Objective: To explore the relationship between an elderly subject's cognitive status and the reliability of multidimensional assessment data.
Design: Survey, with cognitive status as the independent variable and interrater reliability as dependent variable.
Setting: Medicare/Medicaid-certified nursing homes.
Participants: 147 residents age 65 or older.
Measurements: Dual assessments of elderly nursing home residents were performed by nurse assessors using the Health Care Financing Administration's new Minimum Data Set for Nursing Home Resident Assessment and Care Screening (MDS). Assessments were classified on the basis of residents' cognitive status, and levels of disagreement between assessors were analyzed.
Main results: Overall assessment reliability, agreement concerning a resident's activities of daily living status, and the reliability of estimates of his or her communication skills and sensory abilities were significantly affected by a resident's cognitive status. The presence of cognitive impairment made these measurements less reliable--especially those related to communication skills, vision, and hearing.
Conclusions: Assessments of residents suffering from cognitive impairment were significantly less reliable than assessments of cognitively intact residents. However, these differences in reliability were not uniform across all assessment domains. When treating the cognitively impaired elderly, clinicians must exercise caution in their reliance on standardized measurements that may be less reliable for this population.