OBJECTIVE: To investigate whether tumor necrosis factor inhibitor (TNFi) combination therapy with conventional synthetic disease-modifying antirheumatic drugs (csDMARD) is more effective for psoriatic arthritis (PsA) and/or improves TNFi drug survival compared to TNFi monotherapy. METHODS: Five PsA biologics cohorts were investigated between 2000 and 2015: the ATTRA registry (Czech Republic); the Swiss Clinical Quality Management PsA registry; the Hellenic Registry of Biologics Therapies (Greece); the University of Bari PsA biologics database (Italy); and the Bath PsA cohort (UK). Drug persistence was analyzed using Kaplan-Meier and equality of survival using log-rank tests. Comparative effectiveness was investigated using logistic regression with propensity scores. Separate analyses were performed on (1) the combined Italian/Swiss cohorts for change in rate of Disease Activity Score in 28 joints (DAS28); and (2) the combined Italian, Swiss, and Bath cohorts for change in rate of Health Assessment Questionnaire (HAQ). RESULTS: In total, 2294 patients were eligible for the drug survival analysis. In the Swiss (P = 0.002), Greek (P = 0.021), and Bath (P = 0.014) databases, patients starting TNFi in combination with methotrexate had longer drug survival compared to monotherapy, while in Italy the monotherapy group persisted longer (P = 0.030). In eligible patients from the combined Italian/Swiss dataset (n = 1056), there was no significant difference between treatment arms in rate of change of DAS28. Similarly, when also including the Bath cohort (n = 1205), there was no significant difference in rate of change of HAQ. CONCLUSION: Combination therapy of a TNFi with a csDMARD does not appear to affect improvement of disease activity or HAQ versus TNFi monotherapy, but it may improve TNFi drug survival.

A Drosos MD PhD Rheumatology Clinic Department of Internal Medicine Medical School University of Ioannina Ioannina Greece

A Nightingale PhD Department of Pharmacy and Pharmacology University of Bath Bath UK

A Scherer PhD SCQM Foundation Zürich Switzerland N McHugh and A Nightingale are joint senior authors

B Möller Professor Department of Rheumatology Immunology and Allergology Inselspital University Hospital Bern Bern Switzerland

C Cavill BSc R Holland MD Royal National Hospital for Rheumatic Diseases Bath UK

F Iannone MD PhD G Lapadula MD S Lopriore MD Rheumatology Unit DETO University of Bari Bari Italy

G Shaddick PhD Department of Mathematics University of Exeter Exeter UK

J Závada MD PhD K Pavelka MD PhD Institute of Rheumatology Prague Czech Republic

M J Nissen MBBS FRACP Department of Rheumatology University Hospital Geneva Geneva Switzerland

M L Thomas PhD Department of Mathematical Science University of Bath Bath UK

M Uher MSc L Szczuková MD Institute of Biostatistics and Analyses Faculty of Medicine Masaryk University Brno Czech Republic

P Sidiropoulos MD PhD 1 Flouri MD Rheumatology Clinical Immunology and Allergy Department Medical School University of Crete Crete Greece

R B Müller MD Cantonal Hospital Lucerne Switzerland

R Charlton PhD N McHugh MBChB MD FRCP FRCPath Department of Pharmacy and Pharmacology University of Bath Bath UK

R Charlton PhD N McHugh MBChB MD FRCP FRCPath Department of Pharmacy and Pharmacology University of Bath Bath UK;

References provided by Crossref.org

Effectiveness and treatment retention of TNF inhibitors when used as monotherapy versus comedication with csDMARDs in 15 332 patients with psoriatic arthritis. Data from the EuroSpA collaboration