Gastrointestinal bleedings during therapy with new oral anticoagulants are rarely reported.

INTRODUCTION Post-marketing surveillance of drugs relies on spontaneous reporting of adverse drug events to the Danish Health and Medicines Authority. A number of new oral anticoagulants (NOAC) have recently been marketed in Denmark. The purpose of this study was to evaluate the reporting of serious adverse drug events in patients treated with a NOAC and admitted for gastrointestinal bleeding. METHODS This study is based on an electronic free text search in patient records and a search in the electronic medication records of all patients admitted to the Department of Gastroenterology, Surgical Section, Hvidovre Hospital, during a one-year-period. Patients in treatment with NOAC and admitted for gastrointestinal bleeding were identified. Relevant patients were cross-checked for a reported adverse drug event in the Danish Health and Medi-cines Authority's database on adverse medical events. RESULTS A total of 20 patients were acutely admitted for gastrointestinal bleeding while in treatment with a NOAC, an adverse medical event was reported for one of these patients (5%; 95% confidence interval: 0-25%). CONCLUSION Serious adverse events in patients treated with NOAC are underreported which questions the current effectiveness of post-marketing surveillance of adverse drug effects. FUNDING not relevant. TRIAL REGISTRATION The study was registered with clin-icaltrials.gov (NCT02107651).