The Western Ontario and McMaster Osteoarthritis Index pain scale has not been used with cognitively impaired elders to measure their knee or hip pain. This study therefore examined the usefulness of the Western Ontario and McMaster Osteoarthritis Index pain scale for measuring pain in this population.
Fourteen cognitively impaired elders with osteoarthritis of the knee or hip participated in the study. Elders' pain was assessed with the Western Ontario and McMaster Osteoarthritis Index pain scale, the Verbal Descriptor Scale and the Present Pain Intensity Scale, twice 5 minutes apart. Proxy report of pain was provided by the nursing staff.
The correlations among the Western Ontario and McMaster Osteoarthritis Index pain scale, Verbal Descriptor Scale and Present Pain Intensity were between 0.77 and 1.00 (P < 0.01). All pain measures showed high test-retest reliability (r = 0.98-1.00, P < 0.01). Staff's pain ratings using the Western Ontario and McMaster Osteoarthritis Index pain scale were strongly correlated with elders' pain ratings using any pain measure (r = 0.68-0.80, P < 0.05 or P < 0.01). However, staff's pain ratings using either the Verbal Descriptor Scale or Present Pain Intensity had no association with elders' pain ratings (r = -0.07 to -0.30, P = NS).
The study confirmed that the Western Ontario and McMaster Osteoarthritis Index pain scale is as valid and reliable as the Verbal Descriptor Scale and Present Pain Intensity for elders with moderate and mild cognitive impairment. When used by staff, the Western Ontario and McMaster Osteoarthritis Index pain scale provides a better pain assessment for cognitively impaired elders than the Verbal Descriptor Scale or Present Pain Intensity.