A BERNIER-JEAN1, G WONG1, V SAGLIMBENE1,2, M RUOSPO2, S C PALMER3, P NATALE1,2, V GARCIA-LARSEN5, D W JOHNSON6,7, M TONELLI8, J HEGBRANT9, J C CRAIG10, A TEIXEIRA-PINTO1, G FM STRIPPOLI1,4
1School of Public Health, Faculty of Medicine and Health, University of Sydney, 2Diaverum Medical-Scientific Office, 3Department of Medicine, University of Otago, 4Department of Emergency and Organ Transplantation, University of Bari, 5Program in Human Nutrition, Department of International Health, The Johns Hopkins Bloomberg School of Public Health, 6Department of Nephrology, Princess Alexandra Hospital, 7Australasian Kidney Trials Network, University of Queensland, 8University of Calgary, 9Department of Nephrology, Lund University, 10College of Medicine and Public Health, Flinders University
Aim: To assess the association between dietary potassium intake and mortality in adults receiving hemodialysis treatments and whether hyperkalemia mediates this association.
Background: Dietary modification to reduce the risk of hyperkalemia in people undergoing maintenance hemodialysis is standard practice and is commonly recommended in guidelines despite a lack of evidence. A low potassium diet may impair quality of life and nutritional status.
Methods: 9690 adults undergoing maintenance hemodialysis in Europe and South America were recruited in the DIET-HD study, of which 1647 were excluded for lack of data-linkage identifier or incomplete or implausible dietary assessment. We measured baseline potassium intake from the GA²LEN food frequency questionnaire and performed time-to-event and mediation analyses.
Results: The median baseline dietary potassium intake was 3.5 g/day (IQR 2.5 to 5.0). During a median follow-up of 3.97 years (25,890 person-years), we observed 2921 (36%) deaths. After adjusting for baseline characteristics, including the presence of cardiac disease and food groups, dietary potassium intake was not associated with all-cause mortality (HR, 1.00; 95% CI, 0.95 to 1.05). Mediation analysis showed no association of potassium intake with mortality either through or independent of serum potassium (HR, 0.999; 95% CI, 0.996 to 1.002; and 1.000; 95% CI, 0.999 to 1.002 respectively). Higher potassium intake was not associated with higher serum potassium (B=0.04 mEq/L; 95% CI, 0.00 to 0.09) or the prevalence of hyperkalemia (≥ 6.0 mEq/L) at baseline (OR, 1.08; 95% CI, 0.93 to 1.24). Hyperkalemia was associated with cardiovascular death (HR, 1.23; 95% CI, 1.03 to 1.48).
Conclusions: Higher dietary intake of potassium is not associated with hyperkalemia or death in patients treated with maintenance hemodialysis.
Amelie Bernier-Jean is a Canadian nephrologist with a Master of Clinical Epidemiology from the University of Sydney. She is soon to complete a PhD on the epidemiology of lifestyle factors in chronic kidney disease at the Sydney School of Public Health, for which she was awarded an NHMRC Post-Graduate Scholarship.