The researchers assigned patients to either self-management or clinic management. Self-management patients received training and a coagulometer so that they could check their INR values at home. A nurse led the training, which consisted of 2 two-hour sessions. Training covered the use of the coagulometer and dose selection based on INR results. Clinic-management patients visited a clinic every 4 weeks to have clinic staff check INR values and adjust blood thinner dose. When the INR value was not in the target range, clinic staff adjusted the dose of the blood thinner and the timing of the next INR test. The researchers collected INR values from both groups and interviewed all patients monthly by telephone to ask about changes in health, including bleeding or clotting problems, medication changes, and hospitalizations. After following patients for an average of 1 year, the researchers compared the numbers of in-range INR values and the complications in the 2 groups.