Emulating a target trial of proton pump inhibitors and dementia risk using claims data

Methodologies for the Emulation of Biomarker-Guided Trials Using Observational Data: A Systematic Review

Background: Target trial emulation involves the application of design principles from randomised controlled trials (RCTs) to observational data, and is particularly useful in situations where an RCT would be unfeasible. Biomarker-guided trials, which incorporate biomarkers within their design to either guide treatment and/or determine eligibility, are often unfeasible in practice due to sample size requirements or ethical concerns. Here, we undertake a systematic review of methodologies used in target trial emulations, comparing treatment effectiveness, critically appraising them, and considering their applicability to the emulation of biomarker-guided trials. Methods: A comprehensive search strategy was developed to identify studies reporting on methods for target trial emulation comparing the effectiveness of treatments using observational data, and applied to the following bibliographic databases: PubMed, Scopus, Web of Science, and Ovid MEDLINE. A narrative description of methods identified in the review was undertaken alongside a critique of their relative strengths and limitations. Results: We identified a total of 59 papers: 47 emulating a target trial ('application' studies), and 12 detailing methods to emulate a target trial ('methods' studies). A total of 25 papers were identified as emulating a biomarker-guided trial (42%). While all papers reported methods to adjust for baseline confounding, 40% of application papers did not specify methods to adjust for time-varying confounding. Conclusions: This systematic review has identified a range of methods used to control for baseline, time-varying, and residual/unmeasured confounding within target trial emulation and provides a guide for researchers interested in emulation of biomarker-guided trials.

Potential Risks Associated With Long-term Use of Proton Pump Inhibitors and the Maintenance Treatment Modality for Patients With Mild Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) significantly affects the health-related quality of life and healthcare costs. The prevalence of this disease is increasing in Asia, leading to a rapid increase in the demand of proton pump inhibitors (PPIs). Despite effective symptom management during initial treatment, relapse rates after PPI cessation remain high in patients with GERD, warranting longterm maintenance therapy. Concerns regarding potential side effects related to the long-term use of PPIs are escalating with increased usage. Studies have reported diverse side effects of PPIs, such as increased fracture risk, cardiovascular concerns, enteric infections, neurological diseases, and potential associations with gastric cancer. However, definitive causal relationships remain unclear. This review comprehensively summarizes the latest knowledge on the potential risks associated with long-term use of PPIs. Continuous or noncontinuous therapy can be used as a maintenance treatment modality for GERD. For patients with mild GERD, including those with nonerosive and mildly erosive reflux disease, on-demand therapy following a sufficient period of continuous maintenance therapy is recommended as a long-term maintenance treatment option.

Early Addition of Selexipag to Double Therapy for Pulmonary Arterial Hypertension

Importance

A subgroup analysis of a randomized clinical trial established the efficacy of selexipag plus background therapy (monotherapy or double oral therapy [DOT]) vs placebo plus background therapy and found that the addition of selexipag within 6 months had an added benefit. However, the timing of selexipag addition to DOT and the incremental benefit in clinical practice is not well studied.

Objective

To compare triple oral therapy (TOT) consisting of selexipag, endothelin receptor antagonist (ERA), and phosphodiesterase type 5 inhibitor (PDE5i) vs DOT consisting of ERA and PDE5i.

Design, Setting, and Participants

This comparative effectiveness study was conducted using data from the US Komodo claims database to emulate a randomized trial. Patients aged 18 years or older with pulmonary arterial hypertension (PAH) treated with ERA plus PDE5i with records from July 2015 through June 2022 were duplicated to TOT and DOT and artificially censored when observed treatment deviated from assigned treatment. Hypothetical randomization was emulated using inverse probability of treatment weighting, and the study accounted for censoring-induced selection bias using inverse probability of censoring weighting. A pooled logistic model estimated the per-protocol difference between treatment groups. Data were analyzed from November 2022 through July 2023.

Interventions

TOT (addition of selexipag within 3, 6, and 12 months of initiating DOT) vs DOT.

Main Outcomes and Measures

Adjusted risk of all-cause hospitalization, PAH-related hospitalization, and PAH-related disease progression over a 2-year follow-up.

Results

A total of 2966 patients with PAH (mean [SD] age, 54.3 [14.0] years; 2125 female [71.6%]) met eligibility criteria. Adding selexipag within 6 months of ongoing DOT was associated with a reduction in risk for all-cause hospitalization (adjusted hazard ratio [aHR], 0.82; 95% CI, 0.72-0.94), PAH-related hospitalization (aHR, 0.81; 95% CI, 0.70-0.95), and PAH-related progression (aHR, 0.82; 95% CI, 0.70-0.95) vs DOT alone. There were no associations if selexipag was initiated within 12 months for all-cause hospitalization, PAH-related hospitalization, or PAH-related disease progression. The association remained with a greater decrease in risk for disease progression vs DOT for selexipag initiation within 3 months (aHR, 0.74; 95% CI, 0.61-0.90).

Conclusions and Relevance

This study found that early selexipag addition to ERA plus PDE5i was associated with a reduction in risk of hospitalization and disease progression. These findings suggest that delays in selexipag initiation likely contribute to suboptimal patient and health system outcomes.

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.

Target trial emulation of carfilzomib safety among patients with relapsed/refractory multiple myeloma using a nationwide observational data in Korea

PURPOSE

Carfilzomib, commonly used for relapsed/refractory multiple myeloma (RRMM), has been associated with various adverse events in randomized controlled trials (RCTs). However, real-world safety data for a more diverse population are needed, as carfilzomib received expedited approval. This study aimed to evaluate carfilzomib's safety in Korea by comparing new users of KRd (carfilzomib, lenalidomide, and dexamethasone) to Rd (lenalidomide and dexamethasone) using a nationwide administrative claims database.

METHODS

The retrospective cohort study utilized target trial emulation, focusing on adverse events in various organ systems similar to the ASPIRE trial.

RESULTS

This study included 4,580 RRMM patients between 2007 and 2020, and the KRd group showed significantly higher risks of hematologic adverse events (anemia, neutropenia, thrombocytopenia) and some non-hematologic adverse events (cough, hypokalemia, constipation, hypertension, heart failure) compared to the Rd group. Among non-hematologic adverse events, cardiovascular events (heart failure [HR 2.04; 95% CI 1.24-3.35], hypertension [HR 1.58; 95% CI 1.15-2.17]) had the highest risk in the KRd group.

CONCLUSION

The safety profile of carfilzomib in Korean patients was similar to previous RCTs. Therefore, caution should be exercised when using carfilzomib in Asian individuals with RRMM due to the increased risk of cardiovascular adverse events.

Proton pump inhibitors and dementia: A nationwide population-based study

INTRODUCTION

Proton pump inhibitors (PPIs) may increase dementia risk. However, it is currently unknown whether timing of exposure or age at dementia diagnosis influence the risk.

METHODS

We assessed associations between cumulative PPI use and dementia at different ages in a nationwide Danish cohort of 1,983,785 individuals aged 60 to 75 years between 2000 and 2018.

RESULTS

During follow-up, there were 99,384 all-cause dementia incidences. Incidence rate ratio (IRR) of dementia with PPI ever-use compared with never-use was 1.36 (95% CI, 1.29 to 1.43) for age 60 to 69 years at diagnosis, 1.12 (1.09 to 1.15) for 70 to 79 years, 1.06 (1.03 to 1.09) for 80 to 89 years, and 1.03 (0.91 to 1.17) for 90+ years. Longer treatment duration yielded increasing IRRs. For cases below 90 years, increased dementia rate was observed regardless of treatment initiation up to >15 years before diagnosis.

DISCUSSION

Regardless of timing of treatment initiation, PPI use was associated with increased dementia rate before age 90 years. Dementia rates increased with younger age at diagnosis.

HIGHLIGHTS

After following 1,983,785 individuals for a median of 10 years, 99,384 developed dementia PPIs were used by 21.2% of cases and 18.9% of controls PPI use was associated with increased dementia rate regardless of time of treatment onset Magnitude of associations increased with younger age at diagnosis PPI use was not associated with dementia occurring after age 90 years.

Instrumental variables in real-world clinical studies of dementia and neurodegenerative disease: Systematic review of the subject-matter argumentation, falsification test, and study design strategies to justify a valid instrument

OBJECTIVES

We systematically reviewed how investigators argued for and justified the validity of their instrumental variables (IV) in clinical studies of dementia and neurodegenerative disease.

METHODS

We included studies using IV analysis with observational data to investigate causal effects in clinical research studies of dementia and neurodegenerative disease. We reported the subject-matter argumentation, falsification test, and study design strategies used to satisfy the three assumptions of a valid IV: relevance, exclusion restriction, and exchangeability.

RESULTS

Justification for the relevance assumption was performed in all 12 included studies, exclusion restriction in seven studies, and exchangeability in nine studies. Two subject-matter argumentation strategies emerged from seven studies on the relevance of their IV. All studies except one provided quantitative evidence for the strength of the association between the IV and exposure variable. Four argumentation strategies emerged for exclusion restriction from six studies. Four falsification tests were performed across three studies. Three argumentation strategies emerged for exchangeability across four studies. Nine falsification tests were performed across nine studies. Two notable study design strategies were reported.

CONCLUSION

Our results reinforce IV analysis as a feasible option for clinical researchers in dementia and neurodegenerative disease by clarifying known strategies used to validate an IV.

Time-Varying Use of Proton Pump Inhibitors and Cognitive Impairment and Dementia: A Real-World Analysis from Germany

BACKGROUND

Cumulative evidence of dementia risk in patients taking proton pump inhibitors (PPIs) is still inconclusive, probably due to a variety of study designs.

OBJECTIVE

This study aimed to compare how the association between dementia risk and use of PPIs differs by different outcome and exposure definitions.

METHODS

We conceptualized a target trial using claims data with 7,696,127 individuals aged 40 years or older without previous dementia or mild cognitive impairment (MCI) from the Association of Statutory Health Insurance Physicians in Bavaria. Dementia was defined as either including or excluding MCI to compare how the results alter by different outcome definitions. We used weighted Cox models to estimate the PPI initiation effect on dementia risk and weighted pooled logistic regression to assess the effect of time-varying use versus non-use during 9 years of study period, including 1 year of wash-out period (2009-2018). The median follow-up time of PPI initiators and non-initiators was 5.4 and 5.8 years, respectively. We also evaluated the association between each PPI agent (omeprazole, pantoprazole, lansoprazole, esomeprazole, and combined use) and dementia risk.

RESULTS

A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk. A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.

CONCLUSION

Our large study supports existing evidence that PPI use is related to an increased risk of dementia.

Mechanistic Insight into the Inhibition of Choline Acetyltransferase by Proton Pump Inhibitors

Various pharmacoepidemiological investigational studies have indicated that Proton Pump Inhibitors (PPIs) may increase the likelihood of developing Alzheimer's disease (AD) and non-AD related dementias. Previously, we have reported the inhibition of the acetylcholine biosynthesizing enzyme choline acetyltransferase (ChAT) by PPIs, for which omeprazole, lansoprazole, and pantoprazole exhibited IC₅₀ values of 0.1, 1.5, and 5.3 μM, respectively. In this study we utilize a battery of computational tools to perceive a mechanistic insight into the molecular interaction of PPIs with the ChAT binding pocket that may further help in designing novel ChAT ligands. Various in-silico tools make it possible for us to elucidate the binding interaction, conformational stability, and dynamics of the protein-ligand complexes within a 200 ns time frame. Further, the binding free energies for the PPI-ChAT complexes were explored. The results suggest that the PPIs exhibit equal or higher binding affinity toward the ChAT catalytic tunnel and are stable throughout the simulated time and that the pyridine ring of the PPIs interacts primarily with the catalytic residue His₃₂₄. A free energy landscape analysis showed that the folding process was linear, and the residue interaction network analysis can provide insight into the roles of various amino acid residues in stabilization of the PPIs in the ChAT binding pocket. As a major factor for the onset of Alzheimer's disease is linked to cholinergic dysfunction, our previous and the present findings give clear insight into the PPI interaction with ChAT. The scaffold can be further simplified to develop novel ChAT ligands, which can also be used as ChAT tracer probes for the diagnosis of cholinergic dysfunction and to initiate timely therapeutic interventions to prevent or delay the progression of AD.

Do proton pump inhibitors increase the risk of dementia? A systematic review, meta-analysis and bias analysis

AIM

Previous studies on the association between proton pump inhibitor (PPI) intake and the increased risk of dementia has shown discrepancies in their conclusions. We aimed to provide updated evidence based on extensive bias assessments and quantitative sensitivity analyses.

METHODS

We searched the databases PubMed, EMBASE, SCOPUS, CENTRAL and clinicaltrials.gov for prospective studies that examined an association between PPI use and dementia, up to February 2022. Each study was assessed using the Cochrane risk of bias assessment tools for non-randomized studies of interventions (ROBINS-I) or randomized trials (RoB2). Pooled risk ratios (RRs) and 95% prediction intervals were computed using random-effects models. Sensitivity analyses were adjusted for small-study bias.

RESULTS

We included nine observational studies with 204 108 dementia cases in the primary analysis on the association between PPI use vs. non-use and dementia, and the RR was 1.16 (95% CI = 1.00; 1.35). After adjusting for small-study bias by Copas selection model and Rücker's shrinkage procedure, the RR was 1.16 (1.02; 1.32) and 1.15 (1.13; 1.17), respectively. A subgroup analysis of PPI use vs. non-use regarding Alzheimer's disease risk yielded an RR of 1.15 (0.89; 1.50). The secondary analysis on the risk of dementia by use of PPI vs. histamine-2 receptor antagonist showed an RR of 1.03 (0.66; 1.62).

CONCLUSION

This meta-analysis provided no clear evidence for an association between PPI intake and the risk of dementia. Due to discrepancies in sensitivity analyses, however, some risk of dementia by PPI use cannot be ruled out. Since an unequivocal conclusion is still pending, further research is warranted.

Signal and Noise: Proton Pump Inhibitors and the Risk of Dementia?

The association between proton pump inhibitor (PPI) use and dementia remains controversial. This cohort study re-examines this issue, addressing shortcomings identified in previous publications using a population-based and a high-dimension propensity-score matched cohort to follow patients for up to 22 years. Cox regression models using baseline characteristics, a lag period, and time-varying variables were used to examine the risk of dementia by cumulative PPI exposure. High-dose PPI users (> 180 days of use) had significantly higher risk of dementia in crude Cox models. After adjustment for medical diagnoses and prescription drug use, these associations disappeared. Among high-dose users starting PPI therapy between 46 and 55 years old, the unadjusted hazard ratio (HR) was 1.55 (95% confidence interval (CI) 1.14, 2.10); the adjusted hazard ratio (aHR) was 1.10 (95% CI 0.80, 1.51). For high-dose users starting therapy between 56 and 65 years, HR = 1.22 (95% CI1.03, 1.44); aHR = 0.99 (95% CI 0.83, 1.17). High-dose users between the ages of 66 and 75 years had no association with the risk of dementia. The use of lag models or time-varying parameters similarly found some association with dementia in crude, but not multivariable Cox models. Although high-dose PPI users were more likely to develop dementia, they were more likely to be diagnosed with dementia risk factors, such as diabetes and cardiovascular disease, which are risk factors for dementia. Controlling for these conditions using multivariable models or a propensity-score matched cohort eliminated this association.

Hypoglycaemia and the risk of dementia: a population-based cohort study using exposure density sampling

BACKGROUND

Previous studies have shown hypoglycaemia to be associated with an increased risk of dementia; however, there are several design challenges to consider. The objective of this study is to assess the association between hypoglycaemia and dementia while addressing these challenges using a lag period, exposure density sampling (EDS) and inverse probability of treatment weighting (IPTW).

METHODS

This was a population-based cohort using data (1996-2018) from British Columbia, Canada. From a cohort of incident type 2 diabetes patients aged 40-70 years, we created a dynamic sub-cohort of hypoglycaemia-exposed (≥1 episode requiring hospitalization or a physician visit) and unexposed individuals using EDS, in which four unexposed individuals per one exposed were randomly selected into risk sets based on diabetes duration and age. Follow-up was until dementia diagnosis, death, emigration or 31 December 2018. Those diagnosed with dementia within 2 years of follow-up were censored. We adjusted for confounding using IPTW and estimated the hazard ratio (HR, 95% CI) of dementia using weighted conditional cause-specific hazards risk models with death as a competing risk.

RESULTS

Among 13 970 patients with incident type 2 diabetes, 2794 experienced hypoglycaemia. There were 329 dementia events over a median (interquartile range: IQR) follow-up of 5.03 (5.7) years. IPTW resulted in well-balanced groups with weighted incidence rates (95% CI) of 4.59 (3.52, 5.98)/1000 person-years among exposed and 3.33 (2.58, 3.88)/1000 person-years among unexposed participants. The risk of dementia was higher among those with hypoglycaemia (HR, 1.83; 95% CI 1.31, 2.57).

CONCLUSIONS

After addressing several methodological challenges, we showed that hypoglycaemia contributes to an increased risk of all-cause dementia among patients with type 2 diabetes.