OBJECTIVE：The purpose of this study was to examine the problems of tracking patients by single facility for diseases that may be provided by specialists and in collaboration with regional healthcare providers during drug treatment and the applicability of an administrative claims database in Japan as a possible solution to these problems. METHODS：This retrospective cohort study utilized data from the DeSC database (from June 2018 to August 2022). First, we reported the number of facilities visited by patients with chronic thromboembolic pulmonary hypertension (CTEPH) on drug therapy, the frequency of visits at each facility, and new prescriptions of pulmonary vasodilators to identify possible transfers and concurrent consultations during drug therapy. We then reported the number of new diseases with possible adverse events at the facility where antithrombotic prescriptions were initiated and at other facilities among CTEPH patients who visited multiple facilities. RESULTS：We extracted 106 patients of CTEPH patients that were prescribed anticoagulants (77 patients in the multi-facility group and 29 patients in the single-facility group). The mean frequency of visits was 10.1 months/year (standard deviation 2.5) in the single-facility group and 10.4 months/year (standard deviation 2.1) in the multi-facility group, respectively. Whereas, the frequency of visits to only the facility that antithrombotic prescriptions were initiated in the multi-facility group was about half, at 6.5 months/year (standard deviation 4.0). For pulmonary vasodilators, out of the 18 patients (19 events) in the multi-facility group who had the initiation of prescription for pulmonary vasodilators at a facility other than where antithrombotic prescriptions were initiated, 13 of the patients (14 events) did not have the same prescription confirmed at the facility where antithrombotic prescriptions were initiated. These results indicate that CTEPH is a reasonable disease for patients to visit multiple facilities during drug treatment. In the multi-facility group, the newly diagnosed diseases confirmed at facilities other than the one where antithrombotic prescriptions were initiated and not confirmed at the facility where the antithrombotic prescriptions were initiated were：18/19 events of bleeding, 0/1 event of interstitial pulmonary diseases, 17/19 events of upper gastrointestinal motility disorders, 1/1 event of thyroid dysfunction, and 0/0 event of retinal disorders. CONCLUSION：This study showed that there may be safety information that cannot be picked up solely by the facility where the drug prescription was initiated due to multiple facility visits associated with diverse treatments. In cases where specialists may collaborate with community health care providers to treat a target disease during drug treatment, the generation of safety information through a patient-traceable an administrative claims database should be considered for the implementation of appropriate pharmacovigilance activities.

OBJECTIVE：The purpose of this study was to examine the problems of tracking patients by single facility for diseases that may be provided by specialists and in collaboration with regional healthcare providers during drug treatment and the applicability of an administrative claims database in Japan as a possible solution to these problems. METHODS：This retrospective cohort study utilized data from the DeSC database (from June 2018 to August 2022). First, we reported the number of facilities visited by patients with chronic thromboembolic pulmonary hypertension (CTEPH) on drug therapy, the frequency of visits at each facility, and new prescriptions of pulmonary vasodilators to identify possible transfers and concurrent consultations during drug therapy. We then reported the number of new diseases with possible adverse events at the facility where antithrombotic prescriptions were initiated and at other facilities among CTEPH patients who visited multiple facilities. RESULTS：We extracted 106 patients of CTEPH patients that were prescribed anticoagulants (77 patients in the multi-facility group and 29 patients in the single-facility group). The mean frequency of visits was 10.1 months/year (standard deviation 2.5) in the single-facility group and 10.4 months/year (standard deviation 2.1) in the multi-facility group, respectively. Whereas, the frequency of visits to only the facility that antithrombotic prescriptions were initiated in the multi-facility group was about half, at 6.5 months/year (standard deviation 4.0). For pulmonary vasodilators, out of the 18 patients (19 events) in the multi-facility group who had the initiation of prescription for pulmonary vasodilators at a facility other than where antithrombotic prescriptions were initiated, 13 of the patients (14 events) did not have the same prescription confirmed at the facility where antithrombotic prescriptions were initiated. These results indicate that CTEPH is a reasonable disease for patients to visit multiple facilities during drug treatment. In the multi-facility group, the newly diagnosed diseases confirmed at facilities other than the one where antithrombotic prescriptions were initiated and not confirmed at the facility where the antithrombotic prescriptions were initiated were：18/19 events of bleeding, 0/1 event of interstitial pulmonary diseases, 17/19 events of upper gastrointestinal motility disorders, 1/1 event of thyroid dysfunction, and 0/0 event of retinal disorders. CONCLUSION：This study showed that there may be safety information that cannot be picked up solely by the facility where the drug prescription was initiated due to multiple facility visits associated with diverse treatments. In cases where specialists may collaborate with community health care providers to treat a target disease during drug treatment, the generation of safety information through a patient-traceable an administrative claims database should be considered for the implementation of appropriate pharmacovigilance activities.