title: Comparing the cumulative incidences of add-on therapy among the major antihypertensive classes in 2531 Asian patients: a cohort study.
abstract: BACKGROUND
  Published literature addressing the efficacy of different antihypertensive drug classes among Asian patients is scarce.
  
  
  METHODS
  This cohort study included all patients prescribed their first-ever antihypertensive monotherapy without concomitant use of chronic medications in two primary care clinics in Hong Kong during 1990-2002. The incidence of add-on therapy within 48 weeks because of suboptimal blood pressure control was evaluated and compared among different age and gender groups.
  
  
  CONCLUSIONS
  Among the 2531 patients, the incidence of add-on therapy among users of angiotensin converting enzyme inhibitors (ACEI) was highest in young females (31.1%, 95% CI 22.2%, 40.0%, P < 0.001) and elderly females (18.0%, 95% CI 11.3%, 24.7%, P = 0.049) as compared with thiazide diuretics, beta-blockers and calcium channel blockers. The incidence of add-on therapy among young males (20.3%, 95% CI 11.1%, 29.5%; P > 0.50) and elderly males (12.5%, 95% CI 3.8%, 21.2%) was also highest with the ACEI than other drug classes although statistical significance was not reached.
  
  
  CONCLUSIONS
  The incidence of add-on therapy among first-time antihypertensives appear to be significantly different between drug classes. This deserves further investigation.
authors.affiliation: School of Public Health and Department of Community and Family Medicine, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong SAR, China. wong_martin@cuhk.edu.hk
authors.forename: M C S
authors.initials: MC
authors.lastname: Wong
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects*; D015331:Cohort Studies; D016208:Databases, Factual; D004359:Drug Therapy, Combination; D005260:Female; D006723:Hong Kong; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care; D012737:Sex Factors
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents