Association between dialysate sodium concentration and interdialytic weight gain in patients undergoing twice weekly haemodialysis
Date of Award
Master of Medicine (MMed)
Dr. Ahmed Sokwala
Dr. Ahmed Twahir
Dr. Jasmit Shah
Internal Medicine (East Africa)
Background: Chronic kidney disease is highly prevalent in the world with more than two million people worldwide requiring renal replacement therapy. Interdialytic weight gain is the change in body weight between two sessions of haemodialysis. Higher interdialytic weight gain has been associated with an increase in mortality and adverse cardiovascular outcomes. It has long been questioned whether using a lower dialysate sodium concentration during dialysis would reduce the interdialytic weight gain and hence prevent these adverse outcomes.
Objective: The primary objective of this study was to determine the association between the dialysate sodium concentration and interdialytic weight gain in patients undergoing twice-weekly haemodialysis. The secondary objective was to determine the relationship between dialysate sodium concentration and blood pressure in these patients.
Methods: This study was a single-blind cross-over study of adult patients undergoing twiceweekly haemodialysis at the Aga Khan University Hospital Nairobi dialysis unit and Parklands Kidney Centre. It was conducted over two six week periods. Patients were divided into two groups – the first underwent dialysis with a dialysate sodium concentration of 137meq/l, whereas the other underwent dialysis with a sodium concentration of 140meq/l. These groups switched over after a six-week period without a washout period. Interdialytic weight gain, pre, and post dialysis blood pressures were measured at each dialysis session and recorded.
Results: 41 patients were included in the primary analysis after meeting inclusion criteria. Mean age was 61.37 years, and 73% were males. Mean duration for dialysis was 2.53 years. 13% were anuric, 56% were oliguric, and 31% were non-oliguric. 59% of patients had diabetes mellitus and 80% had hypertension. The interdialytic weight gain was not significantly different among the two groups (2.14 for the low DNa (137meq/l) group and 2.35 for the high DNa (140meq/l) group, p = 0.97). Mean blood pressures were as follows. Pre-dialysis: DNa 137meq/l: systolic 152.14 ± 19.99, diastolic 78.99 ± 12.20, DNa 140meq/l: systolic 156.95 ± 26.45, diastolic 79.75 ± 11.25 (p = 0,379, 0.629 respectively). Post-dialysis: DNa 137meq/l: systolic 147.29 ± 22.22, diastolic 77.85 ± 12.82 DNa 140meq/l: systolic 151.48 ± 25.65, diastolic 79.66 ± 15.78 (p = 0,569, 0.621 respectively).
Conclusion: There was no significant difference in the interdialytic weight gain as well as predialysis and post dialysis systolic and diastolic blood pressures between the low dialysate sodium concentrations (DNa 137meq/l) and high dialysate sodium concentration (DNa 140meq/l). Therefore using a lower dialysate sodium concentration does not appear useful in altering the interdialytic weight gain although further studies with a larger sample size are warranted.
Manji, S. (2020). Association between dialysate sodium concentration and interdialytic weight gain in patients undergoing twice weekly haemodialysis (Unpublished master's dissertation). Aga Khan University, East Africa.