Fourth, we did not have access to disease verifications, but self-reports of diagnosed diabetes have been shown to be valid (37).
Owing to these designs, nearly all studies (88%) suffered from the well-described and problematic disease-verification bias (Begg and Greenes, 1983; Lijmer et al, 1999; Mol et al, 2003; Whiting et al, 2004; Rutjes et al, 2005; Biesheuvel et al, 2008).
Although PET-CT performed well for exclusion of disease histological verification was available in only a small number of patients.
Thus, different individuals may not be at the same stage of development along the path to disease, although verification is usually not possible.
The standard analysis includes all study participants, which can create bias in the estimates of diagnostic accuracy since not all participants receive disease status verification.
Although cross-sectional studies are well suited for prevalent but undiagnosed disease, additional verification or development of a new model for incident diabetes based on prospective studies could be needed for the Korean population.
However, our finding of a possible relationship between post-challenge hyperglycaemia and long-term mortality from infectious diseases needs verification and should be interpreted with care.
Items included covered patient spectrum, reference standard, disease progression bias, verification bias, review bias, clinical review bias, incorporation bias, test execution, study withdrawals, and indeterminate results.
For our simulations, we used data sets with 5000 subjects, a 10% incidence of disease and a verification rate as low as 10%.
