Abstract
PURPOSE: Ticlopidine hydrochloride, an antiplatelet agent, is believed to have saved life years in many patients with ischemic cerebral vascular diseases in Japan. But severe adverse events have also been reported. The current investigation aimed to compare two hypothetical cohorts treated with and without ticlopidine in terms of risks and benefits of ticlopidine treatment using Markov model.
METHODS: We conducted Markov decision analysis to estimate the number of lives saved and the increase in quality-adjusted life years (QALYs) over the past 20 years by ticlopidine in Japan. Two cohorts of 60-year-old male patients with previous histories of cerebral infarction, one of which treated with ticlopidine and the other not treated with ticlopidine, were compared with respect to the number of deaths and quality of life (QOL) . Data incorporated were the probabilities of the recurrence of cerebral infarction and the associated mortality, adverse events of the drug, and the utility of health status treated with ticlopidine.
RESULTS: Approximately 1, 630, 000 patients were estimated to be on ticlopidine for variable periods of time during the past 20 years in Japan. With treatment, 17, 130 lives were saved, while 1, 338 patients died because of cerebral bleeding, agranulocytosis, severe hepatic dysfunction, or thrombotic thrombocytic purpura, resulting in a net benefit of 15, 792 lives saved by ticlopidine over the past 20 years. In terms of QOL, there was a total increase of 382, 191 QALYs. Sensitivity analyses showed that the older the patients when ticlopidine therapy was started, the smaller the benefits that were gained by treatment.
CONCLUSIONS: Ticlopidine is considered to have made a great contribution in savingmany lives and improving QALYs in the past 20 years in Japan. This kind of analysis based on Markov model can be employed to demonstrate effectiveness of drugs and medical technologies in terms of population health outcomes.
