Flares after hydroxychloroquine reduction or discontinuation: results from the Systemic Lupus International Collaborating Clinics (SLICC) inception cohort.

Objectives: To evaluate systemic lupus erythematosus (SLE) flares following hydroxychloroquine (HCQ) reduction or discontinuation versus HCQ maintenance.
Methods: We analysed prospective data from the Systemic Lupus International Collaborating Clinics (SLICC) cohort, enrolled from 33 sites within 15 months of SLE diagnosis and followed annually (1999-2019). We evaluated person-time contributed while on the initial HCQ dose ('maintenance'), comparing this with person-time contributed after a first dose reduction, and after a first HCQ discontinuation. We estimated time to first flare, defined as either subsequent need for therapy augmentation, increase of ≥4 points in the SLE Disease Activity Index-2000, or hospitalisation for SLE. We estimated adjusted HRs (aHRs) with 95% CIs associated with reducing/discontinuing HCQ (vs maintenance). We also conducted separate multivariable hazard regressions in each HCQ subcohort to identify factors associated with flare.
Results: We studied 1460 (90% female) patients initiating HCQ. aHRs for first SLE flare were 1.20 (95% CI 1.04 to 1.38) and 1.56 (95% CI 1.31 to 1.86) for the HCQ reduction and discontinuation groups, respectively, versus HCQ maintenance. Patients with low educational level were at particular risk of flaring after HCQ discontinuation (aHR 1.43, 95% CI 1.09 to 1.87). Prednisone use at time-zero was associated with over 1.5-fold increase in flare risk in all HCQ subcohorts.
Conclusions: SLE flare risk was higher after HCQ taper/discontinuation versus HCQ maintenance. Decisions to maintain, reduce or stop HCQ may affect specific subgroups differently, including those on prednisone and/or with low education. Further study of special groups (eg, seniors) may be helpful.
Competing Interests: Competing interests: All the following relationships are outside the submitted work. Dr AEC: consulting fees from AstraZeneca, Bristol Myers Squibb, Exagen Diagnostics and GlaxoSmithKline. Dr CG: consulting fees from the Centers for Disease Control (CDC), Morton Grove Pharmaceutical (MGP), Sanofi and UCB. Dr RR-G: consulting fees from GSK, Immuncor and ThermoFisher. Dr DAI: consulting fees from Amgen, Merck Serono, AstraZeneca and Eli Lilly (the honoraria are passed onto a local arthritis charity). Dr AR: consulting fees from Lilly. Dr PRF: participation on advisory boards from AbbVie, AstraZeneca and Lilly. Dr MAK: consulting fees from GSK. Dr MI: consulting fees from AbbVie, UCB, Novartis, Janssen and Lilly.
(© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY. Published by BMJ.)