Summary cohort characteristics.
| Cohort Characteristics | ERAS | NOAR |
|---|---|---|
| No. successfully genotyped patients with radiograph* | 445 | 1446 |
| Ethnicity | UK whites | UK whites |
| Age at symptom onset, yrs, median (IQR) | 56 (45, 65) | 56 (44, 67) |
| Delay from onset to registration, median (IQR), mo | 7 (4, 12) | 6 (3, 12) |
| Female, n (%) | 293 (66) | 980 (68) |
| HAQ score baseline, median (IQR) | 1 (0.5, 1.63) | 0.81 (0.25, 1.5) |
| Larsen score Year 5, median (IQR) | 10 (2, 26) | 5 (0, 21) |
| Ever RF-positive, n (%) | 389 (87) | 628 (44) |
| Satisfy 1987 ACR criteria during followup, n (%) | 427 (96)** | 1101 (76) |
| Followup yrs, mean (SD) | 10.2 (4.6) | 8.0 (5.1) |
↵* At the time of the study, i.e., when genotyping was performed, ERAS had 1399 white patients with available phenotypic information for epidemiologic studies, but DNA was available for only a fraction of the study population. Of the patients, 445 (32%) had DNA and at least 1 radiographi available, were white, and passed postgenotyping quality control filters. At the time genotyping was performed, NOAR had 3582 patients available for epidemiologic studies, and 1446 patients (40%) satisfied the above conditions. They were therefore available for the longitudinal genetic study presented here.
↵** Four percent had a clinical diagnosis of RA, as determined by the consultant rheumatologist in charge, although the patients did not formally satisfy the classification criteria for RA. IQR: interquartile range; RF: rheumatoid factor; ERAS: Early Rheumatoid Arthritis Study; NOAR: Norfolk Arthritis Register; HAQ: Health Assessment Questionnaire; ACR: American College of Rheumatology.