Table 1.
Characteristics of the study population and outcomes, according to severe nonadherence to HCQ at T0*
| Patients’ characteristics | Overall (n = 660) | Severe nonadherence to HCQ | P value | |
|---|---|---|---|---|
| No (n = 612) | Yes (n = 48) | |||
| Female sex, n (%) | 580 (87.9) | 536 (87.6) | 44 (91.7) | 0.545 |
| Pregnancy, n (%) | 7 (1.1) | 6 (1.0) | 1 (2.1) | 1.00 |
| Black race, n (%) | 107 (16.2) | 96 (15.7) | 11 (22.9) | 0.269 |
| Age at serum sample, mean ± SD, y | 36.2 ± 13.5 | 36.4 ± 13.7 | 33.4 ± 10.7 | 0.132 |
| Months since SLE diagnosis, mean ± SD | 7.2 ± 4.6 | 7.1 ± 4.6 | 8.4 ± 4.9 | 0.062 |
| Education level, n (%) | 0.886 | |||
| Postsecondary | 413 (62.6) | 382 (62.4) | 31 (64.6) | |
| High school or less | 247 (37.4) | 230 (37.6) | 17 (35.4) | |
| Cigarette smoking, n (%) | 0.642 | |||
| Nonsmoker | 437 (66.2) | 408 (66.7) | 29 (60.4) | |
| Current or past smoker | 222 (33.6) | 203 (33.2) | 19 (39.6) | |
| Not available | 1 (0.2) | 1 (0.2) | 0 (0.0) | |
| Main clinical manifestations, n (%) | ||||
| Renal disease | 131 (19.8) | 120 (19.6) | 11 (22.9) | 0.715 |
| Neurologic disorder | 18 (2.7) | 16 (2.6) | 2 (4.2) | 0.861 |
| SLEDAI‐2K at T0, mean ± SD | 4.8 ± 4.9 | 4.8 ± 4.8 | 6.0 ± 5.8 | 0.091 |
| Other comorbidities | ||||
| BMI, mean ± SD, kg/m2 | 25.8 ± 6.1 | 25.7 ± 6.0 | 27.3 ± 7.2 | 0.074 |
| Dyslipidemia, n (%) | 55 (8.3) | 50 (8.2) | 5 (10.4) | 0.786 |
| Diabetes mellitus, n (%) | 17 (2.6) | 16 (2.6) | 1 (2.1) | 0.658 |
| Treatment at T0, n (%) | ||||
| HCQ, daily dose | ||||
| 200 mg/day | 155 (23.5) | 143 (23.4) | 12 (25.0) | 0.936 |
| 400 mg/day | 505 (76.5) | 469 (76.6) | 36 (75.0) | |
| Corticosteroids | 438 (66.4) | 404 (66.0) | 34 (70.8) | 0.602 |
| Other immunosuppressive drugs | 242 (36.7) | 219 (35.8) | 23 (47.9) | 0.127 |
| Azathioprine | 91 (13.8) | 78 (12.7) | 13 (27.1) | 0.011 |
| Cyclophosphamide | 25 (3.8) | 22 (3.6) | 3 (6.2) | 0.592 |
| Methotrexate | 65 (9.8) | 62 (10.1) | 3 (6.2) | 0.537 |
| Mycophenolate mofetil | 58 (8.8) | 53 (8.7) | 5 (10.4) | 0.881 |
| Other immunosuppressant a | 7 (1.1) | 6 (1.0) | 1 (2.1) | 1 |
| Outcomes, n (%) | ||||
| SLE flare within one year | 191 (28.9) | 163 (26.6) | 28 (58.3) | <0.001 |
| ≥4‐point increase in SLEDAI‐2K | 68 (10.3) | 57 (9.3) | 11 (22.9) | 0.006 |
| New steroid and/or IS | 94 (14.2) | 78 (12.7) | 16 (33.3) | <0.001 |
| New renal involvement | 71 (10.8) | 62 (10.1) | 9 (18.8) | 0.107 |
| ≥1‐point increase SDI within 5 y | 167 (25.3) | 152 (24.8) | 15 (31.2) | 0.417 |
| Death within 5 y | 11 (1.7) | 8 (1.3) | 3 (6.2) | 0.047 |
*
HCQ, hydroxychloroquine; IS, immunosuppressive drug; kg/m2, kilograms per square meter; SD, standard deviation; SDI, Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index; SLE, systemic lupus erythematosus; SLEDAI‐2K, Systemic Lupus Erythematosus Disease Activity Index 2000; T0, time zero.
a
Other immunosuppressant users included four patients treated with cyclosporine, one with sulfasalazine, and one with intravenous immunoglobulins (in the “not severely nonadherent” group), and one patient with rituximab (in the “nonadherent” group).