title: Association of ICU or hospital admission with unintentional discontinuation of medications for chronic diseases.
abstract: BACKGROUND
  Patients discharged from acute care hospitals may be at risk for unintentional discontinuation of medications prescribed for chronic diseases. The intensive care unit (ICU) may pose an even greater risk because of the focus on acute events and the presence of multiple transitions in care.
  
  
  OBJECTIVE
  To evaluate rates of potentially unintentional discontinuation of medications following hospital or ICU admission.
  
  
  METHODS
  A population-based cohort study using administrative records from 1997 to 2009 of all hospitalizations and outpatient prescriptions in Ontario, Canada; it included 396,380 patients aged 66 years or older with continuous use of at least 1 of 5 evidence-based medication groups prescribed for long-term use: (1) statins, (2) antiplatelet/anticoagulant agents, (3) levothyroxine, (4) respiratory inhalers, and (5) gastric acid-suppressing drugs. Rates of medication discontinuation were compared across 3 groups: patients admitted to the ICU, patients hospitalized without ICU admission, and nonhospitalized patients (controls). Odds ratios (ORs) were calculated and adjusted for patient demographics, clinical factors, and health services use.
  
  
  METHODS
  The primary outcome was failure to renew the prescription within 90 days after hospital discharge.
  
  
  RESULTS
  Patients admitted to the hospital (n = 187,912) were more likely to experience potentially unintentional discontinuation of medications than controls (n = 208,468) across all medication groups examined. The adjusted ORs (AORs) ranged from 1.18 (95% CI, 1.14-1.23) for discontinuing levothyroxine in 12.3% of hospitalized patients (n = 6831) vs 11.0% of controls (n = 7114) to an AOR of 1.86 (95% CI, 1.77-1.97) for discontinuing antiplatelet/anticoagulant agents in 19.4% of hospitalized patients (n = 5564) vs 11.8% of controls (n = 2535). With ICU exposure, the AORs ranged from 1.48 (95% CI, 1.39-1.57) for discontinuing statins in 14.6% of ICU patients (n = 1484) to an AOR of 2.31 (95% CI, 2.07-2.57) for discontinuing antiplatelet/anticoagulant agents in 22.8% of ICU patients (n = 522) vs the control group. Admission to an ICU was associated with an additional risk of medication discontinuation in 4 of 5 medication groups vs hospitalizations without an ICU admission. One-year follow-up of patients who discontinued medications showed an elevated AOR for the secondary composite outcome of death, emergency department visit, or emergent hospitalization of 1.07 (95% CI, 1.03-1.11) in the statins group and of 1.10 (95% CI, 1.03-1.16) in the antiplatelet/anticoagulant agents group.
  
  
  CONCLUSIONS
  Patients prescribed medications for chronic diseases were at risk for potentially unintentional discontinuation after hospital admission. Admission to the ICU was generally associated with an even higher risk of medication discontinuation.
authors.affiliation: Department of Health Policy, Management, and Evaluation, Keenan Research Centre in Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada. bellc@smh.toronto.on.ca
authors.forename: Chaim M
authors.initials: CM
authors.lastname: Bell
authors.forename: Stacey S
authors.initials: SS
authors.lastname: Brener
authors.forename: Nadia
authors.initials: N
authors.lastname: Gunraj
authors.forename: Cindy
authors.initials: C
authors.lastname: Huo
authors.forename: Arlene S
authors.initials: AS
authors.lastname: Bierman
authors.forename: Damon C
authors.initials: DC
authors.lastname: Scales
authors.forename: Jana
authors.initials: J
authors.lastname: Bajcar
authors.forename: Merrick
authors.initials: M
authors.lastname: Zwarenstein
authors.forename: David R
authors.initials: DR
authors.lastname: Urbach
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease / Q000188:drug therapy*; D015331:Cohort Studies; D003266:Continuity of Patient Care; D004358:Drug Therapy / Q000706:statistics & numerical data; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D055118:Medication Adherence; D008508:Medication Errors; D016017:Odds Ratio; D009864:Ontario; D017063:Outcome Assessment, Health Care; D010343:Patient Admission; D019338:Polypharmacy; D055656:Prescriptions / Q000706:statistics & numerical data*; D012306:Risk