Background For persons with chronic diseases such as rheumatoid arthritis (RA), intact cognitive function is crucial for performing main daily activities and adhering to self-management regimens. Persons with impaired cognitive function have decreased functional independence, reduced quality of life, and increased risk of mortality. Although several mechanisms may influence cognitive function in RA, it has not been well-studied in this population.
Objectives This study explored the prevalence of cognitive impairment in persons with RA using a set of computerized neurocognitive tests and the factors that were significantly correlated with cognitive impairment.
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. Cognitive function 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 . The total cognitive impairment score was calculated by summing the transformed scores, ranging from 0 (no impairment) to 18 (worst impairment). Pearson correlation coefficient analyses were conducted to identify the variables that might be significantly associated with cognitive impairment.
Results Twenty three subjects with a mean (±SD) age of 64.9 (±12.4) years were included in preliminary analyses. 87% were female, 87% were married, and mean educational level was 9.7 (±5.2) years. Mean DAS-28 level was 2.6 (±1.2) and mean disease duration was 116.5 (±85.4) months. Mean HAQ score was 0.6 (±0.8) and mean cardiovascular disease (CVD) risk factors were 3.1 (±1.5). 35% had depression and 70% had sleep problems. The proportion of persons who were classified as cognitively impaired on each test were 34% in Card Sorting Test (executive function), 68% in Trail Making Test (visuo-motor coordination), 78% in Visual Span Test (language memory), 83% in Verbal Learning Test (visuo-spatial memory), 83% in Visual Continuous Performance Test (continuous attention), and 91% in Word-Color Test (selective attention). Mean total cognitive impairment score was 11.0 (±4.2), and ranged from 2–17. 95% were classified as cognitively impaired on five or more test indices. Education (r=-514, p<.05), income (r=-.638, p<.05), and CVD risk factors (r=.434, p<.05) were significantly correlated with total cognitive impairment score.
Conclusions A significant number of RA patients were cognitively impaired. Low educational levels, low income, and increased CVD risk factors may be potential risks of cognitive impairment in this population. These findings suggest that the burden of cognitive impairment in RA is significant, and future studies identifying specific etiological contributors to cognitive impairment are warranted.
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.
Acknowledgement This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (No.2014R1A1A1002988).
Disclosure of Interest None declared