Higher hydroxychloroquine dose based on actual body weight is associated with lower SLE flare risks while maintaining tolerability.

OBJECTIVES

The effects of HCQ dose based on actual body weight (ABW) on SLE remain unclear. We investigated the effects of HCQ dose based on ABW of patients with SLE.

METHODS

Patients were classified into ≥5 mg/kg ABW [high dose (HD)] and <5 mg/kg ABW [low dose (LD)] groups. Patient backgrounds were adjusted using inverse probability of treatment weighting method. The discontinuation rate owing to adverse events of overall cohort (group 1) was evaluated. Subgroups with a disease duration ≥1 year (group 2) and without additional immunosuppressive agents and biologics after HCQ initiation (group 3) were compared with evaluated flare rates, prednisolone dose and serological data.

RESULTS

Among 182 patients in group 1, 60 (33%) comprised the HD group. Five-year discontinuation rates were 18.9% and 13.6% in the HD and LD groups, respectively (P = 0.314). Three-year flare-free rates in HD group were higher than those in LD group: 75.0% (HD) vs 60.7% (LD) (P = 0.239) in group 2, and 79.2% (HD) vs 57.8% (LD) (P = 0.141) in group 3. In group 3, each 0.2 mg/kg increase in the HCQ dose reduced flares (hazard ratio 0.91; 95% CI 0.84-0.99).

CONCLUSION

No clear differences in efficacy and safety were observed between the HD and LD groups; however, a higher HCQ dose was associated with a reduced flare risk. Our findings suggest that a lower HCQ dose may be associated with a higher flare risk in patients with SLE, highlighting the importance of HCQ dose based on ABW.