42 research outputs found

    Pragmatic considerations for negative control outcome studies to guide non-randomized comparative analyses: A narrative review

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    Purpose: This narrative review describes the application of negative control outcome (NCO) methods to assess potential bias due to unmeasured or mismeasured confounders in non-randomized comparisons of drug effectiveness and safety. An NCO is assumed to have no causal relationship with a treatment under study while subject to the same confounding structure as the treatment and outcome of interest; an association between treatment and NCO then reflects the potential for uncontrolled confounding between treatment and outcome. Methods: We focus on two recently completed NCO studies that assessed the comparability of outcome risk for patients initiating different osteoporosis medications and lipid-lowering therapies, illustrating several ways in which confounding may result. In these studies, NCO methods were implemented in claims-based data sources, with the results used to guide the decision to proceed with comparative effectiveness or safety analyses. Results: Based on this research, we provide recommendations for future NCO studies, including considerations for the identification of confounding mechanisms in the target patient population, the selection of NCOs expected to satisfy required assumptions, the interpretation of NCO effect estimates, and the mitigation of uncontrolled confounding detected in NCO analyses. We propose the use of NCO studies prior to initiating comparative effectiveness or safety research, providing information on the potential presence of uncontrolled confounding in those comparative analyses. Conclusions: Given the increasing use of non-randomized designs for regulatory decision-making, the application of NCO methods will strengthen study design, analysis, and interpretation of real-world data and the credibility of the resulting real-world evidence

    Epoetin alfa and outcomes in dialysis amid regulatory and payment reform

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    Erythropoiesis-stimulating agents (ESAs) are commonly used to treat anemia in patients with CKD, including those receiving dialysis, although clinical trials have identified risks associated with ESA use. We evaluated the effects of changes in dialysis payment policies and product labeling instituted in 2011 on mortality and major cardiovascular events across the United States dialysis population in an open cohort study of patients on dialysis from January 1, 2005, through December 31, 2012, with Medicare as primary payer. We compared observed rates of death and major cardiovascular events in 2011 and 2012 with expected rates calculated on the basis of rates in 2005-2010, accounting for differences in patient characteristics and influenza virulence. An abrupt decline in erythropoietin dosing and hemoglobin concentration began in late 2010. Observed rates of all-cause mortality, cardiovascularmortality, andmyocardial infarction in 2011 and 2012 were consistent with expected rates. During 2012, observed rates of stroke, venous thromboembolic disease (VTE), and heart failure were lower than expected (absolute deviation from trend per 100 patient-years [95% confidence interval]: 20.24 [20.08 to 20.37] for stroke, 22.43 [21.35 to 23.70] for VTE, and 20.77 [20.28 to 21.27] for heart failure), although non-ESA-related changes in practice and Medicare payment penalties for rehospitalization may have confounded the results. This initial evidence suggests that action taken to mitigate risks associated with ESA use and changes in payment policy did not result in a relative increase in death or major cardiovascular events and may reflect improvements in stroke, VTE, and heart failure

    Characteristics and outcomes of hospitalised adults with COVID-19 in a Global Health Research Network: A cohort study

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    Objective To examine age, gender, and temporal differences in baseline characteristics and clinical outcomes of adult patients hospitalised with COVID-19. Design A cohort study using deidentified electronic medical records from a Global Research Network. Setting/Participants 67 456 adult patients hospitalised with COVID-19 from the USA; 7306 from Europe, Latin America and Asia-Pacific between February 2020 and January 2021. Results In the US cohort, compared with patients 18-34 years old, patients ≥65 had a greater risk of intensive care unit (ICU) admission (adjusted HR (aHR) 1.73, 95% CI 1.58 to 1.90), acute respiratory distress syndrome(ARDS)/respiratory failure (aHR 1.86, 95% CI 1.76 to 1.96), invasive mechanical ventilation (IMV, aHR 1.93, 95% CI, 1.73 to 2.15), and all-cause mortality (aHR 5.6, 95% CI 4.36 to 7.18). Men appeared to be at a greater risk for ICU admission (aHR 1.34, 95% CI 1.29 to 1.39), ARDS/respiratory failure (aHR 1.24, 95% CI1.21 to 1.27), IMV (aHR 1.38, 95% CI 1.32 to 1.45), and all-cause mortality (aHR 1.16, 95% CI 1.08 to 1.24) compared with women. Moreover, we observed a greater risk of adverse outcomes during the early pandemic (ie, February-April 2020) compared with later periods. In the ex-US cohort, the age and gender trends were similar; for the temporal trend, the highest proportion of patients with all-cause mortality were also in February-April 2020; however, the highest percentages of patients with IMV and ARDS/respiratory failure were in August-October 2020 followed by February-April 2020. Conclusions This study provided valuable information on the temporal trends of characteristics and outcomes of hospitalised adult COVID-19 patients in both USA and ex-USA. It also described the population at a potentially greater risk for worse clinical outcomes by identifying the age and gender differences. Together, the information could inform the prevention and treatment strategies of COVID-19. Furthermore, it can be used to raise public awareness of COVID-19's impact on vulnerable populations

    Trends in characteristics and outcomes among US adults hospitalised with COVID-19 throughout 2020: An observational cohort study

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    Objectives To examine the temporal patterns of patient characteristics, treatments used and outcomes associated with COVID-19 in patients who were hospitalised for the disease between January and 15 November 2020. Design Observational cohort study. Setting COVID-19 subset of the Optum deidentified electronic health records, including more than 1.8 million patients from across the USA. Participants There were 51 510 hospitalised patients who met the COVID-19 definition, with 37 617 in the laboratory positive cohort and 13 893 in the clinical cohort. Primary and secondary outcome measures Incident acute clinical outcomes, including in-hospital all-cause mortality. Results Respectively, 48% and 49% of the laboratory positive and clinical cohorts were women. The 50- 65 age group was the median age group for both cohorts. The use of antivirals and dexamethasone increased over time, fivefold and twofold, respectively, while the use of hydroxychloroquine declined by 98%. Among adult patients in the laboratory positive cohort, absolute age/sex standardised incidence proportion for in-hospital death changed by -0.036 per month (95% CI -0.042 to -0.031) from March to June 2020, but remained fairly flat from June to November, 2020 (0.001 (95% CI -0.001 to 0.003), 17.5% (660 deaths /3986 persons) in March and 10.2% (580/5137) in October); in the clinical cohort, the corresponding changes were -0.024 (95% CI -0.032 to -0.015) and 0.011 (95% CI 0.007 0.014), respectively (14.8% (175/1252) in March, 15.3% (189/1203) in October). Declines in the cumulative incidence of most acute clinical outcomes were observed in the laboratory positive cohort, but not for the clinical cohort. Conclusion The incidence of adverse clinical outcomes remains high among COVID-19 patients with clinical diagnosis only. Patients with COVID-19 entering the hospital are at elevated risk of adverse outcomes

    Using negative control outcomes to assess the comparability of treatment groups among women with osteoporosis in the United States

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    Purpose: In contrast to randomized clinical trials, comparative safety and effectiveness assessments of osteoporosis medications in clinical practice may be subject to confounding by indication. We used negative control outcomes to detect residual confounding when comparing osteoporosis medications. Methods: Using MarketScan Commercial and Supplemental claims, we identified women aged ≥55 years who initiated an oral bisphosphonate (BP) (risedronate, alendronate, or ibandronate), denosumab (an injected biologic), or intravenous zoledronic acid (ZA) from October 1, 2010 to September 30, 2015. Women with Paget's disease or cancer were excluded. We compared individual oral BPs to each other, denosumab to ZA, denosumab to oral BPs, and ZA to oral BPs, with respect to 11 negative control outcomes identified by subject matter experts. We estimated the 12-month cumulative risk difference (RD) using inverse probability of treatment and censoring weights. Results: Among 148 587 women, most initiated alendronate (57%), followed by ibandronate (12%), ZA (11%), risedronate (10%), and denosumab (10%). Compared with denosumab, patients initiating ZA had similar risks of all negative control outcomes. Compared with oral BPs, patients initiating denosumab had a higher risk of a wellness visit (RD = 1.2%, 95% CI: 0.4, 1.9) and a lower risk of receiving herpes zoster vaccine (RD = −0.6%, 95% CI: −1.1, −0.2). Comparing ZA with oral BP initiators resulted in two outcomes with positive associations. Conclusions: Caution is warranted when comparing injectable vs oral osteoporosis medications, given the potential for unmeasured confounding. Evaluating negative control outcomes could be a standard validity check prior to conducting comparative studies

    Supplementary Material for: Trends in Anemia Management Practices in Patients Receiving Hemodialysis and Peritoneal Dialysis: A Retrospective Cohort Analysis

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    <b><i>Background/Aims:</i></b> Recent changes in clinical practice guidelines and reimbursement policies may have affected the use of anemia-related medications and red blood cell (RBC) transfusions in peritoneal dialysis (PD) and hemodialysis (HD) patients. We sought to compare patterns of erythropoiesis-stimulating agents (ESA) and intravenous (IV) iron use, achieved hemoglobin levels, and RBC transfusion use in PD and HD patients. <b><i>Methods:</i></b> In quarterly cohorts of prevalent dialysis patients receiving persistent therapy (>3 months), 2007-2011, with Medicare Parts A and B coverage, we assessed ESA and IV iron use and dose, RBC transfusions, and hemoglobin levels. Quarterly transfusion rates were calculated. <b><i>Results:</i></b> Observable PD and HD patients numbered 14,958 and 221,866 in Q1/2007 and 17,842 and 256,942 in Q4/2011. Adjusted ESA use was lower in PD (71.4-80.1%) than in HD (86.9-92.0%) patients, decreasing from 80.1% (Q1/2010) to 71.4% (Q4/2011) in PD patients, and from 92.0 to 86.9% in HD patients. The mean adjusted ESA dose decreased by 67.5% in PD and 58.4% in HD patients. IV iron use tended to increase, peaking at 39.3% for PD (Q3/2011) and 80.5% for HD (Q2/2011) patients. Adjusted mean hemoglobin levels fell from 11.7 to 10.6 mg/dl in PD and from 12.0 to 10.7 mg/dl in HD ESA users; adjusted transfusion rates increased from 2.4 to 3.0 per 100 patient-months in PD and from 2.6 to 3.3 in HD patients. <b><i>Conclusions:</i></b> In patients receiving persistent dialysis, dose and frequency of ESA administrations decreased during the period 2007-2011. Mean hemoglobin levels decreased by more than 1 g/dl, while transfusion rates increased by approximately 25%
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