title: Risk of ischemic stroke associated with the use of antipsychotic drugs in elderly patients: a retrospective cohort study in Korea.
abstract: OBJECTIVE
  Strong concerns have been raised about whether the risk of ischemic stroke differs between conventional antipsychotics (CAPs) and atypical antipsychotics (AAPs). This study compared the risk of ischemic stroke in elderly patients taking CAPs and AAPs.
  
  
  METHODS
  We conducted a retrospective cohort study of 71,584 elderly patients who were newly prescribed the CAPs (haloperidol or chlorpromazine) and those prescribed the AAPs (risperidone, quetiapine, or olanzapine). We used the National Claims Database from the Health Insurance Review and Assessment Service (HIRA) from January 1, 2006 to December 31, 2009. Incident cases for ischemic stroke (ICD-10, I63) were identified. The hazard ratios (HR) for AAPs, CAPs, and for each antipsychotic were calculated using multivariable Cox regression models, with risperidone as a reference.
  
  
  RESULTS
  Among a total of 71,584 patients, 24,668 patients were on risperidone, 15,860 patients on quetiapine, 3,888 patients on olanzapine, 19,564 patients on haloperidol, and 7,604 patients on chlorpromazine. A substantially higher risk was observed with chlorpromazine (HR = 3.47, 95% CI, 1.97-5.38), which was followed by haloperidol (HR = 2.43, 95% CI, 1.18-3.14), quetiapine (HR = 1.23, 95% CI, 0.78-2.12), and olanzapine (HR = 1.12, 95% CI, 0.59-2.75). Patients who were prescribed chlorpromazine for longer than 150 days showed a higher risk (HR = 3.60, 95% CI, 1.83-6.02) than those who took it for a shorter period of time.
  
  
  CONCLUSIONS
  A much greater risk of ischemic stroke was observed in patients who used chlorpromazine and haloperidol compared to risperidone. The evidence suggested that there is a strong need to exercise caution while prescribing these agents to the elderly in light of severe adverse events with atypical antipsychotics.
authors: Korea Institute of Drug Safety and Risk Management, Seoul, Republic of Korea.
authors: Ju-Young
authors: JY
authors: Shin
authors: Medical Research Collaborating Center, Seoul National University College of Medicine/ Seoul National University Hospital, Seoul, Republic of Korea.
authors: Nam-Kyong
authors: NK
authors: Choi
authors: Medical Research Collaborating Center, Seoul National University College of Medicine/ Seoul National University Hospital, Seoul, Republic of Korea.
authors: Joongyub
authors: J
authors: Lee
authors: Korea Institute of Drug Safety and Risk Management, Seoul, Republic of Korea.
authors: Jong-Mi
authors: JM
authors: Seong
authors: Korea Institute of Drug Safety and Risk Management, Seoul, Republic of Korea.
authors: Mi-Ju
authors: MJ
authors: Park
authors: Korea Institute of Drug Safety and Risk Management, Seoul, Republic of Korea.
authors: Shin Haeng
authors: SH
authors: Lee
authors: Korea Institute of Drug Safety and Risk Management, Seoul, Republic of Korea; Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors: Byung-Joo
authors: BJ
authors: Park
mesh_terms: D000368:Aged; D014150:Antipsychotic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001569:Benzodiazepines / Q000009:adverse effects / Q000627:therapeutic use; D002746:Chlorpromazine / Q000009:adverse effects / Q000627:therapeutic use; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006220:Haloperidol / Q000009:adverse effects / Q000627:therapeutic use; D006801:Humans; D008297:Male; D000077152:Olanzapine; D016016:Proportional Hazards Models; D000069348:Quetiapine Fumarate / Q000009:adverse effects / Q000627:therapeutic use; D056910:Republic of Korea; D012189:Retrospective Studies; D012306:Risk; D020521:Stroke / Q000209:etiology* / Q000473:pathology; D013997:Time Factors
chemical_list: D014150:Antipsychotic Agents; D001569:Benzodiazepines; D000069348:Quetiapine Fumarate; D006220:Haloperidol; D000077152:Olanzapine; D002746:Chlorpromazine