Objective: To prospectively evaluate changes in cognitive function in a cohort of unselected patients with systemic lupus erythematosus (SLE) and controls over a 12 month period.
Methods: Seventy female patients with SLE, 25 patients with rheumatoid arthritis (RA) and 23 healthy subjects (age and sex matched) were evaluated using the Wechsler Adult Intelligence Scale-Revised (WAIS-R), the Wechsler Memory Scale-Revised (WMS-R), the California Verbal Learning Test (CVLT) and the National Adult Reading Test-Revised to identify impairment in 8 areas of cognitive function. Cumulative disease manifestations and current medications were documented, and disease activity was expressed using the SLE disease activity index (SLEDAI). Decision rules were determined for overall cognitive impairment.
Results: At baseline, 21% (15/70) of patients with SLE were impaired compared to 4% (1/25) of patients with RA and 4% (1/23) of healthy subjects (p = 0.042). After a mean interval of 12.8 months (range: 11-17) 84% (59/70) of patients with SLE, 44% (11/25) of patients with RA and 80% (17/23) of healthy subjects were reassessed. This included all subjects who were impaired at the initial assessment. Using the same decision rules as at baseline, 12% (7/59) of patients with SLE were impaired at followup compared to none of the patients with RA and healthy subjects. Over the period of study cognitive impairment persisted in 3 patients with SLE, resolved in 12 and evolved in 4 others. There was no apparent association between changes in cognitive function and concurrent changes in generalized disease activity, overt neuropsychiatric disease or corticosteroid medication.
Conclusion: Our results suggest that cognitive dysfunction in patients with SLE is evanescent, does not necessarily lead to irreversible neurologic compromise and changes independently of other clinical variables.