COMPARISON OF EIGHT METHODS FOR ESTIMATION OF CREATININE CLEARANCE IN MALAYSIA PATIENTS WITH UNSTABLE KIDNEY FUNCTION – A MULTI-CENTER, PROSPECTIVE, OBSERVATIONAL STUDY

Estimation of creatinine clearance (Clcr) has long been a problem in critically ill patients with unstable kidney function. The commonly used methods like the Cockcroft-Gault method require a stable kidney function. A reliable and more accurate tool is needed to estimate Clcrto to guide drug dosage adjustment. The study aimed to compare the eight methods to estimate Clcr with measured Clcr. In addition, the study also aimed to determine the agreement between estimated Clcr with measured Clcr. This was a multicentre, prospective, observational study. Three intensive care units in Malaysia tertiary public hospitals. Two serum creatinine samples over 24 hours apart and simultaneously 24 hours urine collection. A total of 43 patients were recruited. During the early phase of unstable kidney functions (regardless of acute deteriorating or acute improving), only the modified Cockcroft-Gault method showed a non-significant different with the measured Clcr (p = 0.741). A sub-set analysis on 23 patients with acute deteriorating kidney functions was performed. Only the modified Cockcroft-Gault revealed a non-significant different with the measured Clcr (p = 0.843). Sub-set analysis performed on 20 patients with rapid improving kidney functions, the Chiou method greatly underestimated the Clcr by approximately 34%, p < 0.001. Bland-Altman analysis revealed that Clcr estimated with modified Cockcroft-Gault method showed agreement to measured Clcr, p > 0.05. Owing to the precision of estimation and the consistency (reproducibility) as well as the simplicity of the modified Cockcroft-Gault method, it should be the reliable method to assess renal function in critically ill patients with unstable kidney function.