Explanatory variables | OR (95% CI) | p Value |
Female gender | 0.88 (0.59 to 1.32) | 0.498 |
Ethnicity | ||
Caucasian | ||
Hispanic | ||
African American | 0.865† | |
Asian/Pacific Islander | ||
Other (mixed) | ||
Age at SLE diagnosis (years) | ||
⩽20 | 1.33 (0.80 to 2.23) | 0.274 |
>20–⩽40 | 1.27 (0.79 to 2.05) | 0.325 |
>40 | 1.24 (0.75 to 2.04) | 0.397 |
Duration of SLE (per 5 years) | 1.21 (1.14 to 1.29) | 0.013×10−7 |
Ever smoker | 1.27 (1.00 to 1.60) | 0.041 |
History of nephritis‡ | 1.62 (1.28 to 2.06) | 0.045×10−3 |
History of immunomodulator therapy§ | 1.52 (1.21 to 1.90) | 0.0002 |
History of prednisone treatment | 1.79 (1.21 to 2.73) | 0.0029 |
History of hydroxychloroquine treatment | 0.63 (0.48 to 0.83) | 0.0007 |
History of NSAID treatment | 1.00 (0.72 to 1.41) | 0.997 |
aPL¶ | 2.79 (2.21 to 3.53) | <10−9 |
ACL positive | 1.95 (1.47 to 2.58) | <10−9 |
LAC positive | 3.35 (2.18 to 5.14) | <10−9 |
ACL, anti-cardiolipin; aPL, antiphospholipid antibodies; LAC, lupus anticoagulant; NSAID, non-steroidal anti-inflammatory drugs; SLE, systemic lupus erythematosus.
*Significant results are shown in bold font.
†Omnibus test.
‡Nephritis was defined as meeting American College of Rheumatology renal criterion, confirmed by review of medical records and/or renal biopsy consistent with lupus nephritis.
§Cyclophosphamide, azathioprine, methotrexate, ciclosporin, mycofenalate mofetil or chlorambucil. All medications were analysed as “ever” versus “never use”.
¶aPL (ACL IgM or IgM or LAC (measured by Russell Viper Venom Time with confirmatory and mixing studies), positive at least once documented in records).