Winter- And Spring-onset Rheumatoid Arthritis Patients Have Worse 6 Month Outcomes Than Those With Summer Onset

Similarly, patients' mTSS after six months was worse if their first symptoms had occurred in winter (OR=2.61 [1.20; 5.71], p=0.0158) or in spring (OR=2.63 [1.13; 6.14], p=0.0025) versus autumn as the reference season. This effect was not however observed at 12 month follow up, which the study authors suggest could suggest that these initial environmental factors exert less of an effect on longer term radiographic progression.

Dr Gaël Mouterde, Immuno-Rheumatology Department, Lapeyronie Hospital, Montpellier, France who led the research, said: "During our study of predictors of radiographic progression, we have unveiled a distinct relationship between RA progression and seasonal onset and postulate that this could be as a result of either a vitamin D deficiency or environmental factors, such as winter viruses, influencing protein citrullination. Anti-citrullinated protein antibodies (ACPAs) are often found in the immune systems of RA patients. This finding may assist towards the identification of RA patients at a higher risk of developing structural damage, in order to propose early intensive therapy and minimise disease progression."

Of the 736 patients from the multicentre French ESPOIR cohort analysed in the study (48±12 years of age, females 77%, mean disease duration 103+/-53 days, DAS28 5.11±1.31, HAQ score 0.97±0.68, CRP 21.9±32 mg/l, HLA-DRB1*01 or 04 57.5%), those found to have anti-CCP antibodies (total n=290) were also likely to have experienced increased radiographic disease progression (defined by an increase of at least 1 point of the mTSS), than those without anti-CCP antibodies, both after six months (OR=3.73 [2.04;6.82], p<0.0001) and one year (OR=5.38 [3.01;9.65], p<0.0001) compared to those without these antibodies.

Patients presenting with synovitis (inflammation of the membrane that lines the joints, commonly seen in rheumatic diseases) of at least 2 joints for a duration of 6 weeks to 6 months were assessed at baseline in terms of: clinical and biological features of arthritis (including radiographs of hands, wrists and feet), HLA-DRB1 gene typing, socioeconomic factors, comorbidities, IgM RF and anti-CCP auto-antibodies. They were re-assessed at both 6 months and one year.

The sensitivity and specificity of rheumatic factor (RF, an auto-antibody or antibody directed against an individual's own tissues sometimes seen in patients with RA) and anti-CCP at baseline in discriminating between erosive and non erosive disease at 6 months and one year were determined. Optimal cutoffs for these tests were derived from receiver-operating characteristic (ROC) curves using a cost function. Logistic regression was performed to evaluate the association between the radiological progression, and baseline variables.