Factors associated with time to diagnosis in early rheumatoid arthritis.
Predictive Value of Tests
Severity of Illness Index
Early diagnosis and treatment yield optimal outcomes in rheumatoid arthritis (RA); thus, barriers to disease recognition must be identified and addressed. We determined the impact of sociodemographic factors, medical comorbidities, family history, and disease severity at onset on the time to diagnosis in early RA. The Canadian early ArThritis CoHort study data on 1,142 early RA patients were analyzed for predictors of time to diagnosis using regression analysis. Sociodemographic factors (age, sex, income strata, education, ethnicity), measures of disease activity (joint counts, DAS28 score, acute-phase reactants, patient global evaluation, function), family history, serology, chronic musculoskeletal and mental health conditions, and obesity at diagnosis were considered. In multivariate linear regression analysis, more swollen joints (β = -0.047 per joint, 95 % CI -0.085, -0.010, p = 0.014), higher erythrocyte sedimentation rate (ESR) (β = -0.012 per 1 mm/h, 95 % CI -0.022, -0.002, p = 0.0018), and worse patient global scores (β = -0.082 per 1 unit on a visual analogue scale, 95 % CI -0.158, -0.006, p = 0.034) at baseline predicted a shorter time to diagnosis. Anti-cyclic citrullinated peptide (anti-CCP) antibody positivity (β = 0.688, 95 % CI 0.261, 1.115, p = 0.002) and low income (annual <$20,000 β = 1.185, 95 % CI 0.227, 2.143, p = 0.015; annual $20,000-50,000 β = 0.933, 95 % CI 0.069, 1.798, p = 0.034) increased time to diagnosis. In the logistic regression models, the odds of being diagnosed within 6 months of symptom onset were increased for each swollen joint present [odds ratio (OR) 1.04, 95 % CI 1.02-1.06 per joint], each 1 mm/h elevation in the ESR (OR 1.01, 95 % CI 1.00-1.02), and decreased for patients who were either rheumatoid factor or anti-CCP positive compared to both factors being negative (OR 0.68, 95 % CI 0.51-0.91). Higher disease activity results in a more rapid diagnosis for Canadian patients with early RA, but those with lower income have delays in diagnosis. Strategies to identify patients with a less severe disease presentation and in lower socioeconomic strata are needed to ensure equal opportunity for optimal management.