Screening for microalbuminuria to prevent nephropathy in patients with diabetes - A systematic review of the evidence

OBJECTIVE Our goal was to evaluate whether screening patients with diabetes for microalbuminuria (MA) is effective according to the criteria developed by Frame and Carlson and those of the US Preventive Services Task Force. STUDY DESIGN We searched the MEDLINE database (1966-present) and bibliograp hies of relevant articles. OUTCOMES MEASURED We evaluated the impact of MA screening using published c riteria for periodic health screening tests. The effect of the correlation between repeated tests on the accuracy of a currently recommended testing s trategy was analyzed. RESULTS Quantitative tests have reported sensitivities from 56% to 100% and specificities front 81% to 98%. Semiquantitative tests for MA have reporte d sensitivities from 51% to 100% and specificities from 21% to 100%. First morning, morning, or random urine sampling appear feasible. Assuming an ind ividual test sensitivity of 90%, a specificity of 90%, and a 10% prevalence of MA, the correlation between tests would have to be lower than 0.1 to ac hieve a positive predictive value for repeated testing of 75%. CONCLUSIONS Screening for MA meets only 4 of 6 Frame and Carlson criteria f or evaluating screening tests. The recommended strategies to overcome diagn ostic uncertainty by using repeated testing are based on expert opinion, ar e difficult to follow in primary care settings, do not improve diagnostic a ccuracy sufficiently, and have not been tested in a controlled trial. Altho ugh not advocated by the American Diabetes Association, semiquantitative MA screening tests using random urine sampling have acceptable accuracy but m ay not be reliable in all settings.