title: Hydroxyurea adherence and associated outcomes among Medicaid enrollees with sickle cell disease.
abstract: While laboratory and clinical benefits of hydroxyurea for patients with sickle cell disease (SCD) are well-established, few data describe the extent and implications of non-adherence. We sought to assess adherence to hydroxyurea among patients with SCD and investigate associations between adherence and clinical and economic outcomes. Insurance claims of North Carolina Medicaid enrollees (6/2000-8/2008) with SCD were analyzed. Inclusion criteria included age < 65 years, continuous Medicaid enrollment ≥ 12 months before and following hydroxyurea initiation, and ≥ 2 hydroxyurea prescriptions. Three hundred twelve patients, mean age 21 (± 12.2) years, met inclusion criteria and 35% were adherent, defined as a medication possession ration (MPR) ≥ 0.80; mean MPR was 0.60. In the 12 months following hydroxyurea initiation, adherence was associated with reduced risk of SCD-related hospitalization (hazard ratio [HR] = 0.65, p = .0351), all-cause and SCD-related emergency department visit (HR = 0.72, p = .0388; HR = 0.58, p =.0079, respectively), and vaso-occlusive event (HR = 0.66, p = .0130). Adherence was associated with reductions in health care costs such as all-cause and SCD-related inpatient (-$5,286, p < .0001; -$4,403, p < .0001, respectively), ancillary care (-$1,336, p < .0001; -$836, p < .0001, respectively), vaso-occlusive event-related (-$5,793, p < .0001), and total costs (-$6,529, p < .0001; -$5,329, p <.0001, respectively). Adherence to hydroxyurea among SCD patients appears suboptimal and better adherence is associated with improved clinical and economic outcomes.
authors.affiliation: RTI Health Solutions, Research Triangle Park, North Carolina, USA.
authors.forename: Sean D
authors.initials: SD
authors.lastname: Candrilli
authors.forename: Sarah H
authors.initials: SH
authors.lastname: O'Brien
authors.forename: Russell E
authors.initials: RE
authors.lastname: Ware
authors.forename: Milap C
authors.initials: MC
authors.lastname: Nahata
authors.forename: Eric E
authors.initials: EE
authors.lastname: Seiber
authors.forename: Rajesh
authors.initials: R
authors.lastname: Balkrishnan
mesh_terms: D000293:Adolescent; D000328:Adult; D000755:Anemia, Sickle Cell / Q000150:complications / Q000188:drug therapy* / Q000191:economics*; D002648:Child; D003625:Data Collection; D004341:Drug Evaluation; D004630:Emergencies; D005260:Female; D006760:Hospitalization; D006801:Humans; D006918:Hydroxyurea / Q000191:economics / Q000627:therapeutic use*; D008297:Male; D008484:Medicaid; D009657:North Carolina; D010349:Patient Compliance / Q000706:statistics & numerical data*; D016896:Treatment Outcome; D014481:United States; D014652:Vascular Diseases; D055815:Young Adult
chemical_list: D006918:Hydroxyurea