Electrolyte and Acid-Base Imbalance as Early Markers of CKD: A Cluster-Based Analysis in a Rural Indian Setting

Abstract

Background: Electrolyte and acid-base imbalances are early markers of chronic kidney disease (CKD), especially relevant in underserved rural populations. This study evaluates key biochemical parameters, the Electrolyte Stress Index (ESI), and clustering-based patient stratification in a rural Indian cohort. Methods: A cross-sectional study was conducted on 200 adults. Serum electrolytes, uric acid, calcium, creatinine, and eGFR were analyzed using the Vitros 4600 analyzer. ESI was calculated as (Na⁺ + K⁺ + Cl⁻)/HCO₃⁻. Pearson’s correlation, sensitivity-specificity analysis, and k-means clustering were applied for statistical evaluation. Results: Hyponatremia (14.0%), hyperkalaemia (17.5%), low HCO₃⁻ (15.0%), and hyperuricemia (22.0%) were prevalent. HCO₃⁻ showed a strong negative correlation with creatinine (r = -0.47, p < 0.001). ESI ≥15 was linked to lower mean GFR (54.7 ml/min), with a sensitivity of 60%, specificity of 90%, and Youden Index of 0.50. Clustering revealed three distinct biochemical profiles, including high-risk renal phenotypes. Conclusion: Electrolyte abnormalities correlated strongly with renal dysfunction. ESI and cluster analysis offer promising, low-cost tools for early CKD risk stratification in resource-limited settings.