Interdialytic Weight Gain Correlates With Glycosylated Hemoglobin in Diabetic Hemodialysis Patients

Most of the excess mortality and morbidity in diabetic end-stage renal disease patients is ascribed to diabetes associated cardiovascular disease, which is accelerated by uremia. We compared the interdialytic weight gain in 33 diabetic patients (group 1) undergoing maintenance hemodialysis in an ambulatory facility retrospectively over 3 months, with 25 randomly selected nondiabetic hemodialysis patients (group 2); in addition, we assessed glycemic control in the diabetic subjects using glycosylated hemoglobin (HbA1c). Interdialytic weight gain was expressed as a percentage of the immediately preceding postdialysis weight, and a mean was calculated for each subject. In all subjects, predialysis serum aldosterone, plasma renin activity, and the interdialytic change in serum sodium were measured. Both groups received an equivalent amount of dialysis using a cellulose membrane (mean ± SD of thrice weekly dialysis: group 1 = 3.8 ± 0.35 hours, group 2 = 3.86 ± 0.3 hours; P < 0.5) and had similar predialysis serum creatinine, hematocrit, and serum albumin levels. Group 1 patients had a mean age of 56.5 ± 11.4 years (age range, 30 to 71 years) and group 2 had a mean age of 55.8 ± 15.4 years (age range, 29 to 76 years) (P < 0.84). Mean (±SD) duration on maintenance hemodialysis was 18.7 ± 15.3 months (range, 2 to 84 months) for group 1 and 21 ± 28.9 months (range, 3 to 156 months) for group 2 (P < 0.9). Interdialytic weight gain was 30% greater in group 1 (4.2% ± 0.19%) than in group 2 (3.2% ± 0.2%) (P < 0.001). Those diabetic patients (n = 5) with poor glycemic control as measured by a mean HbA1c of 11.96% ± 3.9% had a higher mean (±SEM) interdialytic weight gain (5.6 ± 0.4) than did those diabetic patients (n = 18) with good control (3.9 ± 0.2; HbA,c = 5.78% ± 0.93%) (P < 0.01). Insulin-treated group 1 patients (n = 7) gained more weight (5.3 ± 0.37) than those (n = 13) on oral hypoglycemic agents (4.4 ± 0.19) or dietary control (n = 13) (3.3 ± 0.23) (P by ANOVA < 0.001). Median interdialytic change in serum sodium concentration was -3 mEq/L for diabetic patients and +2 mEq/L for nondiabetic patients. Diabetic subjects had a higher mean (±SEM) predialysis serum aldosterone concentration (43.9 ± 9.5 ng/dL) than did nondiabetic subjects (18.4 ± 5.8 ng/dL) (P < 0.05). The mean plasma renin activity level, however, did not differ significantly between diabetic (3.6 ± 1.2 ng/mL/hr) and nondiabetic subjects (3.7 ± 2.1 ng/mL/hr) (P < 0.96). We conclude that hyperglycemia-induced thirst, and perhaps elevated aldosterone or uremia itself, stimulate increased fluid ingestion, resulting in excess interdialytic weight gain in dialyzed diabetic patients.