A Cochrane review [Abstract] 1 included 13 studies with a total of 2745 individuals. A total of 1413 (51%) had dementia, but prevalence of dementia varied highly (10.5% to 87.4%). The studies were performed in secondary-care settings and included (not necessarily exclusively) Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) to assess the presence of dementia and whether dementia diagnosis was confirmed with clinical assessment. Pooled analysis of all studies using data presented closest to a cut-off of 3.3 indicated that sensitivity was 0.91 (95% CI 0.86 to 0.94); specificity 0.66 (95% CI 0.56 to 0.75); the positive likelihood ratio was 2.7 (95% CI 2.0 to 3.6) and the negative likelihood ratio was 0.14 (95% CI 0.09 to 0.22).There was a statistically significant difference in test accuracy between the general hospital setting and the specialist memory setting (p=0.019), suggesting that IQCODE performs better in a 'general' setting.No significant differences in the test accuracy of the short (16-item) versus the 26-item IQCODE was found, nor in the language of administration.
Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in the number of patients with dementia between studies) and indirectness (9 studies did not require an informant to be present at the consultation).
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