Relationship between the Administration of Tolvaptan and Rehospitalization in Patients with a History of Hospitalization Due to Heart Failure -A retrospective cohort study conducted using a DPC database - - Relationship between the Administration of Tolvaptan and Rehospitalization in Patients with a History of Hospitalization Due to Heart Failure -A retrospective cohort study conducted using a DPC database

A total of 26,181 patients who were hospitalized more than twice because of heart failure (HF) during the period between April 1, 2008, and March 31, 2017, were selected for this study. The patients were divided into Case 1, Case 2, Hcont, and Scont cohorts, each having 719, 1,427, 278, and 6,185, patients, respectively. As the number of patients enrolled in the Hcont cohort was not sufficient to perform analysis, comparison between the Case 1 and Hcont cohorts, which was one of the primary endpoints, was not performed. The number of patients who were re-hospitalized because of HF after I date was obviously higher in the Case 1 cohort (402/719) than in the Case 2 (472/1,427) and Scont (1,830/6,185) cohorts. Patients in the Case 1 and Scont cohorts were matched using predetermined matching factors. The hazard ratio between the matched Case 1 and Scont cohorts (each with 719 patients) was 1.85 (95% CI 1.57-2.18, p<0.001), indicating a statistically significantly higher risk for re-hospitalization in the Case 1 cohort. This result may have been driven by the limited information on patients in the database, such as the absence of laboratory data and insufficiency of data on the clinical seriousness of HF. Considering the circumstance, tolvaptan was used in the re-hospitalized and critical patients, and it was difficult to adjust the factors to continue this drug, which has a high reimbursement price. As the primary endpoint in this study could not be confirmed to be relevant, we decided to not analyze the secondary endpoints and therefore discontinued the study.