Baseline clinical and laboratory characteristics of patients (N = 420) with stable or unstable clinically meaningful aPL profiles at follow-up.
| Total, n = 420 | Clinically Meaningful aPL Profile | P | ||
|---|---|---|---|---|
| Stable, n = 366 | Unstable, n = 54 | |||
| Female | 305 (73) | 267 (73) | 38 (70) | 0.74 |
| Age, yrs, median (IQR) | 48.9 (48.1–50.4) | 48.6 (47.9–49.4) | 48.6 (48–50) | 0.09 |
| White | 279 (78) | 238 (77) | 41 (87) | 0.30 |
| Non-Latin American | 165 (39) | 137 (37) | 28 (52) | 0.46 |
| Autoimmune disease | 0.76 | |||
| aPL/APS only | 278 (66) | 244 (67) | 34 (63) | |
| Other SAID | 148 (35) | 128 (35) | 20 (37) | |
| aPL-related history | ||||
| Vascular eventa (any) | 285 (68) | 245 (67) | 40 (74) | 0.35 |
| Venous event (any) | 183 (64) | 153 (62) | 30 (75) | 0.16 |
| Arterial event (any) | 125 (44) | 115 (47) | 10 (25) | 0.01 |
| TIA (any) | 38 (9) | 37 (10) | 1 (2) | 0.04 |
| Pregnancy morbidityb, n | 136 | 119 | 17 | 0.83 |
| Spontaneous abortionsc, n | 13 | 10 | 3 | 0.21 |
| Premature birthd, n | 37 | 34 | 3 | 0.56 |
| Unexplained fetal deathe, n | 76 | 67 | 9 | 0.80 |
| aPL tests | ||||
| LACf (+) | 319 (80) | 288 (83) | 31 (58) | < 0.001 |
| aCL IgG ≥ 40 U | 202 (48) | 183 (50) | 19 (35) | 0.06 |
| aCL IgM ≥ 40 U | 93 (22) | 89 (24) | 4 (7) | 0.004 |
| anti-β2-GPI IgG ≥ 40 U | 139 (33) | 130 (36) | 9 (17) | 0.005 |
| anti-β2-GPI IgM ≥ 40 U | 81 (19) | 76 (21) | 5 (9) | 0.06 |
| ≥ 2 positive aPL tests | 244 (58) | 226 (62) | 18 (33) | < 0.001 |
| aPL titers, U, median (IQR) | ||||
| aCL IgG | 36(10–93) | 46 (13–100) | 16 (4–56) | < 0.001 |
| aCL IgM | 12 (5–39) | 13 (5–42) | 8.5 (2–15.5) | 0.006 |
| anti-β2-GPI IgG | 19 (3–74) | 22 (3–83) | 3 (1–30) | < 0.001 |
| anti-β2-GPI IgM | 9 (2–33) | 10 (2–39) | 4 (1–20) | 0.04 |
| aPL profiles | ||||
| Triple aPL positivity | 174 (41) | 167 (46) | 7 (13)g | < 0.0001 |
| Double aPL positivityh | 120 (29) | 106 (29) | 13 (26) | 0.75 |
| Isolated LAC test positivity | 84 (20) | 62 (17) | 22 (41) | 0.0002 |
| Isolated aCL IgG/M positivity | 29 (7) | 23 (6) | 6 (11) | 0.24 |
| Isolated anti-β2-GPI IgG/M positivity | 13 (3) | 8 (2) | 5 (9) | 0.02 |
| Medications | ||||
| Aspirin | 201 (48) | 187 (51) | 14 (26) | < 0.001 |
| Warfarin | 223 (53) | 192 (52) | 31 (57) | 0.68 |
| Hydroxychloroquine | 194 (46) | 168 (46) | 26 (48) | 0.82 |
Values are n (%) unless otherwise indicated.
↵aDuring an average follow-up of 5 years, new thrombosis occurred in 30 (7%) of420 patients (24 with history of baseline thrombosis, and 6 patients without), 29/30 had a stable clinically meaningful aPL profile at follow-up.
↵bOut of207 patients with history of pregnancy (with or without morbidity).
↵c3 consecutive unexplained spontaneous abortions before 10th week.
↵dPremature birth before 34th week due to eclampsia, preeclampsia, or placental insufficiency.
↵eUnexplained fetal death at or beyond 10 th week.
↵fLAC test was reported by each center as positive or negative (screening by dilute Russell Viper Venom Time [dRVVT] and activated Partial Thromboplastin Time [aPTT] in 55% of patients, dRVVT in 28%, aPTT in 9%, other methods in 5%, and nonreported methods in 2%).
↵gSeven triple aPL-positive patients with unstable aPL profile were mostly on warfarin with fluctuating LAC test status, and relatively low level aPL ELISA at baseline (2 patients only had IgM isotype).
↵hAny combination of 2 positive aPL tests based on the laboratory criteria of the Updated Sapporo APS Classification Criteria. aCL: anticardiolipin antibody; anti-β GPI: anti-β glycoprotein I antibody; aPL: antiphospholipid antibody; APS: antiphospholipid syndrome; LAC: lupus anticoagulant; SAID: systemic autoimmune diseases; TIA: transient ischemic attack.