To investigate the incidence and predictors of dyspnea on exertion among subjects with rheumatoid arthritis ( RA).
We investigated dyspnea on exertion using a prospective cohort, the Brigham RA Sequential Study ( BRASS). Clinically significant dyspnea on exertion was defined as a score of ≥ 3 (unable to ambulate without breathlessness or worse) on the validated Medical Research Council ( MRC) scale (range 0‐5). We analyzed subjects with MRC score < 3 at BRASS baseline and at ≥ 1 year of follow‐up. The MRC scale was administered annually. We determined the incidence rate ( IR) of dyspnea on exertion. We used Cox regression to estimate the hazard ration ( HR) for dyspnea on exertion occurring one year after potential predictors were assessed.
We analyzed 829 subjects with RA and no clinically significant dyspnea on exertion during a mean follow‐up period of 3.0 years ( SD 1.9). At baseline, mean age was 55.7 years ( SD 13.6), 82.4% of subjects were female, and median RA duration was 8 years. During follow‐up, 112 subjects (13.5%) developed incident dyspnea on exertion during 2476 person‐years of follow‐up (incidence rate 45.2 per 1000 person‐years). Independent predictors of incident dyspnea on exertion were older age ( HR 1.03 per year, 95% CI, 1.01‐1.04), female sex ( HR 2.22, 95% CI, 1.14‐4.29), mild dyspnea ( HR 2.62, 95% CI, 1.60‐4.28), and worsened Multi‐Dimensional Health Assessment Questionnaire score ( HR 2.36 per unit, 95% CI, 1.54‐3.60). Methotrexate use, RA disease activity, and seropositivity were not associated with incident dyspnea on exertion after accounting for other dyspnea risk factors.