title: Risk of ischemic stroke during the initiation period of α-blocker therapy among older men.
abstract: BACKGROUND
  Alpha-blockers are notorious for their first-dose effect of acute hypotension during the early initiation period. Because acute cerebral hypoperfusion may precipitate an episode of ischemic stroke, we aimed to provide a quantitative estimate of the risk of ischemic stroke during the early initiation period of α-blocker therapy, using a self-controlled case series design.
  
  
  METHODS
  We identified all men aged 50 years or more as of 2007 who were incident users of α-blockers and had a diagnosis of ischemic stroke during the 2007-2009 study period using claims data from Taiwan's National Health Insurance claims database. The first day on which the α-blocker was prescribed was the index date. We partitioned different risk periods according to their relationship to the index date (pre-exposure risk periods 1 and 2 = ≤ 21 d and 22-60 d before index date, respectively; post-exposure risk periods 1 and 2 = ≤ 21 d and 22-60 d after index date, respectively); the remainder of the study period was defined as the unexposed period. We estimated the incidence rate ratio (IRR) of ischemic stroke in each risk period relative to the unexposed period using a conditional Poisson regression model.
  
  
  RESULTS
  A total of 7502 men were included. Compared with the risk in the unexposed period, the risk of ischemic stroke was increased in post-exposure risk period 1 among all patients in the study population (adjusted IRR 1.40, 95% confidence interval [CI], 1.22-1.61) and among patients without concomitant prescriptions for other antihypertensive agents (adjusted IRR 2.11, 95% CI 1.73-2.57).
  
  
  CONCLUSIONS
  Alpha-blocker therapy was associated with an increased risk of ischemic stroke during the early initiation period, especially among patients who were not taking other antihypertensive agents.
authors.affiliation: Department of Internal Medicine and Center for Critical Care Medicine (C.-L. Lai), National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan; Department of Internal Medicine (C.-L. Lai), National Taiwan University College of Medicine, Taipei, Taiwan; Institute of Epidemiology and Preventive Medicine (C.-L. Lai, M.-S. Lai) and Institute of Health Policy and Management (Kuo), College of Public Health, National Taiwan University, Taipei, Taiwan; Center for Comparative Effectiveness Research (Kuo, H.-M. Chen, M.-S. Lai), National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan; Departments of Internal Medicine (M.-F. Chen) and Medical Research (Chan), National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Oncology (Chan), National Taiwan University College of Medicine, Taipei, Taiwan chaolunlai@ntu.edu.tw mslai@ntu.edu.tw.
authors.forename: Chao-Lun
authors.initials: CL
authors.lastname: Lai
authors.affiliation: Department of Internal Medicine and Center for Critical Care Medicine (C.-L. Lai), National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan; Department of Internal Medicine (C.-L. Lai), National Taiwan University College of Medicine, Taipei, Taiwan; Institute of Epidemiology and Preventive Medicine (C.-L. Lai, M.-S. Lai) and Institute of Health Policy and Management (Kuo), College of Public Health, National Taiwan University, Taipei, Taiwan; Center for Comparative Effectiveness Research (Kuo, H.-M. Chen, M.-S. Lai), National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan; Departments of Internal Medicine (M.-F. Chen) and Medical Research (Chan), National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Oncology (Chan), National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Raymond Nien-Chen
authors.initials: RN
authors.lastname: Kuo
authors.affiliation: Department of Internal Medicine and Center for Critical Care Medicine (C.-L. Lai), National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan; Department of Internal Medicine (C.-L. Lai), National Taiwan University College of Medicine, Taipei, Taiwan; Institute of Epidemiology and Preventive Medicine (C.-L. Lai, M.-S. Lai) and Institute of Health Policy and Management (Kuo), College of Public Health, National Taiwan University, Taipei, Taiwan; Center for Comparative Effectiveness Research (Kuo, H.-M. Chen, M.-S. Lai), National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan; Departments of Internal Medicine (M.-F. Chen) and Medical Research (Chan), National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Oncology (Chan), National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Ho-Min
authors.initials: HM
authors.lastname: Chen
authors.affiliation: Department of Internal Medicine and Center for Critical Care Medicine (C.-L. Lai), National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan; Department of Internal Medicine (C.-L. Lai), National Taiwan University College of Medicine, Taipei, Taiwan; Institute of Epidemiology and Preventive Medicine (C.-L. Lai, M.-S. Lai) and Institute of Health Policy and Management (Kuo), College of Public Health, National Taiwan University, Taipei, Taiwan; Center for Comparative Effectiveness Research (Kuo, H.-M. Chen, M.-S. Lai), National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan; Departments of Internal Medicine (M.-F. Chen) and Medical Research (Chan), National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Oncology (Chan), National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Ming-Fong
authors.initials: MF
authors.lastname: Chen
authors.affiliation: Department of Internal Medicine and Center for Critical Care Medicine (C.-L. Lai), National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan; Department of Internal Medicine (C.-L. Lai), National Taiwan University College of Medicine, Taipei, Taiwan; Institute of Epidemiology and Preventive Medicine (C.-L. Lai, M.-S. Lai) and Institute of Health Policy and Management (Kuo), College of Public Health, National Taiwan University, Taipei, Taiwan; Center for Comparative Effectiveness Research (Kuo, H.-M. Chen, M.-S. Lai), National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan; Departments of Internal Medicine (M.-F. Chen) and Medical Research (Chan), National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Oncology (Chan), National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: K Arnold
authors.initials: KA
authors.lastname: Chan
authors.affiliation: Department of Internal Medicine and Center for Critical Care Medicine (C.-L. Lai), National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan; Department of Internal Medicine (C.-L. Lai), National Taiwan University College of Medicine, Taipei, Taiwan; Institute of Epidemiology and Preventive Medicine (C.-L. Lai, M.-S. Lai) and Institute of Health Policy and Management (Kuo), College of Public Health, National Taiwan University, Taipei, Taiwan; Center for Comparative Effectiveness Research (Kuo, H.-M. Chen, M.-S. Lai), National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan; Departments of Internal Medicine (M.-F. Chen) and Medical Research (Chan), National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Oncology (Chan), National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Mei-Shu
authors.initials: MS
authors.lastname: Lai
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000009:adverse effects*; D000368:Aged; D000959:Antihypertensive Agents / Q000009:adverse effects; D002545:Brain Ischemia / Q000139:chemically induced* / Q000453:epidemiology; D016022:Case-Control Studies; D006801:Humans; D007022:Hypotension / Q000139:chemically induced; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012306:Risk; D012307:Risk Factors; D020521:Stroke / Q000139:chemically induced* / Q000453:epidemiology; D013624:Taiwan / Q000453:epidemiology; D013997:Time Factors
chemical_list: D000317:Adrenergic alpha-Antagonists; D000959:Antihypertensive Agents