Does microalbuminuria predict illness severity in critically ill patients on the intensive care unit? - A systematic review

Context. Studies assessing the accuracy of microalbuminuria to predict illness severity on the intensive care unit have produced inconsistent results. Objective: To determine the diagnostic accuracy of microalbuminuria to predict illness severity in critically ill patients on the intensive care unit. Data Source. MEDLINE (1951 to September 2004) and EMBASE (1980 to September 2004) electronic databases were searched for relevant studies. Reference lists of all abstracts were manually searched to identify studies not included in the electronic database. Study Selection: Studies that prospectively evaluated the accuracy of microalbuminuria to predict illness severity and/or mortality probability in adult patients on the intensive care unit were selected. Data Extraction: We included nine studies in the review. Data to evaluate methodological quality and results were abstracted. Data Synthesis: The methodological quality of a number of studies was poor. Significant heterogeneity in the design and conduct of the studies circumvented the data being subjected to meta-analysis. Studies also differed in the timing of the index test, in the methods of quantifying microalbuminuria, and in the cutoff values used. Conclusions: This descriptive analysis reveals that microalbuminuria may hold promise as a predictor of illness severity and mortality on the intensive care unit. However, future epidemiologic studies need to be conducted to determine the optimal timing as well as the threshold reference value for the urine albumin creatinine ratio in the adult intensive care unit population. Thereafter, multiple-center prospective epidemiologic studies must be conducted to confirm and validate the findings of these preliminary studies. Future studies should conform to the Standards for Reporting of Diagnostic Accuracy checklist in terms of study design, conduct, and reporting. Presently there is no evidence to warrant the use of this tool on the intensive care unit.