Assessing Cognitive Impairment in the Health and Retirement Study Harmonized Cognitive Assessment Protocol Project: Comparing a Diagnostic Algorithm With a Diagnostic Consensus Panel

BackgroundAccurate classification of cognitive impairment in population studies is challenging.ObjectiveTo compare the performance of a diagnostic algorithm with a clinical consensus panel.SampleIn 2016, the Health and Retirement Study (HRS) implemented the Harmonized Cognitive Assessment Protocol Project (HRS-HCAP) to streamline cognitive assessments for select HRS participants.MethodsThe Manly-Jones HCAP diagnostic classification was used to classify cognitive status as normal, mild cognitive impairment (MCI), or dementia. For this analysis, a consensus panel of five clinicians reviewed 50 cases with high diagnostic uncertainty, each reviewing 30 cases, blinded to the algorithm's classifications.AnalysisDiagnostic concordance was assessed using unweighted and weighted Cohen's kappa (κ).ResultsUnweighted concordance was 70% (35/50), with discordance mostly among MCI cases. Weighted concordance was 84%. Unweighted κ was 0.56 (95% CI 0.30-0.81) and weighted κ was 0.75 (95% CI 0.49-0.91), indicating moderate to substantial agreement between the two methods.