Table 2.
Univariable associations between a positive family history and HLA-B27 carriership in patients suspected of axial spondyloarthritis (n = 594)
| HLA-B27+ (n = 310) | HLA-B27− (n = 284) | OR (95% CI) | p Value | |
|---|---|---|---|---|
| Positive family history according to ASAS definition | ||||
| Stratified by self-reported ethnicity | ||||
| White | 54 | 26 | 2.3 (1.4–3.9) | 0.001 |
| Asian | 38 | 14 | 3.1 (1.6–5.8) | 0.001 |
| Other ethnicitiesa | 2 | 1 | 2.3 (0.2–25.0) | 0.509 |
| Stratified by degree of family relationship | ||||
| First-degree relatives | 79 | 31 | 2.9 (1.8–4.5) | < 0.001 |
| Only second-degree relatives | 15 | 10 | 1.7 (0.7–3.8) | 0.212 |
| Positive family history of AS | ||||
| Stratified by self-reported ethnicity | ||||
| White | 37 | 6 | 7.1 (2.9–17.1) | < 0.001 |
| Asian | 35 | 7 | 5.7 (2.5–13.2) | < 0.001 |
| Other ethnicitiesa | 2 | 0 | n.a. | n.a. |
| Stratified by degree of family relationship | ||||
| First-degree relatives | 61 | 9 | 7.8 (3.8–16.0) | < 0.001 |
| Only second-degree relatives | 13 | 4 | 3.7 (1.2–11.6) | 0.023 |
| Positive family history of AAU | ||||
| Stratified by self-reported ethnicity | ||||
| White | 4 | 0 | n.a. | n.a. |
| Asian | 2 | 1 | 1.9 (0.2–20.7) | 0.613 |
| Other ethnicitiesa | 0 | 0 | n.a. | n.a. |
| Stratified by degree of family relationship | ||||
| First-degree relatives | 5 | 1 | 4.7 (0.5–40.1) | 0.162 |
| Only second-degree relatives | 1 | 0 | n.a. | n.a. |
| Positive family history of ReA | ||||
| Stratified by self-reported ethnicity | ||||
| White | 2 | 2 | 0.9 (0.1–6.5) | 0.924 |
| Asian | 1 | 3 | 0.3 (0.03–2.9) | 0.302 |
| Other ethnicitiesa | 0 | 0 | n.a. | n.a. |
| Stratified by degree of family relationship | ||||
| First-degree relatives | 3 | 2 | 1.4 (0.2–8.2) | 0.735 |
| Only second-degree relatives | 0 | 3 | n.a | n.a |
| Positive family history of IBD | ||||
| Stratified by self-reported ethnicity | ||||
| White | 2 | 7 | 0.3 (0.05–1.2) | 0.089 |
| Asian | 0 | 2 | n.a. | n.a. |
| Other ethnicitiesa | 0 | 1 | n.a. | n.a. |
| Stratified by degree of family relationship | ||||
| First-degree relatives | 1 | 7 | 0.1 (0.02–1.0) | 0.054 |
| Only second-degree relatives | 1 | 3 | 0.3 (0.03–2.9) | 0.294 |
| Positive family history of psoriasis | ||||
| Stratified by self-reported ethnicity | ||||
| White | 16 | 15 | 1.0 (0.5–2.0) | 0.938 |
| Asian | 2 | 2 | 0.9 (0.1–6.5) | 0.926 |
| Other ethnicitiesa | 0 | 1 | n.a. | n.a. |
| Stratified by degree of family relationship | ||||
| First-degree relatives | 15 | 14 | 1.0 (0.5–2.1) | 0.949 |
| Only second-degree relatives | 3 | 4 | 0.7 (0.2–3.1) | 0.620 |
Statistically significant results are printed in bold
Abbreviations: AAU Acute anterior uveitis, AS Ankylosing spondylitis, HLA-B27 Human leukocyte antigen B27, IBD Inflammatory bowel disease, n.a. Not applicable, ReA Reactive arthritis
aSelf-reported ethnicities was missing for five patients, who are included in this category, and other ethnicities are black, East Indian, Hispanic/Latino, mixed, or Turkish