title: Medication Nonadherence Is Associated With Increased Subsequent Acute Care Utilization Among Medicaid Beneficiaries With Systemic Lupus Erythematosus.
abstract: OBJECTIVE
  We examined whether nonadherence to hydroxychloroquine (HCQ) or immunosuppressive medications (ISMs) was associated with higher subsequent acute care utilization among Medicaid beneficiaries with systemic lupus erythematosus (SLE).
  
  
  METHODS
  We utilized US Medicaid data from 2000-2006 to identify adults ages 18-64 years with SLE who were new users of HCQ or ISMs. We defined the index date as receipt of HCQ or ISMs without use in the prior 6 months. We measured adherence using the medication possession ratio (MPR), the proportion of days covered by total days' supply dispensed, for the 1-year post-index date. Our outcomes were all-cause and SLE-related emergency department (ED) visits and hospitalizations in the subsequent year. We used multivariable Poisson regression models to examine the association between nonadherence (MPR <80%) and acute care utilization, adjusting for sociodemographics and comorbidities.
  
  
  RESULTS
  We identified 9,600 HCQ new users and 3,829 ISM new users with SLE. The mean ± SD MPR for HCQ was 47.8% ± 30.3% and for ISMs was 42.7% ± 30.7%. Seventy-nine percent of HCQ users and 83% of ISM users were nonadherent (MPR <80%). In multivariable models, among HCQ users, the incidence rate ratio (IRR) of ED visits was 1.55 (95% confidence interval [95% CI] 1.43-1.69) and the IRR of hospitalizations was 1.37 (95% CI 1.25-1.50), comparing nonadherers to adherers. For ISM users, the IRR of ED visits was 1.64 (95% CI 1.42-1.89) and of hospitalizations was 1.67 (95% CI 1.41-1.96) for nonadherers versus adherers.
  
  
  CONCLUSIONS
  In this cohort, nonadherence to HCQ and ISMs was common and was associated with significantly higher subsequent acute care utilization.
authors.affiliation: Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Candace H
authors.initials: CH
authors.lastname: Feldman
authors.affiliation: University of California San Francisco.
authors.forename: Jinoos
authors.initials: J
authors.lastname: Yazdany
authors.affiliation: Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Hongshu
authors.initials: H
authors.lastname: Guan
authors.affiliation: Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Solomon
authors.affiliation: Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Karen H
authors.initials: KH
authors.lastname: Costenbader
mesh_terms: D000293:Adolescent; D000328:Adult; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D016009:Chi-Square Distribution; D016208:Databases, Factual; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006295:Health Resources / Q000706:statistics & numerical data*; D006760:Hospitalization; D006801:Humans; D006886:Hydroxychloroquine / Q000627:therapeutic use*; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D007342:Insurance Benefits; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D008297:Male; D008484:Medicaid; D055118:Medication Adherence; D008875:Middle Aged; D015999:Multivariate Analysis; D015995:Prevalence; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D018501:Antirheumatic Agents; D007166:Immunosuppressive Agents; D006886:Hydroxychloroquine