title: Oral anticoagulation treatment in the elderly: a nested, prospective, case-control study.
abstract: BACKGROUND
  Whether elderly patients are at increased risk of complications during oral anticoagulant treatment (OAT) is still a matter of debate.
  
  
  METHODS
  Bleeding and thrombotic events occurring during OAT in 461 patients, aged 75 years or older when they started OAT, and in 461 patients younger than 70 years, matched for sex, OAT indication, and treating center, were examined in a prospective, multicenter, inception-cohort study.
  
  
  RESULTS
  Bleeding rate was 9.9% and 6.6% patient-years in elderly and young patients, respectively (P = .07), and 2.1% and 1.1% for major bleeding (P = .19); 6 and 1 events, respectively, were fatal (all intracranial, relative risk, 6.4; P = .05). In the elderly, bleeding rate was lower (4.5%) for international normalized ratios (INRs) between 2.0 and 2.9; it was higher during the first 90 treatment days (P = .05) and when arterial vascular disease was the indication for OAT (P = .03). Thrombosis rate was 4.2% and 2.5% patient-years in elderly and young patients, respectively (P = .10); however, 13 and 5 events were fatal (relative risk, 2.8; P = .04). Thrombosis rate was lower (1.5%) for INRs between 2.0 and 2.9; it was higher during the first 90 treatment days (P<.001) and 6 of 7 venous events occurred at lower than 2.0 INRs.
  
  
  CONCLUSIONS
  A nonsignificant trend was noted toward a higher rate of both bleeding and thrombotic complications in elderly vs matched younger patients. Intracranial bleeding and fatal thrombotic events were significantly more frequent in the elderly. Our results also indicate that lower than 2.0 INRs do not preclude bleeding in the elderly nor offer adequate protection from thrombotic events. Moderate anticoagulation (2.0-3.0 INRs) in elderly patients seems the safest and most effective.
authors.affiliation: Department of Angiology, University Hospital S Orsola-Malpighi, Bologna, Italy. palareti@tin.it
authors.forename: G
authors.initials: G
authors.lastname: Palareti
authors.forename: J
authors.initials: J
authors.lastname: Hirsh
authors.forename: C
authors.initials: C
authors.lastname: Legnani
authors.forename: C
authors.initials: C
authors.lastname: Manotti
authors.forename: A
authors.initials: A
authors.lastname: D'Angelo
authors.forename: V
authors.initials: V
authors.lastname: Pengo
authors.forename: M
authors.initials: M
authors.lastname: Moia
authors.forename: G
authors.initials: G
authors.lastname: Guazzaloca
authors.forename: S
authors.initials: S
authors.lastname: Musolesi
authors.forename: S
authors.initials: S
authors.lastname: Coccheri
mesh_terms: D000284:Administration, Oral; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001777:Blood Coagulation / Q000187:drug effects; D016022:Case-Control Studies; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced*; D006801:Humans; D019934:International Normalized Ratio; D007558:Italy; D008297:Male; D015999:Multivariate Analysis; D016012:Poisson Distribution; D011446:Prospective Studies; D012306:Risk; D013927:Thrombosis / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants