Avoidable flaws in observational analyses: an application to statins and cancer

Global containment policy duration and long-term epidemic progression: A target trial emulation using COVID-19 data from 2020 to 2022

OBJECTIVES

Global countries often apply containment policies (CPs) to combat infectious disease surges. Whether countries with longer cumulative duration of CPs are associated with slower long-term epidemic progression necessitates a thorough evaluation.

METHODS

We collected CP and COVID-19 data of 185 territories during 2020-2022, with a total of 23 CPs. Using the target trial emulation and cloning-censoring-weighting approaches, we assessed the effectiveness of CPs with different cumulative durations in delaying countries from reaching the 1% and 10% cumulative infection incidence end points (i.e. 10,000 and 100,000 COVID-19 cases per million population, respectively) over a 3-year observation period.

RESULTS

For reaching the 1% cumulative infection incidence, recommending closing workplaces and limiting gatherings to 10 people, each presented that a longer cumulative duration of those CPs is associated with a lower proportion of countries achieving this end point throughout 2020-2022. For reaching the 10% cumulative infection incidence, mandatory bans on public events and domestic movements, closing public transports, and screening and quarantining inbound tourists, each showed similar associations. Notably, long-lasting border bans upon high-risk regions are associated with a higher proportion of countries reaching the 10% cumulative infection incidence.

CONCLUSIONS

From the long-term perspective, we highlight CPs that warrant extending the duration to achieve slower epidemic progression. By contrast, our findings demonstrate the limited effectiveness of the ban on regions in slowing the long-term epidemic progression.

Oral Glucocorticoids for Skin Fibrosis in Early Diffuse Systemic Sclerosis: A Target Trial Emulation Study From the European Scleroderma Trials and Research Group Database

OBJECTIVE

The objective of this study is to evaluate whether adding oral glucocorticoids to immunosuppressive therapy improves skin scores and ensures safety in patients with early diffuse cutaneous systemic sclerosis (dcSSc).

METHODS

We performed an emulated randomized trial comparing the changes from baseline to 12 ± 3 months of the modified Rodnan skin score (mRSS: primary outcome) in patients with early dcSSc receiving either oral glucocorticoids (≤20 mg/day prednisone equivalent) combined with immunosuppression (treated) or immunosuppression alone (controls), using data from the European Scleroderma Trials and Research Group. Secondary end points were the difference occurrence of progressive skin or lung fibrosis and scleroderma renal crisis. Matching propensity score was used to adjust for baseline imbalance between groups.

RESULTS

We matched 208 patients (mean age 49 years; 33% male; 59% anti-Scl70), 104 in each treatment group, obtaining comparable characteristics at baseline. In the treated group, patients received a median prednisone dose of 5 mg/day. Mean mRSS change at 12 ± 3 months was similar in the two groups (decrease of 2.7 [95% confidence interval {95% CI} 1.4-4.0] in treated vs 3.1 [95% CI 1.9-4.4] in control, P = 0.64). Similar results were observed in patients with shorter disease duration (≤ 24 months) or with mRSS ≤22. There was no between-group difference for all prespecified secondary outcomes. A case of scleroderma renal crisis occurred in both groups.

CONCLUSION

We did not find any significant benefit of adding low-dose oral glucocorticoids to immunosuppression for skin fibrosis, and at this dosage, glucocorticoid did not increase the risk of scleroderma renal crisis.

Use of β-adrenoreceptor drugs and Parkinson's disease incidence in women from the French E3N cohort study

BackgroundExperimental and observational studies suggest that β-adrenoreceptor drugs (β2-agonists/β-antagonists) are associated with Parkinson's disease (PD) risk. Previous epidemiological studies may be hampered by reverse causation/confounding.ObjectiveWe examined the association of β-adrenoreceptor drugs with PD incidence, while addressing reverse causation and confounding in the E3N cohort study (2004-2018) using a new-user design.MethodsIncident β2-agonists/β-antagonists users were identified through drug claims databases. Incident PD was ascertained using multiple sources and validated by experts. Drugs-PD associations were assessed using time-varying Cox proportional hazards models adjusted for multiple confounders. Main analyses used a 5y-exposure lag to address reverse causation; sensitivity analyses used a 2y-lag or no lag. We set up a nested case-control study to compare trajectories of β2-agonists/β-antagonists prescriptions before diagnosis using logistic mixed models.ResultsAnalyses for β2-agonists were based on 81,890 women; 15,169 started using β2-agonists and 579 developed PD. PD incidence was 36% lower (hazard ratio = 0.64, 95% confidence interval = 0.41-0.98; p-trend = 0.04 for the number of claims) in users of long-acting/ultra-long-acting β2-agonists (LABAs/ultra-LABAs) compared to never users. There was no significant association for β2-agonists overall and short-acting β2-agonists. Analyses for β-antagonists were based on 75,896 women; 13,081 started using β-antagonists and 552 developed PD. PD incidence was similar in ever and never users in analyses with a 5y-lag but was higher in ever than never users in analyses with 2y-lag or no lag.ConclusionsIncident use of LABAs/ultra-LABAs is associated with lower PD incidence in women. Conversely, the association between β-antagonists and PD in women is likely due to reverse causation.

Transcription-Driven Repurposing of Cardiotonic Steroids for Lithium Treatment of Severe Depression

Lithium is prescribed as a mood stabilizer for bipolar disorder and severe depression. However, the mechanism of action of lithium is unknown and there are major side effects associated with prolonged medication. This motivates a search for safer alternative drug repurposing candidates. Given that the drug mechanism may be encoded in transcriptional changes, we generated the gene expression profile for acute lithium treatment of cortical neuronal cultures. We found that the lithium-associated transcription response harbors a significant component that is the reverse of that seen in human brain samples from patients with major depression, bipolar disorder, and a mouse model of depression. Interrogating publicly available drug-driven expression data, we found that cardiotonic steroids drive gene expression in a correlated manner to our acute lithium profile. An analysis of the psychiatric medication cohort of the Norwegian Prescription Database showed that cardiotonic prescription is associated with a lower incidence of lithium prescription. Our transcriptional and epidemiological observations point towards cardiotonic steroids as possible repurposing candidates for lithium. These observations motivate a controlled trial to establish a causal connection and genuine therapeutic benefit in the context of depression.

Comparative effect of aspirin versus clopidogrel monotherapy on incident type 2 diabetes in patients with atherosclerotic cardiovascular diseases: A target trial emulation study

AIMS

To compare the effects of low-dose aspirin and clopidogrel on the risk of incident type 2 diabetes among patients with ASCVD.

METHODS

This target trial emulation study was performed usingthe IQVIA Medical Research Data UK primary care database, including adults with an incident first ASCVD event who initiated low-dose aspirin or clopidogrel between 2004 and 2021. We applied an overlap weighting approach to balance treatment groups. The observational analogues of intention-to-treat and per-protocol effects were estimated using pooled logistic regression.

RESULTS

A total of 111,292 ASCVD patients who initiated aspirin (n = 78,012) or clopidogrel (n = 33,280) were included. In intention-to-treat analyses, aspirin and clopidogrel had similar risks of diabetes (Hazard ratio [HR] 1.02, 95 % Confidence interval [CI] 0.96 to 1.07), cardiovascular events (1.00, 0.95 to 1.05), and bleeding events (1.02, 0.97 to 1.08). In per-protocol analyses, risks remained comparable for diabetes (1.06, 0.97 to 1.15), cardiovascular events (0.96, 0.89 to 1.03), and bleeding events (1.01, 0.92 to 1.10).

CONCLUSIONS

Aspirin and clopidogrel have similar risks of incident diabetes, cardiovascular events, and bleeding events among patients with ASCVD. The choice between these agents may thus be influenced more by factors like cost, patient preference, or tolerance than by clinical outcomes alone.

Effect of Statins in the Watch and Wait Phase of Chronic Lymphocytic Leukemia

BACKGROUND

It is an unclear how cholesterol-lowering statin drugs affect progression of chronic lymphocytic leukemia (CLL).

METHODS

Clinical records of 57 CLL patients were examined to determine how initiating statins in the "watch and wait" phase of management affected disease progression.

RESULTS

After 6.4 ± 0.6 months, when average low-density lipoprotein cholesterol levels had been lowered from 3.58 ± 0.11 mM to 2.1 ± 0.06 mM, blood levels of CLL cells and beta-2-microglobulin (β2M) increased significantly, accompanied by significant decreases in platelets. Following statin institution, rates of change of blood lymphocytes and β2M increased from 1.55 ± 0.39 × 106 to 3.4 ± 0.68 × 106 cells/mL/month (n = 43) and 0.035 ± 0.011 to 0.055 ± 0.007 μg/mL/month (n = 40), respectively. Conventional first-line CLL treatment was ultimately required in 37 patients.

CONCLUSIONS

These observations suggest that statins as single agent do not slow and may even modestly stimulate progression of CLL.

The target trial framework in global health research: barriers and opportunities

A randomised trial is the best way to make causal inferences when evaluating the effectiveness and safety of health interventions in global health research. Trials, however, are inherently expensive, unfeasible in many scenarios, and may raise ethical issues. In these scenarios, we must turn to analyses of observational data to learn what works. The target trial framework provides an organising principle for the design of observational studies that can lead to clinically interpretable results and analytic approaches that can reduce common biases. In this analysis, we describe the global distribution of data sources used in applications of the target trial framework and discuss barriers to its increased use in global health research, such as limited access to high-quality observational data. We then suggest a cost-effective solution of incorporating the collection of additional high-quality observational data into the implementation of large randomised trials in low- and middle-income countries. We found that the target trial framework is underutilised in observational studies conducted in most low- and middle-income countries. The main barriers are little available data and few trained researchers, which can be overcome by incorporating high-quality observational data collection into the data collection phase of large randomised trials, and by introducing small adjustments to the teaching curriculum.

Nonbenzodiazepine hypnotics and police-reported motor vehicle crash risk among older adults: a sequential target trial emulation

Nonbenzodiazepine hypnotics ("Z-drugs") are prescribed for insomnia but might increase the 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, to 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 (RRs) 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 1249 MVCs, respectively. The intention-to-treat RR was 1.06 (95% CL, 0.95-1.16). For the per-protocol estimand, there were 800 MVCs and 1241 MVCs among treated and untreated person-trials, respectively, suggesting a reduced MVC risk (RR, 0.83; 95% CL, 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. This article is part of a Special Collection on Pharmacoepidemiology.

The Target Trial Framework for Causal Inference From Observational Data: Why and When Is It Helpful?

When randomized trials are not available to answer a causal question about the comparative effectiveness or safety of interventions, causal inferences are drawn using observational data. A helpful 2-step framework for causal inference from observational data is 1) specifying the protocol of the hypothetical randomized pragmatic trial that would answer the causal question of interest (the target trial), and 2) using the observational data to attempt to emulate that trial. The target trial framework can improve the quality of observational analyses by preventing some common biases. In this article, we discuss the utility and scope of applications of the framework. We clarify that target trial emulation resolves problems related to incorrect design but not those related to data limitations. We also describe some settings in which adopting this approach is advantageous to generate effect estimates that can close the gaps that randomized trials have not filled. In these settings, the target trial framework helps reduce the ambiguity of causal questions.

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% to 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 nonstarchy 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.

Target trial emulation of preconception serum vitamin D status on fertility outcomes: a couples-based approach

OBJECTIVE

To evaluate associations between preconception 25-hydroxyvitamin D (25(OH)D) levels and biomarkers in female and male partners on live birth (LB), pregnancy loss, and semen quality.

DESIGN

Secondary analysis using the folic acid and zinc supplementation trial of couples seeking infertility treatment at four US centers (2013-2017). A target trial emulation framework was applied to estimate associations. Couples were observed for 9 months or through pregnancy.

SUBJECTS

Couples seeking infertility treatment.

INTERVENTION(S)

Preconception concentrations of 25(OH)D (primary) and associated biomarkers: vitamin D binding protein, calcium, free vitamin D, bioavailable vitamin D.

MAIN OUTCOME MEASURE(S)

Live birth and pregnancy loss were ascertained via self-report and medical records. Semen quality was ascertained 6 months after enrollment. Log-binomial regression estimated risk ratios and 95% confidence intervals (CIs). Individual and joint models and effect measure modification by preconception body mass index were considered.

RESULT(S)

Among 2,370 couples, 19.5% of females and 29.9% of males were 25(OH)D deficient. Females with sufficient status had a 28%-higher likelihood of LB than deficient females (95% CI, 1.05-1.56). Female and male 25(OH)D status were associated with LB among those with normal body mass index (sufficient vs. deficient: female adjusted risk ratio [aRR], 1.39; 95% CI, 1.00-1.99; male aRR, 1.51; 95% CI, 1.01-2.25) and among obese female partners (sufficient vs. deficient: aRR, 1.33; 95% CI, 0.95-1.85). Couples whose both partners had higher 25(OH)D status had increased likelihood of LB (both not deficient vs. both deficient aRR, 1.26; 95% CI, 1.00-1.58). No associations were observed with pregnancy loss or semen quality. Similar results were found for all biomarkers except calcium.

CONCLUSION(S)

Preconception vitamin D status and bioavailability impact fertility among couples seeking infertility therapy, likely unrelated to semen quality. Body mass index stratified analyses demonstrated heterogeneous associations.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01857310.

Effect of nirmatrelvir/ritonavir (Paxlovid) on hospitalization among adults with COVID-19: An electronic health record-based target trial emulation from N3C

BACKGROUND

Nirmatrelvir with ritonavir (Paxlovid) is indicated for patients with Coronavirus Disease 2019 (COVID-19) who are at risk for progression to severe disease due to the presence of one or more risk factors. Millions of treatment courses have been prescribed in the United States alone. Paxlovid was highly effective at preventing hospitalization and death in clinical trials. Several studies have found a protective association in real-world data, but they variously used less recent study periods, correlational methods, and small, local cohorts. Their estimates also varied widely. The real-world effectiveness of Paxlovid remains uncertain, and it is unknown whether its effect is homogeneous across demographic strata. 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 severe COVID-19 outcomes.

METHODS AND FINDINGS

This target trial emulation used a cohort of 703,647 patients with COVID-19 seen at 34 clinical sites across the United States between April 1, 2022 and August 28, 2023. Treatment was defined as receipt of a Paxlovid prescription within 5 days of the patient's COVID-19 index date (positive test or diagnosis). To emulate randomization, we used the clone-censor-weight technique with inverse probability of censoring weights to balance a set of covariates including sex, age, race and ethnicity, comorbidities, community well-being index (CWBI), prior healthcare utilization, month of COVID-19 index, and site of care provision. The primary outcome was hospitalization; death was a secondary outcome. We estimated that Paxlovid reduced the risk of hospitalization by 39% (95% confidence interval (CI) [36%, 41%]; p < 0.001), with an absolute risk reduction of 0.9 percentage points (95% CI [0.9, 1.0]; p < 0.001), and reduced the risk of death by 61% (95% CI [55%, 67%]; p < 0.001), with an absolute risk reduction of 0.2 percentage points (95% CI [0.1, 0.2]; p < 0.001). We also conducted stratified analyses by vaccination status and age group. Absolute risk reduction for hospitalization was similar among patients that were vaccinated and unvaccinate, but was much greater among patients aged 65+ years than among younger patients. We observed disparities in Paxlovid treatment, with lower rates among black and Hispanic or Latino patients, and within socially vulnerable communities. This study's main limitation is that it estimates causal effects using observational data and could be biased by unmeasured confounding.

CONCLUSIONS

In this study of Paxlovid's real-world effectiveness, we observed that Paxlovid is effective at preventing hospitalization and death, including among vaccinated patients, and particularly among older patients. This remains true in the era of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Omicron subvariants. However, disparities in Paxlovid treatment rates imply that the benefit of Paxlovid's effectiveness is not equitably distributed.

Selection processes, transportability, and failure time analysis in life history studies

In life history analysis of data from cohort studies, it is important to address the process by which participants are identified and selected. Many health studies select or enrol individuals based on whether they have experienced certain health related events, for example, disease diagnosis or some complication from disease. Standard methods of analysis rely on assumptions concerning the independence of selection and a person's prospective life history process, given their prior history. Violations of such assumptions are common, however, and can bias estimation of process features. This has implications for the internal and external validity of cohort studies, and for the transportabilty of results to a population. In this paper, we study failure time analysis by proposing a joint model for the cohort selection process and the failure process of interest. This allows us to address both independence assumptions and the transportability of study results. It is shown that transportability cannot be guaranteed in the absence of auxiliary information on the population. Conditions that produce dependent selection and types of auxiliary data are discussed and illustrated in numerical studies. The proposed framework is applied to a study of the risk of psoriatic arthritis in persons with psoriasis.

Effectiveness of Bisphosphonates in Young Adults with Fragility Fractures: Representative Population-Based Cohort Study

CONTEXT

Fragility fractures in young adults present significant clinical challenges due to the limited evidence on the effectiveness of bisphosphonates in preventing subsequent fractures.

OBJECTIVE

To evaluate the effectiveness of bisphosphonate therapy in reducing the fracture risk among premenopausal women with a history of osteoporotic fractures.

DESIGN

A population-based retrospective cohort study was conducted using data from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) in South Korea, covering the years 2003 to 2014.

SETTING

A nationwide healthcare setting utilizing a representative cohort database.

PARTICIPANTS

Among 2,087 premenopausal women with osteoporotic fractures, participants were propensity score-matched based on age and body mass index at a 1:3 ratio, resulting in 132 bisphosphonate users and 396 non-users.

INTERVENTION

Bisphosphonate treatment.

MAIN OUTCOME MEASURES

The incidence of osteoporotic fractures.

RESULTS

Bisphosphonate users had a significantly lower risk of major osteoporotic fractures (HR 0.618, 95% CI 0.396 - 0.963) compared to non-users. Ibandronate users showed significant reductions in both major osteoporotic (HR 0.376, 95% CI 0.164 - 0.861) and nonvertebral fractures (HR 0.214, 95% CI 0.052 - 0.877). Also, longer duration of bisphosphonate use (≥180 days) was associated with a significantly lower risk of major osteoporotic and nonvertebral fractures (HR 0.528, 95% CI 0.300 - 0.929; HR 0.409, 95% CI 0.187 - 0.895, respectively).

CONCLUSIONS

Bisphosphonate therapy significantly reduces fracture risk in premenopausal women with previous osteoporotic fractures, especially at higher cumulative doses. These findings support considering bisphosphonates as a treatment option in premenopausal women at high risk of fractures.

Hormone therapy and venous thromboembolism risk in women of menopausal age: a target trial emulation

Contemporary data from randomized clinical trials focusing on the effect of oral hormone therapy (HT) on venous thromboembolism (VTE) in women aged 50-60 years are scarce despite evolving HT regimens. Here, we evaluated the association between HT and the risk of developing VTE using a target trial emulation among women of menopausal age. This retrospective cohort study applied a target trial emulation framework using claims data from a universal health insurance program in Taiwan. We emulated a sequence of trials in which women aged 50-60 years with no previous history of HT, hysterectomy, gynecologic disorders, or cardiovascular events were enrolled. Eligibility and HT use were evaluated monthly from 2011 to 2019. Eligible women were classified as either HT initiators or non-initiators for each consecutive month. Observational analogs of the intention-to-treat and per-protocol effects were estimated using pooled logistic regression models. Of the 150,686,148 eligible person-trials (3,001,112 women), 192,215 initiators and 768,860 propensity score-matched non-initiators were included in the analysis. The average duration of the HT was 1.25 years. Over a median follow-up of 5.83 years, 3,334 women developed VTE. The estimated hazard ratio (95% confidence interval) was 0.96 (0.88, 1.04) in the intention-to-treat analysis and 0.66 (0.41, 1.05) in per-protocol analysis. The estimated intention-to-treat and per-protocol 5-year VTE-free survival differences (95% confidence interval) were 0.1‰ (- 0.3‰, 0.7‰) and 0.3‰ (- 2.8‰, 4.0‰), respectively. In the contemporary clinical setting, we did not observe an increased VTE risk associated with HT in women aged 50-60 years.

Contemporary menopausal hormone therapy and risk of cardiovascular disease: Swedish nationwide register based emulated target trial

OBJECTIVE

To assess the effect of contemporary menopausal hormone therapy on the risk of cardiovascular disease according to the route of administration and combination of hormones.

DESIGN

Nationwide register based emulated target trial.

SETTING

Swedish national registries.

PARTICIPANTS

919 614 women aged 50-58 between 2007 and 2020 without hormone therapy use in the previous two years, identified from the Swedish population.

INTERVENTIONS

138 nested trials were designed, starting each month from July 2007 until December 2018. Using the prescription registry data for that specific month, women who had not used hormone therapy in the previous two years were assigned to one of eight treatment groups: oral combined continuous, oral combined sequential, oral unopposed oestrogen, oral oestrogen with local progestin, tibolone, transdermal combined, transdermal unopposed oestrogen, or non-initiators of menopausal hormone therapy.

MAIN OUTCOME MEASURES

Hazard ratios with 95% confidence intervals were estimated for venous thromboembolism, as well as for ischaemic heart disease, cerebral infarction, and myocardial infarction separately and as a composite cardiovascular disease outcome. Treatment effects were estimated by contrasting initiators and non-initiators in observational analogues to "intention-to-treat" analyses and continuous users versus never users in "per protocol" analyses.

RESULTS

A total of 77 512 women were initiators of any menopausal hormone therapy and 842 102 women were non-initiators. 24 089 women had an event recorded during the follow-up: 10 360 (43.0%) had an ischaemic heart disease event, 4098 (17.0%) had a cerebral infarction event, 4312 (17.9%) had a myocardial infarction event, and 9196 (38.2%) had a venous thromboembolic event. In intention-to-treat analyses, tibolone was associated with an increased risk of cardiovascular disease (hazard ratio 1.52, 95% confidence interval 1.11 to 2.08) compared with non-initiators. Initiators of tibolone or oral oestrogen-progestin therapy had a higher risk of ischaemic heart disease (1.46 (1.00 to 2.14) and 1.21 (1.00 to 1.46), respectively). A higher risk of venous thromboembolism was observed for oral continuous oestrogen-progestin therapy (1.61, 1.35 to 1.92), sequential therapy (2.00, 1.61 to 2.49), and oestrogen-only therapy (1.57, 1.02 to 2.44). Additional results in per protocol analyses showed that use of tibolone was associated with a higher risk of cerebral infarction (1.97, 1.02 to 3.78) and myocardial infarction (1.94, 1.01 to 3.73).

CONCLUSIONS

Use of oral oestrogen-progestin therapy was associated with an increased risk of heart disease and venous thromboembolism, whereas the use of tibolone was associated with an increased risk of ischaemic heart disease, cerebral infarction, and myocardial infarction but not venous thromboembolism. These findings highlight the diverse effects of different hormone combinations and administration methods on the risk of cardiovascular disease.

Effectiveness of treat-to-target cholesterol-lowering interventions on cardiovascular disease and all-cause mortality risk in the community-dwelling population: a target trial emulation

Little is known about the long-term effectiveness of risk-based treat-to-target cholesterol-lowering interventions on cardiovascular risk. Here, we show the emulated effectiveness of guideline-recommended low-density and non-high-density lipoprotein cholesterol-lowering interventions using the absolute risk reduction (ARR) and the restricted mean event-free time-based number needed to treat (NNT). With 5,375 participants, the 29-year risks for cardiovascular disease (CVD), all-cause mortality, and atherosclerotic CVD were 18.6%, 25.6%, and 17.7%, respectively. Long-term treat-to-target interventions showed significant reductions in CVD (ARR -2.3%, 95%CI -3.4% to -0.8%; NNT 115), all-cause mortality (-3.0%, -4.3% to -1.8%; 95), and atherosclerotic CVD (-2.6%, -3.5% to -1.2%; 104). Such effects appear more pronounced in women, smokers, and those with body mass index < 24 kg/m² or higher adherence rates.

Conducting observational analyses with the target trial emulation approach: a methodological systematic review

OBJECTIVES

Target trial emulation is an approach that is increasingly used to improve transparency in observational studies and help mitigate biases. For studies declaring that they emulated a target trial, we aimed to evaluate the specification of the target trial, examine its consistency with the observational emulation and assess the risk of bias in the observational analysis.

DESIGN

Methodological systematic review reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.

DATA SOURCES

The database MEDLINE (Medical Literature Analysis and Retrieval System Online) was interrogated for all studies published from 1 January 2021 to 3 July 2022. We performed an additional manual search of 20 general medical and specialised journals that spanned the same period.

ELIGIBILITY CRITERIA

All studies that declared emulating a hypothetical or real randomised trial were eligible.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers performed the whole systematic review process (screening and selection of studies, data extraction and risk of bias assessment). The main outcomes were the definition of the key protocol components of the target trial and its emulation, consistency between the target trial and its emulation and risk of bias according to the ROBINS-I (Risk Of Bias In Non-randomised Studies - of Interventions) tool.

RESULTS

Among the selected sample of 100 studies, 24 (24%) did not specify the target trial. Only 40 studies (40%) provided detailed information on all components of the target trial protocol. Eligibility criteria, intervention strategies and outcomes were consistent between the target trial and its emulation in 35 studies (46% of those specifying the target trial). Overall, 28 studies (28%) exhibited serious risk of bias and 41 (41%) had misalignments in the timing of eligibility assessment, treatment assignment and the start of follow-up (time-zero). As compared with studies that did not specify the target trial, those that did specify the trial less frequently seemed to have both time-zero issues (39% vs 52%) and serious risk of bias (26% vs 33%).

CONCLUSIONS

One-quarter of studies declaring that they emulated a target trial did not specify the trial. Target trials and their emulations were particularly inconsistent for studies emulating a real randomised trial. Risk of methodological issues seemed lower in observational analyses that specified versus did not specify the target trial.

Optimizing physician-encounter frequency for type 2 diabetes patients in primary care based on cardiovascular risk assessment: A target trial emulation study

AIM

To investigate whether the physician-encounter interval for patients with type 2 diabetes (T2D) can be optimized from 2-3 to 4-6 months among those with a calculated 10-year cardiovascular disease (CVD) risk score of less than 20% without compromising their long-term outcomes.

MATERIALS AND METHODS

Using territory-wide public electronic medical records in Hong Kong, we emulated a target trial to compare the effectiveness of the physician-encounter intervals of 4-6 versus 2-3 months for T2D patients without prior CVDs and with a predicted risk for CVDs of less than 20% (i.e. those patients not in the high-risk category). Propensity score matching was used to emulate the randomization of participants at baseline, where 42 154 matched individuals were included for analysis. The marginal structural model was applied to estimate the hazard ratio (HR) for CVD incidence and all-cause mortality, the incidence rate ratio of secondary and tertiary care utilization, as well as the between-group differences in HbA1c, blood pressure and cholesterol levels.

RESULTS

During a follow-up period of up to 12 (average: 5.1) years, there was no significantly increased risk of CVD in patients with physician-encounter intervals of 4-6 months compared with those patients with physician-encounter intervals of 2-3 months (HR [95% confidence interval {CI}]: 1.01 [0.90, 1.14]; standardized 10-year risk difference [95% CI]: -0.1% [-0.7%, 0.6%]), nor for all-cause mortality (HR: 1.00 [0.84, 1.20]; standardized 10-year risk difference: -0.1% [-0.5%, 0.3%]). Additionally, there was no observable difference in the utilization of secondary and tertiary care or key clinical parameters between these two follow-up frequencies.

CONCLUSIONS

For T2D patients with a calculated 10-year CVD risk of less than 20%, the interval of regular physician encounters can be optimized from 2-3 to 4-6 months without compromising patients' long-term outcomes and saving substantial service resources in primary care.

Targeting Cholesterol Biosynthesis with Statins Synergizes with AKT Inhibitors in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is responsible for a disproportionate number of breast cancer patient deaths due to extensive molecular heterogeneity, high recurrence rates, and lack of targeted therapies. Dysregulation of the phosphoinositide 3-kinase (PI3K)/AKT pathway occurs in approximately 50% of TNBC patients. Here, we performed a genome-wide CRISPR/Cas9 screen with PI3Kα and AKT inhibitors to find targetable synthetic lethalities in TNBC. Cholesterol homeostasis was identified as a collateral vulnerability with AKT inhibition. Disruption of cholesterol homeostasis with pitavastatin synergized with AKT inhibition to induce TNBC cytotoxicity in vitro in mouse TNBC xenografts and in patient-derived estrogen receptor (ER)-negative breast cancer organoids. Neither ER-positive breast cancer cell lines nor ER-positive organoids were sensitive to combined AKT inhibitor and pitavastatin. Mechanistically, TNBC cells showed impaired sterol regulatory element-binding protein 2 (SREBP-2) activation in response to single-agent or combination treatment with AKT inhibitor and pitavastatin, which was rescued by inhibition of the cholesterol-trafficking protein Niemann-Pick C1 (NPC1). NPC1 loss caused lysosomal cholesterol accumulation, decreased endoplasmic reticulum cholesterol levels, and promoted SREBP-2 activation. Taken together, these data identify a TNBC-specific vulnerability to the combination of AKT inhibitors and pitavastatin mediated by dysregulated cholesterol trafficking. These findings support combining AKT inhibitors with pitavastatin as a therapeutic modality in TNBC. Significance: Two FDA-approved compounds, AKT inhibitors and pitavastatin, synergize to induce cell death in triple-negative breast cancer, motivating evaluation of the efficacy of this combination in clinical trials.

Comparative Effectiveness of Second-Line Antihyperglycemic Agents for Cardiovascular Outcomes: A Multinational, Federated Analysis of LEGEND-T2DM

BACKGROUND

Sodium-glucose cotransporter 2 inhibitors (SGLT2is) and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) reduce the risk of major adverse cardiovascular events (MACE) in patients with type 2 diabetes mellitus (T2DM). However, their effectiveness relative to each other and other second-line antihyperglycemic agents is unknown, without any major ongoing head-to-head clinical trials.

OBJECTIVES

The aim of this study was to compare the cardiovascular effectiveness of SGLT2is, GLP-1 RAs, dipeptidyl peptidase-4 inhibitors (DPP4is), and clinical sulfonylureas (SUs) as second-line antihyperglycemic agents in T2DM.

METHODS

Across the LEGEND-T2DM (Large-Scale Evidence Generation and Evaluation Across a Network of Databases for Type 2 Diabetes Mellitus) network, 10 federated international data sources were included, spanning 1992 to 2021. In total, 1,492,855 patients with T2DM and cardiovascular disease (CVD) on metformin monotherapy were identified who initiated 1 of 4 second-line agents (SGLT2is, GLP-1 RAs, DPP4is, or SUs). Large-scale propensity score models were used to conduct an active-comparator target trial emulation for pairwise comparisons. After evaluating empirical equipoise and population generalizability, on-treatment Cox proportional hazards models were fit for 3-point MACE (myocardial infarction, stroke, and death) and 4-point MACE (3-point MACE plus heart failure hospitalization) risk and HR estimates were combined using random-effects meta-analysis.

RESULTS

Over 5.2 million patient-years of follow-up and 489 million patient-days of time at risk, patients experienced 25,982 3-point MACE and 41,447 4-point MACE. SGLT2is and GLP-1 RAs were associated with lower 3-point MACE risk than DPP4is (HR: 0.89 [95% CI: 0.79-1.00] and 0.83 [95% CI: 0.70-0.98]) and SUs (HR: 0.76 [95% CI: 0.65-0.89] and 0.72 [95% CI: 0.58-0.88]). DPP4is were associated with lower 3-point MACE risk than SUs (HR: 0.87; 95% CI: 0.79-0.95). The pattern for 3-point MACE was also observed for the 4-point MACE outcome. There were no significant differences between SGLT2is and GLP-1 RAs for 3-point or 4-point MACE (HR: 1.06 [95% CI: 0.96-1.17] and 1.05 [95% CI: 0.97-1.13]).

CONCLUSIONS

In patients with T2DM and CVD, comparable cardiovascular risk reduction was found with SGLT2is and GLP-1 RAs, with both agents more effective than DPP4is, which in turn were more effective than SUs. These findings suggest that the use of SGLT2is and GLP-1 RAs should be prioritized as second-line agents in those with established CVD.

A Two-Step Framework for Validating Causal Effect Estimates

BACKGROUND

Comparing causal effect estimates obtained using observational data to those obtained from the gold standard (i.e., randomized controlled trials [RCTs]) helps assess the validity of these estimates. However, comparisons are challenging due to differences between observational data and RCT generated data. The unknown treatment assignment mechanism in the observational data and varying sampling mechanisms between the RCT and the observational data can lead to confounding and sampling bias, respectively.

AIMS

The objective of this study is to propose a two-step framework to validate causal effect estimates obtained from observational data by adjusting for both mechanisms.

MATERIALS AND METHODS

An estimator of causal effects related to the two mechanisms is constructed. A two-step framework for comparing causal effect estimates is derived from the estimator. An R package RCTrep is developed to implement the framework in practice.

RESULTS

A simulation study is conducted to show that using our framework observational data can produce causal effect estimates similar to those of an RCT. A real-world application of the framework to validate treatment effects of adjuvant chemotherapy obtained from registry data is demonstrated.

CONCLUSION

This  study constructs a framework for comparing causal effect estimates between observational data and RCT data, facilitating the assessment of the validity of causal effect estimates obtained from observational data.

Comparative effectiveness and safety of BNT162b2 and CoronaVac in Hong Kong: A target trial emulation

OBJECTIVES

To evaluate the difference between BNT162b2 and CoronaVac in vaccine effectiveness and safety.

METHODS

This target trial emulation study included individuals aged ≥12 during 2022. Propensity score matching was applied to ensure group balance. The Cox proportional hazard model was used to compare the effectiveness outcomes including COVID-19 infection, severity, 28-day hospitalization, and 28-day mortality after infection. Poisson regression was used for safety outcomes including 32 adverse events of special interests between groups.

RESULTS

A total of 639,818 and 1804,388 individuals were identified for the 2-dose and 3-dose comparison, respectively. In 2-dose and 3-dose comparison, the hazard ratios (95% confidence intervals [CI]) were 0.844 [0.833-0.856] and 0.749 [0.743-0.755] for COVID-19 infection, 0.692 [0.656-0.731] and 0.582 [0.559-0.605] for hospitalization, 0.566 [0.417-0.769] and 0.590 [0.458-0.76] for severe COVID-19, and 0.563 [0.456-0.697] and 0.457 [0.372-0.561] for mortality for BNT162b2 recipients versus CoronaVac recipients, respectively. Regarding safety, 2-dose BNT162b2 recipients had a significantly higher incidence of myocarditis (incidence rate ratio [IRR] [95% CI]: 8.999 [1.14-71.017]) versus CoronaVac recipients, but the difference was insignificant in 3-dose comparison (IRR [95% CI]: 2.000 [0.500-7.996]).

CONCLUSION

BNT162b2 has higher effectiveness among individuals aged ≥12 against COVID-19-related outcomes for SARS-CoV-2 omicron compared to CoronaVac, with almost 50% lower mortality risk.

Estimating the Effect of Bariatric Surgery on Cardiovascular Events Using Observational Data?

BACKGROUND

Observational studies have reported strongly protective effects of bariatric surgery on cardiovascular disease, but with oversimplified definitions of the intervention, eligibility criteria, and follow-up, which deviate from those in a randomized trial. We describe an attempt to estimate the effect of bariatric surgery on cardiovascular disease without introducing these sources of bias, which may not be entirely possible with existing observational data.

METHODS

We propose two target trials among persons with diabetes: (1) bariatric operation (vs. no operation) among individuals who have undergone preoperative preparation (lifestyle modifications and screening) and (2) preoperative preparation and a bariatric operation (vs. neither preoperative nor operative component). We emulated both target trials using observational data of US veterans.

RESULTS

Comparing bariatric surgery with no surgery (target trial #1; 8,087 individuals), the 7-year cardiovascular risk was 18.0% (95% CI = 6.9, 32.7) in the surgery group and 18.9% (95% CI = 17.7, 20.1) in the no-surgery group (risk difference -0.9, 95% CI = -12.0, 14.0). Comparing preoperative components plus surgery vs. neither (target trial #2; 10,065 individuals), the 7-year cardiovascular risk was 17.4% (95% CI = 13.6, 22.0) in the surgery group and 18.8% (95% CI = 17.8, 19.9) in the no-surgery group (risk difference -1.4, 95% CI = -5.1, 3.2). Body mass index and hemoglobin A1c were reduced with bariatric interventions in both emulations.

CONCLUSIONS

Within limitations of available observational data, our estimates do not provide evidence that bariatric surgery reduces cardiovascular disease and support equipoise for a randomized trial of bariatric surgery for cardiovascular disease prevention.

Pragmatic Trial Design to Compare Real-world Effectiveness of Different Treatments for Inflammatory Bowel Diseases: The PRACTICE-IBD European Consensus

BACKGROUND AND AIMS

Pragmatic studies designed to test interventions in everyday clinical settings can successfully complement the evidence from registration and explanatory clinical trials. The European consensus project PRACTICE-IBD was developed to identify essential criteria and address key methodological issues needed to design valid, comparative, pragmatic studies in inflammatory bowel diseases [BDs].

METHODS

Statements were issued by a panel of 11 European experts in IBD management and trial methodology, on four main topics: [I] study design; [II] eligibility, recruitment and organisation, flexibility; [III] outcomes; [IV] analysis. The consensus process followed a modified Delphi approach, involving two rounds of assessment and rating of the level of agreement [1 to 9; cut-off ≥7 for approval] with the statements by 18 additional European experts in IBD.

RESULTS

At the first voting round, 25 out of the 26 statements reached a mean score ≥7. Following the discussion that preceded the second round of voting, it was decided to eliminate two statements and to split one into two. At the second voting round, 25 final statements were approved: seven for study design; six for eligibility, recruitment and organisation, flexibility; eight for outcomes; and four for analysis.

CONCLUSIONS

Pragmatic, randomised, clinical trials can address important questions in IBD clinical practice, and may provide complementary, high-level evidence, as long as they follow a methodologically rigorous approach. These 25 statements intend to offer practical guidance in the design of high-quality, pragmatic, clinical trials that can aid decision making in choosing a management strategy for IBDs.

Pharmacologic Treatment of Portal Hypertension

Portal hypertension is the key mechanism driving the transition from compensated to decompensated cirrhosis. In this review, the authors described the pathophysiology of portal hypertension in cirrhosis and the rationale of pharmacologic treatment of portal hypertension. We discussed both etiologic and nonetiologic treatment of portal hypertension and the specific clinical scenarios how nonselective beta-blocker can be used in patients with cirrhosis. Finally, the authors summarized the evidence for emerging alternatives for portal hypertension in patients with cirrhosis.

Long-term statin use and risk of cancers: a target trial emulation study

BACKGROUND AND OBJECTIVES

Controversy exists regarding potential cancer risks associated with long-term statin use. This study aimed to use real-world data to investigate the association between cancer incidence and sustained statin use over a 10-year period.

METHODS

Using territory-wide public electronic medical records in Hong Kong, we emulated a sequence of nested target trials on patients who met indications for statin initiation in each calendar month from January 2009 to December 2011. Statin initiators and noninitiators were matched in a 1:1 ratio to mimic the randomization of eligible person-trials at baseline. Pooled logistic regression was applied to obtain the hazard ratios for the cancer incidence of statin initiation in intention-to-treat analysis, with the adjustment of baseline confounders and the inverse probability weighting accounting for the postbaseline confounders in per-protocol analysis.

RESULTS

Among 8,560,051 eligible person-trials, 119,715 noninitiators were matched to 119,715 initiators for analysis. Over the 10-year study period, the estimated hazard ratio of overall cancer incidence was 0.96 (0.87, 1.05), and the standardized 10-year risk difference was -0.4% (-1.3%, 0.4%) in the per-protocol analysis. For the cancer subtypes of interest (ie, breast cancer, colorectal cancer, hematological cancer, pancreatic cancer, prostate cancer, urothelial carcinoma, and lung cancer), the 10-year risk differences ranged from -0.3% to 0.2% in the per-protocol analysis. No observable risk change for cancer was found in all patient subgroups with regards to their sex, age (<70/≥70 years), Charlson Comorbidity Index (≤4/>4), and statin indication.

CONCLUSION

Statin use has no impact on cancer incidence over a 10-year follow-up period, including all cancer subtypes of interest and patient subgroups with regards to sex, age, comorbidities, and statin indications.

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.

PKMYT1 knockdown inhibits cholesterol biosynthesis and promotes the drug sensitivity of triple-negative breast cancer cells to atorvastatin

Triple negative breast cancer (TNBC) as the most aggressive molecular subtype of breast cancer is characterized by high cancer cell proliferation and poor patient prognosis. Abnormal lipid metabolism contributes to the malignant process of cancers. Study observed significantly enhanced cholesterol biosynthesis in TNBC. However, the mechanisms underlying the abnormal increase of cholesterol biosynthesis in TNBC are still unclear. Hence, we identified a member of the serine/threonine protein kinase family PKMYT1 as a key driver of cholesterol synthesis in TNBC cells. Aberrantly high-expressed PKMYT1 in TNBC was indicative of unfavorable prognostic outcomes. In addition, PKMYT1 promoted sterol regulatory element-binding protein 2 (SREBP2)-mediated expression of enzymes related to cholesterol biosynthesis through activating the TNF/ TNF receptor-associated factor 1 (TRAF1)/AKT pathway. Notably, downregulation of PKMYT1 significantly inhibited the feedback upregulation of statin-mediated cholesterol biosynthesis, whereas knockdown of PKMYT1 promoted the drug sensitivity of atorvastatin in TNBC cells. Overall, our study revealed a novel function of PKMYT1 in TNBC cholesterol biosynthesis, providing a new target for targeting tumor metabolic reprogramming in the cancer.

Phosphodiesterase-5 Inhibitors and Dementia Risk: A Real-World Study

INTRODUCTION

Biological and scarce epidemiological evidence suggested that phosphodiesterase-5 inhibitors (PDE5i) might reduce dementia risk. We aimed to examine the association between PDE5i and dementia using real-world data.

METHODS

Two retrospective cohorts within the database of Clalit, the largest healthcare provider in Israel (2005-2023), were studied. The first cohort included new daily users, older than 50 years of age, of low-dose tadalafil, prescribed for benign prostatic hypertrophy (BPH), propensity-score matched to new-users of alpha-1 blockers, and analyzed using 2-year lag time. The second cohort included patients with erectile dysfunction, with/without any PDE5i treatment, using time-dependent analysis. Individuals in the cohorts were followed through May 2023 for the occurrence of dementia.

RESULTS

The first cohort included 5,204 tadalafil initiators propensity-score matched to 18,565 alpha-1 blockers initiators. There was no association between tadalafil use and dementia risk, HR = 0.99 (95% CI: 0.88-1.12), p = 0.927. Similar results were obtained in a competing risk analysis, and in a sensitivity analysis in which we restricted the cohort to patients older than 60 years at cohort entry. The second cohort of 133,336 patients with erectile dysfunction included new users and nonusers of any PDE5i. In a mean follow-up of 7.9 years, 8,631 patients were newly diagnosed with dementia. In a time-dependent multivariable analysis, PDE5i use was not associated with reduced dementia risk, HR = 0.95 (95% CI: 0.86-1.04). Results were not changed in sensitivity analyses (patients older than 60 years or stratification by PDE5i type).

CONCLUSION

This study suggests that the use of PDE5 inhibitors is not associated with decreased risk of dementia.

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.

Designing observational studies for credible causal inference in addiction research-Directed acyclic graphs, modified disjunctive cause criterion and target trial emulation

Randomized controlled trials (RCTs) are considered the gold standard for causal inference. With a sufficient sample size, randomization removes confounding up to the time of randomization and allows the treatment effect to be isolated. However, RCTs may have limited generalizability and transportability and are often not feasible in addiction research due to ethical or logistical constraints. The importance of observational studies from real-world settings has been increasingly recognized in research on health. This paper provides an overview of modern approaches to designing observational studies that enable causal inference. It illustrates three key techniques, Directed Acyclic Graphs (DAGs), modified Disjunctive Cause Criterion and Target Trial Emulation, and discusses the strengths and limitations of their applications.

Optimising the use of electronic medical records for large scale research in psychiatry

The explosion and abundance of digital data could facilitate large-scale research for psychiatry and mental health. Research using so-called "real world data"-such as electronic medical/health records-can be resource-efficient, facilitate rapid hypothesis generation and testing, complement existing evidence (e.g. from trials and evidence-synthesis) and may enable a route to translate evidence into clinically effective, outcomes-driven care for patient populations that may be under-represented. However, the interpretation and processing of real-world data sources is complex because the clinically important 'signal' is often contained in both structured and unstructured (narrative or "free-text") data. Techniques for extracting meaningful information (signal) from unstructured text exist and have advanced the re-use of routinely collected clinical data, but these techniques require cautious evaluation. In this paper, we survey the opportunities, risks and progress made in the use of electronic medical record (real-world) data for psychiatric research.

Clinical coding of long COVID in primary care 2020-2023 in a cohort of 19 million adults: an OpenSAFELY analysis

Background

Long COVID is the patient-coined term for the persistent symptoms of COVID-19 illness for weeks, months or years following the acute infection. There is a large burden of long COVID globally from self-reported data, but the epidemiology, causes and treatments remain poorly understood. Primary care is used to help identify and treat patients with long COVID and therefore Electronic Health Records (EHRs) of past COVID-19 patients could be used to help fill these knowledge gaps. We aimed to describe the incidence and differences in demographic and clinical characteristics in recorded long COVID in primary care records in England.

Methods

With the approval of NHS England we used routine clinical data from over 19 million adults in England linked to SARS-COV-2 test result, hospitalisation and vaccination data to describe trends in the recording of 16 clinical codes related to long COVID between November 2020 and January 2023. Using OpenSAFELY, we calculated rates per 100,000 person-years and plotted how these changed over time. We compared crude and adjusted (for age, sex, 9 NHS regions of England, and the dominant variant circulating) rates of recorded long COVID in patient records between different key demographic and vaccination characteristics using negative binomial models.

Findings

We identified a total of 55,465 people recorded to have long COVID over the study period, which included 20,025 diagnoses codes and 35,440 codes for further assessment. The incidence of new long COVID records increased steadily over 2021, and declined over 2022. The overall rate per 100,000 person-years was 177.5 cases in women (95% CI: 175.5-179) and 100.5 in men (99.5-102). The majority of those with a long COVID record did not have a recorded positive SARS-COV-2 test 12 or more weeks before the long COVID record.

Interpretation

In this descriptive study, EHR recorded long COVID was very low between 2020 and 2023, and incident records of long COVID declined over 2022. Using EHR diagnostic or referral codes unfortunately has major limitations in identifying and ascertaining true cases and timing of long COVID.

Funding

This research was supported by the National Institute for Health and Care Research (NIHR) (OpenPROMPT: COV-LT2-0073).

Evaluating different low-density lipoprotein cholesterol thresholds to initiate statin for prevention of cardiovascular diseases in patients with type 2 diabetes mellitus: A target trial emulation study

AIM

The present study aimed to evaluate the effect of statin therapy for primary prevention of cardiovascular diseases (CVDs) when initiating therapy at different baseline low-density lipoprotein cholesterol (LDL-C) levels in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Using territory-wide public electronic medical records in Hong Kong, we emulated a sequence of trials on patients with T2DM with elevated LDL-C levels in every calendar month from January 2008 to December 2014. Pooled logistic regression was applied to obtain the hazard ratios for the major CVDs (stroke, myocardial infarction, heart failure), all-cause mortality and major adverse events (myopathies and liver dysfunction) of statin therapy.

RESULTS

The estimated hazard ratios (95% confidence intervals) of CVD incidence for statin initiation were 0.78 (0.72, 0.84) in patients with baseline LDL-C of 1.8-2.5 mmol/L (i.e., 70-99 mg/dL) and 0.90 (0.88, 0.92) in patients with baseline LDL-C ≥2.6 mmol/L (i.e., ≥100 mg/dL) in intention-to-treat analysis, which was 0.59 (0.51, 0.68) and 0.77 (0.74, 0.81) in per-protocol analysis, respectively. No significant increased risks were observed for the major adverse events. The absolute 10-year risk difference of overall CVD in per-protocol analysis was -7.1% (-10.7%, -3.6%) and -3.9% (-5.1%, -2.7%) in patients with baseline LDL-C 1.8-2.5 and ≥2.6 mmol/L, respectively. The effectiveness and safety were consistently observed in patients aged >75 years initiating statin at both LDL-C thresholds.

CONCLUSIONS

Compared with the threshold of 2.6 mmol/L, initiating statin in patients with a lower baseline LDL-C level at 1.8-2.5 mmol/L can further reduce the risks of CVD and all-cause mortality without significantly increasing the risk of major adverse events in patients with T2DM, including patients aged >75 years.

R WE ready for reimbursement? A round up of developments in real-world evidence relating to health technology assessment: part 15

In this latest update we discuss real-world evidence (RWE) guidance from the leading oncology professional societies, the American Society of Clinical Oncology and the European Society for Medical Oncology, and the PRINCIPLED practical guide on the design and analysis of causal RWE studies.

Acceptability of Using Real-World Data to Estimate Relative Treatment Effects in Health Technology Assessments: Barriers and Future Steps

OBJECTIVES

Evidence about the comparative effects of new treatments is typically collected in randomized controlled trials (RCTs). In some instances, RCTs are not possible, or their value is limited by an inability to capture treatment effects over the longer term or in all relevant population subgroups. In these cases, nonrandomized studies (NRS) using real-world data (RWD) are increasingly used to complement trial evidence on treatment effects for health technology assessment (HTA). However, there have been concerns over a lack of acceptability of this evidence by HTA agencies. This article aims to identify the barriers to the acceptance of NRS and steps that may facilitate increases in the acceptability of NRS in the future.

METHODS

Opinions of the authorship team based on their experience in real-world evidence research in academic, HTA, and industry settings, supported by a critical assessment of existing studies.

RESULTS

Barriers were identified that are applicable to key stakeholder groups, including HTA agencies (eg, the lack of comprehensive methodological guidelines for using RWD), evidence generators (eg, avoidable deviations from best practices), and external stakeholders (eg, data controllers providing timely access to high-quality RWD). Future steps that may facilitate future acceptability of NRS include improvements in the quality, integration, and accessibility of RWD, wider use of demonstration projects to highlight the value and applicability of nonrandomized designs, living, and more detailed HTA guidelines, and improvements in HTA infrastructure relating to RWD.

CONCLUSION

NRS can represent a crucial source of evidence on treatment effects for use in HTA when RCT evidence is limited.

Glucagon-like peptide-1 receptor agonists and risk of major adverse liver outcomes in patients with chronic liver disease and type 2 diabetes

OBJECTIVE

Phase II trials suggest glucagon-like peptide-1 receptor (GLP1) agonists resolve metabolic dysfunction-associated steatohepatitis but do not affect fibrosis regression. We aimed to determine the long-term causal effect of GLP1 agonists on the risk of major adverse liver outcomes (MALO) in patients with any chronic liver disease and type 2 diabetes.

DESIGN

We used observational data from Swedish healthcare registers 2010-2020 to emulate a target trial of GLP1 agonists in eligible patients with chronic liver disease and type 2 diabetes. We used an inverse-probability weighted marginal structural model to compare parametric estimates of 10-year MALO risk (decompensated cirrhosis, hepatocellular carcinoma, liver transplantation or MALO-related death) in initiators of GLP1 agonists with non-initiators. We randomly sampled 5% of the non-initiators to increase computational efficiency.

RESULTS

GLP1 agonist initiators had a 10-year risk of MALO at 13.3% (42/1026) vs 14.6% in non-initiators (1079/15 633) in intention-to-treat analysis (risk ratio (RR)=0.91, 95% CI=0.50 to 1.32). The corresponding 10-year per-protocol risk estimates were 7.4% (22/1026) and 14.4% (1079/15 633), respectively (RR=0.51, 95% CI=0.14 to 0.88). The per-protocol risk estimates at 6 years were 5.4% (21/1026) vs 9.0% (933/15 633) (RR=0.60, 95% CI=0.29 to 0.90) and at 8 years 7.2% (22/1026) vs 11.7% (1036/15 633) (RR=0.61, 95% CI=0.21 to 1.01).

CONCLUSION

In patients with chronic liver disease and type 2 diabetes who adhered to therapy over time, GLP1 agonists may result in lower risk of MALO. This suggests that GLP1 agonists are promising agents to reduce risk of chronic liver disease progression in patients with concurrent type 2 diabetes, although this needs to be corroborated in randomised trials.

The association between antenatal corticosteroids exposure and postnatal growth in infants born between 23 and 29 weeks of gestation

OBJECTIVE

To assess the association between antenatal corticosteroids exposure and postnatal growth in infants born at 23-29 weeks' gestation.

STUDY DESIGN

This retrospective study used data from the Pediatrix Clinical Data Warehouse. Maternal-infant dyads from 2018 to 2020 were included. Inverse propensity weighting (IPW) was applied to balance pre-treatment confounders. Primary outcomes included postnatal weight, length, and head circumference growth trajectory percentiles.

RESULT

The unadjusted cohort consisted of 11,912 dyads. After IPW adjustment, there were 23,231 dyads. Exposed infants showed higher postnatal trajectory percentiles for weight (by 3.4%), length (by 1.8%), and head circumference (by 2.5%) when compared to non-exposed infants. The positive association between antenatal corticosteroids and postnatal growth was only observed in infants not exposed to preeclampsia/eclampsia/HELLP syndrome or without fetal growth restriction.

CONCLUSION

Antenatal corticosteroids exposure is associated with better postnatal growth. The study is limited by its retrospective nature.

Identification and analysis of the molecular targets of statins in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in the world. According to several types of research, statins may impact the development and treatment of CRC. This work aimed to use bioinformatics to discover the relationship between statin targets and differentially expressed genes (DEGs) in CRC patients and determine the possible molecular effect of statins on CRC suppression. We used CRC datasets from the GEO database to select CRC-related DEGs. DGIdb and STITCH databases were used to identify gene targets of subtypes of statin. Further, we identified the statin target of CRC DEGs hub genes by using a Venn diagram of CRC DEGs and statin targets. Funrich and enrichr databases were carried out for the KEGG pathway and gene ontology (GO) enrichment analysis, respectively. GSE74604 and GSE10950 were used to identify CRC DEGs. After analyzing datasets,1370 genes were identified as CRC DEGs, and 345 targets were found for statins. We found that 35 genes are CRC DEGs statin targets. We found that statin targets in CRC were enriched in the receptor and metallopeptidase activity for molecular function, cytoplasm and plasma membrane for cellular component, signal transduction, and cell communication for biological process genes were substantially enriched based on FunRich enrichment. Analysis of the KEGG pathways revealed that the overexpressed DEGs were enriched in the IL-17, PPAR, and Toll-like receptor signaling pathways. Finally, CCNB1, DNMT1, AURKB, RAC1, PPARGC1A, CDKN1A, CAV1, IL1B, and HSPD1 were identified as hub CRC DEGs statin targets. The genetic and molecular aspects of our findings reveal that statins might have a therapeutic effect on CRC.

Nanoparticles targeting mutant p53 overcome chemoresistance and tumor recurrence in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) shows high drug resistance and leads to low survival due to the high level of mutated Tumor Protein p53 (TP53). Cisplatin is a first-line treatment option for NSCLC, and the p53 mutation is a major factor in chemoresistance. We demonstrate that cisplatin chemotherapy increases the risk of TP53 mutations, further contributing to cisplatin resistance. Encouragingly, we find that the combination of cisplatin and fluvastatin can alleviate this problem. Therefore, we synthesize Fluplatin, a prodrug consisting of cisplatin and fluvastatin. Then, Fluplatin self-assembles and is further encapsulated with poly-(ethylene glycol)-phosphoethanolamine (PEG-PE), we obtain Fluplatin@PEG-PE nanoparticles (FP NPs). FP NPs can degrade mutant p53 (mutp53) and efficiently trigger endoplasmic reticulum stress (ERS). In this study, we show that FP NPs relieve the inhibition of cisplatin chemotherapy caused by mutp53, exhibiting highly effective tumor suppression and improving the poor NSCLC prognosis.

Comparison of the Test-negative Design and Cohort Design With Explicit Target Trial Emulation for Evaluating COVID-19 Vaccine Effectiveness

BACKGROUND

Observational studies are used for estimating vaccine effectiveness under real-world conditions. The practical performance of two common approaches-cohort and test-negative designs-need to be compared for COVID-19 vaccines.

METHODS

We compared the cohort and test-negative designs to estimate the effectiveness of the BNT162b2 vaccine against COVID-19 outcomes using nationwide data from the United States Department of Veterans Affairs. Specifically, we (1) explicitly emulated a target trial using follow-up data and evaluated the potential for confounding using negative controls and benchmarking to a randomized trial, (2) performed case-control sampling of the cohort to confirm empirically that the same estimate is obtained, (3) further restricted the sampling to person-days with a test, and (4) implemented additional features of a test-negative design. We also compared their performance in limited datasets.

RESULTS

Estimated BNT162b2 vaccine effectiveness was similar under all four designs. Empirical results suggested limited residual confounding by healthcare-seeking behavior. Analyses in limited datasets showed evidence of residual confounding, with estimates biased downward in the cohort design and upward in the test-negative design.

CONCLUSION

Vaccine effectiveness estimates under a cohort design with explicit target trial emulation and a test-negative design were similar when using rich information from the VA healthcare system, but diverged in opposite directions when using a limited dataset. In settings like ours with sufficient information on confounders and other key variables, the cohort design with explicit target trial emulation may be preferable as a principled approach that allows estimation of absolute risks and facilitates interpretation of effect estimates.

Prostate Cancer and the Mevalonate Pathway

Antineoplastic therapies for prostate cancer (PCa) have traditionally centered around the androgen receptor (AR) pathway, which has demonstrated a significant role in oncogenesis. Nevertheless, it is becoming progressively apparent that therapeutic strategies must diversify their focus due to the emergence of resistance mechanisms that the tumor employs when subjected to monomolecular treatments. This review illustrates how the dysregulation of the lipid metabolic pathway constitutes a survival strategy adopted by tumors to evade eradication efforts. Integrating this aspect into oncological management could prove valuable in combating PCa.

Comparative Effectiveness of Second-line Antihyperglycemic Agents for Cardiovascular Outcomes: A Large-scale, Multinational, Federated Analysis of the LEGEND-T2DM Study

Background

SGLT2 inhibitors (SGLT2is) and GLP-1 receptor agonists (GLP1-RAs) reduce major adverse cardiovascular events (MACE) in patients with type 2 diabetes mellitus (T2DM). However, their effectiveness relative to each other and other second-line antihyperglycemic agents is unknown, without any major ongoing head-to-head trials.

Methods

Across the LEGEND-T2DM network, we included ten federated international data sources, spanning 1992-2021. We identified 1,492,855 patients with T2DM and established cardiovascular disease (CVD) on metformin monotherapy who initiated one of four second-line agents (SGLT2is, GLP1-RAs, dipeptidyl peptidase 4 inhibitor [DPP4is], sulfonylureas [SUs]). We used large-scale propensity score models to conduct an active comparator, target trial emulation for pairwise comparisons. After evaluating empirical equipoise and population generalizability, we fit on-treatment Cox proportional hazard models for 3-point MACE (myocardial infarction, stroke, death) and 4-point MACE (3-point MACE + heart failure hospitalization) risk, and combined hazard ratio (HR) estimates in a random-effects meta-analysis.

Findings

Across cohorts, 16·4%, 8·3%, 27·7%, and 47·6% of individuals with T2DM initiated SGLT2is, GLP1-RAs, DPP4is, and SUs, respectively. Over 5·2 million patient-years of follow-up and 489 million patient-days of time at-risk, there were 25,982 3-point MACE and 41,447 4-point MACE events. SGLT2is and GLP1-RAs were associated with a lower risk for 3-point MACE compared with DPP4is (HR 0·89 [95% CI, 0·79-1·00] and 0·83 [0·70-0·98]), and SUs (HR 0·76 [0·65-0·89] and 0·71 [0·59-0·86]). DPP4is were associated with a lower 3-point MACE risk versus SUs (HR 0·87 [0·79-0·95]). The pattern was consistent for 4-point MACE for the comparisons above. There were no significant differences between SGLT2is and GLP1-RAs for 3-point or 4-point MACE (HR 1·06 [0·96-1·17] and 1·05 [0·97-1·13]).

Interpretation

In patients with T2DM and established CVD, we found comparable cardiovascular risk reduction with SGLT2is and GLP1-RAs, with both agents more effective than DPP4is, which in turn were more effective than SUs. These findings suggest that the use of GLP1-RAs and SGLT2is should be prioritized as second-line agents in those with established CVD.

Funding

National Institutes of Health, United States Department of Veterans Affairs.

Statistical and Scientific Considerations Concerning the Interpretation, Replicability, and Transportability of Research Findings

To advance scientific understanding of disease processes and related intervention effects, study results should be free from bias and replicable. More broadly, investigators seek results that are transportable, that is, applicable to a perceived study population as well as in other environments and populations. We review fundamental statistical issues that arise in the analysis of observational data from disease cohorts and other sources and discuss how these issues affect the transportability and replicability of research results. Much of the literature focuses on estimating average exposure or intervention effects at the population level, but we argue for more nuanced analyses of conditional effects that reflect the complexity of disease processes.