Table 2.
Examination, Antibody, and C-reactive Protein Results in 601 Subjects Participating in the Health-fair Rheumatoid Arthritis (RA) Screen
| Findings | N (%) |
|---|---|
| CSQ Positive Responses* | |
| 0 | 198 (32.9) |
| ≥1 | 403 (67.1) |
| ≥2 | 269 (44.8) |
| ≥3 | 165 (27.5) |
| ≥4 | 61 (10.1) |
| Examination Findings (N=601) | |
| ≥1 swollen joint (designated as inflammatory arthritis[IA])** | 84 (14.0%) |
| Number of participants with a specific joint region swollen | |
| Proximal inter-phalangeal (PIP) swollen | 23 (3.8%) |
| - only PIP swollen | 6 (1.0%) |
| Metacarpal-phalangeal (MCP) swollen | 65 (10.8%) |
| Wrist swollen | 15 (2.5%) |
| Elbow swollen | 1 (0.2%) |
| MTP swollen | 0 (0%) |
| ≥2 swollen joints | 60 (10.3%) |
| ≥3 swollen joints | 36 (6.0%) |
| Autoantibody Positivity (N=601) | |
| Any autoantibody positive (RF and/or anti-CCP) | 67 (11.1%) |
| RF (with or without anti-CCP) | 55 (9.2%) |
| RF-only (no anti-CCP) | 44 (7.3%) |
| Anti-CCP (with or without RF) | 23 (3.8%) |
| Anti-CCP-only (no RF) | 12 (2.0%) |
| RF and anti-CCP | 11 (1.8%) |
| CRP Positivity (>0.8 mg/dL) | 66 (11.0%) |
| RF, anti-CCP, and CRP Positivity | 5 (0.8%) |
| Meeting ≥4 ACR RA Criteria (and no prior diagnosis to explain arthritis)*** | 9 (1.5%) |
| ≥1 swollen joint and RF or anti-CCP positivity, not meeting ≥4 ACR RA Criteria | 15 (2.5%) |
| RF and/or anti-CCP positivity and no IA | 41 (6.8%) |
| Anti-CCP positivity and no IA | 14 (2.3%) |
CSQ=Connective Tissue Disease Screening Questionnaire. This is a subject-completed questionnaire which can assess self-reported fulfillment of the following ACR RA criteria: >6 weeks of arthritis symptoms; morning stiffness ≥1 hour, hand arthritis (fingers, wrists), 3 or more joint areas (hands, wrists, elbows, and knees), and symmetric arthritis; nodules. Radiographic findings are not assessed, and for this study, self-reported results of RF testing are not included. Each positive response was determined to be self-reported fulfillment of 1 ACR criteria for RA.
Inflammatory arthritis (IA) was established if subjects had ≥1 swollen joint considered to be synovitis on examination of the PIPs, MCPs, wrists, or elbows by a rheumatologist or nurse trained in joint examination.
Fulfillment of the American College of Rheumatology (ACR) 1987 Revised RA criteria was determined using CSQ responses for morning stiffness >1 hour, examination findings based on joint swelling of the PIPs, MCPs, wrists, and elbows at the time of the RA screen, and RF and/or anti-CCP antibody positivity at RA screen. Nodules and radiographic findings were not assessed.
Abbreviations/units: IA=inflammatory arthritis; RA=rheumatoid arthritis; RF=rheumatoid factor, international units per milliliter (IU/mL), >14 IU/mL positive; anti-CCP=anti-cyclic citrullinated peptide antibody, units per mL, >5 units positive; CRP=C-reactive protein, milligrams per deciliter (mg/dL), ≥0.8 mg/dL positive; ACR=American College of Rheumatology.