Characteristic Total (n=191) HCQ group (n=42) Non-HCQ group (n=149) Effect size (95% CI) P value
Female, n (%) 122 (63.9%) 34 (81.0%) 88 (59.1%) 2.95 (1.28 to 6.80) 0.009
Age, mean (SD), years
At onset 7.9 (3.9) 9.7 (3.4) 7.3 (3.8) -2.38 (-3.58 to -1.16) < 0.001
At HCQ initiation - 12.0 (2.4) - - -
Interval from ITP onset to HCQ initiation, mean (SD), months - 26.4 (24.2) - - -
Platelet counts, mean (SD), 109/L
At onset 26 (23) 25 (22) 26 (23) 1.44 (-7.20 to 10.08) 0.74
At HCQ initiation - 85 (77) - - -
Symptoms associated with autoimmune diseases *, n (%) 55 (28.8%) 20 (47.6%) 35 (23.5%) 2.96 (1.45 to 6.05) 0.002
Positive ANA at baseline, n (%) 67 (35.1%) 21 (50.0%) 46 (30.9%) 2.24 (1.12 to 4.50) 0.02
Other markers associated with autoimmune diseases, n (%) 82/177 (46.3%) 27 (64.3%) 55/135 (40.7%) 2.62 (1.28 to 5.37) 0.008
Positive antiphospholipid antibodies 50/163 (30.7%) 20 (47.6%) 30/121 (24.8%) 2.76 (1.33 to 5.74) 0.006
Low C3/C4 51/131 (38.9%) 15/39 (38.5%) 36/92 (39.1%) 0.97 (0.45 to 2.10) 0.94
Previous treatments, n (%)
Corticosteroids 159 (83.2%) 32 (76.2%) 127 (85.2%) - -
IVIG 133 (69.6%) 27 (64.3%) 106 (71.1%) - -
Rituximab 27 (14.1%) 3 (7.1%) 24 (16.1%) - -
TPO-RAs 33 (17.3%) 4 (9.5%) 29 (19.5%) - -
Splenectomy 2 (1.0%) 1 (2.4%) 1 (0.7%) - -
Follow-up time, median (range), months 37 (12 ~ 160) 56 (17 ~ 146) 34 (12 ~ 160) - -
Response evaluated at last follow-up , n (%) 111 (58.1%) 29 (69.0%) 72 (48.3%) 2.39 (1.15 to 4.95) 0.02
CR at last follow-up, n (%) 73 (38.2%) 22 (52.4%) 51 (34.2%) 2.11 (1.06 to 4.23) 0.03