To identify patients with severe extra-articular RA (ExRA) in an early RA cohort and to investigate potential risk factors.
From a cohort (n = 2900) in a structured programme for newly diagnosed RA, 40 patients with severe ExRA after RA diagnosis were identified. Disease activity score (DAS28), functional disability (HAQ) and treatment with glucocorticosteroids (GCs) and DMARDs were assessed regularly. Cases with ExRA were compared with RA controls from the same cohort matched for age, sex and duration of symptoms at inclusion.
Patients who developed severe ExRA were more often current smokers and had higher mean DAS28, HAQ and CRP at baseline. Among the ExRA cases, 93% had a positive RF vs 59% of the controls. The area under the curve (AUC) of DAS28 odds ratio (OR) 7.79/S.D.; 95% CI 3.04, 19.95, HAQ (OR 2.30/S.D.; 95% CI 1.37, 3.88) and CRP (OR 3.05/S.D.; 95% CI 1.77, 5.26) during the first 2 years of follow-up were strong predictors of subsequent development of ExRA. The most frequently used DMARDs were MTX and SSZ, with similar frequency and duration of treatment among cases and controls. The cases were treated with GC before onset of ExRA more frequently (73 vs 47%; P = 0.005) and with higher mean cumulative dose (3667 vs 2037 mg, P = 0.015).
High levels of disease activity and disability during the first 2 years after RA diagnosis, smoking and RF predict the development of severe extra-articular RA.