Figure 1.
Flow diagram of selection strategy and article reviews.
Flow diagram is in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).
Table 1.
Test properties of the NDSS case definition.
Figure 2.
Forest plots of sensitivities and specificities of the NDSS case definition reported by included validation studies.
ES (95%CI): Summary estimate (95% confidence interval); Charts: Reference standard by medical chart review; Survey: Reference standard by patient self-report from population-based survey.
Figure 3.
Random-effects bivariate regression analysis of the pooled test accuracies from 6 studies.
The Hierarchical Summary Receiver Operator Characteristics (HSROC) curve displays the 95% confidence interval of the summary operating point and the 95% prediction region, which is the confidence region for a forecast of the true sensitivity and specificity in a future study. The shape of the prediction region is generated based on the assumption of a bivariate normal distribution for the random effects model. The Empirical Bayes estimate gives the best estimate of the true sensitivity and specificity of each study and these estimates will be shrunk towards the summary point compared with the study-specific estimates. The stronger the shrinkage, the greater the precision of the test estimate. The random-effects bivariate regression analysis could not be done for the subgroups stratified by validation method because the small number of studies.
Figure 4.
Crude and adjusted prevalence of diabetes in Canada.
Crude prevalence: prevalence of diabetes in Canada for fiscal years 2002/3 through 2006/7 obtained from the NDSS 2009 report [25]; Adjusted prevalence: prevalence after applying correction factors [(Prevalence(%) - 2.1)/0.802)]; The margins of error for all adjusted prevalence and crude prevalence estimates were ∼0.01% (n∼25 000 000). Projected crude prevalence: future prevalence assuming an increase of 0.4% per year; Projected adjusted prevalence: future prevalence after applying correction factors; Total diabetes: Estimated prevalence of physician-diagnosed and undiagnosed diabetes assuming 1/3 of total diabetes is undiagnosed. The crossover point of the crude and adjusted prevalence lines is ∼10.6% around year 2013.