Persistent metabolic acidosis on regular hemodialysis or peritoneal dialysis

Metabolic acidosis is known to have adverse consequences in patients with chronic kidney disease (CKD) including protein-energy wasting, inflammation, bone disease, and disturbance in endocrine function. Unlike in the management of patients with predialysis CKD, bicarbonate levels were not being routinely monitored in dialysis patients at our center. The KDOQI guidelines recommend serum bicarbonate levels ≥22 mEq/L in patients on dialysis. We measured the predialysis serum bicarbonate levels in 100 adult patients on regular hemodialysis (HD) and 41 adult patients on peritoneal dialysis (PD). We also studied the extent of rise in serum bicarbonate levels from predialysis levels after HD in our patients. Predialysis serum bicarbonate level was <22 mEq/L in 73% of patients on HD and 12% of patients on PD. The serum bicarbonate levels remained <22 mEq/L at the end of HD in 41% of patients on HD. Thirty-nine percent of patients were on a HD schedule of thrice a week, and 93% of PD patients performed three PD exchanges a day. The dialysate bicarbonate level was 34 mEq/L. There was a significant increase in serum bicarbonate levels with HD, but the mean postdialysis bicarbonate level was 23.45 mEq/L. A very high proportion of our patients on HD continued to have uncorrected metabolic acidosis, with metabolic acidosis persisting in the immediate postdialysis period in a significant number of patients. Predialysis serum bicarbonate level needs to be monitored in patients on HD. There is an urgent need to modify HD prescription to ensure better correction of metabolic acidosis in our HD population. Compared to HD, the proportion of patients having persistent metabolic acidosis is significantly lower in PD.