Participants who received low-molecular-weight heparin for the additional month had fewer blood clots. These patients bled more, but the additional treatment prevented more blood clots than it caused bleeding. When the researchers looked closely at their findings, they discovered that the benefits of the additional treatment were greater than its harms only for women, persons older than 75 years, and those who were so sick that they were not allowed to leave their bed, even to use the bathroom.