Background and aims: Potassium-wasting (loop diuretics [LD]) and potassium-sparing (spironolactone) medications used for heart failure (HF) may alter renal potassium handling and confound the use of twenty-four-hour (24-h) urine collections as a surrogate marker for potassium intake, an effect that has been observed with dietary sodium assessment. The objective was to determine the strength of association between 24-h urine collections and weighed food records in assessing potassium intake in HF patients stratified by LD usage and spironolactone usage.
Methods and results: Stable outpatients with HF simultaneously completed two 24-h urine collections and two weighed food records on consecutive days. Analyses compared patients stratified by LD and/or spironolactone use. Pearson's correlation and the Bland-Altman method of agreement assessed the relationship between the techniques. Overall, 109 patients (61 ± 11 yrs, 74% male) were included. The mean difference in dietary potassium estimated between 24-h urine collections and food records was -353 ± 1043 mg (p < 0.01) for all patients, with no differences between measures among subgroups. The association between the two methods was r = 0.551 (95% CI, 0.373 to 0.852, p < 0.001) for LD users; r = 0.287 (95% CI, 0.01 to 0.570, p = 0.050) for LD non-users; r = 0.321 (95% CI, 0.13 to 0.798, p = 0.043) for spironolactone users, and; r = 0.534 (95% CI, 0.331 to 0.747, p < 0.001) for spironolactone non-users. There were no significant mean biases identified as part of the Bland-Altman analysis.
Conclusion: Among HF patients, potassium-wasting and potassium-sparing medications do not influence the agreement between the two methods in the assessment of potassium intake.
Keywords: Dietary assessment; Heart failure; Loop diuretics; Potassium intake; Spironolactone; Urine collections; Weighed food records.
Copyright © 2020 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.