Objective: This study was designed to assess the effects of corticosteroids on select aspects of nervous system functioning, specifically, cognition and mood, as well as disease-related symptoms in individual patients with mild systemic lupus erythematosus (SLE) and mild neuropsychiatric (NP) symptoms.
Methods: Ten women who had not been taking corticosteroids for at least 6 months were selected from a referral-based lupus clinic to participate in an N of 1 double-blind, controlled trial consisting of 3 randomly assigned drug/placebo pairings, with a drug dose of 0.5 mg/kg of prednisone daily.
Results: Analysis of variance on the group data yielded significant positive drug effects for cognition (P = 0.02), mood (P = 0.003), and SLE symptom ratings (P = 0.0002). Drug efficacy was also evaluated by an objective decision rule, which yielded evidence of overall drug benefit in 5 of the 8 patients who completed the trial, and a deleterious drug effect in 1 patient. Posttrial clinical results indicated that for the 8 women who completed the trial, "acceptable" decisions, leading to remission of SLE symptoms or appropriate withholding of steroids, were made on the basis of this rule.
Conclusion: Improvement in cognition, mood, and/or SLE symptom ratings can be observed following brief exposure to relatively low doses of corticosteroids in individual women with mild SLE; these persist over repeated drug exposure. The current application of N of 1 methodology represents the first systematic study of steroid efficacy in central nervous system (CNS)-related problems in SLE. The results can now be applied to the design of randomized, controlled trials of the effects of corticosteroids on CNS function in SLE.