SF-36 summary and subscale scores are reliable outcomes of neuropsychiatric events in systemic lupus erythematosus

Abstract

Objective To examine change in health-related quality of life in association with clinical outcomes of neuropsychiatric events in systemic lupus erythematosus (SLE). Methods An international study evaluated newly diagnosed SLE patients for neuropsychiatric eventsattributed to SLE and non-SLE causes. The outcome of events was determined by a physician-completed sevenpoint scale and compared with patient-completed ShortForm 36 (SF-36) health survey questionnaires. Statistical analysis used linear mixed-effects regression models with patient-specific random effects. Results 274 patients (92% female; 68% Caucasian), from a cohort of 1400, had one or more neuropsychiatric event in which the interval between assessments was 12.3±2 months. The overall difference in change between visits in mental component summary (MCS) scores of the SF-36 was significant (p<0.0001) following adjustments for gender, ethnicity, centre and previous score. A consistent improvement in neuropsychiatric status (N=295) was associated with an increase in the mean (SD) adjusted MCS score of 3.66 (0.89) in SF-36 scores. Between paired visits when the neuropsychiatric status consistently deteriorated (N=30), the adjusted MCS score decreased by 4.00 (1.96). For the physical component summary scores the corresponding changes were +1.73 (0.71) and -0.62 (1.58) (p<0.05), respectively. Changes in SF-36 subscales were in the same direction (p<0.05; with the exception of role physical). Sensitivity analyses confirmed these findings. Adjustment for age, education, medications, SLE diseaseactivity, organ damage, disease duration, attribution and characteristics of neuropsychiatric events did not substantially alter the results. Conclusion Changes in SF-36 summary and subscale scores, in particular those related to mental health, are strongly associated with the clinical outcome of neuropsychiatric events in SLE patients.