Different subpopulations of mild cognitive impairment are identified by using Petersen's or DSM-5 criteria

Abstract Objectives In view of differences in the prevalence and conversion rate to dementia of Petersen's (P-MCI) and DSM-5's (DSM-5-MCI) categories of mild cognitive impairment, this paper is intended to examine the diagnostic agreement between the categories and to analyze clinical factors related to the potential discrepancies. Method A representative population cohort of 4580 dementia-free individuals 55+ years of age was examined in Zaragoza, Spain (ZARADEMP). Validated Spanish versions of instruments, including the Geriatric Mental State-AGECAT, were used for assessment. Research psychiatrists diagnosed DSM-5-MCI and P-MCI following operationalized criteria. Between-category differences were analyzed, and the statistical methods included the calculation of Cohen's Kappa coefficients of agreement, and the McNemar's test to compare the performance of the intermediate cognitive definitions. Results Diagnostic concordance in the classification of MCI cases was very limited. In the total sample, 2.7% of individuals did not meet the P-MCI criteria but met the DSM-5-MCI criteria; and 6.4% met the P-MCI criteria, but not the DSM-5-MCI criteria. Overlap of both categories was observed in only 0.6%. The overall Kappa (agreement between both MCI categories) was 0.08 (95% CI: 0.04–0.12; p While no between-category significant differences was observed in cognitive scores, relevant differences in the populations identified had to do with demographic, non-cognitive psychopathological factors, activities of daily living and general health factors. Conclusions This study shows ‘poor’ diagnostic agreement between the P-MCI and the DSM-5-MCI categories. The non-cognitive factors should receive special attention when trying to improve the validity of the MCI construct.