Prevalence and Severity of Metabolic Acidosis in Patients on Maintenance Hemodialysis: A Cross-Sectional Study from Western India
Pallaavi Goel*, Mukhiya GK and Rajan Patel
ABSTRACT
Background: Metabolic acidosis is a modifiable complication of kidney failure that promotes protein catabolism and bone loss. Indian data on its burden in maintenance hemodialysis, where twice-weekly schedules are common, are scarce.
Methods: In this cross-sectional study at a tertiary care centre in Udaipur, India, 120 consecutive adults on maintenance hemodialysis underwent pre-dialysis venous blood gas analysis at the mid-week session. Metabolic acidosis (serum bicarbonate <22 mmol/L) was graded as mild (17.0–21.9), moderate (12.0–16.9) or severe (<12.0 mmol/L). Prevalence was compared across dialysis frequency, residual urine output and diet, and acid-base and electrolyte parameters across severity groups.
Results: Mean age was 50.7 ± 14.9 years; 63.3% were men and 90.0% were dialysed twice weekly. Metabolic acidosis was present in 81 patients (67.5%; 95% CI 58.7–75.2%): mild in 37.5%, moderate in 20.0% and severe in 10.0%. Mean bicarbonate was 19.6 ± 4.8 mmol/L. Blood pH fell (7.42 to 7.23) and the anion gap rose (7.8 to 17.7 mEq/L) from no to severe acidosis (both p < 0.001). Acidosis was more frequent with twice-weekly than thrice-weekly dialysis (72.2% vs 25.0%; p = 0.002) and in patients early in their dialysis course (median vintage 9 vs 36 months); bicarbonate correlated with dialysis vintage (ρ = 0.53; p < 0.001).
Conclusion: Two-thirds of patients on maintenance hemodialysis had metabolic acidosis, and nearly one-third had moderate or severe acidosis. Twice-weekly dialysis and the first year of dialysis identify patients at highest risk. Routine pre-dialysis bicarbonate monitoring and timely correction are warranted.
