Use of oral anticoagulant drugs in older patients with atrial fibrillation in internal medicine wards

Atrial fibrillation (AF) is independently associated with a higher risk of morbidity and mortality, in particular with an increased risk of thromboembolic events [1]. Use of oral anticoagulant (OAC) drugs reduces the risk of stroke and systemic embolism, as well as mortality among patients with AF [1].\r\n\r\nIn recent years, the non-vitamin K antagonist oral anticoagulants (NOACs) have been proved to be at least as effective and safer than warfarin, the most widely used VKA [2], such that NOACs are the recommended choice in many patients [1]. Notwithstanding, the number of untreated patients is still relevant [3]. In particular, in the clinical setting of internal medicine and geriatric wards, previous data showed that elderly hospitalized patients with AF were largely not prescribed with OAC [4] or treated in a non-guideline adherent manner [5]. After NOACs have been marketed, a significant increase in OAC uptake was recorded, but a substantial portion of patients still does not receive the appropriate treatment based on their cardioembolic risk [3,6]. In particular, scarce data are available about NOACs use in the non-cardiologic setting. Furthermore, elderly AF patients are less likely prescribed with OAC compared to the younger ones [5,7], even though the net clinical benefit of OAC treatment in these patients has been demonstrated [8].\r\n\r\nWith the aim to provide evidences about use of OAC and NOACs in older hospitalized patients, we here report data about the retrospective observational phase of the “Simulation-Based Technologies to Improve the Appropriate Use of Oral Anticoagulants in Hospitalized Elderly Patients with Atrial Fibrillation” (SIM-AF) Trial. The SIM-AF is a cluster randomized controlled trial aimed at increasing the rate of OAC prescription in elderly (≥65 years) AF patients admitted to 32 Italian Internal Medicine and Geriatric wards through a simulation-based e-learning educational intervention (ClinicalTrials.gov #NCT03188211). In this retrospective pre-intervention phase, we analysed the medical records of 328 older patients (50.9% females) between October 2016 and May 2017. Median [IQR] age was 83 [78–87] years, with 48 patients (14.6%) in the 65–74 years stratum, 143 (43.6%) and 137 (41.8%) respectively in 75–84 years and ≥85 years strata. Patients enrolled had both high baseline thromboembolic and bleeding risk. Indeed, median [IQR] CHA2DS2-VASc was 5 [[4], [5], [6]] and median [IQR] HAS-BLED was 3 [[2], [3], [4]]. Polypharmacy (i.e. ≥5 drugs) was reported in most of the patients (258 patients, 78.7%), with a median [IQR] number of drugs of 7 [[5], [6], [7], [8], [9]]. Overall, 55 (16.8%) patients were prescribed with antiplatelet drugs [33 (10.1%) of which treated exclusively with antiplatelet drugs], while 221 (67.4%) patients were prescribed with OAC.\r\n\r\nBaseline characteristics according to the use of OAC at baseline are reported in the Table 1. Compared to those not prescribed with OAC, those prescribed had a higher body mass index (BMI) (p = .028), reported a clinical history more burdened with heart failure (p = .032) but with a lower prevalence of previous major bleeding (p < .001). Patients not prescribed with OAC were more likely diagnosed with dementia compared to those prescribed with OAC (p = .001). The HAS-BLED score was lower in patients prescribed with OAC when compared to those not prescribed (p = .003). Using a multivariable logistic model, we found that BMI was independently associated with OAC prescription (hazard ratio [HR]: 1.09, 95% confidence interval [CI]: 1.02–1.17), while smoking habit (HR: 0.47, 95% CI: 0.25–0.89), previous major bleeding (HR: 0.11, 95% CI: 0.05–0.25) and diagnosis of dementia (HR: 0.43, 95% CI: 0.23–0.80) were inversely associated with OAC use.