Background: Microalbuminuria (MA) has long been associated with development of chronic kidney diseases in diabetic or hypertensive patients. However, its value in predicting acute kidney injury (AKI) in an intensive care unit (ICU) setting has never been reported. This study aimed to investigate the link between MA and AKI.
Methods: Septic patients without AKI on entry to the ICU were enrolled from October 2010 to December 2011 in an 18-bed ICU. Urinary albumin to creatinine ratio (ACR) was measured in the morning on day 2. Patients were then followed up for the development of AKI, ICU length of stay (LOS) and hospital mortality, and the associations of those with initial ACR were tested. Diagnostic performance of ACR in predicting AKI was evaluated using receiver operating characteristic curves.
Results: A total of 84 septic patients were enrolled during the study period, of whom 36 developed AKI and 48 did not. ACR on ICU entry was an independent predictor of AKI (odds ratio [OR] = 1.02; p<0.01). The area under the curve of ACR in predicting AKI was 0.86 (95% confidence interval [95% CI], 0.77-0.94), with a sensitivity and specificity of 91.7% and 79.2%, respectively, at a cutoff of 143 mg/g. ACR was significantly higher in nonsurvivors than in survivors (198 vs. 133 mg/g; p = 0.02). In a linear regression model, ACR values significantly correlated to ICU length of stay (LOS = 0.02 × ACR + 8.19; 95% CI for the coefficient: 0.007-0.033; p = 0.002).
Conclusion: ACR obtained on entry to ICU was highly predictive of AKI, and was also associated with mortality rate and ICU length of stay.