Frequency of major complications of aspirin, warfarin, and intravenous heparin for secondary stroke prevention. A population-based study.
BACKGROUND
Complication rates of medical therapy for secondary stroke prevention derived from clinical trials may or may not be applicable to patients with cerebrovascular disease in the general population.


OBJECTIVE
To determine complication rates for aspirin, warfarin, and intravenous heparin administered for secondary stroke prevention after first episodes of ischemic stroke, transient ischemic attack, or amaurosis fugax in a community.


METHODS
Population-based historical cohort study.


METHODS
Rochester, Minnesota.


METHODS
All residents of Rochester who, between 1985 and 1989, received aspirin (n = 339) or warfarin (n = 145) within 2 years after first ischemic stroke, transient ischemic attack, or amaurosis fugax or received intravenous heparin (n = 201) within 2 weeks after first ischemic stroke, transient ischemic attack, or amaurosis fugax.


METHODS
Occurrence of major complications caused by therapy.


RESULTS
Twenty aspirin-associated complications (1 fatal) occurred during an average 1.7 years of treatment, 8 warfarin-associated complications occurred during an average 0.7 years of treatment, and 3 heparin-associated complications (1 fatal) occurred during an average 5.1 days of treatment. Complication rates were 3.5 per 100 person-years (95% CI, 2.1 to 5.4) for aspirin, 7.9 per 100 person-years (CI, 3.4 to 15.6) for warfarin, and 0.30 (CI, 0.06 to 0.86) per 100 person-days for heparin. Rates of fatal complications were 0.2 per 100 person-years (CI, 0 to 1.0) for aspirin, 0 per 100 person-years (CI, 0 to 3.6) for warfarin, and 0.10 per 100 person-days (0 to 0.55) for heparin.


CONCLUSIONS
Complication rates for warfarin and intravenous heparin given as therapy for secondary stroke prevention in Rochester, Minnesota, were lower than rates reported from earlier trials and observational studies. However, complication rates for warfarin were higher than in more recent referral-based studies and multicenter randomized trials. After adjustment for duration of therapy, complication rates for heparin were higher than those for aspirin or warfarin. These rates can be used to judge the applicability of complication rates derived from ongoing clinical trials.
Petty
G W
GW
Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
Brown
R D
RD
Whisnant
J P
JP
Sicks
J D
JD
O'Fallon
W M
WM
Wiebers
D O
DO
D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects*; D000925:Anticoagulants / Q000009:adverse effects*; D001241:Aspirin / Q000009:adverse effects*; D002543:Cerebral Hemorrhage / Q000139:chemically induced; D002561:Cerebrovascular Disorders / Q000517:prevention & control*; D015331:Cohort Studies; D004359:Drug Therapy, Combination; D005260:Female; D006471:Gastrointestinal Hemorrhage / Q000139:chemically induced; D006493:Heparin / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D014859:Warfarin / Q000009:adverse effects*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D000925:Anticoagulants; D014859:Warfarin; D006493:Heparin; D001241:Aspirin