A system for facilitating patient-managed anticoagulant therapy having patient portals for receiving patient information associated with a current case. Each patient portal has a patient portal processor, patient portal memory, and an output device, and the patient information including current factors affecting patient reaction to anticoagulant therapy. The system also has a case repository connected to each patient portal, the case repository having a case repository processor and a case repository memory storing previous cases, each case having previous factors affecting patient reaction to anticoagulant therapy and at least one solution. The patient portal processor and/or the case repository processor are programmed for selecting at least one relevant case similar to the current case and provide the solution to that case for application to the current case. A similarity metric is applied to each previous case to determine the similarity of each previous case to the current case.