[A comparative study of 2- and 24-hour creatinine clearance in patients in intensive care unit]

Objective: To analyze the correlation and consistency of 2- and 24-hour endogenous creatinine clearance rate (Ccr) in patients in the intensive care unit (ICU). Methods: It was a prospective bicentric observational study.According to the inclusion criteria, the patients were selected from the ICU of Fuxing Hospital Affiliate to Capital University of Medical Sciences and Chuiyangliu Hospital Affiliated to Tsinghua University from September 2015 to December 2016.After inclusion, the mixed urine sample was collected at 9-11 am, 9-11 pm and all day long (7 am-7 am, 24 hours). The urine volume was recorded and the urine creatinine was detected.The correlation and consistency analysis of Ccr were applied in the group of 9-11 am, 9-11 pm and 7 am-7 am.Clinical data including sex, age, acute physiology and chronic health evaluation Ⅱ(APACHE Ⅱ), the use of diuretics, mean arterial pressure, blood glucose and body temperature were recorded for the analysis of the factors affecting correlation and consistency of Ccr between 2 h and 24 h. Results: A total of 158 cases were included, 82(51.9%) cases were males, the mean age was (76±13) years, the APACHE Ⅱ score was 19±8.And 83 patients (52.5%) were admitted to the ICU due to pulmonary disease.The average Ccr in the group of 24 h was (70±58) ml/min, the Ccr in 105 patients (66.5%) was less than 80 ml/min, it was less than 60 ml/min in 88 patients (55.7%) and was less than 30 ml/min in 33 patients (20.9%). The fasting serum creatinine level in the second day morning after admitted to ICU was 77.0(52.8, 122.2) μmol/L.The correlation analysis showed that the relative indices of R(2) between the 24hCcr and 2hCcr in the morning (9-11 am) and evening (9-11 pm) was 0.704 and 0.825, respectively, both P<0.01, and the bias was -2.3 and 0.3 ml/min.The patients were divided into group A (D-value≤20%) and B (D-value>20%) according to the Ccr D-value of the 24 h and the 2 h in morning.There were 72 patients (45.6%) in group A, and 86 patients (54.4%) in group B. The multiple Logistic regression analysis indicated that the factors affecting the correlation and consistency between 2hCcr and 24hCcr were body temperature, age and the D-value of serum creatinine, and the odd ratio (95%CI) was 1.844(1.112-3.059), 1.046(1.020-1.072), 1.038(1.003-1.074), respectively, all P<0.05. Conclusions: There is significant correlation and consistency between 2hCcr and 24hCcr in ICU patients.And in most of the cases, the 24hCcr can be replaced by random 2hCcr, but the affecting factors of body temperature, age and the D-value of serum creatinine should be taken into account.