biostudies-literatureImai TMinistry of Health, Labour and Welfare, JapanProgress of the next Cross-ministerial Strategic Innovation Promotion Program (SIP) on “Integrated Health Care System”MEXT KAKENHIFoundation for the Development of the Communitye084092https://www.ebi.ac.uk/biostudies/studies/S-EPMC11481128biostudies-literatureUnknown14(10)<h4>Objectives</h4>Laboratory experiments have indicated that calcium channel blockers (CCBs) inhibit the entry and replication of influenza A virus in cells. However, no clinical studies have assessed the incidence of influenza among patients receiving CCBs. This study aimed to investigate the association between CCB use and the incidence of influenza among patients with hypertension using administrative claims data in Japan.<h4>Design</h4>Retrospective cohort study.<h4>Setting</h4>Administrative health insurance claims database of Kumamoto Prefecture, Japan.<h4>Participants</h4>360 515 patients with hypertension (10th edition of the International Classification of Diseases code I10) who were prescribed CCBs and 171 142 patients who were prescribed angiotensin-converting enzyme inhibitorsBMJ openEffect of calcium channel blockers on influenza incidence: a population-based retrospective cohort study using administrative claims data in Japan.PMC11481128N/A24K1053823AA2003JPJ012425Kanda NHatakeyama SSasabuchi YMatsui HYasunaga HImai THashimoto HfalseEffect of calcium channel blockers on influenza incidence: a population-based retrospective cohort study using administrative claims data in Japan.<h4>Objectives</h4>Laboratory experiments have indicated that calcium channel blockers (CCBs) inhibit the entry and replication of influenza A virus in cells. However, no clinical studies have assessed the incidence of influenza among patients receiving CCBs. This study aimed to investigate the association between CCB use and the incidence of influenza among patients with hypertension using administrative claims data in Japan.<h4>Design</h4>Retrospective cohort study.<h4>Setting</h4>Administrative health insurance claims database of Kumamoto Prefecture, Japan.<h4>Participants</h4>360 515 patients with hypertension (10th edition of the International Classification of Diseases code I10) who were prescribed CCBs and 171 142 patients who were prescribed angiotensin-converting enzyme inhibitors2024-01-01T00:00:00Z2024 Oct2025-04-04T13:54:23.127Z2025-04-04T13:54:23.127ZS-EPMC114811283941428010.1136/bmjopen-2024-084092