Can Rivaroxaban Lead to Anticoagulation-Related Nephropathy?

Anticoagulation-Related Nephropathy (ARN) is a side effect of treatment with blood thinners which leads to kidney dysfunction. A recent review suggests that kidney function should be assessed (by measuring serum creatinine) serially in the first few months of starting a blood thinner. ARN is diagnosed when there is a decline in kidney function after starting the blood thinner and other possible causes of this decline have been excluded. ARN has mainly been studied in relation to the common blood thinner - warfarin, where the prevalence is variable but can be as high as 37% (approximately 1 in 3) in the patients at highest risk. The risk factors that make this side effect more likely include the presence of pre-existing kidney disease, high blood pressure, older age and diabetes mellitus. Studies have shown that the occurence of ARN can lead to an accelerated progression of pre-existing kidney disease and a 65% increase in the risk of death (mortality). The non-vitamin K oral anticoagulants (NOACs) are a new group of drugs which have been recently approved for use as blood thinners. They have a faster onset of action compared to warfarin and unlike warfarin, they do not need frequent monitoring. Rivaroxaban is the most commonly prescribed NOAC at Einstein Medical Center Philadelphia. There are some case reports that other NOACs (such as dabigatran and apixaban) can lead to ARN, however there is no study that has determined the true incidence of ARN in NOACs. Our study is designed to find out the incidence of ARN in patients who are started on rivaroxaban. The investigators intend to serially monitor the kidney function of 40 high risk patients who are recently started on rivaroxaban over a six month period. This will enable us to discover how many patients actually develop ARN after starting a NOAC. The information the investigators will obtain from this study will enable patients and health care providers make better decisions about using blood thinners. If the investigators find that the incidence of ARN with rivaroxaban is less common than that previously reported with warfarin, it can potentially make more patients use the NOACs and hence save them from the morbidity and mortality associated with ARN. Our study is unique because this will be the first study focused on ARN in one of the new blood thinners. The information the investigators get from this study will be a very important foundation for future studies.