Oral anticoagulation treatment in the elderly - A nested, prospective, case-control study

Background: Whether elderly patients are at increased risk of complications during oral anticoagulant treatment (OAT) is still a matter of debate. Method: 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 TO 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 inte rnational normalized ratios (INRs) between 2.0 and 2.9; it was higher durin g the first 90 treatment days (P =.05) and when arterial vascular disease w as the indication for OAT (P =.03). Thrombosis rate was 4.2% and 2.5% patie nt-years in elderly and young patients, respectively (P =.10); however, 13 and 5 events were fatal (relative risk, 2.8; P =.03). Thrombosis rate was l ower (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 patient s. Intracranial bleeding and fatal thrombotic events were significantly mor e frequent in the elderly. Our results also indicate that lower than 2.0 IN Rs do not preclude bleeding in the elderly nor offer adequate protection fr om thrombotic events. Moderate anticoagulation (2.0-3.0 INRs) in elderly pa tients seems the safest and most effective.