Influences of Obesity and Bariatric Surgery on the Clinical and Pharmacologic Profile of Rivaroxaban

Full-dose rivaroxaban in patients with a history of bariatric surgery: bridging the knowledge gap through a phase 1 study

BACKGROUND

Bariatric surgery (BS) induces significant changes in gastrointestinal anatomy, potentially influencing the pharmacokinetics of orally administered drugs such as rivaroxaban.

OBJECTIVES

This phase 1 study aimed to assess the pharmacokinetics and safety of full-dose rivaroxaban in post-BS patients.

METHODS

The ABSORB (Rivaroxaban Pharmacokinetics and Pharmacodynamics After Bariatric Surgery and in Morbid Obesity) study was a single-center, nonrandomized, multiple-dose, parallel-design bioequivalence trial. Adult patients with stable weight after Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) were compared with subjects with class III obesity and healthy controls. Participants received 20 mg of rivaroxaban daily for 8 days.

RESULTS

Post-BS patients exhibited altered rivaroxaban pharmacokinetics, suggesting reduced absorption. Mean area under the concentration-time curve from time 0 to 24 hours after the first dose (RYGB, 1806.8 ng.h/mL; SG, 1648.9 ng.h/mL) was lower compared with that in controls (1893.5 ng.h/mL). At steady state, the area under the concentration-time curve values remained lower in BS groups (RYGB, 2129.9 ng.h/mL; SG, 1946.4 ng.h/mL) than in controls (2224.8 ng.h/mL). The maximum concentration after the first dose was lower in post-RYGB subjects (214.9 ng/mL) than in controls (264.1 ng/mL). This difference was less pronounced at steady state (RYGB, 256.9 ng/mL vs controls, 288.8 ng/mL). Neither BS group met bioequivalence criteria compared with controls, whereas the group with class III obesity met bioequivalence criteria compared with controls at steady state.

CONCLUSION

Rivaroxaban displayed minor pharmacokinetic variations in post-BS patients. Given reported interindividual variability in the general population, these variations are unlikely to be of clinical significance. Our findings support rivaroxaban use in BS patients, emphasizing the need for further research in this area.

[Bariatric surgery and drugs: Review of the literature and Adverse Drug Reactions analysis in French National Pharmacovigilance Database]

INTRODUCTION

Bariatric surgery is the only treatment for severe obesity (BMI>35kg/m2) currently recognized as effective both in achieving tangible and lasting weight loss, and in improving obesity-related comorbidities such as type 2 diabetes, hypertension, and cardiovascular complications. Bariatric surgery, like any other surgery of the digestive tract, can have an impact on nutrient absorption, as well as on drug absorption. The literature on drug management in bariatric surgery patients concerned mainly of case reports and retrospective studies involving a small number of patients. No official guidelines are available.

METHODS

We conducted a literature search on the consequences of bariatric surgery in terms of drug bioavailability and/or effect. The Medline® (PubMed) database was searched using the following keywords: "bariatric surgery", "bioavailability", "gastric bypass", and "obesity". We completed this review with an analysis of reports of adverse drug reactions (ADRs) in post-bariatric surgery patients for obesity registered in the National pharmacovigilance database (PVDB). We selected all cases with the mention of "bariatric surgery and/or gastrectomy" as "medical history". After reading the cases, we excluded those in which the patient had undergone surgery for an indication other than obesity, where the route of administration was other than oral, and cases in which ADRs resulted from voluntary overdose, attempted suicide, allergy, switch to Levothyrox® new formulation, meningioma under progestative drugs, inefficacy related to generic substitution and medication error.

RESULTS

The literature search identified mainly "case report" about the impact of bariatric surgery on so-called "narrow therapeutic window" drugs. We identified 66 informative cases out of a total of 565 cases selected (11%) in the PVDB. Nevertheless, the information does not allow a clear relationship between the occurrence of the ADR and the influence of bariatric surgery.

CONCLUSION

There is a lack of official information and/or recommendations on medication use in subjects who have undergone bariatric surgery. Apart from under-reporting, ADRs reports remain largely uninformative. Health professional and patients would be awareness for improving, quantitatively and qualitatively the reporting of ADRs in this population.

The Effects of Bariatric Surgery on Pharmacokinetics of Drugs: a Review of Current Evidence

PURPOSE OF REVIEW

Obesity constitutes a major public health concern and has been recognized as an epidemic. To date, bariatric surgery remains the most effective way for substantial long-lasting weight loss in severe obesity. The purpose of this review is to summarize how the pharmacokinetics of drugs are affected by the most common types of bariatric surgery, i.e., Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG).

RECENT FINDINGS

Limited data are available regarding the changes in pharmacokinetics of drugs after bariatric surgery. The lack of existing guidelines may lead patients to experience drug toxicity or therapeutic undertreatment. Pharmacokinetic parameters that need to be taken into consideration postoperatively include gastric motility, gastric volume, pH, surface area, bile secretions, carrier proteins, and first-pass metabolism. For drugs with a narrow therapeutic index, other factors need to be monitored closely, including plasma drug levels, patients' clinical outcomes, and laboratory markers. Patients should be followed up frequently and treated in accordance with their response to the drug therapy. Bariatric surgery may affect the pharmacokinetics of various drugs, due to the resultant anatomical changes and the substantial weight loss. Therefore, there is a need to identify those potential changes and adjust patients' medication doses in order to achieve higher efficacy and avoid toxicity.

Long-Term Outcomes of Bariatric Surgery in Patients on Chronic Anticoagulation

BACKGROUND

Approximately 3% of patients undergoing metabolic and bariatric surgery (MBS) are receiving chronic anticoagulation therapy (CAT) prior to operation. The management of these patients is complex, as it involves balancing the potential risk of thrombosis against that of bleeding. Our primary objective is to assess the long-term bleeding risk in patients undergoing MBS. We also aim to observe the trends in anticoagulant dosing after MBS.

METHODS

A single-center retrospective review of patients who underwent either primary Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) with preoperative CAT between 2008 and 2022 was performed. Data on baseline demographics, indication for anticoagulation, type of CAT, and dosing were collected. Events of bleeding and the CAT at event were subsequently evaluated.

RESULTS

A total of 132 patients (82 RYGB and 50 SG) initially on CAT were identified, with atrial fibrillation being the most common indication. Incidence of long-term bleeding was significantly higher in the RYGB group (18.3%) compared to the SG group (4%) (p = 0.017) over a total of 5.2 ± 3.8 years. Bleeding marginal ulcer (MU) was the most common cause of bleeding in the RYGB group (13.4%). 84.2% of all bleeding events occurred in patients on chronic Warfarin therapy.

CONCLUSION

Long-term CAT is associated with an increased risk of bleeding in RYGB patients, particularly MU bleeds. Patients on CAT seeking MBS should be counseled regarding this risk and potential implications. Direct-acting oral anticoagulants offer promise as an alternative to Warfarin in these patients; further research is necessary to better understand their safety.

Rivaroxaban Pharmacokinetics in Obese Subjects: A Systematic Review

INTRODUCTION

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality globally. The direct oral anticoagulants, including rivaroxaban, are relatively novel therapeutic options in the treatment and prevention of VTE. There is a conflicting and inconclusive evidence surrounding the pharmacokinetics (PK) of rivaroxaban in patients with VTE who are obese.

OBJECTIVES

We conducted a systematic review to provide an overview, and to synthesize the available evidence in the current literature pertaining to rivaroxaban PK in obese subjects who are healthy or diseased.

METHODS

The PubMed, Embase, ScienceDirect, Rayyan, and Cochrane Library databases were systematically searched from 1 May 2021 through 28 February 2022. Studies investigating rivaroxaban PK in adult obese subjects were included in the review. Pertinent data, including anthropometric parameters, rivaroxaban dosage regimen, PK parameters, PK model, and outcome measures were extracted. Reference values of rivaroxaban PK parameters in the general population were used for comparison purposes. The review protocol was registered in the PROSPERO database (CRD42020177770).

RESULTS

In the 11 studies included in this systematic review, over 7140 healthy or diseased subjects received rivaroxaban therapy, with varying clinical indications in the diseased population. The reported PK parameters of rivaroxaban in obese subjects compared with reference values in the general population were variable. The reported values of the volume of distribution (V_d) among obese subjects (73.4-82.8 L) fell within the range of values reported/calculated for the general population (59.4-104 L), assuming complete bioavailability. However, some of the reported values of clearance (CL) in obese subjects (7.86-16.8 L.h^-1) do not fall within the range of values reported/calculated for the general population (5.57-11.3 L.h^-1). The reported maximum plasma concentrations in obese subjects versus the general population following a 10 mg dose were 149 vs. 143-180 µg.L^-1, and following a 20 mg dose were 214-305 vs. 299-360 µg.L^-1, respectively. The area under the plasma concentration versus time curves (AUC) over different intervals in obese subjects versus the general population following a 10 mg dose were 1155 (AUC from time zero to infinity [AUC_∞]) vs. 1029 (AUC_∞) µg.h.L^-1; and 1204-2800 (AUC from time zero to 24 h [AUC₂₄]) vs. 3200 (AUC₂₄) µg.h.L^-1, respectively, following a 20 mg dose. The reported values of half-life and time to reach the maximum plasma concentration in obese subjects versus the general population were not consistent across studies.

CONCLUSION

Variable changes and inconsistencies in different rivaroxaban PK parameters were reported in obese subjects. Further well-designed studies are warranted to better characterize the PK and clinical outcomes of rivaroxaban in subjects with obesity.

Adverse events in patients taking apixaban or rivaroxaban who have undergone bariatric surgery: a retrospective case series

Clinical trials comparing direct oral anticoagulants (DOAC) to warfarin excluded patients with a history of bariatric surgery. The anatomic changes from bariatric procedures have several effects on drug absorption which can have serious consequences for these patients. We sought to describe real-world use of DOACs among adults that had a history of bariatric surgery or underwent a bariatric surgery while receiving a DOAC. We conducted a retrospective case series of adult patients, at a large academic medical center, who initiated any DOAC in 2016 thru 2019 and had a history of bariatric surgery or underwent a bariatric surgery while receiving a DOAC. Thrombotic and bleeding events were described using summary statistics and bleeding severity was described using the International Society on Thrombosis and Haemostasis criteria. Twenty-eight patients met the inclusion criteria of having bariatric surgery (Roux-en-Y gastric bypass, sleeve gastrectomy or gastric band) and receiving a DOAC. Twenty (71.4%) were prescribed apixaban and eight (28.6%) were prescribed rivaroxaban. Seven patients (25%) experienced at least one clinically relevant non-major bleeding event, including one patient (3.6%) that had a major bleeding event. Two patients (7.1%) had a thromboembolic event. Coagulation laboratory studies were infrequently performed at the time of the bleeding or clotting events. Among patients with a history of bariatric surgery, use of DOACs were commonly associated with clinically relevant non-major bleeding events and less commonly associated with major bleeding and thromboembolic events. Larger studies may offer further insight into the overall safety and efficacy of DOAC therapy in patients that have undergone bariatric surgery. The specific role of coagulation laboratory studies warrants further evaluation.

Real-world effectiveness and safety of rivaroxaban versus warfarin among non-valvular atrial fibrillation patients with obesity in a US population

OBJECTIVES

Current evidence indicates that the pharmacokinetic profile of rivaroxaban is not significantly impacted by body weight. However, real-world data are needed to better assess the potential clinical benefits and risks associated with rivaroxaban in non-valvular atrial fibrillation (NVAF) patients with obesity. Thus, our objectives were to assess the real-world effectiveness and safety of rivaroxaban versus warfarin among NVAF patients with obesity in the US nationally representative commercially-insured population.

METHODS

Health insurance claims data from the IQVIA PharMetrics Plus database (January 2010-September 2019) were used to identify NVAF patients with obesity (based on diagnosis codes) initiated on rivaroxaban or warfarin. Inverse probability of treatment weighting (IPTW) was used to adjust for imbalances between groups. Study outcomes of interest were evaluated up to 36 months post-treatment initiation and included the composite of stroke or systemic embolism (stroke/SE) and major bleeding. Outcomes were compared using Cox proportional hazards regression models with hazard ratios (HR) and 95% confidence intervals (CIs).

RESULTS

A total of 10,555 patients were initiated on rivaroxaban and 5080 patients on warfarin. Following IPTW, the risk of stroke/SE was 26% lower among patients prescribed rivaroxaban relative to warfarin (HR: 0.74, 95% CI: 0.60, 0.91, p = .004) at 36 months. Rivaroxaban-initiated patients had a risk of major bleeding similar to that of warfarin-initiated patients (HR: 0.85, 95% CI: 0.71, 1.02, p = .085).

CONCLUSIONS

These results suggest that rivaroxaban is an effective and safe treatment option among NVAF patients with obesity in a commercially-insured US population.

Body Mass Index Influence on the Clinical Outcomes for Nonvalvular Atrial Fibrillation Patients Admitted to a Hospital Treated with Direct Oral Anticoagulants: A Retrospective Cohort Study

BACKGROUND

Considering that the current fixed dose of direct oral anticoagulants (DOACs) might have insufficient anticoagulation effect for overweight patients, the aim of this study was to compare the effectiveness and safety of anticoagulation between dabigatran and rivaroxaban in different body mass index (BMI) population.

METHODS

We conducted a retrospective cohort study of 2402 DOAC anticoagulated patients with atrial fibrillation who underwent catheter ablation (1290 dabigatran, 53.7% and 1112 rivaroxaban, 46.3%) between January 2017 and December 2018. Patients were distributed based on the BMI into nonobese (1362, BMI <25 kg/m2), preobese (521, BMI 25.0-29.9 kg/m2), class I obese (344, BMI 30.0-34.9 kg/m2) and class II+ obese (175, BMI ≥35.0 kg/m2). We collected information regarding clinical features, laboratory data, bleeding complications and systemic embolic events from the electrical medical records system during 12 months.

RESULTS

The incidence of systemic embolism and stroke complications was higher in the class II+ obese group (P=0.001 and P=0.003). The incidence of bleeding complications and the levels of anticoagulation parameters under the bleeding threshold were similar among the four groups (P>0.05). Cumulative Kaplan-Meier analysis illustrated that rivaroxaban-treated patients who belonged to higher BMI subgroups were more likely to experience shorter time to thrombosis (TTT) (12-month TTT rates of 0.5% for nonobese vs 1.7% for class I obese patients, HR=3.716, P=0.005; 12-month TTT rates of 0.5%, for nonobese vs 4.0% for class II+ obese patients, HR=6.843, P=0.001). However, no statistical significant difference in terms of the time to bleeding complications and the time to cumulative events among the four groups was observed. By multivariate analysis, a higher BMI value (BMI ≥25 kg/m2) (P=0.019; OR=2.094, 95%CI: 1.129-3.883) was an independent predictor for thrombosis in patients treated with dabigatran or rivaroxaban. Positive linear relationship was observed between BMI levels and occurrence rate of thrombosis and bleeding in under anticoagulation patients with NVAF (R2=0.451 and R2=0.383, respectively).

CONCLUSION

The fixed dose of 15 mg rivaroxaban might carry a risk of under exposure, which would lead to an increase of thromboembolic complications in patients with high BMI. Therefore, rivaroxaban dose increase was suggested for obese patients. Use of DOACs appears to have considerable safety in obese patients.

The Pharmacology, Efficacy, and Safety of Rivaroxaban in Obese Patient Populations

Cardiovascular disease (CVD) remains the leading cause of death in the USA. Several risk factors have been identified, and obesity has become one of prominent concern. Excessive weight is considered a risk factor for CVD based on evidence linking it to a hypercoagulable state. Considering the prevalence of CVD and obesity in the USA, along with the increased risk for thrombus-related events, anticoagulation plays a significant role in prevention and treatment. Direct oral anticoagulants have taken the place of many traditional anticoagulants. Considering the recently approved indications and continued postmarketing studies conducted with rivaroxaban, this updated review provides data on the overall impact of obesity on this compound. This includes data obtained from both healthy obese volunteers and obese patients with various CVD conditions enrolled in rivaroxaban clinical trials, along with data obtained from postmarketing real-world evidence studies. Assessment of the clinical pharmacology and population pharmacokinetics in obese individuals revealed no clinically relevant effects of increased weight. Additionally, subgroup analyses from each of the pivotal phase III trials supporting the current approved labeling also demonstrated consistent efficacy and safety results in obese patients. Lastly, these findings are further supported by several recent real-world evidence studies assessing the continued effectiveness and safety of rivaroxaban. In conclusion, rivaroxaban's overall pharmacological and clinical profile remained consistent in obese adults when assessed in both drug development and postmarketing studies, supporting the premise that higher weight does not necessitate adjustment in either dose strength or regimen.

Risk factors for ecchymosis in patients receiving rivaroxaban for thromboprophylaxis after total knee arthroplasty: a retrospective cohort study

WHAT IS KNOWN AND OBJECTIVE

Ecchymosis of the limb is commonly seen after total knee arthroplasty (TKA) when using anticoagulants for thromboprophylaxis, but it is unknown which factors may predispose patients to an increased risk. The aim of this study was to evaluate risk factors for ecchymosis in patients receiving rivaroxaban after TKA.

METHODS

A retrospective, single-centre cohort analysis was conducted. The electronic medical records of patients admitted to the Department of Orthopedics during January 2018 to December 2019 and who received rivaroxaban 10 mg daily after TKA were reviewed for documentation of ecchymosis. Baseline demographics, laboratory values and surgical information were included for analysing their relationship with ecchymosis.

RESULTS AND DISCUSSION

A total of 227 patients were included in the study. Among them, 54 patients (23.8%) developed ecchymosis, and 173 did not. The ecchymosis group had a higher proportion of patients with a body weight >60 kg [83.33% vs. 50.00%, p = 0.0004] and hypertension [61.11% vs 41.46%, p = 0.0304]. The ecchymosis group also had a higher BMI [26.04 ± 2.71 kg/m² vs 24.52 ± 3.18 kg/m² , p = 0.0066] mean arterial pressure (MAP) recorded from post-operation day 1 to day 3 [105.21 mmHg vs 91.52 mmHg, p = 0.0003]. However, serum albumin concentrations before surgery [3.85 g/dL vs. 4.20 g/dL, p = 0.0225] and on post-operation day 3 [3.50 g/dL vs. 3.91 g/dL, p = 0.0370] were lower in the ecchymosis group. Serum haemoglobin on post-operation day 3 was also lower [10.07 g/dL vs. 11.57 g/dL, p = 0.0459]. Five risk factors for ecchymosis were identified by binary logistic regression: mean MAP (from POD1 to POD3) (OR=2.901, 95% CI: 2.522-3.293, p < 0.001), BMI (OR=2.513, 95% CI: 1.929-3.011, p < 0.001), history of hypertension (OR=2.661, 95% CI: 1.272-4.535, p = 0.032), post-surgery serum albumin level (OR=0.848, 95% CI: 0.735-0.977, p = 0.023) and post-surgery serum haemoglobin level (OR=0.943; 95% CI: 0.898-0.990, p = 0.018).

WHAT IS NEW AND CONCLUSION

The present analyses identified that BMI, history of hypertension, mean MAP (POD1 to POD3), post-surgery serum albumin level and post-surgery serum haemoglobin level were independent risk factors for rivaroxaban-related ecchymosis in patients who underwent TKA. These factors should be considered and optimized before starting rivaroxaban therapy.

Safety and Efficacy of Oral Anticoagulants for Atrial Fibrillation in Patients After Bariatric Surgery

Anticoagulation management is challenging in bariatric surgery patients, due to altered gastrointestinal anatomy and potentially reduced absorption. Few studies have evaluated clinical outcomes in this population. The objective of this study was to compare the efficacy and safety of oral anticoagulants in patients with and without a history of bariatric surgery. A retrospective, matched cohort study was conducted, utilizing data from the OptumLabs Data Warehouse. Patients ≥18 years old, with nonvalvular atrial fibrillation (NVAF), and treated with an oral anticoagulant between January 1, 2010 and December 31, 2018 were included. Outcomes were compared between bariatric and nonbariatric surgery patients. Secondary analysis compared warfarin to the direct oral anticoagulants (DOAC) in the bariatric cohort. The primary efficacy outcome was the rate of ischemic stroke and systemic embolism and the primary safety outcome was major bleeding. A total of 1,673 bariatric surgery and 155,619 nonbariatric surgery patients were identified. There was no significant difference in the rate of ischemic stroke or systemic embolism (0.83 vs 1.32 per 100 person years; Hazard ratio [HR] 0.62, 95% confidence interval [CI] 0.31 to 1.22; p = 0.17) or major bleeding (5.30 vs 4.87 per 100 person years; HR 1.05, 95% CI 0.80 to 1.37; p = 0.73) between bariatric and nonbariatric surgery patients. In bariatric surgery patients alone, efficacy and safety were similar with warfarin compared with the DOACs. Results of this study suggest that bariatric surgery patients are not at an increased thrombotic or bleeding risk when using oral anticoagulants for NVAF. DOACs may be a reasonable alternative to warfarin.

Prophylaxis with rivaroxaban after laparoscopic sleeve gastrectomy could reduce the frequency of portomesenteric venous thrombosis

INTRODUCTION

Portal and mesenteric venous thrombosis is a rare but potentially serious complication after laparoscopic sleeve gastrectomy. There are no consistent studies that prove the safety and effectiveness of oral anticoagulant thromboprophylaxis with rivaroxaban after laparoscopic sleeve gastrectomy. The objective was to evaluate the effect of rivaroxaban on the frequency of portal and mesenteric venous thrombosis and its safety profile after laparoscopic sleeve gastrectomy.

MATERIALS AND METHODS

This retrospective analysis of prospectively collected data includes all laparoscopic sleeve gastrectomies performed by a single surgeon at Pontificia Universidad Católica de Chile Hospital between January 2009 and June 2019. All patients received low molecular weight heparin thromboprophylaxis during the whole hospital stay. Between July 2012 and June 2019, patients received additional post-discharge thromboprophylaxis with rivaroxaban. Patient demographics, impaired renal, post-surgical portal and mesenteric venous thrombosis, and bleeding episodes were registered.

RESULTS

A total of 516 patients were identified; 95 patients were excluded. Results for 421 patients were analysed: 198 received only intrahospital thromboprophylaxis (group 1) and 223 received additional post-discharge thromboprophylaxis with rivaroxaban (group 2). There was no statistically significant difference between the two groups concerning age, sex and body mass index. In group 1, four cases of portal and mesenteric venous thrombosis were registered and no cases were reported in group 2 (p < 0.05). All cases occurred before 30 days after surgery. No bleeding episodes and no adverse reactions were detected in group 2.

CONCLUSIONS

Thromboprophylaxis during the whole hospital stay (two to three days), followed by rivaroxaban 10mg once daily for 10 days after discharge (completing in total 13-14 days of prophylaxis), could reduce cases of post-surgical portal and mesenteric venous thrombosis without an increase in bleeding complications.

Morbidly Obese Patient on Rivaroxaban Presents With Recurrent Upper Extremity Deep Vein Thrombosis: A Case Report

A morbidly obese patient with history of deep vein thrombosis and pulmonary embolism was diagnosed with an acute left upper extremity deep vein thrombosis and started on rivaroxaban. Three months later, the patient returned with swelling in the right arm and was found to have a right brachial thrombosis. Anticoagulant therapy was switched to a low-molecular-weight heparin, and patient was discharged on enoxaparin along with an order to follow-up with a hematologist. Subanalyses from randomized controlled trials, pharmacokinetic/pharmacodynamic, and real-world studies suggest that rivaroxaban may be effective and safe in morbidly obese patients for primary and secondary prevention of venous thromboembolism. However, the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis does not recommend the use of direct-acting oral anticoagulants in this population. If used, drug levels should be monitored to guide the therapy. Due to the disparity in data to show efficacy and safety of rivaroxaban in morbidly obese subjects, the interpatient variability of rivaroxaban’s effects in subjects, and the lack of defined therapeutic range for rivaroxaban drug concentration, rivaroxaban should be used cautiously in this population.

Comparative effectiveness, safety, and costs of rivaroxaban and warfarin among morbidly obese patients with atrial fibrillation

BACKGROUND

There are limited data regarding clinical outcomes and healthcare resource utilization of direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF) who are morbidly obese (body mass index >40 kg/m² or body weight >120 kg).

METHODS

Using data from 2 US healthcare claims databases, we identified patients initiating rivaroxaban or warfarin who had ≥1 medical claim with an AF diagnosis, a diagnostic code for morbid obesity (ICD-9: 278.01, V85.4%; ICD-10: E66.01%, E66.2%, Z68.4%), and a minimum continuous enrollment of 12 months before and 3 months after treatment initiation. Patients were excluded if they had mitral stenosis, a mechanical heart valve procedure, an organ/tissue transplant, or an oral anticoagulant prescription prior to the index date. Rivaroxaban and warfarin patients were 1:1 propensity score matched. Conditional logistic regression was used to compare ischemic stroke/systemic embolism and major bleeding risk. Generalized linear models were used to compare healthcare resource utilization and costs.

RESULTS

A total of 3563 matched pairs of morbidly obese AF patients treated with rivaroxaban or warfarin were identified. The majority (81.4%) of patients in the rivaroxaban cohort were receiving the 20 mg dose. The rivaroxaban and warfarin cohorts were well balanced after propensity score matching. The risks of ischemic stroke/systemic embolism and major bleeding were similar for rivaroxaban and warfarin users (stroke/systemic embolism: 1.5% vs 1.7%; odds ratio [OR]: 0.88; 95% confidence interval [CI]: 0.60, 1.28; P = .5028; major bleeding: 2.2% vs 2.7%; OR: 0.80; 95% CI: 0.59, 1.08; P = .1447). Total healthcare costs including medication costs per patient per year (PPPY) were significantly lower with rivaroxaban versus warfarin ($48,552 vs $52,418; P = .0025), which was primarily driven by lower hospitalization rate (50.2% vs 54.1%; P = .0008), shorter length of stay (7.5 vs 9.1 days; P = .0010), and less outpatient service utilization (86 vs 115 visits PPPY; P < .0001).

CONCLUSIONS

Morbidly obese AF patients treated with rivaroxaban had comparable risk of ischemic stroke/systemic embolism and major bleeding as those treated with warfarin, but lower healthcare resource utilization and costs.

The long-term effect of bariatric surgery on depression and anxiety

BACKGROUND

No previous review has comprehensively assessed long-term changes in anxiety and depressive symptoms in bariatric surgery patients. This systematic review assessed the effects of bariatric surgery on long-term reductions (≥ 24 months) in anxiety and depressive symptom severity in morbidly obese (≥ 35 BMI kg/m²) participants. Short term effects (< 24 months) are briefly reviewed for context.

METHODS

PsychINFO, Google Scholar and PubMed databases were systematically searched for prospective cohort studies published from inception to 14 June 2018 that evaluated long-term (≥ 24 months) changes in anxiety and depressive symptom severity in bariatric surgery patients with a BMI ≥ 35 kg/m² using a combination of the following search terms: bariatric surgery (and surgical approaches included under this term), obesity, depression, depressive disorder, anxiety, anxious, psychiatric disorders, mood disorders.

RESULTS

We reviewed 2058 articles for eligibility; 14 prospective studies were included in the systematic review. 13 studies (93%) reported significant reductions in depressive symptom severity 2-3 years after bariatric surgery. However, all studies recorded statistically significant reductions in depressive symptoms at the conclusion of the study. Similarly, there were reductions in overall anxiety symptom severity at ≥ 24 months follow-up (k = 8 studies, n = 1590 pooled). Pre-operative anxiety or depression scores did not predict outcomes of post-operative BMI. Similarly, post-surgery weight loss did not predict changes in anxiety symptoms.

LIMITATIONS

Very few studies assessed anxiety or depression as a primary outcome. Therefore, we cannot suggest bariatric surgery as a stand-alone therapeutic tool for anxiety and depression based on our findings.

CONCLUSION

Currently available evidence suggests that bariatric surgery is associated with long-term reductions in anxiety and depressive symptoms. This supports existing literature showing that metabolic treatments may be a viable therapeutic intervention for mood disorders.

Warfarin Dose Adjustment After Biliopancreatic Diversion/Duodenal Switch Bariatric Surgery

BACKGROUND

The absorption of drugs and fat-soluble vitamins is impaired after bariatric surgery on which intestinal length and function are altered. In this context, the anticoagulant effect of warfarin is difficult to predict in the postoperative period.

OBJECTIVE

This study aimed at describing the average weekly warfarin dose required to maintain a therapeutic international normalized ratio (INR) before and up to 1 year after sleeve gastrectomy with biliopancreatic diversion and duodenal switch (BPD/DS). Secondary end points included the number of patients requiring a minimal 20% reduction in their weekly dose of warfarin following the BPD/DS.

METHODS

This descriptive and retrospective longitudinal population study included 20 patients using warfarin who underwent BPD/DS. An INR was considered nontherapeutic if it was below or above 15% of the targeted therapeutic range for any given patient.

RESULTS

One month after the surgery, the median weekly dose of warfarin was 55% lower than the preoperative dose ( P < 0.0001). In the 9 patients with full follow-up data, the warfarin dose at 1 year was still 39% lower than the preoperative dose ( P < 0.05). At that time, all patients presented a minimal dose reduction of 20%.

CONCLUSIONS

BPD/DS robustly reduced the requirement of warfarin, which resulted in lower doses after surgery. This persisted over the first year after the surgery, likely because of enhanced sensitivity. The mechanisms for this effect remain multifactorial, and the exact extent of change in dose cannot be predicted.