Salt restriction induced hyponatremia in hypertensive patients in Rwanda: A case control study

Salt restriction is a fundamental principle in the non-pharmacological management of hypertension. The World Health Organization recommends a daily sodium intake of less than 2 g/day. In East African countries, particularly Rwanda, there is a known prevalence of low sodium intake, with a mean sodium intake of 1.6 g/day. However, despite this dietary habit, the national protocol for treating hypertension, as well as common clinical practice, often fail to account for the low salt intake in Rwandan communities. Hypertensive patients are still frequently advised to reduce their salt intake, and in some cases, they are instructed to eliminate salt entirely.

This study was designed to determine the association between salt restriction and hyponatremia in hypertensive patients.

A case-control study was conducted over a period of 6 months at two tertiary hospitals in Rwanda, with hyponatremia as the outcome variable and salt restriction as the exposure variable. Age, gender, and use of diuretics were matched between the case and control groups. Serum sodium concentrations were measured, and participants were then categorized into groups. Questionnaires were used for interviews.

245 participants meeting the inclusion criteria were selected, with 110 (44.9%) classified as cases and 135 (55.1%) as controls. Among them, 159 (64.8%) participants were restricted from consuming salt, with 74 (46.5%) following a salt-free diet. The odds of developing hyponatremia were 9.90 (95% CI, p < 0.001) among salt-restricted participants.

There is a strong association between salt restriction and hyponatremia in hypertensive patients on treatment in this study.