Objectives: To study the yield of three instruments for detection of patients with cognitive impairment in primary care. To investigate whether combining tests is better for detecting impairment than applying them separately.
Methods: Seven primary care physicians (PCP) systematically recruited individuals aged over 49 years with a complaint or suspicion of cognitive impairment. The tests administered were the Mini-Mental State Test (MMS), the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) and the Pfeffer Functional Activities Questionnaire (FAQ). We calculated sensitivity, specificity and the area under the curve (AUC) and applied logistic regression analysis to determine the yield of the tests in combination. The gold standard was the clinical judgement of a neurologist based on a comprehensive assessment, which included a formal neuropsychological workup.
Results: Of the 160 study patients, 90 (56%) had cognitive impairment (15 of these had dementia). The MMS had a sensitivity of 77% and a specificity of 70% in screening for cognitive impairment, with an AUC of 0.82. Incorporation of the IQCODE increased the AUC to 0.86 (P = 0.01). As for dementia, the FAQ reached a sensitivity of 87% and a specificity of 82%, with an AUC of 0.91. Incorporation of the MMS increased the AUC to 0.95 (P = 0.03).
Conclusions: Cognitive impairment is probably underdiagnosed in primary care. The combination of the FAQ and the MMS had excellent performance for dementia detection; however, no satisfactory instrument or instrument combination could be found for cognitive impairment.