Table 3.
ANA patterns over time with indirect immunofluorescence assay (IFA) 1 (n=805) and IFA2 (n=805)
| Pattern | Enrolment n (%) | Year 3 n (%) | Year 5 n (%) | Same ANA Pattern Over 5 years n (%) |
|---|---|---|---|---|
| IFA 1 Patterns | ||||
| Nuclear | 481 (62.1) | 519 (68.1) | 526 (68.7) | 305 (37.9) |
| Cytoplasmic +/− Mitotic | 17 (2.2) | 18 (2.4) | 21 (2.7) | 1 (0.1) |
| Mixed | 276 (35.7) | 225 (29.5) | 219 (28.6) | 81 (10.1) |
| IFA2 Patterns | ||||
| Nuclear | 491 (62.1) | 477 (60.4) | 472 (59.3) | 273 (33.9) |
| Cytoplasmic +/− Mitotic | 9 (1.1) | 6 (0.8) | 4 (0.5) | 0 (0.0) |
| Mixed | 291 (36.8) | 308 (38.8) | 320 (40.2) | 114 (14.2) |
| IFA1 and 2 agreement (k) | ||||
| Agreement (95%CI) | 74.0 (70.7–77.0)* | 71.4 (68.0–74.6)* | 71.0 (67.7–74.2)* | |
| Kappa (95%CI) | 0.46 (0.39–0.53) | 0.39 (0.33–0.46) | 0.39 (0.33–0.46) | |
Abbreviations: ANA, anti-nuclear antibodies; IFA; indirect immunofluorescence assay.
*
p<0.0001 using unweighted kappa (k) statistics.