Background There is an increased appreciation of the burden of cognitive impairment in persons with rheumatoid arthritis (RA). Research shows a gap between subjective and objective measures of cognitive impairment in persons with chronic diseases.
Objectives This study explored the relationship between subjective cognitive dysfunction and computerized neuropsychological performance in Korean older adults with RA.
Methods Individuals with RA were recruited by their rheumatologists during follow-up visits at one university hospital in Korea. After getting signed consents, a trained research nurse assessed participants with a range of physical, psychosocial, and biological metrics. Subjective cognitive dysfunction was assessed using the Perceived Deficits Questionnaire (PDQ; range 0–20, higher score=greater impairment). Objective cognitive impairment was assessed using a set of 6 computerized neurocognitive tests yielding 18 indices covering a range of cognitive domains. Subjects were classified as “impaired” if they performed 1 SD below age-based population norms on each test . A total cognitive impairment score was calculated by summing the transformed scores (range: 0–18, higher score=greater impairment). Multiple regression analysis controlling for education, disease severity, and depression was conducted to identify the relationship between objective and subjective cognitive measures.
Results Fifty four subjects with a mean (±SD) age of 63.6 (±10.5) years were included in the final analyses. 85% were female and 87% were married. Mean educational level was 10.2 (±4.9) years and mean disease duration was 8.9 (±8.5) years. 25.9% had depression and 55.6% had sleep problem. Mean PDQ score was 11.8 (±4.5, range 5–25) and mean total cognitive impairment score was 11.0 (±4.1, range=2–18). 92% were classified as cognitively impaired on five or more test indices. There was no significant correlation between PDQ score and total cognitive function score (r=.260, p=.068). However, psychological factors including depression (r=.621, p<.001) and sleep problem (r=.577, p<.001) were significantly correlated with PDQ score. In the multivariate analysis, there was no significant relationship between PDQ score and total cognitive impairment score. However, functional limitations and depression (=0.317, p=0.048; =0.334, p=0.019) were significantly associated with the PDQ score.
Conclusions There was no significant relationship between subjective cognitive dysfunction and computerized neuropsychological performance in this cohort. Functional limitations and depression were significantly associated with perceived cognitive dysfunction. Findings emphasize the gap between subjective and objective measures of cognitive impairment and the importance of considering psychological factors in the context of cognitive complaints in clinical settings.
Kozora, E., Ellison, M. C., & West, S. (2004). Reliability and validity of the proposed American College of Rheumatology neuropsychological battery for systemic lupus erythematosus. Arthritis Care & Research, 51(5), 810–818.
Acknowledgements This research was supported by the 2015 Inje University research grant (No.20151092).
Disclosure of Interest None declared