Why carry out this study?

The pharmacokinetics of hydroxychloroquine (HCQ) are complex, and its blood concentrations vary greatly between treated patients, leading to differences in efficacy.

A low blood concentration of HCQ is a marker and predictor of disease progression in patients with SLE.

What was learned from the study?

Gender, age, weight, duration of HCQ use, systemic lupus erythematosus disease activity index (SLEDAI), platelet count, and immunoglobulin G levels might explain the differences in concentration.

Combining blood HCQ or desethylhydroxychloroquine (DHCQ) concentrations with individual patient characteristics to optimize dosage might help improve treatment outcomes in Chinese patients with SLE.