Discordance between Self-Reported and 24-Hour Urine Sodium Intake and Predictors of Sodium Non-Adherence

Aims: A low-sodium diet is important for HF management to prevent fluid retention. Prior studies have found that patients have trouble judging their adherence to a low salt diet. Concordance between self-reported and objectively measured sodium levels was assessed and predictors of nonadherence to sodium recommendations were identified. Methods and Results: This was a secondary analysis of data collected from a prospective observational study. The Self Care of Heart Failure Index and 24hour urine sodium excretion were used to measure self-reported and objective adherence to a low-sodium diet in 280 Stage C HF patients. Mixed effect models were used to quantify the correlation between self-reported and objective measures at enrollment, 3and 6-months. There was no association between self-reported low-sodium diet and urinary sodium levels after controlling for age, gender, race, perceived health, income, comorbid conditions, data collection site, NYHA functional class, cognitive status, HF etiology, left ventricular ejection fraction, body mass index and diuretic use. Logistic regression was used to identify predictors of nonadherence. The odds of nonadherence to a low-sodium diet was about double for people who are obese (1.1-3.5, p50.028), male (1.13.6, p50.017), or have a low self-reported income (1.21-6.35, p50.016). The odds of non-adherence declined 3% for each year of age (1.0-5.0, p50.005). Conclusion: Clinicians should be cautious about basing clinical decisions on self-reported sodium intake without objective verification. Patient predictors of nonadherence such as male gender, obesity, lower income levels and younger age may help clinicians identify patients at risk for poor dietary adherence.