Estimates of Overall Survival in Patients With Cancer Receiving Different Treatment Regimens: Emulating Hypothetical Target Trials in the Surveillance, Epidemiology, and End Results (SEER)-Medicare Linked Database

Comparative effectiveness of treatment approaches for early invasive breast cancer

BACKGROUND

Randomized controlled trials (RCTs) suggested breast conserving therapy (BCT) and mastectomy have similar survival for early-stage breast cancer, whereas observational studies reported survival advantage for BCT. We aimed to address biases in observational studies to compare the effect of BCT and mastectomy on survival.

METHODS

We emulated a target trial using institutional cancer registry. We included adult women diagnosed with early invasive first primary breast tumors ≤ 5 cm between July 2011 and December 2017. We used cloning, censoring, and weighting to estimate risk differences (RDs) and risk ratios (RRs) for all-cause mortality and recurrence or all-cause mortality between BCT and mastectomy (reference).

RESULTS

Our study population comprised 534 observations with breast cancer. Median age was 56 years and 65 % were racial/ethnic minorities. The 8-year RD was 1.5 % (95 % confidence limits [CL]: -7.0 %, 9.8 %) and RR was 1.1 (95 % CL: 0.57, 2.2) for all-cause mortality. Results for recurrence or mortality were similar.

CONCLUSIONS

Our results suggest that target trial emulation to mitigate selection and immortal-time biases in observational studies may generate estimates that are more compatible with RCTs when comparing the effects of BCT and mastectomy on survival. Studies with longer follow-up and more events are needed to confirm our findings.

Effect of Paxlovid Treatment During Acute COVID-19 on Long COVID Onset: An EHR-Based Target Trial Emulation from the N3C and RECOVER Consortia

Preventing and treating post-acute sequelae of SARS-CoV-2 infection (PASC), commonly known as Long COVID, has become a public health priority. In this study, we examined whether treatment with Paxlovid in the acute phase of COVID-19 helps prevent the onset of PASC. We used electronic health records from the National Covid Cohort Collaborative (N3C) to define a cohort of 426,352 patients who had COVID-19 since April 1, 2022, and were eligible for Paxlovid treatment due to risk for progression to severe COVID-19. We used the target trial emulation (TTE) framework to estimate the effect of Paxlovid treatment on PASC incidence. We estimated overall PASC incidence using a computable phenotype. We also measured the onset of novel cognitive, fatigue, and respiratory symptoms in the post-acute period. Paxlovid treatment did not have a significant effect on overall PASC incidence (relative risk [RR] = 0.98, 95% confidence interval [CI] 0.95-1.01). However, it had a protective effect on cognitive (RR = 0.90, 95% CI 0.84-0.96) and fatigue (RR = 0.95, 95% CI 0.91-0.98) symptom clusters, which suggests that the etiology of these symptoms may be more closely related to viral load than that of respiratory symptoms.

Effectiveness of post-COVID-19 primary care attendance in improving survival in very old patients with multimorbidity: a territory-wide target trial emulation

OBJECTIVES

Older individuals with multimorbidity are at an elevated risk of infection and complications from COVID-19. Effectiveness of post-COVID-19 interventions or care models in reducing subsequent adverse outcomes in these individuals have rarely been examined. This study aims to examine the effectiveness of attending general outpatient within 30 days after discharge from COVID-19 on 1-year survival among older adults aged 85 years or above with multimorbidity.

DESIGN

Retrospective cohort study emulating a randomised target trial using electronic health records.

SETTING

We used data from the Hospital Authority and the Department of Health in Hong Kong, which provided comprehensive electronic health records, COVID-19 confirmed case data, population-based vaccination records and other individual characteristics for the study.

PARTICIPANTS

Adults aged 85 years or above with multimorbidity who were discharged after hospitalisation for COVID-19 between January 2020 and August 2022.

INTERVENTIONS

Attending a general outpatient within 30 days of last COVID-19 discharge defined the exposure, compared to no outpatient visit.

MAIN OUTCOME MEASURES

Primary outcome was all-cause mortality within one year. Secondary outcomes included mortality from respiratory, cardiovascular and cancer causes.

RESULTS

A total of 6183 eligible COVID-19 survivors were included in the analysis. The all-cause mortality rate following COVID-19 hospitalisation was lower in the general outpatient visit group (17.1 deaths per 100 person-year) compared with non-visit group (42.8 deaths per 100 person-year). After adjustment, primary care consultations within 30 days after discharge were associated with a significantly greater 1-year survival (difference in 1-year survival: 11.2%, 95% CI 8.1% to 14.4%). We also observed significantly better survival from respiratory diseases in the general outpatient visit group (difference in 1-year survival: 6.3%, 95% CI 3.5% to 8.9%). In a sensitivity analysis for different grace period lengths, we found that the earlier participants had a general outpatient visit after COVID-19 discharge, the better the survival.

CONCLUSIONS

Timely primary care consultations after COVID-19 hospitalisation may improve survival following COVID-19 hospitalisation among older adults aged 85 or above with multimorbidity. Expanding primary care services and implementing follow-up mechanisms are crucial to support this vulnerable population's recovery and well-being.

Timing of follow-up visits after hospital discharge for COPD: Application of a new method

RATIONALE

A common strategy to reduce COPD readmissions is to encourage patient follow-up with a physician within 1 to 2 weeks of discharge, yet evidence confirming its benefit is lacking. We used a new study design called target randomized trial emulation to determine the impact of follow-up visit timing on patient outcomes.

METHODS

All Ontario residents aged 35 or older discharged from a COPD hospitalization were identified using health administrative data and randomly assigned to those who received and did not receive physician visit follow-up by within seven days. They were followed to all-cause emergency department visits, readmissions or death. Targeted randomized trial emulation was used to adjust for differences between the groups. COPD emergency department visits, readmissions or death was also considered.

RESULTS

There were 94,034 patients hospitalized with COPD, of whom 73.5% had a physician visit within 30 days of discharge. Adjusted hazard ratio for all-cause readmission, emergency department visits or death for people with a visit within seven days post discharge was 1.03 (95% Confidence Interval [CI]: 1.01-1.05) and remained around 1 for subsequent days; adjusted hazard ratio for the composite COPD events was 0.97 (95% CI 0.95-1.00) and remained significantly lower than 1 for subsequent days.

CONCLUSION

While a physician visit after discharge was found to reduce COPD events, a specific time period when a physician visit was most beneficial was not found. This suggests that follow-up visits should not occur at a predetermined time but be based on factors such as anticipated medical need.

Abbreviated Versus Standard Dual Antiplatelet Therapy Times After Percutaneous Coronary Intervention in Patients With High Bleeding Risk With Acute Coronary Syndrome: Insights From the SWEDEHEART Registry

BACKGROUND

Dual antiplatelet therapy (DAPT) reduces ischemic events but increases bleeding risk, especially in patients with high bleeding risk (HBR). This study aimed to compare outcomes of abbreviated versus standard DAPT strategies in patients with HBR with acute coronary syndrome undergoing percutaneous coronary intervention.

METHODS AND RESULTS

Patients from the SWEDEHEART (Swedish Web-system for Enhancement and Development of Evidence-Based Bare in Heart Disease Evaluated According to Recommended Therapies) registry with at least 1 HBR criterion who underwent percutaneous coronary intervention for acute coronary syndrome were identified and included. Patients were divided into 2 groups based on their planned DAPT time at discharge: 12-month DAPT or an abbreviated DAPT strategy and matched according to their prescribed P2Y12 inhibitor at discharge. The primary outcome assessed was time to net adverse clinical events at 1 year, which encompassed cardiac death, myocardial infarction, ischemic stroke, or clinically significant bleeding. Time to major adverse cardiovascular events and the individual components of net adverse clinical events were considered secondary end points. A total of 4583 patients were included in each group. The most frequently met HBR criteria was age older than 75 years (65.6%) and Predicting Bleeding Complications in Patients Undergoing Stent Implantation and Subsequent Dual Antiplatelet Therapy score ≥25 (44.6%) in the standard DAPT group and oral anticoagulant therapy (79.6%) and age 75 years and older (55.2%) in the abbreviated DAPT group. There was no statistically significant difference in net adverse clinical events (12.9% versus 13.1%; hazard ratio [HR], 0.99 [95% CI, 0.88-1.11], P=0.83), major adverse cardiovascular events (8.6% versus 7.9%; HR, 1.08 [95% CI, 0.94-1.25]), or their components between groups. The results were consistent among all of the investigated subgroups.

CONCLUSIONS

In patients with HBR undergoing percutaneous coronary intervention due to acute coronary syndrome, abbreviated DAPT was associated with comparable rates of net adverse clinical events and major adverse cardiovascular events to a DAPT duration of 12 months.

Designing target trials using electronic health records: A case study of second-line disease-modifying anti-rheumatic drugs and cardiovascular disease outcomes in patients with rheumatoid arthritis

BACKGROUND

Emulation of the "target trial" (TT), a hypothetical pragmatic randomized controlled trial (RCT), using observational data can be used to mitigate issues commonly encountered in comparative effectiveness research (CER) when randomized trials are not logistically, ethically, or financially feasible. However, cardiovascular (CV) health research has been slow to adopt TT emulation. Here, we demonstrate the design and analysis of a TT emulation using electronic health records to study the comparative effectiveness of the addition of a disease-modifying anti-rheumatic drug (DMARD) to a regimen of methotrexate on CV events among rheumatoid arthritis (RA) patients.

METHODS

We used data from an electronic medical records-based cohort of RA patients from Northwestern Medicine to emulate the TT. Follow-up began 3 months after initial prescription of MTX (2000-2020) and included all available follow-up through June 30, 2020. Weighted pooled logistic regression was used to estimate differences in CVD risk and survival. Cloning was used to handle immortal time bias and weights to improve baseline and time-varying covariate imbalance.

RESULTS

We identified 659 eligible people with RA with average follow-up of 46 months and 31 MACE events. The month 24 adjusted risk difference for MACE comparing initiation vs non-initiation of a DMARD was -1.47% (95% confidence interval [CI]: -4.74, 1.95%), and the marginal hazard ratio (HR) was 0.72 (95% CI: 0.71, 1.23). In analyses subject to immortal time bias, the HR was 0.62 (95% CI: 0.29-1.44).

CONCLUSION

In this sample, we did not observe evidence of differences in risk of MACE, a finding that is compatible with previously published meta-analyses of RCTs. Thoughtful application of the TT framework provides opportunities to conduct CER in observational data. Benchmarking results of observational analyses to previously published RCTs can lend credibility to interpretation.

Emulating trial to evaluate the effectiveness of routine supportive care on mortality among cancer patients experiencing distress at the time of diagnosis

INTRODUCTION

Few studies have evaluated the effectiveness of interventions for distress during cancer diagnosis on clinical outcomes in a real-world setting. We aimed to evaluate whether routine information and psychosocial support to patients experiencing distress at the time of diagnosis could decrease the risk of mortality within 1 and 3 years after diagnosis.

MATERIAL AND METHODS

We conducted a retrospective cohort study of 4880 newly diagnosed cancer patients who reported distress scores of ≥4 using the tablet or kiosk-based screening between July 2014 and December 2017 at a university-affiliated cancer center in Seoul, South Korea. We performed an emulated target trial with two groups: those that received information and psychosocial support and those that did not. Cox proportional hazards models were used to identify the associations between information and psychosocial support and all-cause mortality.

RESULTS

Of all the patients, 16.6 % had routine information and psychosocial support. The hazard ratio (HR) for one-year mortality comparing participants with information and psychosocial support to those without it were 0.73 (95 % confidence interval (CI) = 0.54, 0.99). Age < 50 and 50 - <60 group had a stronger effect of information and psychosocial support on reducing mortality within one-year than these in age ≥ 60 (p for interaction = 0.03). In terms of three-year mortality, the HR comparing participants with information and psychosocial support to those without it was 0.93 (95 % CI = 0.76, 1.14).

CONCLUSION

This large-scale real-world study suggests that timely psychosocial care benefits newly diagnosed cancer patients who had distress during pre-treatment period.

Partial Hepatectomy and Ablation for Survival of Early-Stage Hepatocellular Carcinoma Patients: A Bayesian Emulation Analysis

Partial hepatectomy and ablation therapy are two widely used surgical procedures for localized early-stage hepatocellular carcinoma (HCC) patients. This article aimed to evaluate their relative effectiveness in terms of overall survival. An emulation analysis approach was first developed based on the Bayesian technique. We estimated propensity scores via Bayesian logistic regression and adopted a weighted Bayesian Weibull accelerated failure time (AFT) model incorporating prior information contained in the published literature. With the Surveillance, Epidemiology, and End Results (SEER)-Medicare data, an emulated target trial with rigorously defined inclusion/exclusion criteria and treatment regimens for early-stage HCC patients over 66 years old was developed. For the main cohort with tumor size less than or equal to 5 cm, a total of 1146 patients were enrolled in the emulated trial, with 301 and 845 in the partial hepatectomy and ablation arms, respectively. The analysis suggested ablation to be significantly associated with inferior overall survival (hazard ratio [HR] = 1.35; 95% credible interval [CrI]: 1.14, 1.60). For the subgroup with tumor size less than or equal to 3 cm, there was no significant difference in overall survival between the two arms (HR = 1.15; 95% CrI: 0.88, 1.52). Overall, the comparative treatment effect of ablation and partial hepatectomy on survival remains inconclusive. This finding may provide further insight into HCC clinical treatment.

Learning interpretable causal networks from very large datasets, application to 400,000 medical records of breast cancer patients

Discovering causal effects is at the core of scientific investigation but remains challenging when only observational data are available. In practice, causal networks are difficult to learn and interpret, and limited to relatively small datasets. We report a more reliable and scalable causal discovery method (iMIIC), based on a general mutual information supremum principle, which greatly improves the precision of inferred causal relations while distinguishing genuine causes from putative and latent causal effects. We showcase iMIIC on synthetic and real-world healthcare data from 396,179 breast cancer patients from the US Surveillance, Epidemiology, and End Results program. More than 90% of predicted causal effects appear correct, while the remaining unexpected direct and indirect causal effects can be interpreted in terms of diagnostic procedures, therapeutic timing, patient preference or socio-economic disparity. iMIIC's unique capabilities open up new avenues to discover reliable and interpretable causal networks across a range of research fields.

Optimal age to discontinue long-term surveillance of intraductal papillary mucinous neoplasms: comparative cost-effectiveness of surveillance by age

OBJECTIVE

Current guidelines recommend long-term image-based surveillance for patients with low-risk intraductal papillary mucinous neoplasms (IPMNs). This simulation study aimed to examine the comparative cost-effectiveness of continued versus discontinued surveillance at different ages and define the optimal age to stop surveillance.

DESIGN

We constructed a Markov model with a lifetime horizon to simulate the clinical course of patients with IPMNs receiving imaging-based surveillance. We calculated incremental cost-effectiveness ratios (ICERs) for continued versus discontinued surveillance at different ages to stop surveillance, stratified by sex and IPMN types (branch-duct vs mixed-type). We determined the optimal age to stop surveillance as the lowest age at which the ICER exceeded the willingness-to-pay threshold of US$100 000 per quality-adjusted life year. To estimate model parameters, we used a clinical cohort of 3000 patients with IPMNs and a national database including 40 166 patients with pancreatic cancer receiving pancreatectomy as well as published data.

RESULTS

In male patients, the optimal age to stop surveillance was 76-78 years irrespective of the IPMN types, compared with 70, 73, 81, and 84 years for female patients with branch-duct IPMNs <20 mm, =20-29 mm, ≥30 mm and mixed-type IPMNs, respectively. The suggested ages became younger according to an increasing level of comorbidities. In cases with high comorbidity burden, the ICERs were above the willingness-to-pay threshold irrespective of sex and the size of branch-duct IPMNs.

CONCLUSIONS

The cost-effectiveness of long-term IPMN surveillance depended on sex, IPMN types, and comorbidity levels, suggesting the potential to personalise patient management from the health economic perspective.

Causal machine learning for predicting treatment outcomes

Causal machine learning (ML) offers flexible, data-driven methods for predicting treatment outcomes including efficacy and toxicity, thereby supporting the assessment and safety of drugs. A key benefit of causal ML is that it allows for estimating individualized treatment effects, so that clinical decision-making can be personalized to individual patient profiles. Causal ML can be used in combination with both clinical trial data and real-world data, such as clinical registries and electronic health records, but caution is needed to avoid biased or incorrect predictions. In this Perspective, we discuss the benefits of causal ML (relative to traditional statistical or ML approaches) and outline the key components and steps. Finally, we provide recommendations for the reliable use of causal ML and effective translation into the clinic.

Early Mortality After the First Dose of COVID-19 Vaccination: A Target Trial Emulation

BACKGROUND

Vaccine hesitancy persists alongside concerns about the safety of coronavirus disease 2019 (COVID-19) vaccines. We aimed to examine the effect of COVID-19 vaccination on risk of death among US veterans.

METHODS

We conducted a target trial emulation to estimate and compare risk of death up to 60 days under two COVID-19 vaccination strategies: vaccination within 7 days of enrollment versus no vaccination through follow-up. The study cohort included individuals aged ≥18 years enrolled in the Veterans Health Administration system and eligible to receive a COVID-19 vaccination according to guideline recommendations from 1 March 2021 through 1 July 2021. The outcomes of interest included deaths from any cause and excluding a COVID-19 diagnosis. Observations were cloned to both treatment strategies, censored, and weighted to estimate per-protocol effects.

RESULTS

We included 3 158 507 veterans. Under the vaccination strategy, 364 993 received vaccine within 7 days. At 60 days, there were 156 deaths per 100 000 veterans under the vaccination strategy versus 185 deaths under the no vaccination strategy, corresponding to an absolute risk difference of -25.9 (95% confidence limit [CL], -59.5 to 2.7) and relative risk of 0.86 (95% CL, .7 to 1.0). When those with a COVID-19 infection in the first 60 days were censored, the absolute risk difference was -20.6 (95% CL, -53.4 to 16.0) with a relative risk of 0.88 (95% CL, .7 to 1.1).

CONCLUSIONS

Vaccination against COVID-19 was associated with a lower but not statistically significantly different risk of death in the first 60 days. These results agree with prior scientific knowledge suggesting vaccination is safe with the potential for substantial health benefits.

Adjuvant Ovarian Function Suppression in Premenopausal Hormone Receptor-Positive Breast Cancer

Importance

Few oncology studies have assessed the effectiveness of adjuvant ovarian function suppression (OFS) in observational settings for premenopausal hormone receptor-positive breast cancer. Target trial emulation is increasingly used for estimating treatment outcomes in observational cohorts.

Objectives

To describe hormone therapy and OFS treatment patterns (aim 1), examine the association between adding OFS to tamoxifen (TAM) or aromatase inhibitor (AI) and survival (aim 2), and examine the association between duration of hormone treatment (TAM or AI) plus OFS (H-OFS) and survival (aim 3).

Design, Setting, and Participants

This population-based cohort study included all premenopausal, early-stage breast cancer diagnoses between 2010 and 2020 in Alberta, Canada. Target trial emulation was conducted. Eligibility criteria were directly modeled after the Suppression of Ovarian Function Trial (SOFT) and Tamoxifen and Exemestane Trial (TEXT). Participants were followed up for a maximum of 5 years. Data were analyzed from July 2022 through March 2023.

Exposures

For aim 2, exposures were receiving the following baseline treatments for 2 years: AI + OFS (AI-OFS), TAM + OFS (T-OFS), and TAM alone. For aim 3, exposures were a 2-year or greater and a less than 2-year duration of H-OFS.

Main Outcomes and Measures

Recurrence-free survival was the primary outcome of interest. Marginal structural Cox models with inverse probability treatment and censoring weights were used to estimate hazard ratios (HRs), adjusted for baseline and time-varying confounding variables.

Results

Among 3434 female patients with premenopausal, early-stage breast cancer diagnoses (median [IQR] age, 45 [40-48] years), 2647 individuals satisfied SOFT and TEXT eligibility criteria. There were 2260 patients who initiated TAM, 232 patients who initiated T-OFS, and 155 patients who initiated AI-OFS; 192 patients received H-OFS for 2 or more years, and 195 patients received H-OFS for less than 2 years. The 5-year recurrence risks were not significantly lower in AI-OFS vs TAM (HR, 0.76; 95% CI, 0.38-1.33) or T-OFS vs TAM (HR, 0.87; 95% CI, 0.50-1.45) groups. Patients receiving H-OFS for 2 or more years had significantly better 5-year recurrence-free survival compared with those receiving H-OFS for less than 2 years (HR, 0.69; 95% CI, 0.54-0.90).

Conclusions and Relevance

This study found no significant reductions in recurrence risk for AI-OFS and T-OFS compared with TAM alone. H-OFS duration for at least 2 years was associated with significantly improved recurrence-free survival.

Effectiveness of Biologic Agents Among Hispanic Patients With Metastatic Colorectal Cancer

BACKGROUND

Randomized clinical trials have defined the survival advantage with the addition of biologic drugs to chemotherapy in patients with metastatic colorectal cancer (mCRC). Under representation of Hispanics contributes to poorly defined outcomes in this group. We aim to determine whether the real-world benefit of biologics extends to Hispanics using a comparative effectiveness research approach.

METHODS

This retrospective cohort study included all treatment centers contributing to SEER registry with available claims in the SEER-Medicare linked database (2001-2011) and 2 hospitals (2004-2016) catering to minorities. Metastatic CRC patients were classified as receiving chemotherapy or biochemotherapy (CT plus biologics; if initiated within 3 months of chemotherapy). The primary outcome was overall survival (OS) among the Hispanic patients calculated from time of administration of first dose of chemotherapy to death or last follow-up. A weighted Cox regression model was used to assess differences in survival.

RESULTS

We identified 182 Hispanic patients with mCRC from the Patient Entitlement and Diagnosis Summary (PEDSF) file (n = 101) and hospital database (n = 81). Overall, 52% were women and 72% received biologics. The median OS was 11.3 and 17.0 months in chemotherapy and biochemotherapy group, respectively. Biochemotherapy offered a survival benefit compared with chemotherapy alone, with an average hazard rate reduction of 39% (95% CI 6%-60%, p = .0236) using inverse probability of treatment weighting (IPTW) based analysis.

CONCLUSION

In this cohort of Hispanic patients with mCRC, biochemotherapy was associated with longer survival. Clinicians may offer biochemotherapy therapy to all patients regardless of race/ethnicity to maximize clinical benefit.

Comparative Effectiveness of Alternative Treatment Approaches to Secondary Hyperparathyroidism in Patients Receiving Maintenance Hemodialysis: An Observational Trial Emulation

RATIONALE & OBJECTIVE

Optimal approaches to treat secondary hyperparathyroidism (SHPT) in patients on maintenance hemodialysis (HD) have yet to be established in randomized controlled trials (RCTs).

STUDY DESIGN

Two observational clinical trial emulations.

SETTING & PARTICIPANTS

Both emulations included adults receiving in-center HD from a national dialysis organization. The patients who had SHPT in the period between 2009 and 2014, were insured for≥180 days by Medicare as primary payer, and did not have contraindications or poor health status limiting theoretical trial participation.

EXPOSURE

The parathyroid hormone (PTH) Target Trial emulation included patients with new-onset SHPT (first PTH 300-600pg/mL), with 2 arms defined as up-titration of either vitamin D sterols or cinacalcet within 30 days (lower target) or no up-titration (higher target). The Agent Trial emulation included patients with a PTH≥300 pg/mL while on≥6μg weekly of vitamin D sterol (paricalcitol equivalent dose) and no prior history of cinacalcet. The 2 arms were defined by the first dose or agent change within 30 days (vitamin D-favoring [vitamin-D was up-titrated] vs cinacalcet-favoring [cinacalcet was added] vs nondefined [neither applies]). Multiple trials per patient were allowed in trial 2.

OUTCOME

The primary outcome was all-cause death over 24 months; secondary outcomes included cardiovascular (CV) hospitalization or the composite of CV hospitalization or death.

ANALYTICAL APPROACH

Pooled logistic regression.

RESULTS

There were 1,152 patients in the PTH Target Trial (635 lower target and 517 higher target). There were 2,726 unique patients with 6,727 patient trials in the Agent Trial (6,268 vitamin D-favoring trials and 459 cinacalcet-favoring trials). The lower PTH target approach was associated with reduced adjusted hazard of death (HR, 0.71 [95% CI, 0.52-0.93]), CV hospitalization (HR, 0.78 [95% CI, 0.63-0.98]), and their composite (HR, 0.74 [95% CI, 0.61-0.89]). The cinacalcet-favoring approach demonstrated lower adjusted hazard of death compared to the vitamin D-favoring approach (HR, 0.79 [95% CI, 0.62-0.99]), but not of CV hospitalization or the composite outcome.

LIMITATIONS

Potential for residual confounding; low use of cinacalcet with low power.

CONCLUSIONS

SHPT management that is focused on lower PTH targets may lower mortality and CV disease in patients receiving HD. These findings should be confirmed in a pragmatic randomized trial.

PLAIN-LANGUAGE SUMMARY

Optimal approaches to treat secondary hyperparathyroidism (SHPT) have not been established in randomized controlled trials. Data from a national dialysis organization was used to identify patients with SHPT in whom escalated treatment may be indicated. The approach to treatment was defined based on observed upward titration of SHPT-controlling medications: earlier titration (lower target) versus delayed titration (higher target); and the choice of medication (cinacalcet vs vitamin D sterols). In the first trial emulation, we estimated a 29% lower rate of death and 26% lower rate of cardiovascular disease or death for patients managed with a lower versus higher target approach. Cinacalcet versus vitamin D-favoring approaches were not consistently associated with outcomes in the second trial emulation. This observational study suggests the need for additional clinical trials of SHPT treatment intensity.

Socioeconomic disparities in treatment and survival in patients with hypopharyngeal malignancy

BACKGROUND

This retrospective study utilizes The Surveillance, Epidemiology, and End Results database to investigate socioeconomic factors leading to treatment disparities in hypopharyngeal malignancy.

METHODS

Treatment was compared to National Cancer Care Network guidelines. Novel analyses, including logistic modeling, allowed survival analysis and identification of socioeconomic variables not previously considered in staging and management guidelines.

RESULTS

Black and older patients, and residence in low-income areas predict lower likelihood of standard therapy (p < 0.05). Early-stage disease and standard therapy correlate with improved survival (p < 0.001). Medicaid, advanced age, advanced disease, and treatment outside of consensus guidelines correlated with lower survival (p < 0.0001).

CONCLUSIONS

There are clear socioeconomic factors impacting treatment and survival in hypopharyngeal malignancies. Standard therapy affords superior survival rate. Black, low socioeconomic status, and older patients are less likely to receive standard therapy. Education and language isolation do not predict treatment or survival. Understanding these discrepancies is paramount to palliating disparities in healthcare.

Reporting of Observational Studies Explicitly Aiming to Emulate Randomized Trials: A Systematic Review

Importance

Observational (nonexperimental) studies that aim to emulate a randomized trial (ie, the target trial) are increasingly informing medical and policy decision-making, but it is unclear how these studies are reported in the literature. Consistent reporting is essential for quality appraisal, evidence synthesis, and translation of evidence to policy and practice.

Objective

To assess the reporting of observational studies that explicitly aimed to emulate a target trial.

Evidence Review

We searched Medline, Embase, PsycINFO, and Web of Science for observational studies published between March 2012 and October 2022 that explicitly aimed to emulate a target trial of a health or medical intervention. Two reviewers double-screened and -extracted data on study characteristics, key predefined components of the target trial protocol and its emulation (eligibility criteria, treatment strategies, treatment assignment, outcome[s], follow-up, causal contrast[s], and analysis plan), and other items related to the target trial emulation.

Findings

A total of 200 studies that explicitly aimed to emulate a target trial were included. These studies included 26 subfields of medicine, and 168 (84%) were published from January 2020 to October 2022. The aim to emulate a target trial was explicit in 70 study titles (35%). Forty-three studies (22%) reported use of a published reporting guideline (eg, Strengthening the Reporting of Observational Studies in Epidemiology). Eighty-five studies (43%) did not describe all key items of how the target trial was emulated and 113 (57%) did not describe the protocol of the target trial and its emulation.

Conclusion and Relevance

In this systematic review of 200 studies that explicitly aimed to emulate a target trial, reporting of how the target trial was emulated was inconsistent. A reporting guideline for studies explicitly aiming to emulate a target trial may improve the reporting of the target trial protocols and other aspects of these emulation attempts.

Target trial emulation with multi-state model analysis to assess treatment effectiveness using clinical COVID-19 data

BACKGROUND

Real-world observational data are an important source of evidence on the treatment effectiveness for patients hospitalized with coronavirus disease 2019 (COVID-19). However, observational studies evaluating treatment effectiveness based on longitudinal data are often prone to methodological biases such as immortal time bias, confounding bias, and competing risks.

METHODS

For exemplary target trial emulation, we used a cohort of patients hospitalized with COVID-19 (n = 501) in a single centre. We described the methodology for evaluating the effectiveness of a single-dose treatment, emulated a trial using real-world data, and drafted a hypothetical study protocol describing the main components. To avoid immortal time and time-fixed confounding biases, we applied the clone-censor-weight technique. We set a 5-day grace period as a period of time when treatment could be initiated. We used the inverse probability of censoring weights to account for the selection bias introduced by artificial censoring. To estimate the treatment effects, we took the multi-state model approach. We considered a multi-state model with five states. The primary endpoint was defined as clinical severity status, assessed by a 5-point ordinal scale on day 30. Differences between the treatment group and standard of care treatment group were calculated using a proportional odds model and shown as odds ratios. Additionally, the weighted cause-specific hazards and transition probabilities for each treatment arm were presented.

RESULTS

Our study demonstrates that trial emulation with a multi-state model analysis is a suitable approach to address observational data limitations, evaluate treatment effects on clinically heterogeneous in-hospital death and discharge alive endpoints, and consider the intermediate state of admission to ICU. The multi-state model analysis allows us to summarize results using stacked probability plots that make it easier to interpret results.

CONCLUSIONS

Extending the emulated target trial approach to multi-state model analysis complements treatment effectiveness analysis by gaining information on competing events. Combining two methodologies offers an option to address immortal time bias, confounding bias, and competing risk events. This methodological approach can provide additional insight for decision-making, particularly when data from randomized controlled trials (RCTs) are unavailable.

Comparative Effectiveness Analysis of Lumpectomy and Mastectomy for Elderly Female Breast Cancer Patients: A Deep Learning-based Big Data Analysis

Objectives: To evaluate the comparative effectiveness of treatments, a randomized clinical trial remains the gold standard but can be challenged by a high cost, a limited sample size, an inability to fully reflect the real world, and feasibility concerns. The objective is to showcase a big data approach that takes advantage of large electronic medical record (EMR) data to emulate clinical trials. To overcome the limitations of regression analysis, a deep learning-based analysis pipeline was developed. Study Design and Setting: Lumpectomy (breast-conserving surgery) and mastectomy are the two most commonly used surgical procedures for early-stage female breast cancer patients. An emulation trial was designed using the Surveillance, Epidemiology, and End Results (SEER)-Medicare data to evaluate their relative effectiveness in overall survival. The analysis pipeline consisted of a propensity score step, a weighted survival analysis step, and a bootstrap inference step. Results: A total of 65,997 subjects were enrolled in the emulated trial, with 50,704 and 15,293 in the lumpectomy and mastectomy arms, respectively. The two surgery procedures had comparable effects in terms of overall survival (survival year change = 0.08, 95% confidence interval (CI): -0.08, 0.25) for the elderly SEER-Medicare early-stage female breast cancer patients. Conclusion: This study demonstrated the power of "mining large EMR data + deep learning-based analysis," and the proposed analysis strategy and technique can be potentially broadly applicable. It provided convincing evidence of the comparative effectiveness of lumpectomy and mastectomy.

Implementation of the trial emulation approach in medical research: a scoping review

BACKGROUND

When conducting randomised controlled trials is impractical, an alternative is to carry out an observational study. However, making valid causal inferences from observational data is challenging because of the risk of several statistical biases. In 2016 Hernán and Robins put forward the 'target trial framework' as a guide to best design and analyse observational studies whilst preventing the most common biases. This framework consists of (1) clearly defining a causal question about an intervention, (2) specifying the protocol of the hypothetical trial, and (3) explaining how the observational data will be used to emulate it.

METHODS

The aim of this scoping review was to identify and review all explicit attempts of trial emulation studies across all medical fields. Embase, Medline and Web of Science were searched for trial emulation studies published in English from database inception to February 25, 2021. The following information was extracted from studies that were deemed eligible for review: the subject area, the type of observational data that they leveraged, and the statistical methods they used to address the following biases: (A) confounding bias, (B) immortal time bias, and (C) selection bias.

RESULTS

The search resulted in 617 studies, 38 of which we deemed eligible for review. Of those 38 studies, most focused on cardiology, infectious diseases or oncology and the majority used electronic health records/electronic medical records data and cohort studies data. Different statistical methods were used to address confounding at baseline and selection bias, predominantly conditioning on the confounders (N = 18/49, 37%) and inverse probability of censoring weighting (N = 7/20, 35%) respectively. Different approaches were used to address immortal time bias, assigning individuals to treatment strategies at start of follow-up based on their data available at that specific time (N = 21, 55%), using the sequential trial emulations approach (N = 11, 29%) or the cloning approach (N = 6, 16%).

CONCLUSION

Different methods can be leveraged to address (A) confounding bias, (B) immortal time bias, and (C) selection bias. When working with observational data, and if possible, the 'target trial' framework should be used as it provides a structured conceptual approach to observational research.

Target trial emulation to assess real-world efficacy in the Epidemiological Strategy and Medical Economics metastatic breast cancer cohort

BACKGROUND

Real-world data studies usually consider biases related to measured confounders. We emulate a target trial implementing study design principles of randomized trials to observational studies; controlling biases related to selection, especially immortal time; and measured confounders.

METHODS

This comprehensive analysis emulating a randomized clinical trial compared overall survival in patients with HER2-negative metastatic breast cancer (MBC), receiving as first-line treatment, either paclitaxel alone or combined to bevacizumab. We used data from 5538 patients extracted from the Epidemiological Strategy and Medical Economics-MBC cohort to emulate a target trial using advanced statistical adjustment techniques including stabilized inverse-probability weighting and G-computation, dealing with missing data with multiple imputation, and performing a quantitative bias analysis for residual bias due to unmeasured confounders.

RESULTS

Emulation led to 3211 eligible patients, and overall survival estimates achieved with advanced statistical methods favored the combination therapy. Real-world effect sizes were close to that assessed in the existing E2100 randomized clinical trial (hazard ratio = 0.88, P = .16), but the increased sample size allowed to achieve a higher level of precision in real-world estimates (ie, reduced confidence intervals). Quantitative bias analysis confirmed the robustness of the results with respect to potential unmeasured confounding.

CONCLUSION

Target trial emulation with advanced statistical adjustment techniques is a promising approach to investigate long-term impact of innovative therapies in the French Epidemiological Strategy and Medical Economics-MBC cohort while minimizing biases and provides opportunities for comparative efficacy through the synthetic control arms provided.

DATABASE REGISTRATION

clinicaltrials.gov Identifier NCT03275311.

Emulating Target Trials With Real-World Data to Inform Health Technology Assessment: Findings and Lessons From an Application to Emergency Surgery

OBJECTIVES

International health technology assessment (HTA) agencies recommend that real-world data (RWD) are used in some circumstances to add to the evidence base about the effectiveness and cost-effectiveness of health interventions. The target trial framework applies the design principles of randomized-controlled trials to RWD and can help alleviate inevitable concerns about bias and design flaws with nonrandomized studies. This article aimed to tackle the lack of guidance and exemplar applications on how this methodology can be applied to RWD to inform HTA decision making.

METHODS

We use Hospital Episode Statistics data from England on emergency hospital admissions from 2010 to 2019 to evaluate the cost-effectiveness of emergency surgery for 2 acute gastrointestinal conditions. We draw on the case study to describe the main challenges in applying the target trial framework alongside RWD and provide recommendations for how these can be addressed in practice.

RESULTS

The 4 main challenges when applying the target trial framework to RWD are (1) defining the study population, (2) defining the treatment strategies, (3) establishing time zero (baseline), and (4) adjusting for unmeasured confounding. The recommendations for how to address these challenges, mainly around the incorporation of expert judgment and use of appropriate methods for handling unmeasured confounding, are illustrated within the case study.

CONCLUSIONS

The recommendations outlined in this study could help future studies seeking to inform HTA decision processes. These recommendations can complement checklists for economic evaluations and design tools for estimating treatment effectiveness in nonrandomized studies.

Target Trial Emulation to Improve Causal Inference from Observational Data: What, Why, and How?

ABSTRACT

Target trial emulation has drastically improved the quality of observational studies investigating the effects of interventions. Its ability to prevent avoidable biases that have plagued many observational analyses has contributed to its recent popularity. This review explains what target trial emulation is, why it should be the standard approach for causal observational studies that investigate interventions, and how to do a target trial emulation analysis. We discuss the merits of target trial emulation compared with often used, but biased analyses, as well as potential caveats, and provide clinicians and researchers with the tools to better interpret results from observational studies investigating the effects of interventions.

Effect of Nirmatrelvir/Ritonavir (Paxlovid) on Hospitalization among Adults with COVID-19: an EHR-based Target Trial Emulation from N3C

This study leverages electronic health record data in the National COVID Cohort Collaborative's (N3C) repository to investigate disparities in Paxlovid treatment and to emulate a target trial assessing its effectiveness in reducing COVID-19 hospitalization rates. From an eligible population of 632,822 COVID-19 patients seen at 33 clinical sites across the United States between December 23, 2021 and December 31, 2022, patients were matched across observed treatment groups, yielding an analytical sample of 410,642 patients. We estimate a 65% reduced odds of hospitalization among Paxlovid-treated patients within a 28-day follow-up period, and this effect did not vary by patient vaccination status. Notably, we observe disparities in Paxlovid treatment, with lower rates among Black and Hispanic or Latino patients, and within socially vulnerable communities. Ours is the largest study of Paxlovid's real-world effectiveness to date, and our primary findings are consistent with previous randomized control trials and real-world studies.

Target Trial Emulation Using Hospital-Based Observational Data: Demonstration and Application in COVID-19

Methodological biases are common in observational studies evaluating treatment effectiveness. The objective of this study is to emulate a target trial in a competing risks setting using hospital-based observational data. We extend established methodology accounting for immortal time bias and time-fixed confounding biases to a setting where no survival information beyond hospital discharge is available: a condition common to coronavirus disease 2019 (COVID-19) research data. This exemplary study includes a cohort of 618 hospitalized patients with COVID-19. We describe methodological opportunities and challenges that cannot be overcome applying traditional statistical methods. We demonstrate the practical implementation of this trial emulation approach via clone-censor-weight techniques. We undertake a competing risk analysis, reporting the cause-specific cumulative hazards and cumulative incidence probabilities. Our analysis demonstrates that a target trial emulation framework can be extended to account for competing risks in COVID-19 hospital studies. In our analysis, we avoid immortal time bias, time-fixed confounding bias, and competing risks bias simultaneously. Choosing the length of the grace period is justified from a clinical perspective and has an important advantage in ensuring reliable results. This extended trial emulation with the competing risk analysis enables an unbiased estimation of treatment effects, along with the ability to interpret the effectiveness of treatment on all clinically important outcomes.

Self-reported physical activity behaviors of childhood cancer survivors: comparison to a general adolescent population in Korea

PURPOSE

Adequate physical activity (PA) can significantly contribute to the prevention of undesirable health outcomes in childhood cancer survivors (CCS). This study aimed to identify the patterns of PA and related factors in Korean CCS.

METHODS

Study subjects were 184 adolescents selected from an ongoing cohort study of Korean CCS and 1,840 sex- and school grade-matched controls randomly selected from the participants of the 2019 Korea Youth Risk Behavior Web-based Survey. Information on PA and sedentary behaviors was collected by self-administered questionnaire. We estimated body mass index (BMI)-adjusted odds ratio (OR) and 95% confidence interval (CI) for the advisable healthy behaviors of CCS compared with healthy controls using conditional logistic regression analysis. In addition, the associations of advisable healthy behaviors of CCS with sociodemographic and clinical factors were estimated using multiple logistic regression analysis.

RESULTS

CCS were less likely to be physically active than controls, but this finding was evident only in males. The ORs (95% CIs) for regular exercise, moderate intensity PA, vigorous intensity PA, and walking were 0.42 (0.27-0.65), 0.39 (0.24-0.63), 0.53 (0.33-0.84), and 0.64 (0.42-0.98), respectively, in male CCS compared with same-sex controls. Compared with same-sex controls, male CCS were 4.60 times and female survivors were 15.19 times more likely to sleep longer than 8 h a day. Among CCS, males were 2.92 times and 3.07 times more likely to perform moderate intensity PA and muscle-strengthening exercise, respectively, than female. Higher BMI (OR: 1.16), highest family income (OR: 3.98), and a caregiver who performed regular exercise (OR: 2.08) were positively associated with vigorous intensity PA of CCS. With increasing time after treatment completion, the probability of engaging in sedentary activity for less than 6 h per day decreased (OR = 0.89, 95% CI 0.79-1.00).

CONCLUSION

Korean adolescent CCS were physically inactive compared with control adolescents. Several sociodemographic factors such as sex, family income, caregiver PA, and obesity level were associated with PA behaviors of CCS.

IMPLICATIONS

Strategic effort would be needed to increase physical activity of childhood cancer survivors in adolescent period with consideration of various sociodemographic factors found in this study.

Head-to-head comparison of FOLFIRINOX versus gemcitabine plus nab-paclitaxel in advanced pancreatic cancer: a target trial emulation using real-world data

PURPOSE

To emulate a hypothetical target trial assessing the effect of initiating 5-fluorouracil, folinic acid, irinotecan, and oxaliplatin (FOLFIRINOX) versus gemcitabine plus nab-paclitaxel (GN) within 8 weeks of diagnosis on overall survival.

METHODS

An observational cohort study was conducted using population-level data from Alberta, Canada. Individuals diagnosed with advanced pancreatic cancer between April 2015 and December 2019 were identified through the provincial cancer registry and followed until March 2021. Records were linked to other administrative databases containing information on relevant variables. Individuals were excluded if they did not have adequate hemoglobin, platelet, white blood cell, and serum creatinine measures or if they received prior therapy. The observational analog of the per-protocol effect was estimated using inverse probability weighted Kaplan-Meier curves with bootstrapped 95% confidence intervals.

RESULTS

Four hundred seven individuals were eligible. The weighted median overall survival was 8.3 months (95% CI, 5.7-11.9) for FOLFIRINOX and 5.1 months (95% CI: 4.3 to 5.8) for GN. The adjusted difference in median overall survival was 3.2 months (95% CI, 1.1-7.4) and the mortality hazard ratio was 0.78 (95% CI, 0.61-0.97).

CONCLUSIONS

Our estimates favored the initiation of FOLFIRINOX over GN with respect to overall survival.

No short-term mortality from benzodiazepine use post-acute ischemic stroke after accounting for bias

BACKGROUND AND OBJECTIVES

Older adults receive benzodiazepines for agitation, anxiety, and insomnia after acute ischemic stroke (AIS). No trials have been conducted to determine if benzodiazepine use affects poststroke mortality in the elderly.

METHODS

We examined the association between initiating benzodiazepines within 1 week after AIS and 30-day mortality. We included patients ≥65 years, admitted for new nonsevere AIS (NIH-Stroke-Severity[NIHSS]≤ 20), 2014-2020, with no recorded benzodiazepine use in the previous 3 months and no contraindication for use. We linked a stroke registry to electronic health records, used inverse-probability weighting to address confounding, and estimated the risk difference (RD). A process of cloning, weighting, and censoring was used to avoid immortal time bias.

RESULTS

Among 2,584 patients, 389 received benzodiazepines. The crude 30-day mortality risk from treatment initiation was 212/1,000 among patients who received benzodiazepines, while the 30-day mortality was 34/1,000 among those who did not. When follow-up was aligned on day of AIS admission and immortal time was assigned to the two groups, the estimated risks were 27/1,000 and 22/1,000, respectively. Upon further adjustment for confounders, the RD was 5 (-12 to 19) deaths/1,000 patients.

CONCLUSION

The observed higher 30-day mortality associated with benzodiazepine initiation within 7 days was largely due to bias.

Virtual Trials: Causally-validated treatment effects efficiently learned from an observational cancer registry

Randomized controlled trials (RCTs) offer a clear causal interpretation of treatment effects, but are inefficient in terms of information gain per patient. Moreover, because they are intended to test cohort-level effects, RCTs rarely provide information to support precision medicine, which strives to choose the best treatment for an individual patient. If causal information could be efficiently extracted from widely available real-world data, the rapidity of treatment validation could be increased, and its costs reduced. Moreover, inferences could be made across larger, more diverse patient populations. We created a "virtual trial" by fitting a multilevel Bayesian survival model to treatment and outcome records self-reported by 451 brain cancer patients. The model recovers group-level treatment effects comparable to RCTs representing over 3200 patients. The model additionally discovers the feature-treatment interactions needed to make individual-level predictions for precision medicine. By learning from heterogeneous real-world data, virtual trials can generate more causal estimates with fewer patients than RCTs, and they can do so without artificially limiting the patient population. This demonstrates the value of virtual trials as a complement to large randomized controlled trials, especially in highly heterogeneous or rare diseases.

Transporting observational study results to a target population of interest using inverse odds of participation weighting

Inverse odds of participation weighting (IOPW) has been proposed to transport clinical trial findings to target populations of interest when the distribution of treatment effect modifiers differs between trial and target populations. We set out to apply IOPW to transport results from an observational study to a target population of interest. We demonstrated the feasibility of this idea with a real-world example using a nationwide electronic health record derived de-identified database from Flatiron Health. First, we conducted an observational study that carefully adjusted for confounding to estimate the treatment effect of fulvestrant plus palbociclib relative to letrozole plus palbociclib as a second-line therapy among estrogen receptor (ER)-positive, human epidermal growth factor receptor (HER2)-negative metastatic breast cancer patients. Second, we transported these findings to the broader cohort of patients who were eligible for a first-line therapy. The interpretation of the findings and validity of such studies, however, rely on the extent that causal inference assumptions are met.

Emulation of a target trial with sustained treatment strategies: an application to prostate cancer using both inverse probability weighting and the g-formula

As with many chronic illnesses, recurrent prostate cancer generally requires sustained treatment to prolong survival. However, initiating treatment immediately after recurrence may negatively impact quality of life without any survival gains. Therefore, we consider sustained strategies for initiating treatment based on specific characteristics of prostate-specific antigen (PSA), which can indicate disease progression. We define the protocol for a target trial comparing treatment strategies based on PSA doubling time, in which androgen deprivation therapy is initiated only after doubling time decreases below a certain threshold. Such a treatment strategy means the timing of treatment initiation (if ever) is not known at baseline, and the target trial protocol must explicitly specify the frequency of PSA monitoring until the threshold is met, as well as the duration of treatment. We describe these and other components of a target trial that need to be specified in order for such a trial to be emulated in observational data. We then use the parametric g-formula and inverse-probability weighted dynamic marginal structural models to emulate our target trial in a cohort of prostate cancer patients from clinics across the United States.

Trimodality Therapy vs Definitive Chemoradiation in Older Adults With Locally Advanced Esophageal Cancer

BACKGROUND

The comparative effectiveness of trimodality therapy vs definitive chemoradiation for treating locally advanced esophageal cancer in older adults is uncertain. Existing trials lack generalizability to older adults, a population with heightened frailty. We sought to emulate a hypothetical trial comparing these treatments using real-world data.

METHODS

A cohort of adults aged 66-79 years diagnosed with locally advanced esophageal cancer between 2004 and 2017 was identified in the Surveillance Epidemiology and End Results-Medicare database. The clone-censor-weight method was leveraged to eliminate time-related biases when comparing outcomes between treatments. Outcomes included overall mortality, esophageal cancer-specific mortality, functional adverse events, and healthy days at home.

RESULTS

A total of 1240 individuals with adenocarcinomas and 661 with squamous cell carcinomas were identified. For adenocarcinomas, the standardized 5-year risk of mortality was 73.4% for trimodality therapy and 83.8% for definitive chemoradiation (relative risk [RR] = 0.88, 95% confidence interval [CI] = 0.82 to 0.95). Trimodality therapy was associated with mortality risk reduction for squamous cell carcinomas (RR = 0.87, 95% CI = 0.70 to 1.01). The 1-year incidence of functional adverse events was higher in the trimodality group (adenocarcinomas RR = 1.40, 95% CI = 1.22 to 1.65; squamous cell carcinomas RR = 1.21, 95% CI = 1.00 to 1.49). Over 5 years, trimodality therapy was associated with 160 (95% CI = 67 to 229) and 177 (95% CI = 51 to 313) additional home days in individuals with adenocarcinomas and squamous cell carcinomas, respectively.

CONCLUSIONS

Compared with definitive chemoradiation, trimodality therapy was associated with reduced mortality but increased risk of function-related adverse events. Discussing these tradeoffs may help optimize care plans.

Benefits and Risks Associated With Continuation of Anti-Tumor Necrosis Factor After 24 Weeks of Pregnancy in Women With Inflammatory Bowel Disease : A Nationwide Emulation Trial

BACKGROUND

Continuation of biologics for inflammatory disorders during pregnancy is still a difficult decision. Many women with inflammatory bowel diseases (IBDs) stop anti-tumor necrosis factor (anti-TNF) treatment after 24 weeks.

OBJECTIVE

To evaluate the benefits and risks of anti-TNF continuation after 24 weeks of pregnancy for mothers with IBD and their offspring.

DESIGN

Target trial emulation between 2010 and 2020.

SETTING

Nationwide population-based study using the Système National des Données de Santé.

PATIENTS

All pregnancies with birth exposed to anti-TNF between conception and 24 weeks of pregnancy in women with IBD.

INTERVENTION

Continuation of anti-TNF after 24 weeks of pregnancy.

MEASUREMENTS

Occurrence of maternal IBD relapse up to 6 months after pregnancy, adverse pregnancy outcomes, and serious infections in the offspring during the first 5 years of life was compared according to anti-TNF continuation after 24 weeks of pregnancy using inverse probability-weighted marginal models.

RESULTS

A total of 5293 pregnancies were included; among them, anti-TNF treatment was discontinued before 24 weeks for 2890 and continued beyond 24 weeks for 2403. Continuation of anti-TNF was associated with decreased frequencies of maternal IBD relapse (35.8% vs. 39.0%; adjusted risk ratio [aRR], 0.93 [95% CI, 0.86 to 0.99]) and prematurity (7.6% vs. 8.9%; aRR, 0.82 [CI, 0.68 to 0.99]). No difference according to anti-TNF continuation was found regarding stillbirths (0.4% vs. 0.2%; aRR, 2.16 [CI, 0.64 to 7.81]), small weight for gestational age births (13.1% vs. 12.9%; aRR, 1.01 [CI, 0.88 to 1.17]), and serious infections in the offspring (54.2 vs. 50.2 per 1000 person-years; adjusted hazard ratio, 1.08 [CI, 0.94 to 1.25]).

LIMITATION

Algorithms rather than clinical data were used to identify patients with IBD, pregnancies, and serious infections.

CONCLUSION

Continuation of anti-TNF after 24 weeks of pregnancy appears beneficial regarding IBD activity and prematurity, while not affecting neonatal outcomes and serious infections in the offspring.

PRIMARY FUNDING SOURCE

None.

Retrospective observational studies in ultra-rare sarcomas: A consensus paper from the Connective Tissue Oncology Society (CTOS) community of experts on the minimum requirements for the evaluation of activity of systemic treatments

BACKGROUND

In ultra-rare sarcomas (URS) the conduction of prospective, randomized trials is challenging. Data from retrospective observational studies (ROS) may represent the best evidence available. ROS implicit limitations led to poor acceptance by the scientific community and regulatory authorities. In this context, an expert panel from the Connective Tissue Oncology Society (CTOS), agreed on the need to establish a set of minimum requirements for conducting high-quality ROS on the activity of systemic therapies in URS.

METHODS

Representatives from > 25 worldwide sarcoma reference centres met in November 2020 and identified a list of topics summarizing the main issues encountered in ROS on URS. An online survey on these topics was distributed to the panel; results were summarized by descriptive statistics and discussed during a second meeting (November 2021).

RESULTS

Topics identified by the panel included the use of ROS results as external control data, the criteria for contributing centers selection, modalities for ensuring a correct pathological diagnosis and radiologic assessment, consistency of surveillance policies across centers, study end-points, risk of data duplication, results publication. Based on the answers to the survey (55 of 62 invited experts) and discussion the panel agreed on 18 statements summarizing principles of recommended practice.

CONCLUSIONS

These recommendations will be disseminated by CTOS across the sarcoma community and incorporated in future ROS on URS, to maximize their quality and favor their use as control data when results from prospective studies are unavailable. These recommendations could help the optimal conduction of ROS also in other rare tumors.

Target Trial Emulation for Transparent and Robust Estimation of Treatment Effects for Health Technology Assessment Using Real-World Data: Opportunities and Challenges

Evidence about the relative effects of new treatments is typically collected in randomised controlled trials (RCTs). In many instances, evidence from RCTs falls short of the needs of health technology assessment (HTA). For example, RCTs may not be able to capture longer-term treatment effects, or include all relevant comparators and outcomes required for HTA purposes. Information routinely collected about patients and the care they receive have been increasingly used to complement RCT evidence on treatment effects. However, such routine (or real-world) data are not collected for research purposes, so investigators have little control over the way patients are selected into the study or allocated to the different treatment groups, introducing biases for example due to selection or confounding. A promising approach to minimise common biases in non-randomised studies that use real-world data (RWD) is to apply design principles from RCTs. This approach, known as 'target trial emulation' (TTE), involves (1) developing the protocol with respect to core study design and analysis components of the hypothetical RCT that would answer the question of interest, and (2) applying this protocol to the RWD so that it mimics the data that would have been gathered for the RCT. By making the 'target trial' explicit, TTE helps avoid common design flaws and methodological pitfalls in the analysis of non-randomised studies, keeping each step transparent and accessible. It provides a coherent framework that embeds existing analytical methods to minimise confounding and helps identify potential limitations of RWD and the extent to which these affect the HTA decision. This paper provides a broad overview of TTE and discusses the opportunities and challenges of using this approach in HTA. We describe the basic principles of trial emulation, outline some areas where TTE using RWD can help complement RCT evidence in HTA, identify potential barriers to its adoption in the HTA setting and highlight some priorities for future work.

Comparative Effectiveness of Biologic Agents Among Black and White Medicare Patients in the US With Metastatic Colorectal Cancer

Importance

Randomized clinical trials have defined the survival benefit provided by the addition of biologic drugs to chemotherapy in patients with metastatic colorectal cancer (mCRC). However, Black patients may be underrepresented in trial populations, and outcomes in this group remain poorly defined.

Objective

To determine whether the real-world benefit of biologic drugs in Black patients is consistent with the real-world benefit of biologic drugs in White patients using a comparative effectiveness research approach.

Design, Setting, and Participants

Population-based retrospective comparative effectiveness analysis of a cohort of patients aged 65 years or older with mCRC diagnosed between 2004 and 2011 who had received at least 1 dose of chemotherapy and had complete Medicare claims data using the Surveillance, Epidemiology, and End Result (SEER)-Medicare linked database. Data were analyzed from August 1, 2020, to March 31, 2021.

Interventions

Patient data were classified according to whether patients received chemotherapy (oxaliplatin, irinotecan, and 5-fluorouracil or capecitabine) or biochemotherapy (bevacizumab, cetuximab, panitumumab, ramucirumab, or aflibercept, started within 3 months of chemotherapy).

Main Outcomes and Measures

Overall survival (OS) defined as the time from starting chemotherapy to death or last follow-up. A weighted Cox regression model was used to assess differences in survival.

Results

A total of 5617 patients with mCRC were identified in the SEER-Medicare linked database, and 4542 patients were included in the main analysis. Of the 5617 patients, 3969 (70.7%) received biologic agents at any point between 2004 and 2011; biologic agent therapy was started within 3 months of chemotherapy in 2894 patients (72.9%). Among 4542 patients with data on race and ethnicity, the median age was 72 years (IQR, 68-78 years), 2365 (52.0%) were female, 3445 (75.8%) had colon as the primary site, 552 (12.2%) were Black patients, and 3990 (87.8%) were White patients. There was no difference in the receipt of 1 (76.7% and 74.8%) vs 2 or more (23.3% and 25.2%: P = .92) lines of therapy, and in the receipt of biologic agents (63.6% vs 64.3% P = .33), among White patients and Black patients, respectively. Biochemotherapy was associated with a significant survival benefit compared with chemotherapy alone in the overall population (biochemotherapy median OS, 17.9 [95% CI, 17.3-18.7] months vs chemotherapy median OS, 8.3 [95% CI, 9.1-9.9] months; P < .001). The survival benefit was similar among White patients (17.8 vs 9 months; average hazard ratio, 0.59; 95% CI, 0.55-0.64; P < .001) and Black patients (18.6 vs 9.9; average hazard ratio, 0.58; 95% CI, 0.47-0.71; P < .001).

Conclusions and Relevance

In this comparative effectiveness analysis of a cohort of Medicare recipients with mCRC, biochemotherapy was associated with an improvement in OS with a similar rate of reduction in mortality among Black and White patients. Clinicians may offer biochemotherapy therapy to all patients to maximize clinical benefit, factoring in clinical variables, but not their race.

Estimating the effect of nutritional interventions using observational data: the American Heart Association's 2020 Dietary Goals and mortality

BACKGROUND

Because randomized trials of sustained dietary changes are sometimes impractical for long-term outcomes, the explicit emulation of a (hypothetical) target trial using observational data may be an important tool for nutritional epidemiology.

OBJECTIVES

We describe a methodological approach that aims to emulate a target trial of dietary interventions sustained over many years using data from observational cohort studies.

METHODS

We estimated the 20-y risk of all-cause mortality under the sustained implementation of the food-based goals of the American Heart Association (AHA) 2020 using data from 3 prospective observational studies of US men [Health Professionals Follow-up Study (HPFS)] and women [Nurses' Health Study (NHS) and Nurses' Health Study II (NHS II)]. We applied the parametric g-formula to estimate the 20-y mortality risk under a dietary intervention and under no dietary intervention.

RESULTS

There were 165,411 participants who met the eligibility criteria. The mean age at baseline was 57.4 y (range, 43-82 y) in the HPFS, 52.4 y (range, 39-66 y) in the NHS, and 40.2 y (range, 30-50 y) in the NHS II. During 20 y of follow-up, 13,241 participants died. The estimated 20-y mortality risks under a dietary intervention versus no intervention were 21.9% compared with 25.8%, respectively, in the HPFS (risk difference, -3.9%; 95% CI: -4.9% to -3.2%); 10.0% compared with 12.6%, respectively, in the NHS (risk difference, -2.6%; 95% CI: -3.1% to -1.8%); and 2.1% compared with 2.5%, respectively, in the NHS II (risk difference, -0.35%; 95% CI: -0.56% to -0.09%). The corresponding risk ratios were 0.85 (95% CI: 0.81-0.88) in the HPFS, 0.79 (95% CI: 0.75-0.85) in the NHS, and 0.86 (95% CI: 0.78-0.96) in the NHS II.

CONCLUSIONS

We estimated that adherence to the food-based AHA 2020 Dietary Goals starting in midlife may reduce the 20-y risk of mortality.

Withholding Primary Pneumocystis Pneumonia Prophylaxis in Virologically Suppressed Patients With Human Immunodeficiency Virus: An Emulation of a Pragmatic Trial in COHERE

BACKGROUND

Using data from the COHERE collaboration, we investigated whether primary prophylaxis for pneumocystis pneumonia (PcP) might be withheld in all patients on antiretroviral therapy (ART) with suppressed plasma human immunodeficiency virus (HIV) RNA (≤400 copies/mL), irrespective of CD4 count.

METHODS

We implemented an established causal inference approach whereby observational data are used to emulate a randomized trial. Patients taking PcP prophylaxis were eligible for the emulated trial if their CD4 count was ≤200 cells/µL in line with existing recommendations. We compared the following 2 strategies for stopping prophylaxis: (1) when CD4 count was >200 cells/µL for >3 months or (2) when the patient was virologically suppressed (2 consecutive HIV RNA ≤400 copies/mL). Patients were artificially censored if they did not comply with these stopping rules. We estimated the risk of primary PcP in patients on ART, using the hazard ratio (HR) to compare the stopping strategies by fitting a pooled logistic model, including inverse probability weights to adjust for the selection bias introduced by the artificial censoring.

RESULTS

A total of 4813 patients (10 324 person-years) complied with eligibility conditions for the emulated trial. With primary PcP diagnosis as an endpoint, the adjusted HR (aHR) indicated a slightly lower, but not statistically significant, different risk for the strategy based on viral suppression alone compared with the existing guidelines (aHR, .8; 95% confidence interval, .6-1.1; P = .2).

CONCLUSIONS

This study suggests that primary PcP prophylaxis might be safely withheld in confirmed virologically suppressed patients on ART, regardless of their CD4 count.

Prone Positioning and Survival in Mechanically Ventilated Patients With Coronavirus Disease 2019-Related Respiratory Failure

OBJECTIVES

Therapies for patients with respiratory failure from coronavirus disease 2019 are urgently needed. Early implementation of prone positioning ventilation improves survival in patients with acute respiratory distress syndrome, but studies examining the effect of proning on survival in patients with coronavirus disease 2019 are lacking. Our objective was to estimate the effect of early proning initiation on survival in patients with coronavirus disease 2019-associated respiratory failure.

DESIGN

Data were derived from the Study of the Treatment and Outcomes in Critically Ill Patients with coronavirus disease 2019, a multicenter cohort study of critically ill adults with coronavirus disease 2019 admitted to 68 U.S. hospitals. Using these data, we emulated a target trial of prone positioning ventilation by categorizing mechanically ventilated hypoxemic (ratio of Pao2 over the corresponding Fio2 ≤ 200 mm Hg) patients as having been initiated on proning or not within 2 days of ICU admission. We fit an inverse probability-weighted Cox model to estimate the mortality hazard ratio for early proning versus no early proning. Patients were followed until death, hospital discharge, or end of follow-up.

SETTING

ICUs at 68 U.S. sites.

PATIENTS

Critically ill adults with laboratory-confirmed coronavirus disease 2019 receiving invasive mechanical ventilation with ratio of Pao2 over the corresponding Fio2 less than or equal to 200 mm Hg.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among 2,338 eligible patients, 702 (30.0%) were proned within the first 2 days of ICU admission. After inverse probability weighting, baseline and severity of illness characteristics were well-balanced between groups. A total of 1,017 (43.5%) of the 2,338 patients were discharged alive, 1,101 (47.1%) died, and 220 (9.4%) were still hospitalized at last follow-up. Patients proned within the first 2 days of ICU admission had a lower adjusted risk of death compared with nonproned patients (hazard ratio, 0.84; 95% CI, 0.73-0.97).

CONCLUSIONS

In-hospital mortality was lower in mechanically ventilated hypoxemic patients with coronavirus disease 2019 treated with early proning compared with patients whose treatment did not include early proning.

Clinical Trials of Systemic Chemotherapy for Resectable Pancreatic Cancer: A Review

Importance

Adjuvant chemotherapy is the standard of care for resected pancreatic ductal adenocarcinoma (PDAC) based on level 1 evidence, but some studies suggest that a neoadjuvant approach (which is standard for borderline resectable PDAC) may be preferable for upfront resectable PDAC. An in-depth review was conducted of all randomized clinical trials that investigated neoadjuvant and adjuvant treatment of patients with resectable or resected PDAC, focusing on trial design, characteristics of enrolled population, and long-term outcomes.

Observations

The existing resectable PDAC trials have good internal validity but variable applicability because of their restrictive eligibility criteria. In these trials, overall survival is the criterion standard end point, but disease-free survival is more feasible, proximate, and specific to the assigned intervention (at the cost of subjective outcome assessment) and thus an acceptable end point in certain contexts. The prolonged survival in the PRODIGE 24 trial highlights both the success of mFOLFIRINOX (modified fluorouracil, leucovorin, irinotecan, and oxaliplatin) and the importance of patient selection. Neoadjuvant and perioperative trials have shown promising preliminary results; however, the number of patients who are not subsequently eligible for surgery reflects the limitations of this approach. Head-to-head comparisons of neoadjuvant and adjuvant treatments are limited to date in Western countries. Precision oncology with genomic and somatic testing for actionable mutations has promising preliminary results and may refine the management of PDAC, although the implications for early-stage disease and neoadjuvant therapy are unknown.

Conclusions and Relevance

This review found that adjuvant chemotherapy with mFOLFIRINOX is currently the standard of care in fit patients with resected PDAC; however, the role of neoadjuvant treatment is expanding. Precision oncology may help individualize the treatment regimen and sequence and improve outcomes. Enrollment of patients with resectable PDAC in clinical trials is strongly encouraged.

Emulating a Randomised Controlled Trial With Observational Data: An Introduction to the Target Trial Framework

Randomised controlled trials (RCTs) are often considered to be the highest quality of evidence owing to the absence of baseline confounding, the simplicity of analyses, and direct estimation of causal effects. However, observational studies can be designed to mimic RCTs and estimate causal treatment effects. In this review, we describe the target trial framework to illustrate how observational studies can successfully emulate RCTs. We focus on key design elements of RCTs and how to emulate them with observational data. These elements include 1) eligibility criteria, 2) treatment assignment and randomisation, 3) specification of "time zero", 4) outcomes, 5) follow-up, 6) causal contrasts (intention-to-treat vs per-protocol), and 7) statistical analyses. In addition, we describe the design of an example target trial created to emulate the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel Thrombolysis in Myocardial Infarction (TRITON-TIMI) 38 trial and compare effect estimates. Overall, careful design of a target trial using observational data can produce causal effect estimates that are often comparable to RCTs.

Comparing Effect Estimates in Randomized Trials and Observational Studies From the Same Population: An Application to Percutaneous Coronary Intervention

Background

To understand when results from observational studies and randomized trials are comparable, we performed an observational emulation of a target trial designed to ask similar questions as the VALIDATE (Bivalirudin Versus Heparin in ST‐Segment and Non–ST‐Segment Elevation Myocardial Infarction in Patients on Modern Antiplatelet Therapy) randomized trial. The VALIDATE trial compared the effect of bivalirudin and heparin during percutaneous coronary intervention on the risk of death, myocardial infarction, and bleeding across Sweden.

Methods and Results

We specified the protocol of a target trial similar to the VALIDATE trial, then emulated the target trial in the period before the VALIDATE trial took place using data from the SWEDEHEART (Swedish Web System for Enhancement and Development of Evidence‐Based Care in Heart Disease Evaluated According to Recommended Therapies) registry—the same registry in which the trial was undertaken. The target trial emulation and the VALIDATE trial both estimated little or no effect of bivalirudin versus heparin on the risk of death or myocardial infarction by 180 days (target trial emulation risk ratio for death, 1.21 [95% CI, 0.88 – 1.54]; VALIDATE trial hazard ratio for death, 1.05 [95% CI, 0.78 – 1.41]). The observational data, however, could not capture less severe cases of bleeding, resulting in an inability to define a bleeding outcome like the trial, and could not accurately estimate the comparative risk of death by 14 days, which may be the result of intractable confounding early in follow‐up or the inability to precisely emulate the trial’s eligibility criteria.

Conclusions

Using real‐world data to emulate a target trial can deliver accurate effect estimates. Yet, even with rich observational data, it is not always possible to estimate the short‐term effect of interventions or the effect on outcomes for which data are not routinely collected.

Thrombosis, Bleeding, and the Observational Effect of Early Therapeutic Anticoagulation on Survival in Critically Ill Patients With COVID-19

BACKGROUND

Hypercoagulability may be a key mechanism of death in patients with coronavirus disease 2019 (COVID-19).

OBJECTIVE

To evaluate the incidence of venous thromboembolism (VTE) and major bleeding in critically ill patients with COVID-19 and examine the observational effect of early therapeutic anticoagulation on survival.

DESIGN

In a multicenter cohort study of 3239 critically ill adults with COVID-19, the incidence of VTE and major bleeding within 14 days after intensive care unit (ICU) admission was evaluated. A target trial emulation in which patients were categorized according to receipt or no receipt of therapeutic anticoagulation in the first 2 days of ICU admission was done to examine the observational effect of early therapeutic anticoagulation on survival. A Cox model with inverse probability weighting to adjust for confounding was used.

SETTING

67 hospitals in the United States.

PARTICIPANTS

Adults with COVID-19 admitted to a participating ICU.

MEASUREMENTS

Time to death, censored at hospital discharge, or date of last follow-up.

RESULTS

Among the 3239 patients included, the median age was 61 years (interquartile range, 53 to 71 years), and 2088 (64.5%) were men. A total of 204 patients (6.3%) developed VTE, and 90 patients (2.8%) developed a major bleeding event. Independent predictors of VTE were male sex and higher D-dimer level on ICU admission. Among the 2809 patients included in the target trial emulation, 384 (11.9%) received early therapeutic anticoagulation. In the primary analysis, during a median follow-up of 27 days, patients who received early therapeutic anticoagulation had a similar risk for death as those who did not (hazard ratio, 1.12 [95% CI, 0.92 to 1.35]).

LIMITATION

Observational design.

CONCLUSION

Among critically ill adults with COVID-19, early therapeutic anticoagulation did not affect survival in the target trial emulation.

PRIMARY FUNDING SOURCE

None.

Imaging Biomarkers in Lung Cancer with 68Ga-DOTATATE, 18F-Fluoride, and 18F-FDG PET/CT Scans and the Theranostics Paradigm

Lung cancer is the number 1 cause of cancer deaths in the United States. The prognosis is quite grim with the exception of stage 1. When faced with several failed therapeutic regimens and rapid progression of the disease, considering alternative therapies such as radiopharmaceutical therapies may be an option. We describe the case of a 36-y-old man with lung adenocarcinoma who had imaging molecular characterization of his disease with ¹⁸F-FDG, ⁶⁸Ga-DOTATATE, and ¹⁸F-fluoride PET/CT scans that were able to shed some light on molecular characterization of his disease and serve as a guide to potential targeted or personalized radiopharmaceutical therapeutic options.

Association of a Shortened Duration of Adjuvant Chemotherapy With Overall Survival Among Individuals With Stage III Colon Cancer

IMPORTANCE

Several real-world oncology studies have produced findings that contradict those from randomized clinical trials. Such disparities may be associated with methodological shortcomings.

OBJECTIVE

To examine the association between a shortened duration of adjuvant chemotherapy among individuals with stage III colon cancer using real-world data.

DESIGN, SETTING, AND PARTICIPANTS

This comparative effectiveness study included individuals diagnosed with stage III colon cancer between January 2004 and December 2015 who initiated adjuvant chemotherapy at oncology clinics within the province of Alberta, Canada. Patients were identified through record linkage of various administrative databases and were followed up until September 2017. Eligibility criteria were modeled after those used in the International Duration Evaluation of Adjuvant (IDEA) trial. A target trial emulation and naive observational analysis were conducted. Results from both cohorts were benchmarked against findings from the IDEA trial. Data analysis was conducted from March to December 2020.

EXPOSURE

A shortened duration of adjuvant 5-fluorouracil/leucovorin plus oxaliplatin (FOLFOX) or capecitabine plus oxaliplatin (CAPOX) chemotherapy, defined as 3 to 5 months of treatment vs 6 months.

MAIN OUTCOMES AND MEASURES

Overall survival assessed via vital statistics. The per-protocol hazard ratio (HR) was estimated using a weighted pooled logistic regression model. Subgroup analyses were conducted by treatment regimen (ie, FOLFOX vs CAPOX) and cancer stage (ie, T1-3 and N1 vs T4 or N2).

RESULTS

From an initial cohort of 3086 patients, 485 (16%) were eligible for inclusion in the target trial analysis. The median age was 59 years (range, 19-81 years), and 230 (47%) were women. The maximum follow-up was 11.6 years. Median overall survival was not reached. A total of 90 patients (19%) died. The 5-year Kaplan Meier overall survival estimate was 0.79 (95% CI, 0.75-0.84). Estimates from the trial emulation were similar to those from the IDEA trial. For example, a shortened duration of adjuvant chemotherapy was not associated with overall survival among patients prescribed CAPOX in the IDEA trial (HR, 0.96; 95% CI, 0.85-1.08) or in the trial emulation (HR, 0.96; 95% CI, 0.43-2.14). In contrast, the naive observational analysis suggested that a shortened duration of CAPOX was significantly associated with worse survival (HR, 3.33; 95% CI, 1.04-10.65).

CONCLUSIONS AND RELEVANCE

In this study, the explicit emulation of a target trial better approximated results from an analogous well-conducted randomized clinical trial.

Extracorporeal membrane oxygenation in patients with severe respiratory failure from COVID-19

PURPOSE

Limited data are available on venovenous extracorporeal membrane oxygenation (ECMO) in patients with severe hypoxemic respiratory failure from coronavirus disease 2019 (COVID-19).

METHODS

We examined the clinical features and outcomes of 190 patients treated with ECMO within 14 days of ICU admission, using data from a multicenter cohort study of 5122 critically ill adults with COVID-19 admitted to 68 hospitals across the United States. To estimate the effect of ECMO on mortality, we emulated a target trial of ECMO receipt versus no ECMO receipt within 7 days of ICU admission among mechanically ventilated patients with severe hypoxemia (PaO₂/FiO₂ < 100). Patients were followed until hospital discharge, death, or a minimum of 60 days. We adjusted for confounding using a multivariable Cox model.

RESULTS

Among the 190 patients treated with ECMO, the median age was 49 years (IQR 41-58), 137 (72.1%) were men, and the median PaO₂/FiO₂ prior to ECMO initiation was 72 (IQR 61-90). At 60 days, 63 patients (33.2%) had died, 94 (49.5%) were discharged, and 33 (17.4%) remained hospitalized. Among the 1297 patients eligible for the target trial emulation, 45 of the 130 (34.6%) who received ECMO died, and 553 of the 1167 (47.4%) who did not receive ECMO died. In the primary analysis, patients who received ECMO had lower mortality than those who did not (HR 0.55; 95% CI 0.41-0.74). Results were similar in a secondary analysis limited to patients with PaO₂/FiO₂ < 80 (HR 0.55; 95% CI 0.40-0.77).

CONCLUSION

In select patients with severe respiratory failure from COVID-19, ECMO may reduce mortality.

Association Between Early Treatment With Tocilizumab and Mortality Among Critically Ill Patients With COVID-19

Importance

Therapies that improve survival in critically ill patients with coronavirus disease 2019 (COVID-19) are needed. Tocilizumab, a monoclonal antibody against the interleukin 6 receptor, may counteract the inflammatory cytokine release syndrome in patients with severe COVID-19 illness.

Objective

To test whether tocilizumab decreases mortality in this population.

Design, Setting, and Participants

The data for this study were derived from a multicenter cohort study of 4485 adults with COVID-19 admitted to participating intensive care units (ICUs) at 68 hospitals across the US from March 4 to May 10, 2020. Critically ill adults with COVID-19 were categorized according to whether they received or did not receive tocilizumab in the first 2 days of admission to the ICU. Data were collected retrospectively until June 12, 2020. A Cox regression model with inverse probability weighting was used to adjust for confounding.

Exposures

Treatment with tocilizumab in the first 2 days of ICU admission.

Main Outcomes and Measures

Time to death, compared via hazard ratios (HRs), and 30-day mortality, compared via risk differences.

Results

Among the 3924 patients included in the analysis (2464 male [62.8%]; median age, 62 [interquartile range {IQR}, 52-71] years), 433 (11.0%) received tocilizumab in the first 2 days of ICU admission. Patients treated with tocilizumab were younger (median age, 58 [IQR, 48-65] vs 63 [IQR, 52-72] years) and had a higher prevalence of hypoxemia on ICU admission (205 of 433 [47.3%] vs 1322 of 3491 [37.9%] with mechanical ventilation and a ratio of partial pressure of arterial oxygen to fraction of inspired oxygen of <200 mm Hg) than patients not treated with tocilizumab. After applying inverse probability weighting, baseline and severity-of-illness characteristics were well balanced between groups. A total of 1544 patients (39.3%) died, including 125 (28.9%) treated with tocilizumab and 1419 (40.6%) not treated with tocilizumab. In the primary analysis, during a median follow-up of 27 (IQR, 14-37) days, patients treated with tocilizumab had a lower risk of death compared with those not treated with tocilizumab (HR, 0.71; 95% CI, 0.56-0.92). The estimated 30-day mortality was 27.5% (95% CI, 21.2%-33.8%) in the tocilizumab-treated patients and 37.1% (95% CI, 35.5%-38.7%) in the non-tocilizumab-treated patients (risk difference, 9.6%; 95% CI, 3.1%-16.0%).

Conclusions and Relevance

Among critically ill patients with COVID-19 in this cohort study, the risk of in-hospital mortality in this study was lower in patients treated with tocilizumab in the first 2 days of ICU admission compared with patients whose treatment did not include early use of tocilizumab. However, the findings may be susceptible to unmeasured confounding, and further research from randomized clinical trials is needed.