The association between cognitive function and objective adherence to dietary sodium guidelines in patients with heart failure

Background: Although cognitive impairment is common in heart failure (HF) patients, its effects on sodium adherence recommendations are unknown. Purpose: Our aim is to examine if cognitive function is associated with patient sodium adherence. Methods: Sodium collection/excretion and cognitive function were assessed for 339 HF patients over a 5-8-week period. Neuropsychological testing was performed at baseline (Visit 1), whereas two 24-hour urine samples were collected within 7 weeks postbaseline. The ability to collect two 24-hour urine samples and the estimation of sodium excretion levels from these samples were used to estimate sodium adherence recommendations. Results: Nearly half (47%) of the study participants (n=159) were unable to give two valid 24-hour urine samples. Participants who were unable to adhere to two valid 24-hour urine samples had significantly poorer attention and global cognition tests (P<0.044), with a trend for poorer executive function (P=0.064). Among those with valid samples, urine sodium level was not associated with global cognitive function, attention, executive function, or memory after adjusting for covariates. Female sex was associated with lower sodium excretion (all P<0.01); individuals with knowledge of sodium guidelines had less intake of sodium, resulting in excretion of less sodium (all P <= 0.03). Conversely, higher socioeconomic status (SES) and body mass index (BMI) were associated with greater sodium (all P <= 0.02 and P <= 0.01). Conclusion: Adherence to urine sodium collection was poor, especially among those with poorer cognitive function. Sodium consumption exceeded recommended amounts and was unrelated to cognitive function. Interventions for improving sodium adherence should focus on at-risk groups (high SES and BMI) and at improving knowledge of recommended salt intake.