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]. In 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]. With 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. Baseline 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.