The OAC³-PAD Risk Score Predicts Major Bleeding Events one Year after Hospitalisation for Peripheral Artery Disease.

Abstract

There is a paucity of evidence concerning the risk of bleeding after hospitalisation for symptomatic peripheral artery disease (PAD) in everyday clinical practice, as randomised clinical trials commonly exclude patients with heightened risk. The current study aimed to develop a pragmatic risk score that enables prediction of major bleeding during the first year after index discharge. Unselected retrospective data from the second largest insurance fund in Germany, BARMER, were used to identify patients with a first hospitalisation for PAD registered between 1 January 2010 and 31 December 2018. Within a separate training cohort, final predictors were selected using penalised Cox regression (least absolute shrinkage and selection operator with ten fold cross validation) with one year major bleeding requiring hospitalisation as outcome. The risk score was internally validated. Four different risk groups were constructed. A total of 81 930 patients (47.2% female, 72.3 years) underwent hospitalisation for symptomatic PAD. After one year, 1 831 (2.2%) of the patients had a major bleeding event. Independent predictors were previous oral anticoagulation, age over 80, chronic limb threatening ischaemia, congestive heart failure, severe chronic kidney disease, previous bleeding event, anaemia, and dementia. The OAC³-PAD risk score exhibited adequate calibration and discrimination between four risk groups (c = 0.69, 95% confidence interval 0.67 - 0.71) from low risk (1.3%) to high risk (6.4%). A pragmatic risk score was developed to predict the individual major bleeding risk classifying a fifth of the cohort as high risk patients. Individual prediction scores such as the one proposed here may help to inform the risk and benefit of intensified antithrombotic strategies.