Evaluation of clinical outcomes among nonvalvular atrial fibrillation patients treated with rivaroxaban or warfarin, stratified by renal function
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BACKGROUND: Renal dysfunction increases the risk of thromboembolic and bleeding events in patients with nonvalvular atrial fibrillation (NVAF). MATERIALS AND METHODS: Adult NVAF patients with ≥ 6 months prior to first warfarin or rivaroxaban dispensing were selected from the IMS Health Real-World Data Adjudicated Claims database (05/2011 - 06/2015) with electronic medical records. Ischemic stroke events, thromboembolic events (venous thromboembolism, myocardial infarction, or ischemic stroke), and major bleeding events were compared between patients by renal function identified by 1) relevant ICD-9-CM diagnosis codes and 2) estimated creatinine clearance (eCrCl). Baseline confounders were adjusted using inverse probability of treatment weights. RESULTS: The diagnosis-based analysis included 39,872 rivaroxaban and 48,637 warfarin users (3,572 and 8,230 with renal dysfunction, respectively). The eCrCl-based analysis included 874 rivaroxaban and 1,069 warfarin users (66 and 208 with eCrCl < 60 mL/min, respectively). In the diagnosis-based analysis, rivaroxaban users with renal dysfunction had a significantly lower stroke rate (HR = 0.55, p = 0.0004) compared to warfarin users; rivaroxaban users with and without renal dysfunction had significantly lower thromboembolic event rates (HR = 0.62, p < 0.0001; and HR = 0.64, p < 0.0001, respectively), and similar major bleeding rates to warfarin users. In the eCrCl-based analysis, rivaroxaban users with eCrCl ≥ 60 mL/min had a significantly lower thromboembolic event rate, but other outcomes were not statistically significant. CONCLUSION: Rivaroxaban-treated NVAF patients with diagnosed renal dysfunction had a significantly lower stroke rate compared to warfarin-treated patients. Regardless of renal dysfunction diagnoses, rivaroxaban users had lower thromboembolic event rates compared to warfarin users, and a similar rate of major bleeding. eCrCl-based analysis was limited by a small sample size.
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CODA: an open-source platform for federated analysis and machine learning on distributed healthcare data.

OBJECTIVES: Distributed computations facilitate multi-institutional data analysis while avoiding the costs and complexity of data pooling. Existing approaches lack crucial features, such as built-in medical standards and terminologies, no-code data visualizations, explicit disclosure control mechanisms, and support for basic statistical computations, in addition to gradient-based optimization capabilities. MATERIALS AND METHODS: We describe the development of the Collaborative Data Analysis (CODA) platform, and the design choices undertaken to address the key needs identified during our survey of stakeholders. We use a public dataset (MIMIC-IV) to demonstrate end-to-end multi-modal FL using CODA. We assessed the technical feasibility of deploying the CODA platform at 9 hospitals in Canada, describe implementation challenges, and evaluate its scalability on large patient populations. RESULTS: The CODA platform was designed, developed, and deployed between January 2020 and January 2023. Software code, documentation, and technical documents were released under an open-source license. Multi-modal federated averaging is illustrated using the MIMIC-IV and MIMIC-CXR datasets. To date, 8 out of the 9 participating sites have successfully deployed the platform, with a total enrolment of >1M patients. Mapping data from legacy systems to FHIR was the biggest barrier to implementation. DISCUSSION AND CONCLUSION: The CODA platform was developed and successfully deployed in a public healthcare setting in Canada, with heterogeneous information technology systems and capabilities. Ongoing efforts will use the platform to develop and prospectively validate models for risk assessment, proactive monitoring, and resource usage. Further work will also make tools available to facilitate migration from legacy formats to FHIR and DICOM.

LI-RADS for CT diagnosis of hepatocellular carcinoma: performance of major and ancillary features.

PURPOSE: To evaluate the diagnostic performance of Liver Imaging Reporting and Data System (LI-RADS) v2017 major features, the impact of ancillary features, and categories on contrast-enhanced computed tomography (CECT) for the diagnosis of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: This retrospective study included 59 patients (104 observations including 72 HCCs) with clinical suspicion of HCC undergoing CECT between 2013 and 2016. Two radiologists independently assessed major and ancillary imaging features for each liver observation and assigned a LI-RADS category based on major features only and in combination with ancillary features. The composite reference standard included pathology or imaging. Per-lesion estimates of diagnostic performance of major features, ancillary features, and LI-RADS categories were assessed by generalized estimating equation models. RESULTS: Major features (arterial phase hyperenhancement, washout, capsule, and threshold growth) respectively had a sensitivity of 86.1%, 81.6%, 20.7%, and 26.1% and specificity of 39.3%, 67.9%, 89.9%, and 85.0% for HCC. Ancillary features (ultrasound visibility as discrete nodule, subthreshold growth, and fat in mass more than adjacent liver) respectively had a sensitivity of 42.6%, 50.8%, and 15.1% and a specificity of 79.2%, 66.9%, and 96.4% for HCC. Ancillary features modified the final category in 4 of 104 observations. For HCC diagnosis, categories LR-3, LR-4, LR-5, and LR-TIV (tumor in vein) had a sensitivity of 5.3%, 29.0%, 53.7%, and 10.7%; and a specificity of 49.1%, 84.4%, 97.3%, and 96.4%, respectively. CONCLUSION: On CT, LR-5 category has near-perfect specificity for the diagnosis of HCC and ancillary features modifies the final category in few observations.

Implications of stroke and bleeding risk scores and comorbidities on episode-based bundled payments for patients with nonvalvular atrial fibrillation.

OBJECTIVES: Due to the high cost of nonvalvular atrial fibrillation (NVAF), this condition may be a suitable candidate for condition-specific bundled payments. This paper evaluates the healthcare cost of NVAF and uses common bleeding and stroke risk scores (HAS-BLED and CHA2DS2-VASc) to explore the risk-based healthcare cost differences among NVAF patients. METHODS: MarketScan claims of NVAF patients (ICD-9-CM code 427.31) were analyzed from January 2010 to April 2015. These claims feature more than 196 million covered lives and more than 300 contributing employers and 25 contributing health plans. A retrospective cohort design was used to assess episodes of care costs among patients with NVAF. Previously and newly diagnosed NVAF patients were selected from adult patients with ≥2 diagnoses of NVAF, and without valvular disease. Total all-cause healthcare costs at 1 year were stratified by stroke (CHA2DS2-VASc) and bleeding (HAS-BLED) risk scores. Study data was extracted in the MarketScan Commercial Claims and Encounters Database (Commercial Database) and the MarketScan Medicare Supplemental and Coordination of Benefits Database (Medicare Supplemental Database). RESULTS: Mean all-cause 1 year cost of care based on stroke risk (CHA2DS2-VASc) varied from $15,703 to $59,163 for previously diagnosed and $25,992 to $62,458 for newly diagnosed NVAF. Similarly, mean cost varied base on bleeding risk (HAS-BLED) for previously and newly diagnosed NVAF from $17,950 to $57,029 and $26,356 to $67,104 respectively. CONCLUSION: NVAF patients accrue variable healthcare costs. Stroke and bleeding risk should be taken into account during the creation of NVAF payment bundles.

Impact of renal function on ischemic stroke and major bleeding rates in nonvalvular atrial fibrillation patients treated with warfarin or rivaroxaban: a retrospective cohort study using real-world evidence.

OBJECTIVES: Renal dysfunction is associated with increased risk of cardiovascular disease and is an independent predictor of stroke and systemic embolism. Nonvalvular atrial fibrillation (NVAF) patients with renal dysfunction may face a particularly high risk of thromboembolism and bleeding. The current retrospective cohort study was designed to assess the impact of renal function on ischemic stroke and major bleeding rates in NVAF patients in the real-world setting (outside a clinical trial). METHODS: Medical claims and Electronic Health Records were retrieved retrospectively from Optum's Integrated Claims-Clinical de-identified dataset from May 2011 to August 2014. Patients with NVAF treated with warfarin (2468) or rivaroxaban (1290) were selected. Each treatment cohort was stratified by baseline estimated creatinine clearance (eCrCl) levels. Confounding adjustments were made using inverse probability of treatment weights (IPTWs). Incidence rates and hazard ratios of ischemic stroke and major bleeding events were calculated for both cohorts. RESULTS: Overall, patients treated with rivaroxaban had an ischemic stroke incidence rate of 1.9 per 100 person-years (PY) while patients treated with warfarin had a rate of 4.2 per 100 PY (HR = 0.41 [0.21-0.80], p = .009). Rivaroxaban patients with an eCrCl below 50 mL/min (N = 229) had an ischemic stroke rate of 0.8 per 100 PY, while the rate for the warfarin cohort (N = 647) was 6.0 per 100 PY (HR = 0.09 [0.01-0.72], p = .02). For the other renal function levels (i.e. eCrCl 50-80 and ≥80 mL/min) HRs indicated no statistically significant differences in ischemic stroke risks. Bleeding events did not differ significantly between cohorts stratified by renal function. CONCLUSIONS: Ischemic stroke rates were significantly lower in the overall NVAF population for rivaroxaban vs. warfarin users, including patients with eCrCl below 50 mL/min. For all renal function groups, major bleeding risks were not statistically different between treatment groups.

Growing social inequality in the prevalence of type 2 diabetes in Canada, 2004-2012.

OBJECTIVES: The prevalence of diabetes in Canada has nearly doubled since 2000. Trends in social inequalities in diabetes across Canada and its different regions have not been assessed. We estimated relative and absolute social inequalities in type 2 diabetes prevalence in Canada between 2004 and 2012. METHODS: We used the relative (RII) and slope (SII) indices of inequality to measure relative and absolute education-based inequalities respectively in type 2 diabetes prevalence in a sample of 413,453 men and women surveyed as part of the Canadian Community Health Survey between 2004 and 2012. RESULTS: Across regions and time periods, inequalities were more pronounced for women than for men, both on the absolute and relative scales. The difference in the prevalence of type 2 diabetes between individuals with the highest level of educational attainment compared to the lowest, as reflected by the SII, expanded from approximately 2.5% to 4.5% for women and 1.4% to 2.3% for men between 2004 and 2012. CONCLUSIONS: Monitoring and tracking social inequalities in the burden of diabetes over time can help to assess whether Canadian diabetes strategies are effective at reaching marginalized populations and mitigating inequalities. Our results signal the need for interventions to address growing social inequalities in Canada with regard to type 2 diabetes, particularly among women.