Objective: To compare the diagnostic accuracy of an outcome measurement scale of the Minimum Data Set of the Resident Assessment Instrument for nursing homes (MDS/RAI-NH), the Cognitive Performance Scale (CPS) and the Mini-Mental State Exam (MMSE) for the detection of cognitive impairment. The Cambridge Examination for Mental Disorders of the Elderly--Revised (CAMDEX-R) was used as the reference standard.
Study design and setting: This study was part of a larger prospective study (QUALIDEM) involving a diagnostic procedure and two-year follow-up on the quality of primary care for demented patients. CAMDEX-R and MDS/RAI-NH were administered to 198 residents, aged 65 or more, living in 42 low and high care institutions for aged people.
Main outcome measures: Indicators of diagnostic accuracy: sensitivity, specificity, predictive values, likelihood ratios, odds ratio and area under receiver operating characteristics curve (AUC).
Results: The CAMDEX-based prevalence of cognitive impairment was 75%. The diagnostic values of a CPS score of two or more for the detection of cognitive impairment were: sensitivity = 0.81; specificity = 0.80; PPV = 0.92; NPV = 0.57. The diagnostic values of a MMSE score of less than or equal 23 were: sensitivity = 0.97; specificity = 0.59; PPV = 0.88; NPV = 0.85. For CPS, the area under the receiver operating characteristic (ROC) curve was 0.87 (95% CI, 0.81-0.91), and not significantly different (p = 0.63) from the MMSE score, 0.88 (0.83-0.93).
Conclusions: CPS and MMSE demonstrated similar performance to detect cognitive impairment in nursing home residents.