Cardiologists should reconsider recommending a strict salt restriction diet to patients with heart failure with preserved ejection fraction (HFpEF) as new evidence shows the approach could be harmful in this particular group of patients. 

A post hoc analysis of 1713 people aged 50 and above with heart failure with HFpEF from the TOPCAT trial found an overstrict cooking salt restriction was significantly associated with higher risks of the composite primary endpoint of cardiovascular death, HF hospitalisation and aborted cardiac arrest compared to patients who took a more relaxed approach. 

Patients with a strict salt restriction also had a higher risk of HF hospitalisation but not cardiovascular or all-cause mortality. 

A subgroup analysis revealed that the association between overstrict salt restriction and poor outcomes was more predominant in patients aged ≤70 years and of non-white race, the researchers reported in Heart.

The research team from Guangzhou, China, noted that lower sodium intake was associated with lower blood pressure and a lower risk of cardiovascular disease in the general population and in those with hypertension through a reduction in fluid retention which in turn alleviates  reninangiotensin-aldosterone system activation.

“However, in the setting of HF, the effect of sodium intake restriction is complicated. Low sodium intake may lead to intravascular volume contraction, which could in turn reduce congestion and diuretic requirement, leading to HF compensation,” they wrote.

They noted that optimal salt intake in patients with HF had been studied for decades but most excluded patients with HFpEF, leaving the effect of salt intake restriction in this patient population under explored.

“As with the SODIUM HF trial, physicians should reconsider the practice of recommending salt restriction to patients with HFpEF (not just as little as possible), and high-quality trials to investigate the optimal salt restriction range for patients with HFpEF are needed,” they concluded.