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Ann Rheum Dis doi:10.1136/annrheumdis-2013-204601
  • Clinical and epidemiological research
  • Extended report

Current smoking status is a strong predictor of radiographic progression in early rheumatoid arthritis: results from the SWEFOT trial

Open Access
  1. for the SWEFOT study group
  1. 1Rheumatology Unit, Department of Medicine, Karolinska University Hospital and Karolinska Institute, Stockholm, Sweden
  2. 2Unit for Clinical Therapy Research, Karolinska Institute, Stockholm, Sweden
  3. 3Section of Rheumatology, Institution of Clinical Science, University Hospital, Lund, Sweden
  4. 4Skane University Hospital, Epi-centrum Skane, Lund, Sweden
  5. 5Department of Rheumatology, Danderyd Hospital, Stockholm, Sweden
  6. 6Department of Medicine, Section of Rheumatology, Helsingborg Hospital, Helsingborg, Sweden
  1. Correspondence to Dr Saedis Saevarsdottir, Rheumatology Unit, Karolinska University Hospital, Solna 17176, Stockholm, Sweden; saedis.saevarsdottir{at}ki.se
  • Received 19 September 2013
  • Revised 9 March 2014
  • Accepted 15 March 2014
  • Published Online First 4 April 2014

Abstract

Objectives To study clinical predictors for radiographic progression after 1 year in an early rheumatoid arthritis (RA) trial.

Methods In the SWEFOT trial population, disease modifying antirheumatic drug (DMARD) naïve RA patients started methotrexate; 3-month responders (DAS28 <3.2) continued (n=147), while non-responders were randomised to addition of sulfasalazine+hydroxychloroquine (n=130) or infliximab (n=128). X-rays were scored by the Sharp-van der Hejde score (SHS) method and radiographic progression was defined as a ≥5 increase after 1 year. Potential baseline predictors of radiographic progression were tested using multivariable logistic regression, adjusted for potential confounders.

Results 79 of 311 patients with available radiographs at baseline and follow-up had radiographic progression. The following baseline parameters were independent predictors of radiographic progression at 1 year: baseline erosions (adjusted OR=2.29, 95% CI 1.24 to 4.24), erythrocyte sedimentation rate (adjusted OR per tertile increase=1.72, 95% CI 1.12 to 2.65) and C-reactive protein (adjusted OR per tertile increase=1.52, 95% CI 1.03 to 2.26). Current smoking was an independent predictor of radiographic progression (adjusted OR=2.17, 95% CI 1.06 to 4.45). These results remained after further adjustment for treatment strategy. Three-dimensional matrix including current smoking status, erosions and C-reactive protein tertiles showed a 12–63% risk gradient from patients carrying none compared with all predictors. Rheumatoid factor (RF)/anti-cyclic citrullinated peptide (anti-CCP) positivity did not significantly predict radiographic progression using SHS increase ≥5 as cut-off. In a secondary exploratory analysis using cut-off >1, both RF and anti-CCP positivity were significant predictors in the unadjusted, but not the adjusted analyses. The other parameters also remained significant using this lower cut-off.

Conclusions In addition to previously described predictors, we identified smoking as a strong independent risk factor for radiographic progression in early RA.

Trial registration number NCT00764725.

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