Is the presence of mild to moderate cognitive impairment associated with self-report of non-cancer pain? A cross-sectional analysis of a large population-based study.

Abstract

Research, guidelines, and experts in the field suggest that persons with cognitive impairment report pain less often and at a lower intensity than those without cognitive impairment. However, this presupposition is derived from research with important limitations, namely, inadequate power and lack of multivariate adjustment. We conducted a cross-sectional analysis of the Canadian Study of Health and Aging to evaluate the relationship between cognitive status and pain self-report. Cognitive status was assessed using the Modified Mini-Mental State Examination. Pain was assessed using a 5-point verbal descriptor scale. For analysis, responses were dichotomized into "no pain" vs. "any pain" and "pain at a moderate or higher intensity" vs. "pain not at a moderate or higher intensity." Additional predictors included demographics, physical function, depression, and comorbidity. Of 5,703 eligible participants, 306 (5.4%) did not meet inclusion criteria, leaving a total of 5,397, of whom 876 (16.2%) were cognitively impaired. In the unadjusted analysis, significantly more cognitively intact (n=2,541; 56.2%) than cognitively impaired (n=456; 52.1%; P=0.03) participants reported noncancer pain. There was no significant difference in the proportion of cognitively intact (n=1,623; 35.9%) and impaired (n=329; 37.6%; P=0.36) participants who reported pain to be at moderate or higher intensity. In multivariate analyses, cognitively impaired participants did not have lower odds of reporting any noncancer pain (odds ratio [OR]=0.83 [0.68-1.01]; P=0.07) or pain at a moderate or higher intensity (OR=0.95 [0.78-1.16]; P=0.62). Non-cancer pain was equally prevalent in people with and without cognitive impairment, which contrasts with the currently held opinion that cognitively impaired persons report noncancer pain less often and at a lower intensity.