Validation of capillary glycemia as a strategy for the screening of diabetes mellitus in adolescents

Abstract

To compare the degree of concordance between plasma and capillary glucose for screening of diabetes mellitus in adolescents. The plasma and capillary glucose of 119 adolescents aged 10-19 yr (36 males and 83 females) from public schools in Niterói, Rio de Janeiro State, Brazil, were verified after a 12-h fast. Agreement was assessed through kappa statistics (k), McNemar's chi-squared test, and the intraclass correlation coefficient (ICC). The paired Student's t-test for comparison of means, the approaches by Altman and Bland, and the survival-agreement plot were also applied. Mean values of plasma glucose were 7.9 points higher than the capillary values (91.5 vs. 83.6 mg/dL, p < 0.001; ICC = 0.419). A regular agreement between the methods (k = 0.31, p < 0.001) for assessing proportions of adolescents with glycemia > or =100 mg/dL is observed. Using the strategy of adding 8 mg/dL to the capillary levels, the agreement improved (k = 0.46, p < 0.001) and a significant difference was not observed between the estimated prevalences (p = 0.815). The results suggest a satisfactory agreement between the two methods when capillary glucose is corrected, and this may be a useful and low-cost tool for the epidemiologic investigation of diabetes mellitus prevalence in adolescents.