Background Systemic lupus erythematosus (SLE) is a highly heterogeneous autoimmune rheumatic disease characterized by inflammation across multiple organ systems. The assessment of lupus patients is difficult and requires a complex approach. Multiple instruments to evaluate disease activity and damage have been developed in SLE but there is no agreement on a single activity index to be used universally.
Objectives To critically appraise the validity of activity and damage indices used in the assessment of patients with SLE.
Methods A systematic literature search was performed in MEDLINE, EMBASE, and the Cochrane Library (up to March 2012). Validation studies, cohort studies, reviews and meta-analyses were included. Selection criteria were: a) age ≥ 18 years, b) diagnosis of SLE defined by the ACR criteria, and c) the assessment of instruments to evaluate disease activity or damage, and assessment of validity of the instruments. A reviewer screened title/abstracts and collected data concerning validation using ad hoc forms.
Results From 704 initial studies captured, 37 articles and 1 review meeting the predefined criteria were identified. Studies addressed validation of 6 composite indices to evaluate disease activity: the British Isles Lupus Assessment Group (BILAG), the European Consensus Lupus Activity Measurement (ECLAM), the Systemic Lupus Activity Index (SLAM), the Systemic Lupus Erythematosus Disease Activity Measure (SLEDAI), the UCSF/JHU Lupus Activity Index (LAI) and the Systemic Lupus Activity Questionnaire (SLAQ); and 2 indices to evaluate damage: the Systemic Lupus International Collaborating clinics/American College of Rheumatology-Damage Index (SLICC/ACE-DI; SDI) and its patient self-administered version the Lupus Damage Index Questionnaire (LDIQ). Only the SLAQ and the LDIQ were self-administered, the others were completed by the physician. Internal consistency was only studied in the BILAG, the SLAQ and the SDI; Cronbach’s α ranged from 0.35 to 0.87. The reliability intra-observer or test-retest examined by intraclass correlation coefficient (ICC) ranged from 0.48 to 0.81. Construct validity, examined by means of convergence with other instruments, was generally similar between indices. Responsiveness was tested in all indices except LAI, SDI and LDIQ, with a standardized response mean (SRM) ranging from 0.12 to 0.75.
Conclusions Multiple instruments of disease activity have been fully validated for use in SLE. We found no direct evidence of what is the most useful index to follow up patients with SLE, although the two indices with a most completed validation and more used in RCT and cohorts are the BILAG and the SLEDAI.
Disclosure of Interest None Declared