Some sources urge caution when prescribing hydroxychloroquine (HCQ) to patients with G6PDH deficiency, presumably due to a risk of hemolytic anemia. There are limited published data, however, to support this risk. Additionally, not all patients with G6PDH deficiency are at similar risk for hemolysis, and people with the African variant are at particularly low risk. Through a retrospective chart review, we aimed to quantify the frequency of G6PDH-deficient patients with hemolysis attributed to HCQ.

We identified Duke University Medical Center rheumatology patients with HCQ use and a measured G6PDH level. A retrospective chart review was performed, recording demographics, G6PDH levels, episodes of anemia, laboratory values consistent with hemolysis, and HCQ use.

Of the 275 patients reviewed, 84% were female; 46% were African American and 48% were white. The leading diagnoses were systemic lupus erythematosus (32%), rheumatoid arthritis (29%), and inflammatory arthritis (14%). Only 4% of patients were G6PDH deficient (all African American). Two G6PDH-deficient patients had hemolysis during severe lupus flares that occurred while not taking HCQ. There were no reported episodes of hemolysis in more than 700 months of HCQ exposure among the 11 G6PDH-deficient patients.

This is the largest study to date evaluating G6PDH deficiency with concurrent use of HCQ. Of 11 patients with G6PDH deficiency, 2 had episodes of hemolysis, but these did not occur during HCQ therapy. These data do not support routine measurement of G6PDH levels or withholding HCQ therapy among African American patients with G6PDH deficiency.