Diagnostic accuracy of the Brief Assessment of Impaired Cognition case-finding instrument in a general practice setting and comparison with other widely used brief cognitive tests-a cross-validation study.

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The aim of this study was to examine the discriminative validity of the Brief Assessment of Impaired Cognition (BASIC) case-finding instrument in a general practice (GP) setting and compare it with other widely used brief cognitive instruments. Patients aged ≥70 years were prospectively recruited from 14 Danish GP clinics. Participants were classified as having either normal cognition (n = 154) or cognitive impairment (n = 101) based on neuropsychological test performance, reported instrumental activities of daily living, and concern regarding memory decline. Comparisons involved the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the Rowland Universal Dementia Assessment Scale (RUDAS), the Mini-Cog, the 6-item Clock Drawing Test (CDT-6) and the BASIC Questionnaire (BASIC-Q). BASIC demonstrated good overall classification accuracy with an area under the receiver operating characteristic curve (AUC) of 0.88 (95% confidence interval [CI] 0.84-0.92), a sensitivity of 0.72 (95% CI 0.62-0.80) and a specificity of 0.86 (95% CI 0.79-0.91). Pairwise comparisons of the AUCs of BASIC, MMSE, MoCA and RUDAS produced non-significant results, but BASIC had significantly higher classification accuracy than Mini-Cog, BASIC-Q and CDT-6. Depending on the pretest probability of cognitive impairment, the positive predictive validity of BASIC varied from 0.83 to 0.36, and the negative predictive validity from 0.97 to 0.76. BASIC demonstrated good discriminative validity in a GP setting. The classification accuracy of BASIC is equivalent to more complex, time-consuming instruments, such as the MMSE, MoCA and RUDAS, and higher than very brief instruments, such as the CDT-6, Mini-Cog and BASIC-Q.