Emulating a Target Trial of Shorter Compared to Longer Course of Antibiotic Therapy for Gram-Negative Bacteremia.

BACKGROUND: Despite the availability of antimicrobial therapies, gram-negative bacteremia remains a significant cause of morbidity and mortality on a global level. Recent randomized controlled trials support shorter antibiotic treatment duration for individuals with uncomplicated gram-negative bacteremia. The target trial framework using the cloning approach utilizes real-world data but eliminates the issue of immortal time bias seen in observational studies by emulating the analysis of randomized trials with full adherence. METHOD: A hypothetical target trial allocating individuals with gram-negative bacteremia to either short antibiotic treatment duration (5-7 days) or longer antibiotic treatment duration (8-14 days) was specified and emulated using the cloning, censoring, and weighting approach. The primary outcome was 90-day all-cause mortality. Secondary outcome was a composite endpoint of clinical and microbiological relapse. The emulated trial included individuals from four hospitals in Copenhagen from 2018 through 2021. RESULTS: In sum, 1040 individuals were included. The median age of the cohort was 76 years, the majority were male (54%), had community-acquired gram-negative bacteremia (86%), urinary tract infection as the source of the infection (78%), and Escherichia coli as the pathogen of the infection (73%). The adjusted 90-day risk difference in all-cause mortality was 1.3% (95% confidence interval [CI]: -.7, 3.3), and the risk ratio was 1.12 (95% CI: .89, 1.37). The adjusted 90-day risk difference in relapse was 0.7% (95% CI: -2.3, 3.8), and the risk ratio was 1.07 (95% CI: .71, 1.45). CONCLUSIONS: We found comparative outcomes for shorter treatment duration compared to longer treatment duration in patients with gram-negative bacteremia.

Identifying Veterans Who Benefit From Nirmatrelvir-Ritonavir: A Target Trial Emulation.

BACKGROUND: Nirmatrelvir-ritonavir is recommended for persons at risk for severe coronavirus disease 2019 (COVID-19) but remains underutilized. Information on which eligible groups are likely to benefit from treatment is needed. METHODS: We conducted a target trial emulation study in the Veterans Health Administration comparing nirmatrelvir-ritonavir treated versus matched untreated veterans at risk for severe COVID-19 who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from April 2022 through March 2023. We measured incidence of any hospitalization or all-cause mortality at 30 days. Outcomes were measured for the entire cohort, as well as among subgroups defined by 30-day risk of death or hospitalization, estimated using an ensemble risk prediction model. RESULTS: Participants were 87% male with median age 66 years and 16% unvaccinated. Compared with matched untreated participants, those treated with nirmatrelvir-ritonavir (n = 24 205) had a lower 30-day risk for hospitalization (1.80% vs 2.30%; risk difference [RD], -0.50% points [95% confidence interval {CI}: -.69 to -.35]) and death (0.11% vs 0.30%; RD, -0.20 [95% CI: -.24 to -.13]). The greatest reductions in combined hospitalization or death were observed in the highest risk quartile (RD -2.85 [95% CI: -3.94 to -1.76]), immunocompromised persons (RD -1.91 [95% CI: -3.09 to -.74]), and persons aged ≥75 years (RD -1.16 [95% CI: -1.73 to -.59]). No reductions were observed in the 2 lowest risk quartiles or persons younger than 65 years. CONCLUSIONS: Nirmatrelvir-ritonavir was effective in reducing 30-day hospitalization and death in older veterans, those at highest predicted risk for severe outcomes, and immunocompromised groups. Benefit was not observed in younger veterans or groups at lower predicted risk for hospitalization and death.

Sustained Hypothetical Interventions on Midlife Alcohol Consumption in Relation to All-Cause and Cancer Mortality: The Australian Longitudinal Study on Women's Health.

No randomized controlled trial has evaluated the effect of long-term alcohol interventions on mortality. Results reported in existing observational studies may be subject to selection bias and time-varying confounding. Using data from the Australian Longitudinal Study on Women's Health 1946-1951 birth cohort, collected regularly from 1996-2016, we estimated all-cause and cancer mortality had women been assigned various alcohol interventions (in categories ranging from 0 to >30 g/day ethanol, or reduced to ≤20 g/day if higher) at baseline, and had they maintained these levels of consumption. The cumulative risks for all-cause and cancer mortality were 5.6% (10,118 women followed for 20 years) and 2.9% (18 years), respectively. For all-cause and cancer mortality, baseline ethanol up to 30 g/day showed lower risk and >30 g/day showed higher risk relative to abstention. Had women sustainedly followed the interventions, a similar relationship was observed for all-cause mortality. However, the negative association observed for intakes ≤30 g/day and positive association for intakes >30 g/day was not evident for cancer mortality. Our findings suggest that all-cause mortality could have been lower than observed if this cohort of women had consumed some alcohol (no more than 30 g/day) rather than no consumption, but cancer mortality might not.

How much could anemia-related interventions reduce the HIV disparity in adverse birth outcomes?

Women and other people of childbearing potential living with HIV (WLHIV) have a higher risk of adverse birth outcomes than those without HIV (WWHIV). A higher risk of anemia in WLHIV could partially explain this disparity. Using a birth outcomes surveillance study in Botswana, we emulated target trials corresponding to currently available or feasible interventions on anemia. The first target trial evaluated two interventions: initiate multiple micronutrient supplementation (MMS), and MMS or iron and folic acid supplementation by 24 weeks gestation. The remaining target trials evaluated the interventions: eliminate anemia before pregnancy; and jointly eliminate anemia before pregnancy and initiate MMS. We estimated the observed disparity in adverse birth outcomes between WLHIV and WWHIV and compared the observed disparity measure (ODM) to the counterfactual disparity measure (CDM) under each intervention. Of 137,499 individuals (22% WLHIV), the observed risk of any adverse birth outcome was 26.0% in WWHIV and 34.5% in WLHIV (ODM, 8.5% [95% CI, 7.9-9.1%]). CDMs (95% CIs) ranged from 6.6% (4.8-8.4%) for the intervention to eliminate anemia and initiate MMS to 8.4% (7.7-9.1%) for the intervention to eliminate anemia only. Preventing anemia and expanding MMS may reduce HIV disparities in birth outcomes, but interventions with greater impact should be identified.

Effect of Different Durations of Treatment With Antihypertensive Drugs With Anticholinergic Effects on the Risk of Dementia: A Target Trial Emulation Study.

Studying the effect of duration of treatment on prognostic outcomes using real-world data is challenging because only people who survive for a long time can receive a treatment for a long time. Specifying a target trial helps overcome such challenge. We aimed to estimate the effect of different durations of treatment with antihypertensive drugs with anticholinergic properties (AC AHT) on the risk of vascular dementia and Alzheimer's disease by emulating a target trial using the UK CPRD GOLD database (2001-2017). Comparing treatment for 3-6 years versus ≤3 years yielded null results for both types of dementia. Comparing a longer duration of treatment, >6 years versus ≤3 years, yielded a 10-year risk ratio of 0.69 (95% CI, 0.54-0.90) for vascular dementia and 0.91 (95% CI, 0.77-1.10) for Alzheimer's disease. For illustration, we performed an analysis that failed to emulate a target trial by assigning exposure categories using post-baseline information, obtaining implausible beneficial estimates. Our findings indicate a modest benefit of longer duration of treatment with AC AHT on vascular dementia and highlight the value of the target trial emulation to avoid selection bias in the evaluation of the effect of different durations of treatment.

Emulations of Oncology Trials Using Real-World Data: A Systematic Literature Review.

By evaluating published emulations of oncology RCTs studies in which both the active and comparator groups are sourced from RWD and target trial results are available for benchmarking, this systematic review aims to gain insight into factors related to emulation performance. Thirteen oncology emulation studies using various types of RWD were identified through an online database search of PubMed through 2022. Based on the ROBINS-I tool, most studies (N=8) had a serious risk of overall bias driven by risk of bias from confounding. Approximately half of the studies (N=6) fully proxied the RCT entry criteria. Of 11 RWD studies that provided sufficient detail to quantify emulation performance, the emulation HR estimate fell within the 95% CI of the trial estimate in 9 of the studies. There were no clear trends between risk of bias or degree to which the entry criteria were proxied and emulation performance. Findings may have been influenced by publication bias and researcher degrees of freedom, as only one emulation study pre-registered its protocol. Tools for comprehensively characterizing factors that affect emulation performance, including the real-world clinical context as it relates to the RCT research question, are needed to evaluate the feasibility of a RCT emulation.

Emulating target trials of postexposure vaccines using observational data.

Postexposure vaccination has the potential to prevent or modify the course of clinical disease among those exposed to a pathogen. However, due to logistical constraints, postexposure vaccine trials have been difficult to implement in practice. In place of trials, investigators have used observational data to estimate the effectiveness or optimal timing window for postexposure vaccines, but the relationship between these analyses and those that would be conducted in a trial is often unclear. Here, we define several possible target trials for postexposure vaccination and show how, under certain conditions, they can be emulated using observational data. We emphasize the importance of the incubation period and the timing of vaccination in trial design and emulation. As an example, we specify a protocol for postexposure vaccination against mpox and provide a step-by-step description of how to emulate it using data from a healthcare database or contact tracing program. We further illustrate some of the benefits of the target trial approach through simulation.

Non-benzodiazepine Hypnotics and Police-Reported Motor Vehicle Crash Risk among Older Adults: A Sequential Target Trial Emulation.

Non-benzodiazepine hypnotics ( "Z-drugs") are prescribed for insomnia, but might increase risk of motor vehicle crash (MVC) among older adults through prolonged drowsiness and delayed reaction times. We estimated the effect of initiating Z-drug treatment on the 12-week risk of MVC in a sequential target trial emulation. After linking New Jersey driver licensing and police-reported MVC data to Medicare claims, we emulated a new target trial each week (July 1, 2007 - October 7, 2017) in which Medicare fee-for-service beneficiaries were classified as Z-drug-treated or untreated at baseline and followed for an MVC. We used inverse probability of treatment and censoring weighted pooled logistic regression models to estimate risk ratios (RR) and risk differences with 95% bootstrap confidence limits (CLs). There were 257,554 person-trials, of which 103,371 were Z-drug-treated and 154,183 untreated, giving rise to 976 and 1,249 MVCs, respectively. The intention-to-treat RR was 1.06 (95%CLs 0.95, 1.16). For the per-protocol estimand, there were 800 MVCs and 1,241 MVCs among treated and untreated person-trials, respectively, suggesting a reduced MVC risk (RR 0.83 [95%CLs 0.74, 0.92]) with sustained Z-drug treatment. Z-drugs should be prescribed to older patients judiciously but not withheld entirely over concerns about MVC risk.

Evaluating recommendation-based dietary and physical activity strategies for prostate cancer prevention: a target trial emulation in the Health Professionals Follow-up Study.

The 2018 World Cancer Research Fund/American Institute for Cancer Research recommends sustained strategies of physical activity and diet for cancer prevention, but evidence for long-term prostate cancer risk is limited. Using observational data from 27,859 men in the Health Professionals Follow-up Study, we emulated a target trial of recommendation-based physical activity and dietary strategies and 26-year risks of prostate cancer, adjusting for risk factors via the parametric g-formula. Compared with no intervention, limiting sugar-sweetened beverages showed a 0.4% (0.0-0.9%) lower risk of lethal (metastatic or fatal) disease and 0.5% (0.1-0.9%) lower risk of fatal disease. Restricting consumption of processed foods showed a 0.4-0.9% higher risk of all prostate cancer outcomes. Estimated risk differences for clinically significant disease were close to null for strategies involving fruits and non-starchy vegetables, whole grains and legumes, red meat, and processed meat, as well as under a joint strategy of physical activity and diet. Compared with a "low adherence" strategy, maintaining recommended physical activity levels showed a 0.4% (0.1-0.8%) lower risk of lethal and 0.5% (0.2-0.8%) lower risk of fatal disease. Adhering to specific components of current physical activity and dietary recommendations may help to prevent lethal and fatal prostate cancer over 26 years.

Can metformin prevent cancer relative to sulfonylureas? A target trial emulation accounting for competing risks and poor overlap via double/debiased machine learning estimators.

There is mounting interest in the possibility that metformin, indicated for glycemic control in type 2 diabetes, has a range of additional beneficial effects. Randomized trials have shown that metformin prevents adverse cardiovascular events, and metformin use has also been associated with reduced cognitive decline and cancer incidence. In this paper, we dig more deeply into whether metformin prevents cancer by emulating target randomized trials comparing metformin to sulfonylureas as first line diabetes therapy using data from Clinical Practice Research Datalink, a U.K. primary care database (1987-2018). We included individuals with diabetes, no prior cancer diagnosis, no chronic kidney disease, and no prior diabetes therapy who initiated metformin (N=93353) or a sulfonylurea (N=13864). In our cohort, the estimated overlap weighted additive separable direct effect of metformin compared to sulfonylureas on cancer risk at 6 years was -1% (.95 CI=-2.2%, 0.1%), which is consistent with metformin providing no direct protection against cancer incidence or substantial protection. The analysis faced two methodological challenges-poor overlap, and pre-cancer death as a competing risk. To address these issues while minimizing nuisance model misspecification, we develop and apply double/debiased machine learning estimators of overlap weighted separable effects in addition to more traditional effect estimates.

Antipsychotic drugs in first-episode psychosis: a target trial emulation in the FEP-CAUSAL Collaboration.

Good adherence to antipsychotic therapy helps prevent relapses in first-episode psychosis (FEP). We used data from the FEP-CAUSAL Collaboration, an international consortium of observational cohorts, to emulate a target trial comparing antipsychotics, with treatment discontinuation as the primary outcome. Other outcomes included all-cause hospitalization. We benchmarked our results to estimates from the European First Episode Schizophrenia Trial, a randomized trial conducted in the 2000s. We included 1097 patients with a psychotic disorder and less than 2 years since psychosis onset. Inverse-probability weighting was used to control for confounding. The estimated 12-month risks of discontinuation for aripiprazole, first-generation agents, olanzapine, paliperidone, quetiapine, and risperidone were 61.5% (95% CI, 52.5-70.6), 73.5% (95% CI, 60.5-84.9), 76.8% (95% CI, 67.2-85.3), 58.4% (95% CI, 40.4-77.4), 76.5% (95% CI, 62.1-88.5), and 74.4% (95% CI, 67.0-81.2), respectively. Compared with aripiprazole, the 12-month risk differences were -15.3% (95% CI, -30.0 to 0.0) for olanzapine, -12.8% (95% CI, -25.7 to -1.0) for risperidone, and 3.0% (95% CI, -21.5 to 30.8) for paliperidone. The 12-month risks of hospitalization were similar between agents. Our estimates support use of aripiprazole and paliperidone as first-line therapies for FEP. Benchmarking yielded similar results for discontinuation and absolute risks of hospitalization as in the original trial, suggesting that data from the FEP-CAUSAL Collaboration sufficed to remove confounding for these clinical questions. This article is part of a Special Collection on Mental Health.

Evaluating the Effectiveness of Systemic Heparin During Arteriovenous Fistula Creation by Emulating a Target Trial.

Most of the 800,000 people living with end-stage kidney disease in the United States rely on a functioning vascular access to provide life-sustaining hemodialysis, yet one-third of arteriovenous fistulas experience early failures. Determining the safety and effectiveness of systemic heparin during fistula creation could improve the quality and quantity of life for these vulnerable patients. In this paper, a pragmatic randomized trial was emulated to assess the effect of systemic heparin administration (vs. none) during radiocephalic arteriovenous fistula creation on early bleeding and thrombosis using data from two international multicenter randomized trials performed between 2014 and 2019. Marginal risks were estimated using inverse probability weighted parametric survival analysis and confidence intervals were generated with bootstrapping. A total of 914 patients were enrolled and 61% received systemic heparin; median (IQR) age was 58 (49, 67) years and 45% were on hemodialysis at enrollment. No difference in the risk of bleeding events was observed, with a risk difference (95% CI) at 14 days of -0.1% (-1.6, 1.4). The risk of access thrombosis was lower in the heparin group, with a risk of 3.7% (2.6, 4.8) after heparin and 5.3% (3.4, 7.4) without heparin at 14 days (risk ratio 0.72, 95% CI 0.50, 0.98).

Prenatal exposure to benzodiazepine and z-hypnotics and fifth-grade scholastic skills - emulating target trials using data from the Norwegian Mother, Father and Child Cohort Study.

Evidence is limited regarding the effect of prenatal benzodiazepine and z-hypnotic exposure and long-term neurodevelopment in childhood. The objective of this study was to investigate the effects of initiating benzodiazepine or z-hypnotic treatment in early, mid and late pregnancy on fifth-grade numeracy and literacy scholastic skills in children, by emulating three target trials. The trials are identical except for the timing of enrollment and the number of eligible individuals. Eligibility to the trials required a history of anxiety and/or depression prior to pregnancy. We used data from the Norwegian Mother, Father and Child Cohort Study, linked to the Medical Birth Registry of Norway, to emulate the trials. We adjusted for baseline covariates that were available at time 0 for each trial by inverse probability of treatment weighting using the propensity score. The findings of this study did not show any effect of mothers' initiation of treatment with benzodiazepines or z-hypnotics in early, mid or late pregnancy on the children's 5th grade test scores in numeracy and literacy. The study results provide reassurance for patients in need of benzodiazepines and z-hypnotics during pregnancy; however, these findings need to be interpreted with caution due to low study power in some of the analyses.

Short- and long-term impact of aspirin cessation in older adults: a target trial emulation.

BACKGROUND: The net benefit of aspirin cessation in older adults remains uncertain. This study aimed to use observational data to emulate a randomized trial of aspirin cessation versus continuation in older adults without cardiovascular disease (CVD). METHODS: Post hoc analysis using a target trial emulation framework applied to the immediate post-trial period (2017-2021) of a study of low-dose aspirin initiation in adults aged ≥ 70 years (ASPREE; NCT01038583). Participants from Australia and the USA were included if they were free of CVD at the start of the post-trial intervention period (time zero, T0) and had been taking open-label or randomized aspirin immediately before T0. The two groups in the target trial were as follows: aspirin cessation (participants who were taking randomized aspirin immediately before T0; assumed to have stopped at T0 as instructed) versus aspirin continuation (participants on open-label aspirin at T0 regardless of their randomized treatment; assumed to have continued at T0). The outcomes after T0 were incident CVD, major adverse cardiovascular events (MACE), all-cause mortality, and major bleeding during 3, 6, and 12 months (short-term) and 48 months (long-term) follow-up. Hazard ratios (HRs) comparing aspirin cessation to continuation were estimated from propensity-score (PS) adjusted Cox proportional-hazards regression models. RESULTS: We included 6103 CVD-free participants (cessation: 5427, continuation: 676). Over both short- and long-term follow-up, aspirin cessation versus continuation was not associated with elevated risk of CVD, MACE, and all-cause mortality (HRs, at 3 and 48 months respectively, were 1.23 and 0.73 for CVD, 1.11 and 0.84 for MACE, and 0.23 and 0.79 for all-cause mortality, p > 0.05), but cessation had a reduced risk of incident major bleeding events (HRs at 3 and 48 months, 0.16 and 0.63, p < 0.05). Similar findings were seen for all outcomes at 6 and 12 months, except for a lowered risk of all-cause mortality in the cessation group at 12 months. CONCLUSIONS: Our findings suggest that deprescribing prophylactic aspirin might be safe in healthy older adults with no known CVD.

Effectiveness of intravenous methylprednisolone pulse in patients with severe microscopic polyangiitis and granulomatosis with polyangiitis.

OBJECTIVES: To evaluate the effectiveness and safety of two different intravenous methylprednisolone (IVMP) pulse doses in patients with severe microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA). METHODS: We emulated a target trial using observational data from the nationwide registry in Japan. Patients with severe glomerulonephritis or diffuse alveolar haemorrhage were selected and pseudo-randomized into three groups using propensity score-based overlap weighting as follows: non-IVMP, IVMP 0.5 g/day and IVMP 1.0 g/day. The primary outcome was all-cause mortality, and the secondary outcomes were composite all-cause mortality and kidney failure, severe relapse and serious infection from 2 to 48 weeks after treatment initiation. To estimate the treatment effects, the Cox proportional hazard model and Fine-Gray subdistribution hazard model were used. RESULTS: In this emulated target trial, of 201 eligible patients (MPA, 175; GPA, 26), 6 (3%) died, 4 (2.0%) had kidney failure, 11 (5.5%) had severe relapse, and 40 (19.9%) had severe infections. Hazard ratios (HR) for IVMP 0.5 g/day and IVMP 1.0 g/day pulse groups compared with non-IVMP pulse were as follows: all-cause mortality 0.46 (95% CI: 0.07, 2.81) and 0.07 (95% CI: 0.01, 0.41), respectively; all-cause mortality/kidney failure 1.18 (95% CI: 0.26, 5.31) and 0.59 (95% CI: 0.08, 4.52), respectively; subdistribution HRs for severe relapse were 1.26 (95% CI: 0.12, 13.70) and 3.36 (95% CI: 0.49, 23.29), respectively; and for serious infection 1.88 (95% CI: 0.76, 4.65) and 0.94 (95% CI: 0.28, 3.13), respectively. CONCLUSION: IVMP 1.0 g/day pulse may improve 48-week mortality in patients with severe MPA/GPA.

Survival outcomes of primary vs interval cytoreductive surgery for International Federation of Gynecology and Obstetrics stage IV ovarian cancer: a nationwide population-based target trial emulation.

BACKGROUND: The effect of primary cytoreductive surgery vs interval cytoreductive surgery on International Federation of Gynecology and Obstetrics stage IV ovarian cancer outcomes remains uncertain and may vary depending on the stage and the location of extraperitoneal metastasis. Emulating target trials through causal assessment, combined with propensity score adjustment, has become a leading method for evaluating interventions using observational data. OBJECTIVE: This study aimed to assess the effect of primary vs interval cytoreductive surgery on progression-free and overall survival in patients with International Federation of Gynecology and Obstetrics stage IV ovarian cancer using target trial emulation. STUDY DESIGN: Using the comprehensive French national health insurance database, we emulated a target trial to explore the causal impacts of primary vs interval cytoreductive surgery on stage IV ovarian cancer prognosis (Surgery for Ovarian cancer FIGO 4: SOFI-4). The clone method with inverse probability of censoring weighting was used to adjust for informative censoring and to balance baseline characteristics between the groups. Subgroup analyses were conducted based on the stages and extraperitoneal metastasis locations. The study included patients younger than 75 years of age, in good health condition, who were diagnosed with stage IV ovarian cancer between January 1, 2014, and December 31, 2022. The primary and secondary outcomes were respectively 5-year progression-free survival and 7-year overall survival. RESULTS: Among the 2772 patients included in the study, 948 (34.2%) were classified as having stage IVA ovarian cancer and 1824 (65.8%) were classified as having stage IVB ovarian cancer at inclusion. Primary cytoreductive surgery was performed for 1182 patients (42.6%), whereas interval cytoreductive surgery was conducted for 1590 patients (57.4%). The median progression-free survival for primary cytoreductive surgery was 19.7 months (interquartile range, 19.3-20.1) as opposed to 15.7 months (interquartile range, 15.7-16.1) for those who underwent interval cytoreductive surgery. The median overall survival was 63.1 months (interquartile range, 61.7-65.4) for primary cytoreductive surgery in comparison with 55.6 months (interquartile range, 53.8-56.3) for interval cytoreductive surgery. The findings of our study indicate that primary cytoreductive surgery is associated with a 5.0-month increase in the 5-year progression-free survival (95% confidence interval, 3.8-6.2) and a 3.9-month increase in 7-year overall survival (95% confidence interval, 1.9-6.2). These survival benefits of primary over interval cytoreductive surgery were observed in both the International Federation of Gynecology and Obstetrics stage IVA and IVB subgroups. Primary cytoreductive surgery demonstrated improved progression-free survival and overall survival in patients with pleural, supradiaphragmatic, or extra-abdominal lymph node metastasis. CONCLUSION: This study advocates for the benefits of primary cytoreductive surgery over interval cytoreductive surgery for patients with stage IV ovarian cancer and suggests that extraperitoneal metastases like supradiaphragmatic or extra-abdominal lymph nodes should not automatically preclude primary cytoreductive surgery consideration in suitable patients.

The Inflation Reduction Act: An Opportunity to Accelerate Confidence in Real-World Evidence in the United States.

OBJECTIVES: The Inflation Reduction Act (IRA), enacted in 2022, brings substantial reforms to the US healthcare system, particularly regarding Medicare. A key aspect includes the introduction of Medicare price negotiation. The objective of this commentary is to explore the implications of the IRA for US pharmaceutical companies, with a specific focus on the role of real-world evidence (RWE) in the context of Medicare reforms. METHODS: This commentary uses a qualitative analysis of the IRA's provisions related to healthcare and pharmaceutical regulation, focusing on how these reforms change the evidence requirements for pharmaceutical companies. It discusses the methodological aspects of generating and using RWE, including techniques such as target trial emulation and quantitative bias analysis methods to address biases inherent in RWE. RESULTS: This commentary highlights that the IRA introduces a unique approach to value assessment in the United States by evaluating drug value several years after launch, as opposed to at launch, similar to health technology assessments in other regions. It underscores the central role of RWE in comparing drug effectiveness across diverse clinical scenarios to improve the accuracy of real-world data comparisons. Furthermore, this article identifies key methodologies for managing the inherent biases in RWE, which are crucial for generating credible evidence for IRA price negotiations. CONCLUSIONS: This article underscores the importance of these methodologies in ensuring credible evidence for IRA price negotiations. It advocates for an integrated approach in evidence generation, positioning RWE as pivotal for informed pricing discussions in the US healthcare landscape.

Flexible Approaches Based on Multistate Models and Microsimulation to Perform Real-World Cost-Effectiveness Analyses: An Application to Proprotein Convertase Subtilisin-Kexin Type 9 Inhibitors.

OBJECTIVES: This study aims to show the application of flexible statistical methods in real-world cost-effectiveness analyses applied in the cardiovascular field, focusing specifically on the use of proprotein convertase subtilisin-kexin type 9 inhibitors for hyperlipidemia. METHODS: The proposed method allowed us to use an electronic health database to emulate a target trial for cost-effectiveness analysis using multistate modeling and microsimulation. We formally established the study design and provided precise definitions of the causal measures of interest while also outlining the assumptions necessary for accurately estimating these measures using the available data. Additionally, we thoroughly considered goodness-of-fit assessments and sensitivity analyses of the decision model, which are crucial to capture the complexity of individuals' healthcare pathway and to enhance the validity of this type of health economic models. RESULTS: In the disease model, the Markov assumption was found to be inadequate, and a "time-reset" timescale was implemented together with the use of a time-dependent variable to incorporate past hospitalization history. Furthermore, the microsimulation decision model demonstrated a satisfying goodness of fit, as evidenced by the consistent results obtained in the short-term horizon compared with a nonmodel-based approach. Notably, proprotein convertase subtilisin-kexin type 9 inhibitors revealed their favorable cost-effectiveness only in the long-term follow-up, with a minimum willingness to pay of 39 000 Euro/life years gained. CONCLUSIONS: The approach demonstrated its significant utility in several ways. Unlike nonmodel-based or alternative model-based methods, it enabled to (1) investigate long-term cost-effectiveness comprehensively, (2) use an appropriate disease model that aligns with the specific problem under study, and (3) conduct subgroup-specific cost-effectiveness analyses to gain more targeted insights.

Comparison of Kidney Graft Function and Survival in an Emulated Trial With Living Donors and Brain-Dead Donors.

Living donation (LD) transplantation is the preferred treatment for kidney failure as compared to donation after brain death (DBD), but age may play a role. We compared the 1-year estimated glomerular filtration rate (eGFR) after kidney transplantation for recipients of LD and DBD stratified by recipient and donor age between 2015 and 2018 in a matched cohort. The strength of the association between donation type and 1-year eGFR differed by recipient age (P interaction < 0.0001). For LD recipients aged 40-54 years versus same-aged DBD recipients, the adjusted odds ratio (aOR) for eGFR ≥60 mL/min/1.73 m2 was 1.48 (95% CI: 1.16-1.90). For DBD recipients aged ≥ 60 years, the aOR was 0.18 (95% CI: 0.12-0.29) versus DBD recipients aged 40-54 years but was 0.91 (95% CI: 0.67-1.24) versus LD recipients aged ≥60 years. In the matched cohort, 4-year graft and patient survival differed by donor age and type. As compared with DBD grafts, LD grafts increased the proportion of recipients with 1-year eGFR ≥60 mL/min/1.73 m2. Recipients aged ≥60 years benefited most from LD transplantation, even if the donor was aged ≥60 years. For younger recipients, large age differences between donor and recipient could also be addressed with a paired exchange program.

The perpetual need of randomized clinical trials: challenges and uncertainties in emulating the REDUCE-AMI trial.

Trial emulations in observational data analyses can complement findings from randomized clinical trials, inform future trial designs, or generate evidence when randomized studies are not feasible due to resource constraints and ethical or practical limitations. Importantly, trial emulation designs facilitate causal inference in observational data analyses by enhancing counterfactual thinking and comparisons of real-world observations (e.g. Mendelian Randomization) to hypothetical interventions. In order to enhance credibility, trial emulations would benefit from prospective registration, publication of statistical analysis plans, and subsequent prospective benchmarking to randomized clinical trials prior to their publication. Confounding by indication, however, is the key challenge to interpreting observed intended effects of an intervention as causal in observational data analyses. We discuss the target trial emulation of the REDUCE-AMI randomized clinical trial (ClinicalTrials.gov ID NCT03278509; beta-blocker use in patients with preserved left ventricular ejection fraction after myocardial infarction) to illustrate the challenges and uncertainties of studying intended effects of interventions without randomization to account for confounding. We furthermore directly compare the findings, statistical power, and clinical interpretation of the results of the REDUCE-AMI target trial emulation to those from the simultaneously published randomized clinical trial. The complexity and subtlety of confounding by indication when studying intended effects of interventions can generally only be addressed by randomization.