Despite evidence demonstrating the benefits of the medication hydroxyurea for patients with sickle cell anemia and frequent pain crises, an analysis suggests that more than 3 of 4 patients who might benefit were not treated with this safe and inexpensive drug, according to a study in JAMA.

The recommendation from the 2014 National Heart, Lung, and Blood Institute guidelines to treat all adults with sickle cell anemia (SCA) and 3 or more moderate to severe pain crises within 1 year with hydroxyurea was rated as strong based on high-quality evidence reviewed in 2008. Despite benefits in reducing pain crises, hospitalizations, and blood transfusions, it is thought that hydroxyurea is underused, although the extent of its use is unknown, according to background information in the article.

Nicolas Stettler, M.D., M.S.C.E., of the Lewin Group, Falls Church, Va., and colleagues examined the use of hydroxyurea when indicated for SCA in the Optum Normative Health Informatics database, a nationwide sample of commercial health and pharmacy claims from more than 36 million residents in all 50 states and Washington, D.C. Adults (18 years or older) with 1 or more inpatient or outpatient claims between January 2009 and June 2013 for SCA were identified. Patients were selected when they had 3 or more hospitalizations, emergency department (ED) visits, or both within 12 months that included 1 of the 5 most frequent diagnosis codes used for patients with SCA and pain crises. Treatment was defined as filling 1 or more hydroxyurea prescriptions during the 3, 6, or 12 months of continued enrollment following the third episode.

Of an enrolled population of 26,631,901, the researchers identified 2,086 adults with probable SCA. Of these, 677 had at least 3 pain-related hospitalizations or ED visits within 12 months and 570 had at least 3 months of coverage after the third episode. Among them, 86 (15 percent) were treated with hydroxyurea within 3 months of their third encounter. The percentage of treated patients increased slightly to 18 percent at 6 months and to 23 percent at 12 months.

The authors write that several barriers to treatment have been identified, including fear of adverse events, lack of clinician training, and failure to engage in shared decision making. "Our estimate reflects the combined effect of all barriers to treatment, regardless of source."

"Our data do not include the large uninsured or publicly insured population who may have more limited access to health care or awareness of treatment options. Therefore, these findings may not be representative of the entire U.S. population with SCA and may be a conservative estimate of the hydroxyurea treatment gap. To address this gap, it may be necessary to enhance patient outreach and clinician training and develop health care quality measures aimed at increasing the use of hydroxyurea for all patients who would benefit."