Adults with sickle cell disease who received recommended doses of hydroxyurea had higher fetal hemoglobin (HbF) levels, less organ dysfunction, and improved survival, compared with those who did receive recommended hydroxyurea doses, according to researchers.

“Our data suggest that even moderate increases, and not necessarily maximum HbF induction, may improve survival in patients with sickle cell anemia,” wrote Dr. Courtney D. Fitzhugh, assistant clinical investigator in the Laboratory of Sickle Mortality Prevention at the National Heart, Lung, and Blood Institute, Bethesda, Md., and her colleagues (PLoS One. 2015 Nov 17; doi:10.1371/journal.pone.0141706).

From 2001 to 2010, 383 patients with sickle cell disease underwent data clinical, laboratory, and echocardiographic evaluations every 2 years during a median follow-up of 2.6 years (range, 0.1-11.7).

In total, 59 patients died, and the median age at death was 46 years for men and 44.5 for women. Deceased subjects had lower fetal hemoglobin (P = .0044), were less likely to have taken hydroxyurea (56% vs. 68%, P = .040), and had a smaller proportion who were prescribed hydroxyurea within the recommended dose range (29% vs. 46%, P = .0039). Study participants who received a dose between 15 and 35 mg/kg/day more likely survived than those who never took hydroxyurea (P = .005). To assess the impact of hydroxyurea-induced HbF on organ injury, the study compared laboratory values from the highest and lowest HbF quartiles. For the lowest HbF quartile, alkaline phosphatase, a marker of organ damage, was consistently lower. “Because organ dysfunction may limit dosing, and hydroxyurea may not reverse severe tissue injury, we recommend treatment before organ damage occurs,” the researchers wrote.

Dr. Fitzhugh reported having no disclosures.