Background SLEDAI-2K Responder Index-50 (S2K RI-50) is a novel index that measures partial recovery (PR), ≥50% improvement in active descriptors.
Objectives To determine: 1) PR and complete recovery (CR) in active systems on standard of care (SOC) treatment and 2) the benefit of measuring ≥50% improvement in active descriptors with S2K RI-50.
Methods Patients seen from February 2009 to May 2012 with at least one active system were analysed. We excluded patients with CNS or with nephrotic range proteinuria lupus nephritis. CR was measured with SLEDAI-2K and PR with S2K RI-50.
Results 548 patients (90% F) with at least one active SLEDAI-2K system were analyzed. Age at lupus diagnosis was 29.2 ± 12.3 years and disease duration at study inclusion was 15.2 ± 11.0 years. Among the 8 system studied at baseline, the most commonly represented systems were: immunology, renal, mucocutaneous and musculoskeletal. In 117 patients with mucocutaneous involvement, CR by SLEDAI-2K was achieved by 68 patients at 6 months, by 95 patients at 12 months and 106 patients at 2 years. PR and CR by S2K RI-50 were identified in 83 patients at 6 months, 105 patients at 12 months and 113 patients at 2 years. The number of patients who achieved PR and CR by S2K RI-50 was greater than the number of patients who achieved CR by SLEDAI-2K in all studied systems (Table 1). The total possible score for the mucocutaneous system by SLEDAI-2K is 6. At baseline visit the total score for the mucocutaneous system was 2.56±1.01. At 6 months the score decreased to 1.02±1.51, at 12 months to 0.47±1.07 and to 0.27±0.91 at 2 years by SLEDAI-2K. At 6 months the score decreased to 0.87±1.35, 12 months to 0.40±0.95 and at 2 years to 0.20±0.67. The decrease of S2K RI-50 scores was greater than the decrease of SLEDAI-2K scores in all active systems.
Conclusions With SOC treatment, patients improve progressively over a 2 year period. The use of S2K RI-50 allows the capture of an additional number of patients with ≥50% improvement in active systems not discerned by SLEDAI-2K. S2K RI-50 will allow for an earlier signal of efficacy with new agents in therapeutic trials.
Disclosure of Interest None Declared