UCSF

The purpose of this dissertation was to examine the prevalence and possible predictors of cognitive impairment, and the relationship of cognitive impairment with functional limitations and disability in persons with rheumatoid arthritis (RA). Individuals from a longitudinal cohort study of RA participated in study visits that included physical, psychosocial, and biological metrics. Cognitive function was assessed using a battery of 12 standardized neuropsychological measures yielding 16 indices covering a range of cognitive domains. On each test, subjects were classified as impaired if they performed 1 SD below age-based population norms. Total cognitive function scores were calculated by summing the transformed scores (range 0-16; higher scores=greater impairment). Functional limitations and disability were assessed with both performance-based and self-reported measures. Logistic regression analyses were conducted to identify which of the following were significant predictors of cognitive impairment: gender, race, income, education, depression, disease duration, disease severity, C-reactive protein (CRP), glucocorticoid use, and cardiovascular disease (CVD) risk factors. Multiple regression analyses, controlling for gender, race, education, marital status, income, disease duration, disease severity, CRP, and depression were conducted to identify whether cognitive impairment was independently associated with physical function difficulties. The proportion of persons who were classified as cognitively impaired on at least 4 of 16 indices was 31%. Education, income, glucocorticoid use, and CVD risk factors independently predicted cognitive impairment controlling for gender, race, disease duration, disease severity, CRP, and depression. Individuals with cognitive impairment were more likely to have low education (OR = 6.18, 95% CI: 1.6-23.87), low income (OR = 7.12, 95% CI: 1.35-37.51), use oral glucocorticoids (OR = 2.92, 95% CI: 1.05-8.12), and have increased CVD risk factors (OR = 1.61, 95% CI: 1.19-2.17 per risk factor). In multivariate regression models, total cognitive function scores were significantly associated with greater functional limitations (p<.05) but not with disability (p=.120). The findings of this study suggest that the burden of cognitive impairment in RA is significant, and future studies identifying specific etiological contributors to cognitive impairment are warranted. In addition, consideration of cognitive impairment may be warranted to improve functional status in persons with RA..