INTRODUCTION: Patients taking non-vitamin K antagonist oral anticoagulants (NOACs) such as dabigatran, rivaroxaban, and apixaban have reported experiencing angioedema in randomized trials and routine care.
OBJECTIVE: The aim of this study was to quantify the association between NOACs and angioedema relative to warfarin among routinely treated patients with atrial fibrillation in a cohort study. We also compared warfarin users with non-users in a case-crossover study.
METHODS: We utilized a cohort design that drew eligible patients from the Truven Health MarketScan Commercial database, the Optum Clinformatics Data Mart, and Medicare. Within each database, we compared the 6-month relative rate of angioedema among new users of NOACs (dabigatran, rivaroxaban, apixaban) and new users of warfarin. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) after adjusting for confounders using propensity score stratification, and meta-analyzed the database-specific HRs using a random-effects model. We also estimated an odds ratio (OR) for the association between warfarin and angioedema using a case-crossover design, a self-controlled design that controls for time-invariant confounders.
RESULTS: In the cohort study, we observed 249 incident angioedema events among 267,681 NOAC initiators and 281,143 warfarin initiators across all databases. The meta-analyzed HR for angioedema comparing any NOAC versus warfarin was 0.98 (95% CI 0.76-1.27). In the case-crossover design, the OR for the association between warfarin and angioedema was 0.91 (95% CI 0.68-1.21) based on 431 cases.
CONCLUSIONS: Our estimates were inconsistent with substantial short-term relative increases in the rate of angioedema associated with oral anticoagulant therapy.
JoshuaJGagneFDA: "Patients should continue taking metformin...until they consult with their health care professional who can prescribe a replacement. Patients with type 2 diabetes could face dangerous health risks if they stop taking their prescribed metformin."
JoshuaJGagne@annaedney makes some important points:
- FDA has not found NDMA in the immediate release versions that they have tested
- The immediate release version is more common (~75% of all metformin prescriptions)