title: A long-term risk-benefit analysis of low-dose aspirin in primary prevention.
abstract: BACKGROUND
  The long-term risk-benefit effect of occasional and regular use of low-dose aspirin (≤ 100 mg per day) in primary prevention of vascular diseases and cancers was calculated.
  
  
  METHODS
  One representative database of 1 000 000 participants from Taiwan's National Health Insurance scheme in 1997-2000 was used. The potential study subjects were those aged 30-95 years, were found not to have been prescribed aspirin before 1 January 2000, but to have first been prescribed low-dose aspirin (≤ 100 mg per day) after that date and were followed up to 31 December 2009. Participants prescribed low-dose aspirin < 20% during the study period were considered occasional users and those prescribed ≥ 80% regular users. After the propensity score matching, rate differences of haemorrhage, ischaemia and cancer between these users were calculated their net clinical risk.
  
  
  RESULTS
  A total of 1720 pairs were analysed. During the study period, haemorrhage and ischaemia occurred in 25 (1·45%) and 67 participants (3·90%) in occasional users and 69 (4·01%) and 100 participants (5·81%) in regular users, whereas cancer occurred in 32 participants (1·86%) in occasional users and 26 participants (1·51%) in regular users. The crude and adjusted net clinical risks of low-dose aspirin use between the two frequency of users (≥ 80% vs. < 20%) were 4·12% (95% CI = 2·19%, 6·07%; P < 0·001) and 3·93% (95% CI = 2·01%, 5·84%; P < 0·001).
  
  
  CONCLUSIONS
  A long-term regular use of low-dose aspirin might not be better than occasional use in the primary prevention against major vascular diseases and cancer.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.|Faculty of Medicine, Department of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: I-Chen
authors.initials: IC
authors.lastname: Wu
authors.affiliation: Department of Public Health, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Hui-Min
authors.initials: HM
authors.lastname: Hsieh
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.|Faculty of Medicine, Department of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Fang-Jung
authors.initials: FJ
authors.lastname: Yu
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Meng-Chieh
authors.initials: MC
authors.lastname: Wu
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Tzung-Shiun
authors.initials: TS
authors.lastname: Wu
authors.affiliation: Department of Public Health, Kaohsiung Medical University, Kaohsiung, Taiwan.|Department of Family Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.|Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Ming-Tsang
authors.initials: MT
authors.lastname: Wu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000517:prevention & control*; D016208:Databases, Factual; D005260:Female; D006471:Gastrointestinal Hemorrhage / Q000139:chemically induced / Q000453:epidemiology; D006470:Hemorrhage / Q000139:chemically induced* / Q000453:epidemiology; D006801:Humans; D020300:Intracranial Hemorrhages / Q000139:chemically induced / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology / Q000517:prevention & control; D009369:Neoplasms / Q000453:epidemiology / Q000517:prevention & control*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D011322:Primary Prevention; D018570:Risk Assessment; D020521:Stroke / Q000453:epidemiology / Q000517:prevention & control; D013624:Taiwan / Q000453:epidemiology
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin
keywords: cancer; haemorrhage; low-dose aspirin; primary prevention; risk-benefit analysis; vascular disease