Low-sodium salt substitutes reduce blood pressure but do not affect risk for other cardiovascular diseases

Hernandez AV, Emonds EE, Chen BA, et al. Effect of low-sodium salt substitutes on blood pressure, detected hypertension, stroke and mortality. Heart. 2019;105:953-60.

Review question

In patients with or without high blood pressure (hypertension), does using a low-sodium salt substitute reduce blood pressure, new or existing hypertension, or death compared with regular salt?

Background

Lowering salt intake can reduce blood pressure and the risk for cardiovascular diseases such as stroke. There are low-sodium products available that use other minerals like potassium. This review looks at whether using a salt substitute can improve blood pressure and cardiovascular outcomes.

How the review was done

The researchers did a systematic review of studies available up to May 2018. They found 21 randomized controlled trials (RCTs) with 7,403 people (between 14% to 68% men per trial). The average age of the people studied was 59 years.

The key features of the RCTs were:

• 15 RCTs included only people with high blood pressure, 2 RCTs included only people without high blood pressure, and 4 RCTs included both;
• 14 different low-sodium substitutes were used;
• trials lasted for 1 week to 44 months.

What the researchers found

The evidence for the effect of low-sodium salt substitutes was very low to moderate, which means that new studies are likely to find different results.

Compared with regular salt use, low-sodium salt substitutes:

• reduced systolic and diastolic blood pressure in people with or without hypertension;
• did not affect risk for new or existing hypertension;
• did not affect risk for death.

Conclusion

In people with or without hypertension, using low-sodium salt substitutes reduced blood pressure but did not affect new or existing hypertension or death.

Low-sodium salt substitutes vs regular salt in people with or without hypertension

*Evidence quality was rated using GRADE (Grading of Recommendations Assessment, Development, and Evaluation).