Current smoking status is a strong predictor of radiographic progression in early rheumatoid arthritis: results from the SWEFOT trial
- Saedis Saevarsdottir1,2,
- Hamed Rezaei1,2,
- Pierre Geborek3,
- Ingemar Petersson4,
- Sofia Ernestam1,
- Kristina Albertsson5,
- Kristina Forslind3,6,
- Ronald F van Vollenhoven2,
- for the SWEFOT study group
- 1Rheumatology Unit, Department of Medicine, Karolinska University Hospital and Karolinska Institute, Stockholm, Sweden
- 2Unit for Clinical Therapy Research, Karolinska Institute, Stockholm, Sweden
- 3Section of Rheumatology, Institution of Clinical Science, University Hospital, Lund, Sweden
- 4Skane University Hospital, Epi-centrum Skane, Lund, Sweden
- 5Department of Rheumatology, Danderyd Hospital, Stockholm, Sweden
- 6Department of Medicine, Section of Rheumatology, Helsingborg Hospital, Helsingborg, Sweden
- Correspondence to Dr Saedis Saevarsdottir, Rheumatology Unit, Karolinska University Hospital, Solna 17176, Stockholm, Sweden;
- Received 19 September 2013
- Revised 9 March 2014
- Accepted 15 March 2014
- Published Online First 4 April 2014
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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