ABSTRACT
BACKGROUND: Recent guidelines recommend using direct oral anticoagulants (DOACs) as first-line agents in patients with non-valvular atrial fibrillation (NVAF). Research is currently investigating the use of Apixaban in underweight patients, with some results suggesting altered pharmacokinetics, decreased drug absorption, and potential overdosing in this population. This study examined the effectiveness and safety of standard Apixaban dosing in adult patients with atrial NVAF weighing less than 50 kg. METHODS: This is a retrospective cohort study conducted at King Abdulaziz Medical City (KAMC); adult patients with a body mass index (BMI) below 25 who received a standard dose of Apixaban (5 mg twice daily) were categorized into two sub-cohorts based on their weight at the time of Apixaban initiation. Underweight was defined as patients weighing ≤ 50 kg, while the control group (Normal weight) comprised patients weighing > 50 kg. We followed the patients for at least one year after Apixaban initiation. The study's primary outcome was the incidence of stroke events, while secondary outcomes included bleeding (major or minor), thrombosis, and venous thromboembolism (VTE). Propensity score (PS) matching with a 1:1 ratio was used based on predefined criteria and regression model was utilized as appropriate. RESULTS: A total of 1,433 patients were screened; of those, 277 were included according to the eligibility criteria. The incidence of stroke events was lower in the underweight than in the normal weight group at crude analysis (0% vs. 9.1%) p-value = 0.06), as well in regression analysis (OR (95%CI): 0.08 (0.001, 0.76), p-value = 0.002). On the other hand, there were no statistically significant differences between the two groups in the odds of major and minor bleeding (OR (95%CI): 0.39 (0.07, 2.03), p-value = 0.26 and OR (95%CI): 1.27 (0.56, 2.84), p-value = 0.40, respectively). CONCLUSION: This exploratory study revealed that underweight patients with NVAF who received standard doses of Apixaban had fewer stroke events compared to normal-weight patients, without statistically significant differences in bleeding events. To confirm these findings, further randomized controlled trials with larger sample sizes and longer observation durations are required.
ABSTRACT
BACKGROUND: Hospitalized elderly patients are at high risk of venous thromboembolism (VTE), and the appropriate use of thromboprophylaxis can significantly reduce the incidence of VTE in high-risk patients. We investigated the pattern of VTE prophylaxis administration among elderly medical patients and assessed its appropriateness based on the American College of Chest Physicians (ACCP) recommendations. METHODS: A cross-sectional single-center study was conducted between October 2019 and March 2020, including hospitalized (> 48 h), elderly (≥ 60 years), medical patients, and excluding patients receiving anticoagulant for other reason, having contraindication to thromboprophylaxis, or had VTE diagnosed within 48 h. The Padua prediction score was used to determine the patients' risk for VTE, and thromboprophylaxis use was assessed against the ACCP recommendations. RESULTS: The study included 396 patients with an average age of 75.0 ± 9.01 years, and most patients (71.7%) were classified as high risk for VTE development (Padua score ≥ 4 points). Thromboprophylaxis use was inappropriate in 27.3% of patients, of whom 85.2% were ineligible but still received thromboprophylaxis. Patients who were classified as low risk of VTE were more likely to receive inappropriate thromboprophylaxis (AOR = 76.5, 95% CI: 16.1-363.2), whereas patients with acute infection or rheumatologic disorder were less likely to receive inappropriate thromboprophylaxis (AOR = 0.46, 95% CI: 0.22-0.96). CONCLUSIONS: Although the use of thromboprophylaxis among high-risk elderly patients was reasonably adequate, a large proportion of low-risk patients were exposed to unnecessary risk through inappropriate overutilization of thromboprophylaxis. Thus, healthcare providers should accurately assess patients' risk before prescribing thromboprophylaxis to ensure patient safety.
