Does reducing salt intake impact CV outcomes?

An intervention aimed at reducing sodium intake in patients with heart failure (HF) does not reduce the risk of emergency department (ED) presentation or hospitalization for cardiovascular (CV) causes or all-cause death, according to results of the SODIUM-HF* trial. However, patients did experience improvements in quality of life (QoL) and New York Heart Association (NYHA) class.

“While the intervention didn’t reduce clinical events, we found the low-sodium group had modest improvements in QoL and NYHA HF class, which we think will be quite important and valued by patients and clinicians alike,” said study lead author Professor Justin Ezekowitz from the University of Alberta in Edmonton, Canada, who presented the results at ACC.22.

The multinational (26 medical centres in six countries), open-label trial involved 841 adults (median age 67 years, 33 percent female) receiving optimally tolerated medical therapy for chronic HF**, irrespective of ejection fraction (median 36 percent), who were randomized 1:1 to usual care (general advice to reduce sodium intake) or a reduction of dietary sodium intake to <1,500 mg/day (intervention). Patients were advised on their sodium intake through nutritional counselling and 3-day food questionnaires that were distributed throughout the study period. Forty-seven percent of patients had coronary artery disease and 41 percent atrial fibrillation.

Patients in the intervention group were provided with sample menus according to energy requirement, with foods that were individualized to each region or country.

At baseline, median intake of sodium was 2,217 mg/day. At 6 months, daily sodium intake was a median 1,651 and 2,052 mg in the intervention and usual care groups, respectively. At 12 months, daily sodium intake was a median 1,658 and 2,073 mg, respectively, with a statistically significant difference of 415 mg/day between the two groups (p<0.0001).

At 12 months, the incidence of the composite outcome of CV-related hospitalization, CV-related ED visit, or all-cause death did not significantly differ between patients assigned to the intervention or usual care groups (hazard ratio [HR], 0.89, 95 percent confidence interval [CI], 0.63–1.26; p=0.53). [ACC.22, abstract 22-LBCT-15752-ACC]

The intervention did not appear to affect any of the individual outcomes of the composite (CV-related hospitalization: HR, 0.82; p=0.36; CV-related ED visit: HR, 1.21; p=0.6; all-cause mortality: HR, 1.38; p=0.32).  

There was a significant improvement in QoL, as per the Kansas City Cardiomyopathy Questionnaire, at 12 months with the intervention vs usual care (overall summary score: difference, 3.38, 95 percent CI, 0.79–5.96; p=0.011; physical limitation score: difference, 3.77, 95 percent CI, 0.67–6.87; p=0.017).

“[S]cores were significantly better in the low-sodium group compared to the usual care group, and these improvements in QoL scores were consistent across all the assessments and across time,” said Ezekowitz.

“This improvement was quite marked compared to other clinical trials, for example, trials for pharmacological interventions,” he continued.

There was also a significant improvement in NYHA class with the intervention compared with usual care at 6 months (odds ratio [OR], 0.61, 95 percent CI, 0.43–0.86; p=0.005) and 12 months (OR, 0.59, 95 percent CI, 0.40–0.86; p=0.006).

However, 6-minute walk test did not significantly differ between the intervention and usual care groups, be it at 6 months (difference, 13.8; p=0.076) or 12 months (difference, 6.60; p=0.405).

Ezekowitz noted that the trial was stopped early and had a lower-than-anticipated event rate. He also queried if certain patients may derive more benefits from the intervention.

“We need to explore further whether there might be a way to individualize recommendations from our trial to see if the QoL benefits might make it worth it for certain patients [to reduce sodium intake],” he said. “[G]reater reductions in daily sodium or alternatively, enrolling patients with markedly higher dietary sodium may or may not produce different results.”