THE MDS COGNITION SCALE - A VALID INSTRUMENT FOR IDENTIFYING AND STAGING NURSING-HOME RESIDENTS WITH DEMENTIA USING THE MINIMUM DATA SET

OBJECTIVE: We report the development and validation of an MDS-based co gnitive index, the MDS Cognition Scale (MDS-COGS), by evaluating it ag ainst two popular dementia rating scales, the Global Deterioration Sca le (GDS) and the Mini-Mental State Examination (MMSE). DESIGN: A Cross -sectional study. PARTICIPANTS: Two hundred nursing home residents. ME ASUREMENTS: Each study participant was assessed on the GDS and the MMS E by trained medical students. At the same time, but independent of th e medical students, a geriatric nurse completed the Minimum Data Set ( MDS) instrument on each participant. MAIN RESULTS: The Cognitive Perfo rmance Scale (CPS), a categorical measure of cognition that uses MDS i tems, was compared with the GDS in 133 subjects, using a split-sample technique. The GDS was found to be more appropriate as a 4-stage than a 7-stage scale, with GDS stages 1-4 acting as a single stage. The CPS showed very poor percent agreement with GDS stages 5 and 7 (50% or le ss) and, therefore, was revised by adding other MDS predictors. The ne w instrument, designated MDS-COGS, is a 0-10 point scale generated fro m eight MDS cognitive items. The MDS-COGS was then validated against t he 4-stage GDS and MMSE in the remaining 67 nursing home residents. Ch ance-corrected agreement (kappa) between the MDS-COGS and GDS in the 6 7 subjects was 0.80 (95% CI = 0.70, 0.88), and percent agreement with GDS stages 5 and 7 was 60% and 85%, respectively. The MDS-COGS was als o demonstrated to be a valid measure of cognitive impairment as define d by the MMSE, with sensitivity, specificity, chance-corrected agreeme nt (kappa), and area under the ROC curve, all above 0.80. CONCLUSIONS: The MDS Cognition Scale, the MDS-COGS, provides a valid measure of th e presence and severity of cognitive impairment in nursing home reside nts using items from the Minimum Data Set.