Effect of anti-TNF and conventional synthetic disease-modifying anti-rheumatic drug treatment on work disability and clinical outcome in a multicentre observational cohort study of psoriatic arthritis

OBJECTIVE: To determine the effect of medical treatment on work disability in patients with active PsA in a real-world setting. METHODS: Four hundred patients with active PsA commencing or switching to anti-TNF or conventional synthetic DMARD (csDMARD) were recruited to a multicentre UK prospective observational cohort study. Work disability was measured using the work productivity and activity-specific health problem instrument and peripheral joint activity was measured with the disease activity in PsA composite measure. RESULTS: Four hundred patients were recruited, of whom 229 (57.25%) were working (of any age). Sixty-two patients of working age (24%) were unemployed. At 6 months there was a 10% improvement in presenteeism (P = 0.007) and a 15% improvement in work productivity (P = 0.001) among working patients commenced on csDMARDs (n = 164) vs a larger and more rapid 30% improvement in presenteeism (P < 0.001) and 40% improvement in work productivity (P < 0.001) among those commenced on anti-TNF therapy (n = 65). Clinical response was poor among patients commenced on a csDMARD (n = 272), with an 8.4 point improvement in disease activity in PsA (P < 0.001) vs those commenced on anti-TNF therapy (n = 121), who had a 36.8 point improvement (P < 0.001). CONCLUSION: We report significant and clinically meaningful improvements in both work disability and clinical outcomes after commencement of anti-TNF therapy in a real-world setting. Improvements in all outcomes among those commencing csDMARDs were slower and of a smaller magnitude.