Domains for inclusion in a novel Treatment Response Measure for Systemic Lupus Erythematosus (TRM-SLE): results of a modified Delphi study.

Objectives: To achieve consensus on domains of active disease for inclusion in a novel outcome measure for SLE randomised controlled trials (RCTs), the Treatment Response Measure for SLE (TRM-SLE).

Methods: Domains nominated by TRM-SLE Taskforce members were rated in a two-stage modified Delphi study. Each stage comprised two online survey rounds separated by a structured discussion meeting. In Stage 1, expert lupus clinicians and patient representatives rated domain 'importance' (impact on symptoms, function or survival). In Stage 2, clinicians rated 'important' domains on three characteristics relevant to RCT utility: 'appropriateness' for evaluating change in disease activity, 'representation' in patients with active SLE and 'measurability' in an RCT context. Consensus for domain inclusion was prespecified as all four characteristics achieving a rating ≥7 on a 1-9 scale by ≥70% of participants.

Results: Domain nominations from 36/59 (61%) TRM-SLE Taskforce members yielded 34 potential domains which were rated in the modified Delphi study. At least one Delphi round was completed by 87 clinicians and 13 patient representatives. In Stage 1, 14 domains met consensus on 'importance' in both clinician and patient groups, and 11 domains met consensus among patients only. After Stage 2, eight of these domains also reached consensus on 'appropriateness', 'representation' and 'measurability': alopecia, arthritis, haemolytic anaemia, nephritis, mucosal ulcers, rash, serositis and thrombocytopenia.

Conclusions: Considering patient and clinician perspectives, we reached consensus to include eight disease activity domains for future development into the novel TRM-SLE clinical trial outcome measure, aiming to improve trial interpretability and success.