Remission definitions guiding immunosuppressive therapy in rheumatoid arthritis: which is best fitted for the purpose?

Abstract

Objective: To assess which definition of remission best predicts good radiographic outcome (GRO) and good functional outcome (GFO) in rheumatoid arthritis, focusing the updated American College of Rheumatology/European Alliance of Associations for Rheumatology criteria.

Material and methods: Meta-analyses of individual patient data (IPD) from randomised controlled trials (RCTs). Six definitions of remission were considered: (1) Boolean with Patient Global Assessment (PGA)≤1 (Boolean); (2) Simplified Disease Activity Index (SDAI)≤3.3; (3) Clinical Disease Activity Index (CDAI)≤2.8; (4) Boolean with PGA≤2 (Updated-Boolean); (5) Boolean with Physician Global Assessment (PhGA≤1) replacing PGA (Boolean-PhGA) and (6) Boolean excluding PGA (3VBoolean). GRO was defined as a worsening ≤0.5 units in radiographic score and GFO as a no worsening in Health Assessment Questionnaire (HAQ), that is, ∆HAQ-DI≤0.0 units. Relationships between each remission definition at 6 and/or 12 months and GRO and GFO during the second year were analysed. Pooled probabilities for each outcome for each definition and their predictive accuracy were estimated.

Results: IPD from eight RCTs (n=4423) were analysed. Boolean, SDAI, CDAI, Updated-Boolean, Boolean-PhGA and 3VBoolean were achieved by 24%, 27%, 28%, 32%, 33% and 43% of all patients, respectively. GRO among patients achieving remission ranged from 82.4% (3VBoolean) to 83.9% (SDAI). 3VBoolean showed the highest predictive accuracy for GRO: 51.1% versus 38.8% (Boolean) and 44.1% (Updated-Boolean). The relative risk of GFO ranged from 1.16 (Boolean) to 1.05 (3VBoolean). However, the proportion of GFO correctly predicted was highest for the 3VBoolean (50.3%) and lowest for the Boolean (43.8%).

Conclusion: 3VBoolean definition provided the most accurate prediction of GRO and GFO, avoiding the risk of overtreatment in a substantial proportion of patients without increment in radiographic damage progression, supporting the proposal that 3VBoolean remission is preferable to guide immunosuppressive treatment. The patient's perspective, which must remain central, is best served by an additional patient-oriented target: a dual-target approach.

Keywords: health care; outcome assessment; patient reported outcome measures; rheumatoid arthritis.

Figure 1

Meta-analysis of risk ratio of obtaining good radiographic outcome (ΔmTSS≤0.5) for patients in remission versus non-remission, per definition. (A) Boolean remission; (B) SDAI remission; (C) CDAI remission; (D) Updated-Boolean remission; (E) Boolean-PhGA remission and (F) 3VBoolean remission. CDAI, Clinical Disease Activity Index; GRO, good radiographic outcome; ΔmTSS, change in the modified total Sharp score; PhGA, Physician’s Global Assessment; SDAI, Simplified Disease Activity Index.