining good hydration throughout life may slow down decline in cardiac function and decrease prevalence of HF.

Key question
Is there an association between chronic subclinical hypohydration elevating serum sodium within normal range and risk of heart failure?

Key finding
Middle age serum sodium >142–143 mmol/L (water deficit >1% body weight; tonicity >290 mosmol/kg):
• Increased risk of heart failure (HF) (by ∼40%)
• Increased odds of left ventricular hypertrophy (LVH) (∼80%)
• Increased HF/LVH prevalence
• LV hypertrophic remodelling

Take-home message
Middle age serum sodium >142 mmol/L is a risk factor for LVH and HF hypothesis: Drinking recommended amounts of fluids (1.6–2.1 L for women; 2–3 L for men) may reduce risk of HF and LVH.

 

European Heart Journal article – Middle age serum sodium levels in the upper part of normal range and risk of heart failure (Open access)

 

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