Objectives: The aim of this study was to apply a previously published method for evaluating radiographic progression, namely, predicted vs. observed radiographic progression in early rheumatoid arthritis (POPeRA), to the Swedish pharmacotherapy (SWEFOT) trial.
Method: In SWEFOT, 487 patients with eRA were given methotrexate (MTX), and non-responders were randomized to group A [triple therapy: MTX+sulfasalazine (SSZ)+hydroxychloroquine (HCQ)] and group B [anti-tumour necrosis factor (anti-TNF) therapy: MTX+infliximab]. Responders continued on MTX. Predicted progression for 343 eligible patients was calculated based on the baseline total Sharp/van der Heijde score (SHS) divided by symptom duration, compared to observed progression at 12 and 24 months.
Results: Observed radiographic progression was reduced from predicted by a mean of 50.1% (A), 72.3% (B), and 73.9% (MTX) at 12 months and by 87.2, 89.8, and 87.8% at 24 months, respectively. Among completers, reductions of 56.7% (A) and 76.5% (B) at 12 months and of 91.0% and 96.0% at 24 months, respectively, were observed. At 12 months, there were no significant between-group differences. At 24 months, progression was reduced more in group B than in group A (first quartile difference 8.5% favouring group B) and in MTX [n=316, 89.8% (sd±32.0) vs. 87.2% (±32.2), p=0.021; vs. 87.8% (±27.8), p=0.013, respectively].
Conclusions: The POPeRA method confirms the original SWEFOT finding in that anti-TNF therapy was statistically marginally superior (2.6%) to triple therapy in preventing radiographic progression at 24 months among initial MTX non-responders. The simulation provided through POPeRA may facilitate comparisons of the relative efficacy of various treatments in preventing radiographic progression.