Predictors of bleeding during heparin therapy.

Among 2,656 patients receiving heparin sodium therapy, bleeding was a dose-related phenomenon that occurred most commonly among women, severely ill patients, and patients who received asprin during heparin therapy. Except for dose, factors that predisposed patients to bleeding were more strongly associated with major bleeding than with minor bleeding. Heavy alcohol drinkers were at particularly high risk for major bleeding episodes during heparinization. The seven-day cumulative risk for any bleeding was 9.1%. Risk was greatest on the third day of heparin administration.