Table 4

Adjusted HRs with 95% CIs for SLE flares associated with HCQ reduction/discontinuation versus maintenance: main and stratified analyses

HCQ reduction versus maintenanceHCQ discontinuation versus maintenance
No. of patientsAbsolute flare rate/100 person-years (95% CI)Adjusted HR (95% CI)*No. of patientsAbsolute flare rate/100 person-years (95% CI)Adjusted HR (95% CI)*
Main analysis134240.0 (36.4 to 43.9) vs 31.9 (29.0 to 35.1)1.20 (1.04 to 1.38)96641.3 (36.7 to 46.4) vs 30.0 (26.7 to 33.6)1.56 (1.31 to 1.86)
Stratified analyses:
Low disease activity‡ state at time-zero
 Yes81537.5 (33.2 to 42.4) vs 27.8 (24.5 to 31.6)1.32 (1.10 to 1.60)59235.5 (30.4 to 41.3) vs 26.6 (22.8 to 30.9)1.62 (1.28 to 2.05)
 No52743.9 (38.0 to 50.6) vs 39.8 (34.3 to 46.1)1.04 (0.84 to 1.29)37453.6 (44.7 to 64.2) vs 36.4 (30.5 to 43.5)1.60 (1.22 to 2.09)
Remission† at time-zero
 Yes19626.2 (20.1 to 34.1) vs 13.2 (9.5 to 18.4)2.14 (1.34 to 3.42)13324.7 (17.7 to 34.6) vs 12.2 (8.0 to 18.8)2.77 (1.46 to 5.26)
 No114646.3 (41.9 to 51.1) vs 41.7 (37.8 to 46.0)1.14 (0.98 to 1.32)83347.9 (42.3 to 54.2) vs 39.2 (35.0 to 43.9)1.50 (1.25 to 1.81)
  • *Adjusted for sex, race, age at SLE diagnosis, education, geographic residence and the following variables assessed at time-zero: SLE duration, renal damage according to SLICC Damage Index, body mass index, smoking, prednisone, immunosuppressives and biologics. The main analysis was additionally adjusted by disease activity at time-zero.

  • †Remission was defined as SLEDAI-2K=0 and no prednisone or immunosuppressives use during the last year.

  • ‡Low disease activity state was defined as SLEDAI-2K <4 and current prednisone dose ≤7.5 mg/day.

  • HCQ, hydroxychloroquine; SLE, systemic lupus erythematosus; SLEDAI-2K, SLE Disease Activity Index-2000; SLICC, Systemic Lupus International Collaborating Clinics.