title: Impact of early nonadherence to oral antipsychotics on clinical and economic outcomes among patients with schizophrenia.
abstract: BACKGROUND
  To quantify early nonadherence to antipsychotic medications in patients with schizophrenia and its impact on short-term antipsychotic adherence, healthcare utilization, and costs.
  
  
  METHODS
  Patients who initiated oral antipsychotic treatment between January 1, 2006 to September 30, 2009 were identified from the MarketScan® Commercial Claims and Encounters (CCE) database (Truven Health Analytics, Ann Arbor, Michigan, USA). Patients were required to have a diagnosis of schizophrenia determined by the International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) code 295.x, be 13-65 years of age, and have ≥ 12 months of continuous coverage prior to and after (follow-up) the earliest antipsychotic usage (index event). Medication discontinuation was defined as a gap of 30 days in available therapy; early nonadherence was defined as having the gap 90 days from the index event. During the follow-up period, medication adherence was estimated with quarterly medication possession ratios (MPR), and all-cause and schizophrenia-related healthcare resource utilization and costs were determined.
  
  
  RESULTS
  The mean time to discontinuation (TTD) was 39.5 ± 20.1 days for early nonadherence patients (n = 873) and 250.7 ± 103.3 days for patients who were adherent early (n = 589). Early nonadherence resulted in more hospitalizations (0.57 vs. 0.38; P = 0.0006) with longer length of stay (LOS, 5.0 vs. 3.0 days; P = 0.0013) and higher costs ($5,850 vs. $4,211; P = 0.0244); schizophrenia-related hospitalizations, LOS, and costs were also greater. Patients that were adherent used more schizophrenia-related medications (10.4 vs. 4.7; P < 0.0001), increasing pharmacy costs ($3,684 vs. $1,549; P < 0.0001). Early nonadherence was correlated with lower drug adherence at each quarter of the follow-up period.
  
  
  CONCLUSIONS
  Approximately 60% of patients with schizophrenia are nonadherent to antipsychotic medication early in treatment and are less likely to be adherent later. Early nonadherence resulted in more all-cause and schizophrenia-related hospitalizations with a greater LOS and cost of care.
authors.affiliation: Otsuka America Pharmaceutical, Inc., 1 University Square Drive, Princeton, New Jersey 08540, USA. Steve.Offord@otsuka-us.com
authors.forename: Steve
authors.initials: S
authors.lastname: Offord
authors.forename: Jay
authors.initials: J
authors.lastname: Lin
authors.forename: Dario
authors.initials: D
authors.lastname: Mirski
authors.forename: Bruce
authors.initials: B
authors.lastname: Wong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D017048:Health Care Costs; D006296:Health Services / Q000191:economics / Q000706:statistics & numerical data; D006760:Hospitalization / Q000191:economics / Q000706:statistics & numerical data; D006801:Humans; D007902:Length of Stay / Q000191:economics / Q000706:statistics & numerical data; D008297:Male; D008605:Mental Health Services / Q000191:economics / Q000706:statistics & numerical data*; D008875:Middle Aged; D012559:Schizophrenia / Q000188:drug therapy* / Q000191:economics; D014481:United States; D055815:Young Adult; D016903:Drug Monitoring
chemical_list: D014150:Antipsychotic Agents