Impact of cognitive function on assessments of nursing home residents' pain

Objectives: We sought to examine the impact of residents' cognitive function on the quality of Minimum Data Set (MDS) pain data using the latent variable approach. Research Design: Using the Resident Assessment Instrument (RAI) protocol, nursing home (NH) staff and well-trained study nurses independently assessed 3736 NH residents. Measures: Inter-rater agreement of pain ratings between NH staff and study nurses was quantified by weighted kappas and polychoric correlations and compared among groups of residents with no/mild, moderate, and severe cognitive impairment. Probit models were built to examine the effect of residents' cognitive function on thresholds raters used to rate pain. Results: Of 3736 residents, 40.4% had no/mild, 35.9% moderate, and 23.7% severe cognitive impairment. Both NH staff and study nurses recorded less frequent and less severe pain for residents with more severe cognitive impairment. The inter-rater agreement on pain ratings between NH staff and study nurses was goodweighted kappas were greater than 0.5 and polychoric correlations greater than 0.7. The thresholds raters used to record pain were similar for NH staff and study nurses and progressively increased when raters recorded pain for residents with more severe cognitive impairment. Conclusions: Given the RAI protocols, the quality of MDS pain data collected by NH staff was similar to that of well-trained nurses regardless of residents' cognitive function. Our results strongly support the notion that specialized pain assessment instruments are needed to adequately detect pain for the large proportion of cognitive impaired NH residents.