Cognitive dysfunction in systemic lupus erythematosus : a study comparing three criteria definition

Author(s)

Bruna Siqueira Bellini

• Document type: Master's Dissertation
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas
• Defense date: 28-08-2012

Examining board members

Cláudia Saad Magalhães; Maria Augusta Santos Montenegro

• Advisor: Simone Appenzeller

Abstract

Systemic Lupus Erythematosus (SLE) is an autoimmune disease, caused by an immune system dysfunction. Approximately, 15% of all cases of SLE are diagnosed in childhood. Non-specific cognitive deficits are common, affecting 30-78% of children and adolescents, and occur even in inactivity of disease or other neuropsychiatric manifestations. The aim of this study was to determine the frequency of cognitive impairment in patients with juvenile SLE and to identify the relationship with clinical and treatment aspects. Patients and Methods: We performed a cross-sectional study including patients with age of onset of disease ? 16 years and controls with the same gender, age and education. The subjects were divided in two groups according to the age evaluation: WISC group - age evaluation ? 16 years and 9 months; WAIS group - age evaluation ? 16 years and 10 months. We performed a battery of tests, selected from the American College of Rheumatology battery. Fifteen subtests were used to evaluate 13 cognitive functions. Cognitive dysfunction has been identified using three different criteria, according to the cutoff adopted and the number of abnormal functions required. Symptoms of anxiety and depression were assessed by the Beck scales. Disease activity was assessed by SLEDAI and cumulative damage by SLICC. The presence of antibodies and medication were also evaluated. Statistical analysis was performed using SPSS and significance level was 5% (p<0.05). Results: Sixty-four patients and 71 controls were included. The mean age of patients in the assessment WISC group was 13.43 ± 2.10 (mean ± SD, range 8-16 years) with a mean age of onset of 11.23 ± 3.21 and duration of 2.20 ± 2.63 years. In the WAIS group, the mean age at evaluation was 20.34 ± 3.42 (range: 16-29), with a mean age of onset and duration 13.76 ± 4.08 to 6.59 ± 4.72 years. Disease activity according to SLEDAI was identified in 40% of patients in WISC and 48.3% in WAIS. The frequency of dysfunction ranged from 11.4 to 60% in WISC and from 10.3 to 41.4% in WAIS. The criteria 1 (dysfunction = score of more than 2 SD below the standardized mean in 1 cognitive function, or scores between 1 and 2 SD below the mean in 2 or more functions) had the largest percentage of patients with deficits in both groups. The WAIS group showed a statistically significant difference in the frequency of dysfunction measured by criteria 1 and 2. In the whole group, this difference remained only for the criteria 2 (dysfunction = score more than 2 SD below the normative mean in 1 or more cognitive functions and cognitive decline = scores between 1.5 and 1.9 SD below published norms in 1 or more functions). The most affected cognitive functions in the WISC group were: processing speed and mental flexibility; in the WAIS group were processing speed, motor skills and semantic memory. The relationship with clinical-laboratory variables and treatment differed between the groups, according to the definition criteria adopted. There was no relation between cognitive impairment and education, age of onset / duration of illness, cumulative damage, presence of antibodies ds-DNA, Ro and Sm, chloroquine and use of immunosuppressive therapy. Conclusion: Changes in criteria for defining cognitive dysfunction led to significant changes in frequency rates. (AU)