Cognitive assessment in elderly patients admitted to hospital: the relationship between the Abbreviated Mental Test and the Mini-Mental State Examination

Objective: To determine the relationship between Abbreviated Mental Test (A MT) and the Mini-Mental State Examination (MMSE) in elderly patients admitt ed to hospital. Design: Prospective study of 364 consecutive admissions to an elderly medic ine unit. Eighty-eight (24.2%) patients were excluded. The AMT and MMSE wer e administered to the remaining 276 patients and the relationship between t he two tests evaluated statistically. Setting: inner city teaching hospital. Subjects: Two hundred and seventy-six patients admitted to the elderly medi cine unit during October and November 1997. Main outcome measures: Predictive efficiency of the AMT for cognitive state by MMSE (the percentage of patients whose cognitive state by the MMSE was correctly categorized by the AMT). Association and predictive relationship between individual AMT and MMSE scores. Results: There was a significant relationship between cognitive state as de termined by the AMT and MMSE: chi(2) = 101.3, df = 1, p <0.001, The predict ive efficiency of the AMT was 79.0% (218/276). A strong association was fou nd between the AMT and MMSE (Somers' d statistic 0.75. p <0.001). Simple li near regression allowed prediction of the MMSE score from the AMT score as follows: MMSE score = 7.06 + (1.94 x AMT score); p <0.001. Conclusions: In patients admitted to the elderly medicine unit, the AMT gav e predictive information about cognitive status as determined by the MMSE, and also a prediction of likely MMSE score.