Background

Psoriatic arthritis (PsA) is a very heterogeneous disease; patient profiles in randomised controlled trials (RCTs) may not reflect patients in usual clinical practice.

Objectives

The objective of this study was to compare characteristics of PsA patients between RCTs of biologic disease-modifying antirheumatic drugs (bDMARDs) through a meta-analysis, and a real-world study recruiting over the same timeframe, PsABio.

Methods

Data sources: (a) Literature review and meta-analysis of phase III RCTs of bDMARDs in PsA published between 2015-2020; (b) International observational study of PsA patients starting a bDMARD enrolled in 2015–2018 (PsABio, NCT02627768). Data collected at baseline included swollen and tender joint counts (SJC, TJC), enthesitis, skin involvement (body surface area -BSA-), C-reactive protein (CRP) and patient-reported outcomes (HAQ, PGA of pain and disease activity). Univariate random-effects meta-analysis was conducted to calculate pooled means and proportions.

Results

Overall, 5654 patients from 10 RCTs were compared with 930 PsABio patients. Demographic data were similar across studies. SJC and TJC were higher in RCTs than in PsABio (pooled means, 11.8/21.5, versus 5.7/11.9 respectively, p<0.001). Enthesitis was more frequent in RCTs (64.7% vs 48.2%, p<0.001), as was dactylitis (37.7% vs 19.8%, p<0.001). Patients with a BSA>3% were more frequent in RCTs (62.2% vs 54.0%, p<0.001). In contrast, patient-reported disease impact was high and similar in both data sources (pooled mean HAQ 1.2 vs 1.1; pain 60mm vs 61mm), while CRP was statistically significantly higher in PsABio (1.1 vs 1.4 mg/dl, p=0.002) (Table 1). Overall, almost half of PsABio participants starting bDMARDs in clinical practice would not have been eligible for inclusion in these bDMARD RCTs as they failed to meet the disease activity inclusion criteria.

Conclusion

RCTs largely represent patients with highly active polyarticular PsA; in contrast, in routine clinical practice, many patients receiving biologics have mild/moderate joint disease, and limited skin psoriasis. However, patients with PsA starting a bDMARD in both settings reported high and similar physician global assessment and patient-reported disease burden, while CRP was higher in PsABio, supporting the decision to start a bDMARD therapy in clinical practice. The extrapolation of RCT data in clinical practice should take these elements into account.

References

¹Gossec L, et al. Long-term effectiveness and persistence of ustekinumab and TNF inhibitors in patients with psoriatic arthritis: Final 3-year results from the PsABio real-world study. Ann. Rheum. Dis. 2023;82:496–506.