CLINICAL AND STATISTICAL EVALUATION OF SELF-MONITORING BLOOD-GLUCOSE METERS

OBJECTIVE - Our objective was to compare statistical and clinical meth ods for the evaluation of five self-monitoring blood glucose (SMBG) me ters. RESEARCH DESIGN AND METHODS - Two successive capillary blood glu cose measurements were performed, and a simultaneous laboratory venous glucose measurement was used as the reference value. Accuracy was stu died by comparing each of the two successive meter values with the ref erence value by 1) a Spearman's correlation test, 2) a Wilcoxon's pair ed test, 3) the percentage of values within the 10% interval of the re ference Value according to the American Diabetes Association consensus statement, and 4) the error grid analysis. RESULTS - The first two me thods did not discriminate between the SMBG systems: r was >0.92 for t he five meters, and a significant difference between the meter and ref erence values was found for all but one meter. The two other methods a llowed classification of the devices into three groups according to th eir accuracy: good (two meters), acceptable (two meters), and unaccept able tone meter). These two methods gave consistent results and both h ad a good reproducibility, because the classification was similar for the two successive measurements. CONCLUSIONS - Both the Spearman's and Wilcoxon's paired tests, although commonly used, are inappropriate to evaluate SMBG systems. The percentage of SMBG values within the +/-10 % interval and the error grid analysis are more accurate, because they consistently classified the five glucose meters tested in our study w ith a high degree of reproducibility;