Causal inference from longitudinal studies with baseline randomization

Hepatic real-world outcomes with obeticholic acid in primary biliary cholangitis (HEROES): A trial emulation study design

BACKGROUND AND AIMS

Primary biliary cholangitis is a rare, progressive liver disease. Obeticholic acid (OCA) received accelerated approval for treating patients with primary biliary cholangitis in whom ursodeoxycholic acid failed, based on a surrogate endpoint of reduction in ALP. Analysis of the long-term safety extension with 2 external control groups demonstrated a significant increase in event-free survival in OCA-treated patients. This fully real-world evidence study assessed the effect of OCA treatment on clinical outcomes.

APPROACH AND RESULTS

This trial emulation used data from the Komodo Healthcare Map claims database linked to US national laboratory, transplant, and death databases. Patients with compensated primary biliary cholangitis and intolerance/inadequate response to ursodeoxycholic acid who initiated OCA therapy were compared with patients who were OCA-eligible but not OCA-treated. The primary endpoint was time to the first occurrence of death, liver transplant, or hospitalization for hepatic decompensation, analyzed using a propensity-score weighted Cox proportional hazards model. Baseline prognostic factors were balanced using standardized morbidity ratio weighting. For the primary analysis, 4174 patients contributed 11,246 control index dates, and 403 patients contributed OCA indexes. Weighted groups were well balanced. Median (95% CI) follow-up in the OCA and non-OCA arms was 9.3 (8.4-10.6) months and 17.5 (16.2-18.6) months (weighted population; censored at discontinuation). Eight events occurred in the OCA arm and 32 in the weighted control (HR = 0.37; 95% CI = 0.14-0.75; p < 0.001). Effects were consistent for each component of the composite endpoint.

CONCLUSIONS

We identified a 63% reduced risk of hospitalization for hepatic decompensation, liver transplant, or death in OCA-treated versus non-OCA-treated individuals.

TRIAL REGISTRATION

HEROES; ClinicalTrials.gov NCT05292872.

Using the counterfactual framework to estimate non-intention-to-treat estimands in randomised controlled trials: A methodological scoping review

BACKGROUND

Randomised controlled trials (RCTs) commonly estimate intention-to-treat (ITT) estimands. However, when nonadherence to assigned treatment occurs, ITT estimands reflect the effect of being offered treatment, rather than adhering to it and thus are less useful for clinical decision-making.

OBJECTIVE

Summarise current literature on non-ITT estimands used in RCTs to estimate the effect of adhering to treatment and counterfactual framework estimators that are employed to obtain these non-ITT estimands.

STUDY DESIGN AND SETTING

We conducted a methodological scoping review and searched MEDLINE and EMBASE from inception to March 2024, with forward and backward citation searching. Eligible records discussed counterfactual framework estimators to obtain non-ITT estimands in RCTs or simulation studies based on empirical RCTs.

RESULTS

From 746 records screened, our search identified 56 eligible records. 47 (84 %) described specific estimators for addressing nonadherence and 9 (16 %) described frameworks for overall methodological approach. In the 47 estimator records, 51 non-ITT estimands were reported, including poorly defined estimands (n = 21, 41 %), complier average causal effects (n = 17, 33 %), switching-adjusted estimands (n = 7, 14 %), and per-protocol estimands (n = 6, 12 %). There were 83 estimator applications, including inverse probability weighting (n = 22, 27 %), instrumental variables (IVs) for time-varying treatments (n = 15, 18 %), and standard IVs (n = 14, 17 %). Other estimators included doubly-robust estimators using machine learning.

CONCLUSION

Non-ITT estimands in RCTs tended to be poorly defined and lacked relevance for clinical decision-making. Further research on using estimators from the counterfactual framework to estimate well-defined estimands, particularly per-protocol estimands, is needed to support greater uptake in practice and policy decision making.

Systematic Review and Meta-Analysis: Multisystemic Therapy and Functional Family Therapy Targeting Antisocial Behavior in Adolescence

OBJECTIVE

Youth criminal justice systems are under growing pressure to reduce re-offending behavior and to support young people's health and developmental needs. This systematic review and meta-analysis sought to synthesise evidence for 2 prominent community-based interventions for delinquent and antisocial behavior, namely, multisystemic therapy (MST) and functional family therapy (FFT).

METHOD

We searched Medline, PsycInfo, Scopus, Web of Science, and Social Services Abstracts for randomized controlled trials (RCTs) and quasi-experimental studies evaluating MST/FFT. Included studies involved participants aged under 18 years; included interventions targeted delinquent/antisocial behavior, but not maltreatment. We estimated effect sizes for 6 primary outcomes, synthesising RCTs comparing MST/FFT to usual care using correlated hierarchical effects meta-analysis. We assessed risk of bias and evidence strength using best-practice tools. Given the additional resources needed to implement MST/FFT, we rated evidence strength against a minimum clinically important difference rather than a null effect. This study is registered with PROSPERO, CRD42021279736.

RESULTS

We included 35 studies for MST (16 RCTs meta-analyzed comprising 4,095 participants, 26% female) and 19 studies for FFT (7 RCTs meta-analyzed comprising 1,471 participants, 22% female). MST had a likely clinically important effect on time in out-of-home care, but no clinically important effects on other primary outcomes (delinquency, new offenses/convictions, placement in out-of-home care, substance use), with low-to-moderate evidence strength. FFT demonstrated possible clinically important effects for the number of new offenses/convictions, time in out-of-home care, and substance use, but evidence strength was low.

CONCLUSION

Contrary to reports in some evidence clearinghouses indicating that MST/FFT are supported by the highest level of evidence strength, there is limited evidence that these interventions are superior to usual care in reducing delinquent and antisocial behavior in adolescence. These findings should be viewed in the context of important methodological differences with prior reviews, including the rating of evidence strength against a minimum clinically important difference.

PLAIN LANGUAGE SUMMARY

Delinquent and antisocial behavior by young people imposes high costs on the wellbeing of individuals and the broader community. This systematic review summarized evidence for two prominent community-based interventions for delinquent and antisocial behavior: multisystemic therapy ([MST], 35 studies) and functional family therapy ([FFT], 19 studies). MST led to a reduced time in out-of-home care compared to usual treatment. FFT had larger favorable effects on delinquency, new offenses and convictions, placement in out-of-home care, and substance use, but the quality of the evidence was poor. The authors concluded that there is limited evidence that either MST or FFT are superior to usual care in reducing delinquent and antisocial behavior in adolescence.

STUDY PREREGISTRATION INFORMATION

The effect of Multi-Systemic Therapy and Functional Family Therapy in addressing child and adolescent delinquent and/or antisocial behavior and childhood maltreatment; https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=279736.

Executive function is associated with behaviour problems in children and adolescents with cerebral palsy and intellectual disability

BACKGROUND

Children and adolescents with cerebral palsy (CP) commonly have behaviour problems. The present study aimed to determine which of the most common clinical features experienced by children and adolescents with CP and intellectual disability are associated with behaviour problems.

METHOD

We investigated 11 possible associated variables including epilepsy, visual and hearing impairments, motor difficulties, communication and speech difficulties, pain, sleep disturbance, executive function (EF) deficits, type of CP, and parent stress. Thirty-eight parents or guardians of children aged 6 to 17 years with CP and intellectual disability (parent informed) completed proxy and self-report standardised questionnaires.

RESULTS

EF deficits and parent stress were significantly associated with behavioural problems.

CONCLUSION

For children and adolescents with CP and intellectual disability, the present study suggests close attention should be placed on specific clinical features including EF deficits and parent stress when considering variables associated with behaviour problems.

Top-down infliximab plus azathioprine versus azathioprine alone in patients with acute severe ulcerative colitis responsive to intravenous steroids: a parallel, open-label randomised controlled trial, the ACTIVE trial

BACKGROUND

It is unknown which maintenance therapy is the most effective option for patients admitted for an acute severe ulcerative colitis (ASUC) episode responding to intravenous steroids.

METHODS

We conducted a multicentre, parallel-group, open-label randomised controlled trial among 23 French centres in thiopurine and biologics-naïve adults admitted for ASUC responding to intravenous steroids. Eligible patients were randomly assigned to receive infliximab (IFX) and azathioprine (AZA) with a 7-day steroid tapering scheme (IFX+AZA arm) or AZA and conventional standardised steroid tapering regimen (AZA arm). The primary composite endpoint was treatment failure at week 52, defined as the absence of steroid-free clinical remission, the absence of endoscopic response, the use of a prohibited treatment for relapse, severe adverse event leading to treatment interruption, colectomy or death. Multiple imputation for missing data was performed.

FINDINGS

Among the 64 patients randomised (Lichtiger score 13.5±2.0; median age of 34.5 (P25-P75 26.3-50.3) years, median C reactive protein of 29.0 (12.8-96.8) mg/L at baseline): 32 were assigned to the IFX+AZA arm and 32 to the AZA arm. In the ITT population, treatment failure at week 52 was observed in 22/27 (81.5%) in the AZA arm and 16/30 (53.3%) in the IFX+AZA arm (risk ratio 3.85, 95% CI (1.15 to 12.88), p=0.03). 29 adverse events were severe, including 13 disease exacerbations, 6 severe infections without any difference between both arms.

INTERPRETATION

Combination therapy with IFX+AZA was more effective at 1 year than AZA alone to avoid treatment failure in patients with ASUC responding to intravenous steroids.

TRIAL REGISTRATION NUMBER

NCT02425852.

Clinical Effectiveness and Cost-Effectiveness of Multigene Panel Sequencing in Advanced Melanoma: A Population-Level Real-World Target Trial Emulation

PURPOSE

Targeted therapy and immunotherapy promise improved survival in patients with advanced melanoma, yet the effectiveness and cost-effectiveness of multigene panel sequencing compared with single-gene BRAF testing to guide therapeutic decisions is unknown.

METHODS

Our population-based quasi-experimental retrospective target trial emulation used comprehensive patient-level data for 364 British Columbia, Canada, adults with an advanced melanoma diagnosis receiving multigene panel sequencing or single-gene BRAF testing between September 1, 2016, and December 31, 2018. We 1:1 matched multigene panel patients to controls using genetic algorithm-based matching. Outcomes included 3-year overall survival (OS) and health care costs (2021 Canadian dollars [CAD]) with incremental net monetary benefit for life-years gained (LYG). Outcomes were analyzed using inverse probability of censoring weighted linear regression for the intention-to-treat (ITT) effect. The per-protocol (PP) effect estimation also included stabilized inverse probability of treatment weights. We then used Weibull regression and Kaplan-Meier survival analysis.

RESULTS

We matched 147 multigene panel patients to controls, achieving balance for all covariates. After matching, ITT incremental costs were $19,447 CAD (95% CI, -$18,516 to $76,006) and incremental LYG were 0.22 (95% CI, -0.05 to 0.49). We found uncertainty in differences on OS using Kaplan-Meier (P = .11) and Weibull regression (hazard ratio [HR], 0.73 [95% CI, 0.51 to 1.03]) in the ITT. PP incremental costs were $36,367 CAD (95% CI, -$6,653 to $120,216]) and incremental LYG were 0.56 (95% CI, 0.39 to 1.24), with corresponding differences in OS using Kaplan-Meier (P = .02) and Weibull regression (HR, 0.56 [95% CI, 0.36 to 0.87]). The probability of multigene panels being cost-effective at $100,000/LYG CAD was 55% for ITT and 65% for PP.

CONCLUSION

The cost-effectiveness of multigene panels was evenly poised at higher thresholds, even when accounting for treatment initiation. Health systems reimbursing multigene panels and expensive therapies may be confronted with a value tradeoff, in which there may be improved survival albeit with a modest change in cost-effectiveness.

Effect of Four Hemoglobin Transfusion Threshold Strategies in Patients With Acute Myocardial Infarction and Anemia : A Target Trial Emulation Using MINT Trial Data

BACKGROUND

The optimal hemoglobin threshold to guide red blood cell (RBC) transfusion for patients with acute myocardial infarction (MI) and anemia is uncertain.

OBJECTIVE

To estimate the efficacy of 4 individual hemoglobin thresholds (<10 g/dL [<100 g/L], <9 g/dL [<90 g/L], <8 g/dL [<80 g/L], and <7 g/dL [<70 g/L]) to guide transfusion in patients with acute MI and anemia.

DESIGN

Prespecified secondary analysis of the MINT (Myocardial Ischemia and Transfusion) trial using target trial emulation methods. (ClinicalTrials.gov: NCT02981407).

SETTING

144 clinical sites in 6 countries.

PARTICIPANTS

3492 MINT trial participants with acute MI and a hemoglobin level below 10 g/dL.

INTERVENTION

Four transfusion strategies to maintain patients' hemoglobin concentrations at or above thresholds of 10, 9, 8, or 7 g/dL. Protocol exceptions were permitted for specified adverse clinical events.

MEASUREMENTS

Data from the MINT trial were leveraged to emulate 4 transfusion strategies and estimate per protocol effects on the composite outcome of 30-day death or recurrent MI (death/MI) and 30-day death using inverse probability weighting.

RESULTS

The 30-day risk for death/MI was 14.8% (95% CI, 11.8% to 18.4%) for a <10-g/dL strategy, 15.1% (CI, 11.7% to 18.2%) for a <9-g/dL strategy, 15.9% (CI, 12.4% to 19.0%) for a <8-g/dL strategy, and 18.3% (CI, 14.6% to 22.0%) for a <7-g/dL strategy. Absolute risk differences and risk ratios relative to the <10-g/dL strategy for 30-day death/MI increased as thresholds decreased, although 95% CIs were wide. Findings were similar and imprecise for 30-day death.

LIMITATION

Unmeasured confounding may have persisted despite adjustment.

CONCLUSION

The 30-day risks for death/MI and death among patients with acute MI and anemia seem to increase progressively with lower hemoglobin concentration thresholds for transfusion. However, the imprecision around estimates from this target trial analysis precludes definitive conclusions about individual hemoglobin thresholds.

PRIMARY FUNDING SOURCE

National Heart, Lung, and Blood Institute.

Medication-Induced Weight Change Across Common Antidepressant Treatments : A Target Trial Emulation Study

BACKGROUND

Antidepressants are among the most commonly prescribed medications, but evidence on comparative weight change for specific first-line treatments is limited.

OBJECTIVE

To compare weight change across common first-line antidepressant treatments by emulating a target trial.

DESIGN

Observational cohort study over 24 months.

SETTING

Electronic health record (EHR) data from 2010 to 2019 across 8 U.S. health systems.

PARTICIPANTS

183 118 patients.

MEASUREMENTS

Prescription data determined initiation of treatment with sertraline, citalopram, escitalopram, fluoxetine, paroxetine, bupropion, duloxetine, or venlafaxine. The investigators estimated the population-level effects of initiating each treatment, relative to sertraline, on mean weight change (primary) and the probability of gaining at least 5% of baseline weight (secondary) 6 months after initiation. Inverse probability weighting of repeated outcome marginal structural models was used to account for baseline confounding and informative outcome measurement. In secondary analyses, the effects of initiating and adhering to each treatment protocol were estimated.

RESULTS

Compared with that for sertraline, estimated 6-month weight gain was higher for escitalopram (difference, 0.41 kg [95% CI, 0.31 to 0.52 kg]), paroxetine (difference, 0.37 kg [CI, 0.20 to 0.54 kg]), duloxetine (difference, 0.34 kg [CI, 0.22 to 0.44 kg]), venlafaxine (difference, 0.17 kg [CI, 0.03 to 0.31 kg]), and citalopram (difference, 0.12 kg [CI, 0.02 to 0.23 kg]); similar for fluoxetine (difference, -0.07 kg [CI, -0.19 to 0.04 kg]); and lower for bupropion (difference, -0.22 kg [CI, -0.33 to -0.12 kg]). Escitalopram, paroxetine, and duloxetine were associated with 10% to 15% higher risk for gaining at least 5% of baseline weight, whereas bupropion was associated with 15% reduced risk. When the effects of initiation and adherence were estimated, associations were stronger but had wider CIs. Six-month adherence ranged from 28% (duloxetine) to 41% (bupropion).

LIMITATION

No data on medication dispensing, low medication adherence, incomplete data on adherence, and incomplete data on weight measures across time points.

CONCLUSION

Small differences in mean weight change were found between 8 first-line antidepressants, with bupropion consistently showing the least weight gain, although adherence to medications over follow-up was low. Clinicians could consider potential weight gain when initiating antidepressant treatment.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Causal Inference About the Effects of Interventions From Observational Studies in Medical Journals

Importance

Many medical journals, including JAMA, restrict the use of causal language to the reporting of randomized clinical trials. Although well-conducted randomized clinical trials remain the preferred approach for answering causal questions, methods for observational studies have advanced such that causal interpretations of the results of well-conducted observational studies may be possible when strong assumptions hold. Furthermore, observational studies may be the only practical source of information for answering some questions about the causal effects of medical or policy interventions, can support the study of interventions in populations and settings that reflect practice, and can help identify interventions for further experimental investigation. Identifying opportunities for the appropriate use of causal language when describing observational studies is important for communication in medical journals.

Observations

A structured approach to whether and how causal language may be used when describing observational studies would enhance the communication of research goals, support the assessment of assumptions and design and analytic choices, and allow for more clear and accurate interpretation of results. Building on the extensive literature on causal inference across diverse disciplines, we suggest a framework for observational studies that aim to provide evidence about the causal effects of interventions based on 6 core questions: what is the causal question; what quantity would, if known, answer the causal question; what is the study design; what causal assumptions are being made; how can the observed data be used to answer the causal question in principle and in practice; and is a causal interpretation of the analyses tenable?

Conclusions and Relevance

Adoption of the proposed framework to identify when causal interpretation is appropriate in observational studies promises to facilitate better communication between authors, reviewers, editors, and readers. Practical implementation will require cooperation between editors, authors, and reviewers to operationalize the framework and evaluate its effect on the reporting of empirical research.

Longitudinal joint modeling for assessing parallel interactive development of latent ability and processing speed using responses and response times

To measure the parallel interactive development of latent ability and processing speed using longitudinal item response accuracy (RA) and longitudinal response time (RT) data, we proposed three longitudinal joint modeling approaches from the structural equation modeling perspective, namely unstructured-covariance-matrix-based longitudinal joint modeling, latent growth curve-based longitudinal joint modeling, and autoregressive cross-lagged longitudinal joint modeling. The proposed modeling approaches can not only provide the developmental trajectories of latent ability and processing speed individually, but also exploit the relationship between the change in latent ability and processing speed through the across-time relationships of these two constructs. The results of two empirical studies indicate that (1) all three models are practically applicable and have highly consistent conclusions in terms of the changes in ability and speed in the analysis of the same data set, and (2) additional analysis of the RT data and acquisition of individual processing speed measurements can reveal the parallel interactive development phenomena that are difficult to detect using RA data alone. Furthermore, the results of our simulation study demonstrate that the proposed Bayesian Markov chain Monte Carlo estimation algorithm can ensure accurate model parameter recovery for all three proposed longitudinal joint models. Finally, the implications of our findings are discussed from the research and practice perspectives.

Association of Longitudinal B-Type Natriuretic Peptide Monitoring With Kidney Failure in Patients With CKD: A Cohort Study

RATIONALE & OBJECTIVE

Both hypervolemia and hypovolemia are associated with chronic kidney disease (CKD) progression. Although longitudinal monitoring of B-type natriuretic peptide (BNP) may aid physicians' decision making about the optimization of volume status, its clinical benefit remains uncertain in CKD. This study assessed the association between BNP monitoring and the risk of incident kidney replacement therapy (KRT).

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

A total of 2,998 outpatients with stages 3-5 of nondialyzed CKD referred to the department of nephrology at an academic hospital.

EXPOSURE

BNP monitoring.

OUTCOME

KRT, acute kidney injury (AKI), and heart failure hospitalization.

ANALYTICAL APPROACH

Marginal structural models, which create a balanced pseudo population at each time point, were applied to account for potential time-dependent confounders. Inverse probability weighted pooled logistic regression models were employed to estimate hazard ratios.

RESULTS

At baseline, the median age and estimated glomerular filtration rate were 66 years and 38.1mL/min/1.73m2, respectively. During the follow-up period (median, 5.9 [IQR, 2.8-9.9] years), 449 patients required KRT, 765 had AKI, and 236 were hospitalized for heart failure. After adjustment for time-updated clinical characteristics and physician-specific practice styles, BNP monitoring was associated with lower risks of KRT (HR, 0.44 [95% CI, 0.21-0.92]), AKI (HR, 0.36 [95% CI, 0.18-0.72]), and heart failure hospitalization (HR, 0.37 [95% CI, 0.14-0.95]). The association between BNP monitoring and KRT was attenuated after additional adjustment for AKI or heart failure hospitalization as a time-varying covariate.

LIMITATIONS

Residual confounding by measured and unmeasured variables or indications for BNP measurements.

CONCLUSIONS

BNP monitoring was associated with a lower risk of KRT among patients with CKD that did not require dialysis. This association is potentially mediated through a reduced risk of AKI or heart failure hospitalization.

PLAIN-LANGUAGE SUMMARY

Both volume overload and volume depletion are deleterious to kidney function. B-type natriuretic peptide (BNP) is a biomarker that reflects volume status not only in heart failure but also in nondialysis chronic kidney disease (CKD). Although longitudinal BNP monitoring may aid physicians' decision making about the optimization of volume status, its clinical benefit remains uncertain in CKD. In this cohort study analyzing 2,998 patients with nondialyzed CKD, BNP monitoring was associated with a lower risk of kidney replacement therapy, acute kidney injury, and heart failure hospitalization over the follow-up period. The association with kidney replacement therapy may be mediated through a reduced risk of acute kidney injury or heart failure hospitalization. BNP monitoring may aid physicians in optimal fluid management, potentially conferring better kidney outcomes.

A non-parametric Bayesian approach for adjusting partial compliance in sequential decision making

Existing methods for estimating the mean outcome under a given sequential treatment rule often rely on intention-to-treat analyses, which estimate the effect of following a certain treatment rule regardless of compliance behavior of patients. There are two major concerns with intention-to-treat analyses: (1) the estimated effects are often biased toward the null effect; (2) the results are not generalizable and reproducible due to the potentially differential compliance behavior. These are particularly problematic in settings with a high level of non-compliance, such as substance use disorder studies. Our work is motivated by the Adaptive Treatment for Alcohol and Cocaine Dependence study (ENGAGE), which is a multi-stage trial that aimed to construct optimal treatment strategies to engage patients in therapy. Due to the relatively low level of compliance in this trial, intention-to-treat analyses essentially estimate the effect of being randomized to a certain treatment, instead of the actual effect of the treatment. We obviate this challenge by defining the target parameter as the mean outcome under a dynamic treatment regime conditional on a potential compliance stratum. We propose a flexible non-parametric Bayesian approach based on principal stratification, which consists of a Gaussian copula model for the joint distribution of the potential compliances, and a Dirichlet process mixture model for the treatment sequence specific outcomes. We conduct extensive simulation studies which highlight the utility of our approach in the context of multi-stage randomized trials. We show robustness of our estimator to non-linear and non-Gaussian settings as well.

Protective effect of intensive glucose lowering therapy on all-cause mortality, adjusted for treatment switching using G-estimation method, the ACCORD trial

Previous analysis of the action to control cardiovascular risk in diabetes showed an increased risk of mortality among patients receiving intensive glucose lowering therapy using conventional regression method with intention to treat approach. This method is biased when time-varying confounder is affected by the previous treatment. We used 15 follow-up visits of ACCORD trial to compare the effect of time-varying intensive vs. standard treatment of glucose lowering drugs on cardiovascular and mortality outcomes in diabetic patients. The treatment effect was estimated using G-estimation and compared with accelerated failure time model using two modeling strategies. The first model adjusted for baseline confounders and the second adjusted for both baseline and time-varying confounders. While the hazard ratio of all-cause mortality for intensive compared to standard therapy in AFT model adjusted for baseline confounders was 1.17 (95% CI 1.01-1.36), the result of time-dependent AFT model  was compatible with both protective and risk effects. However, the hazard ratio estimated by G-estimation was 0.64 (95% CI 0.39-0.92). The results of this study revealed a protective effect of intensive therapy on all-cause mortality compared with standard therapy in ACCORD trial.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Effect of a physical activity intervention on lower body bone health in childhood cancer survivors: A randomized controlled trial (SURfit)

It remains controversial whether physical activity promotes bone health in childhood cancer survivors (CCS). We aimed to assess the effect of a one-year general exercise intervention on lower body bone parameters of CCS. CCS ≥16 years at enrollment, <16 years at diagnosis and ≥5 years in remission were identified from the national Childhood Cancer Registry. Participants randomized to the intervention group were asked to perform an additional ≥2.5 hours of intense physical activity/week, controls continued exercise as usual. Bone health was assessed as a secondary trial endpoint at baseline and after 12-months. We measured tibia bone mineral density (BMD) and morphology by peripheral quantitative computed tomography and lumbar spine, hip and femoral neck BMD by dual-energy x-ray absorptiometry. We performed intention-to-treat, per protocol, and an explorative subgroup analyses looking at low BMD using multiple linear regressions. One hundred fifty-one survivors (44% females, 7.5 ± 4.9 years at diagnosis, 30.4 ± 8.6 years at baseline) were included. Intention-to-treat analysis revealed no differences in changes between the intervention and control group. Per protocol analyses showed evidence for an improvement in femoral neck and trabecular BMD between 1.5% and 1.8% more in participants being compliant with the exercise program. Trabecular BMD increased 2.8% more in survivors of the intervention group with BMD z-score ≤-1 compared to those starting at z-score >-1. A nonstandardized personalized exercise programs might not be specific enough to promote bone health in CCS, although those compliant and those most in need may benefit. Future trials should include bone stimulating exercise programs targeting risk groups with reduced bone health and motivational features to maximize compliance.

Comparing Pharmacist-Led Telehealth Care and Clinic-Based Care for Uncontrolled High Blood Pressure: The Hyperlink 3 Pragmatic Cluster-Randomized Trial

BACKGROUND

A team approach is one of the most effective ways to lower blood pressure (BP) in uncontrolled hypertension, but different models for organizing team-based care have not been compared directly.

METHODS

A pragmatic, cluster-randomized trial compared 2 interventions in adult patients with moderately severe hypertension (BP≥150/95 mm Hg): (1) clinic-based care using best practices and face-to-face visits with physicians and medical assistants; and (2) telehealth care using best practices and adding home BP telemonitoring with home-based care coordinated by a clinical pharmacist or nurse practitioner. The primary outcome was change in systolic BP over 12 months. Secondary outcomes were change in patient-reported outcomes over 6 months.

RESULTS

Participants (N=3071 in 21 primary care clinics) were on average 60 years old, 47% male, and 19% Black. Protocol-specified follow-up within 6 weeks was 32% in clinic-based care and 27% in telehealth care. BP decreased significantly during 12 months of follow-up in both groups, from 157/92 to 139/82 mm Hg in clinic-based care patients (adjusted mean difference -18/-10 mm Hg) and 157/91 to 139/81 mm Hg in telehealth care patients (adjusted mean difference -19/-10 mm Hg), with no significant difference in systolic BP change between groups (-0.8 mm Hg [95% CI, -2.84 to 1.32]). Telehealth care patients were significantly more likely than clinic-based care patients to report frequent home BP measurement, rate their BP care highly, and report that BP care visits were convenient.

CONCLUSIONS

Telehealth care that includes extended team care is an effective and safe alternative to clinic-based care for improving patient-centered care for hypertension.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02996565.

Why context matters when changing the diet: A narrative review of placebo, nocebo, and psychosocial context effects and implications for outcome research and nutrition counselling

Placebo (PE) and nocebo effects (NE) have been subjects of systematic research in medicine and psychotherapy for many decades to distinguish between the (specific) pharmacological effect of medication and the (unspecific) effect of the context. Despite this significant research, the awareness, operationalisation, and reflection of the multiplicity of PE, NE, and psychosocial context effects (PSCE) is currently limited when researching outcomes of diet changes in studies without randomisation and placebo control. This neglection is critical as it could systematically influence outcomes by moderating and mediating them and thus reducing the validity and evidence base of these studies. Therefore, we performed a (non-systematic) narrative review (NR) on the following objectives: (1) present a concise overview about the relevance of PE, NE, and PSCE in medicine and nutrition research; (2) review the current state of research on reflecting context effects when studying diet changes; (3) provide useful theoretical foundations via consideration and integration of micro- and macro context effects; (4) operationalise as hypotheses the potential PE, NE, and PSCE which are specific for researching diet changes; and (5) derive their impact for future research as well as for nutrition counselling. The electronic search in this NR for objective (2) identified N = 5 publications and for objective (4) we found N = 61 articles retrieved in the first round of search, additional references were identified by a manual and snowball search among the cited references resulting finally in N = 37. This NR offers a synoptical basis to foster awareness and operationalisation of a variety of PE, NE, and PSCE. Interdisciplinary research teams should monitor these factors using, e.g., qualitative, mixed-method studies, process evaluation, item bank approaches, moderator and mediator analysis that might reveal substantially new insights, and outcomes of relevance to science and nutrition counselling. Nevertheless, the present NR has several limitations, especially as it is non-systematic, because it is a very heterogeneous field of research, in which the topic we are investigating is usually regarded as marginal and subordinate. Therefore, future research should conduct systematic reviews and particularly theory-based primary studies (experimental research) on hypotheses of PE, NE, and PSCE in outcome research in diet changes.

Mediterranean Diet and Cardiovascular Prevention: Why Analytical Observational Designs Do Support Causality and Not Only Associations

Causal reductions in cardiovascular disease (CVD) with the Mediterranean diet (MedDiet) are supported by randomized trials, but the ability of nonrandomized studies to provide causal inferences in nutritional epidemiology is questioned. The "Seguimiento Universidad de Navarra" (SUN) project, conducted during 1999-2019 with 18,419 participants, was used to try to refute non-causal explanations for the inverse association found between adherence to the MedDiet and reduced CVD risk. A framework of different analytical strategies is proposed: alternative definitions of the exposure, exploration of residual confounding, resampling methods, depiction of absolute risks across the follow-up period, trial emulation, and negative controls. Additionally, we calculated the rate advancement period (RAP). We found that one standard deviation increase in the most frequently used MedDiet score was associated with a 29% relative reduction in CVD risk (95% Confidence Interval [CI] 14-41%), which is almost identical to that found in 2 randomized trials. The RAP of CVD would be postponed by an average of 7.9 years (95% CI: 1.6 to 14.2 years) by switching from low (MDS = 0 to2) to high (MDS = 7 to 9) adherence to the MedDiet in the fully adjusted model. Sensitivity analyses, graphical representations of absolute risks, trial emulation, and negative controls also supported causality. In conclusion, a framework of analytical approaches supported the causal effect of the MedDiet on CVD prevention using observational data. Similar methodology could be applied for causal inferences regarding other hypotheses.

Couples-based interventions and postpartum contraceptive uptake: A systematic review

OBJECTIVE

Systematically review the existing evidence about couples-based interventions and postpartum contraceptive uptake and generate recommendations for future research.

DATA SOURCES

PubMed, Web of Science, PsycINFO, Embase, and CINAHL through June 7, 2021.

STUDY SELECTION AND DATA EXTRACTION

Studies with a couples-based intervention assessing postpartum contraceptive uptake. Two independent reviewers screened studies, extracted data, and assessed risk of bias with RoB-2 (Cochrane Risk of Bias 2) for randomized and ROBINS-I (Risk of Bias in Non-Randomized Studies - Interventions) for observational studies. Data were synthesized in tables, figures, and a narrative review.

RESULTS

A total of 925 papers were identified, 66 underwent full text review, and 17 articles, which included 18 studies - 16 randomized, 2 observational - were included. The lack of intervention and outcome homogeneity precluded meta-analysis and isolating the effect of partner involvement. Four studies were partner-required, where partner involvement was a required component of the intervention, and 14 were partner-optional. Unadjusted risk differences ranged from 0.01 to 0.51 in favor of couples-based interventions increasing postpartum contraceptive uptake versus standard of care. Bias assessment of the 16 randomized studies classified 8, 3, and 5 studies as at a high, some concern, and low risk of bias. Common sources of bias included intervention non-adherence and missing outcome data. One observational study was at a high and the other at a low risk of bias.

CONCLUSIONS

Future studies that assess couples-based interventions must clearly define and measure how partners are involved in the intervention and assess how intervention adherence impacts postpartum contraceptive uptake.

The association between black stain and lower risk of dental caries in children: a systematic review and meta-analysis

BACKGROUND

Previous literature shows that children with dental black stain might be less susceptible to dental caries. The aim of this study was to systematically review the available literature to determine whether black stain presence could influence the prevalence or severity of dental caries in primary dentition.

METHODS

A systematic search of PubMed, Web of Science, Scopus, Google Scholar, OpenGrey, and Egyptian Universities Libraries Consortium was conducted up to December 2020. Quality assessment was done using a modified version of Down's and Black checklist. Meta-analyses were performed to assess the association between dental black stain and: (i) Likelihood of developing dental caries/being caries-free (ii) Number of teeth affected by dental caries (iii) Number of tooth surfaces affected.

RESULTS

The database search yielded 2164 results, 14 of which matched the eligibility criteria. The meta-analysis showed that the likelihood of developing caries (Fixed effect model: OR [95% CI]: 0.67 [0.54; 0.82]; I²=37%; τ²=0.05), number of teeth affected (Random effects model: MD [95% CI]: -0.98 [-1.54; -0.42]; I²=79%; τ² =0.44), and number of surfaces affected (Random-effects model: MD [95% CI]: -2.34 [-4.23; -0.44]; I²=85%; τ² =2.93), were all lower in children with black stain.

CONCLUSIONS

It is suggested that dental black stain is associated with lower dental caries experience in children with primary dentition. However, it is questionable whether black stain has a protective effect against dental caries, or whether children at low risk of dental caries are more likely to develop BS because their oral microbiome favors BS-forming organisms.

Evaluation of Serum Testosterone Levels Following Three Months of SA3X (Spilanthes acmella) Supplementation

Introduction: Low testosterone is usually associated with erectile dysfunction (ED). SA3X (Spilanthes acmella) has proven to be effective in alleviating symptoms of ED, which could be due to an alteration in serum testosterone levels. This study was carried out to evaluate the change in testosterone levels in participants with ED supplemented with SA3X for three months.

Materials and Methods: A group of 326 sexually active men aged 25-60 years was investigated from November 2021 to May 2022 in Hyderabad. The participants were subjected to supplementation with SA3X capsules for three months, and a follow-up was done at the end of six months with serum testosterone assessment in each visit. The change in testosterone level was assessed using a mixed model repeated measures analysis.

Results: A significant increase was observed in the mean serum testosterone levels by the end of the second month (323.91 ± 13.76 ng/dL vs. 309.84 ± 14.11 ng/dL; p=0.03) and third month (332.27 ± 12.85 ng/dL vs. 309.84 ± 14.11 ng/dL; p<0.01) of SA3X therapy. The adjusted mean change in testosterone levels was found to be 22.43 ng/dL at the end of the three-month therapy. It was also observed that the change in testosterone levels was significantly lower in participants having diabetes mellitus, hypercholesterolemia, and a history of substance abuse. However, participants on phosphodiesterase-5 inhibitors had an increased change in testosterone levels.

Conclusion: Supplementation with SA3X capsules for three months increases the serum testosterone levels. However, causality cannot be ascertained owing to the longitudinal nature of the study, and further controlled trials are required for the same.

Effects of Long-term Metformin and Lifestyle Interventions on Cardiovascular Events in the Diabetes Prevention Program and Its Outcome Study

BACKGROUND

Lifestyle intervention and metformin have been shown to prevent diabetes; however, their efficacy in preventing cardiovascular disease associated with the development of diabetes is unclear. We examined whether these interventions reduced the incidence of major cardiovascular events over a 21-year median follow-up of participants in the DPP trial (Diabetes Prevention Program) and DPPOS (Diabetes Prevention Program Outcomes Study).

METHODS

During DPP, 3234 participants with impaired glucose tolerance were randomly assigned to metformin 850 mg twice daily, intensive lifestyle or placebo, and followed for 3 years. During the next 18-year average follow-up in DPPOS, all participants were offered a less intensive group lifestyle intervention, and unmasked metformin was continued in the metformin group. The primary outcome was the first occurrence of nonfatal myocardial infarction, stroke, or cardiovascular death adjudicated by standard criteria. An extended cardiovascular outcome included the primary outcome or hospitalization for heart failure or unstable angina, coronary or peripheral revascularization, coronary heart disease diagnosed by angiography, or silent myocardial infarction by ECG. ECGs and cardiovascular risk factors were measured annually.

RESULTS

Neither metformin nor lifestyle intervention reduced the primary outcome: metformin versus placebo hazard ratio 1.03 (95% CI, 0.78-1.37; P = 0.81) and lifestyle versus placebo hazard ratio 1.14 (95% CI, 0.87-1.50; P = 0.34). Risk factor adjustment did not change these results. No effect of either intervention was seen on the extended cardiovascular outcome.

CONCLUSIONS

Neither metformin nor lifestyle reduced major cardiovascular events in DPPOS over 21 years despite long-term prevention of diabetes. Provision of group lifestyle intervention to all, extensive out-of-study use of statin and antihypertensive agents, and reduction in the use of study metformin together with out-of-study metformin use over time may have diluted the effects of the interventions.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifiers: DPP (NCT00004992) and DPPOS (NCT00038727).

Long-Term Beta-Blocker Therapy in Patients With Stable Coronary Artery Disease After Percutaneous Coronary Intervention

Background

It is unclear whether beta-blocker treatment is advantageous in patients with stable coronary artery disease (CAD) who underwent percutaneous coronary intervention (PCI). We evaluated the clinical impact of long-term beta-blocker maintenance in patients with stable CAD after PCI with drug-eluting stent (DES).

Methods

From a nationwide cohort database, we identified the stable CAD patients without current or prior history of myocardial infarction or heart failure who underwent DES implantation. An intention-to-treat principle was used to analyze the impact of beta-blocker treatment on long-term outcomes of major adverse cardiovascular events (MACE) composed of cardiovascular death, myocardial infarction, and hospitalization with heart failure.

Results

After stabilized inverse probability of treatment weighting, a total of 78,380 patients with stable CAD was enrolled; 45,746 patients with and 32,634 without beta-blocker treatment. At 5 years after PCI with a 6-month quarantine period, the adjusted incidence of MACE was significantly higher in patients treated with beta-blockers [10.0 vs. 9.1%; hazard ratio (HR) 1.11, 95% CI 1.06–1.16, p &lt; 0.001] in an intention-to-treat analysis. There was no significant difference in all-cause death between patients treated with and without beta-blockers (8.1 vs. 8.2%; HR 0.99, 95% CI 0.94–1.04, p = 0.62). Statistical analysis with a time-varying Cox regression and rank-preserving structure failure time model revealed similar results to the intention-to-treat analysis.

Conclusions

Among patients with stable CAD undergoing DES implantation, long-term maintenance with beta-blocker treatment might not be associated with clinical outcome improvement.

Trial Registration

ClinicalTrial.gov (NCT04715594).

Minimax designs for causal effects in temporal experiments with treatment habituation

In many modern settings, such as an online marketplace, randomized experiments need to be executed over multiple time periods. In such temporal experiments, it has been observed that the effects of an intervention on an experimental unit may be large when the unit is first exposed to it, but then it attenuates after repeated exposures. This is typically due to units’ habituation to the intervention, or some other form of learning, such as when users gradually start to ignore repeated mails sent by a promotional campaign. This paper proposes randomized designs for estimating causal effects in temporal experiments when habituation is present. We show that our designs are minimax optimal in a large class of practical designs. Our analysis is based on the randomization framework of causal inference, and imposes no parametric modelling assumptions on the outcomes.

Motives and Passion of Adults from Pakistan toward Physical Activity

Globally, a large proportion of people do not participate in adequate physical activity to gain health benefits. Physical inactivity is a primary risk factor for global mortality. Research suggests that motives and passion influence participation in physical activity. The main purposes of the present study were to examine the relationship between motives and passion for participation in physical activity among adults, and to examine whether motives and passion predicted physical activity. Prior to data collection, we translated and validated the Physical Activity and Leisure Motivation Scale (PALMS) and the Passion Scale (PS) into Urdu. With the research sample, both translated questionnaires showed acceptable internal consistency, test-retest reliability, and factorial validity. To address the main purposes, we then employed a quantitative, cross-sectional research design, with a sample of 572 adults between 18 and 65 years (31.51 ± 10.25), who regularly participated in moderate-to-vigorous physical activity. Participants completed the PALMS, the PS, and the International Physical Activity Questionnaire (IPAQ). Correlation coefficients showed strong relationships between motives and harmonious passion, and weaker, negative relationships between motives and obsessive passion. We used stepwise multiple regression to test whether motives and passion subscales were significant predictors of overall PA measured by the IPAQ. In step 1 of the regression model, mastery and physical condition motives were significant predictors of overall physical activity. Further, in step 2, the mastery motive and harmonious passion were significant predictors of overall physical activity, accounting for 26% of the variance, with F (5, 566) = 38.84, p < 0.01. The present study provides a basis for physical activity interventions examining whether increasing motives and passion leads to higher adherence to and lowered dropout from physical activity.

Bounding the Implications of Noncompliance in Randomized Controlled Trials in Orthopaedics: An Example in Arthroscopic Surgery

INTRODUCTION

Randomized controlled trials (RCTs) are not impervious to bias especially when there are substantial numbers of patients who cross over from the treatment assigned by randomization to another treatment group, leading to loss of confidence in study results. The goals of this study were to (1) quantify the effects of crossovers on RCTs, (2) describe the specific effects of crossovers on RCTs for arthroscopic meniscectomy for osteoarthritis of the knee (APM/OAK), and (3) assess the confidence in APM/OAK in which there have been substantial numbers of patients crossing over to another treatment group than that assigned.

METHODS

Studies were included that were RCTs of APM/OAK with intention-to-treat (ITT) analysis and illustrated the problem of crossovers on confidence in the analysis. Studies were excluded if they consisted of APM for conditions other than OAK or had unavailability of data needed for the analysis. For eligible RCTs, the ITT effect was calculated; bounds for the average treatment effect (ATE) and the complier ATE were assessed by estimating confidence intervals for the bound through robust Bayesian analysis.

RESULTS

The eligible studies had different comparators and, therefore, were analyzed individually. Data were not pooled. The most extreme point estimates (with 95% confidence interval) for ITT ranged from -0.01 to 0.04 (-0.16 to 0.16); for ATE with no assumptions, 0.38 (-0.58 to 0.43) to 0.62 (0.56 to 0.70); for ATE with minimum assumptions, -0.50 (-0.22 to 0.10) to 0.61 (0.53 to 0.57); and for complier ATE, -0.01 to 0.07 (-0.22 to 0.24).

DISCUSSION

These data suggest large bounds, crossing the threshold of "no effect," which indicates a high degree of uncertainty and low confidence in the RCTs studied. The results demonstrate that when there are crossovers, ITT analyses do not estimate the ATE and confidence in the results of these RCTs is low.

DATA AVAILABILITY

All analyzed data are provided in the article.

LEVEL OF EVIDENCE

Level I (therapeutic study = RCT).

Estimating the Impact of Sustained Social Participation on Depressive Symptoms in Older Adults

BACKGROUND

Social participation has been suggested as a means to prevent depressive symptoms. However, it remains unclear whether a one-time boost suffices or whether participation needs to be sustained over time for long-term prevention. We estimated the impacts of alternative hypothetical interventions in social participation on subsequent depressive symptoms among older adults.

METHODS

Data were from a nationwide prospective cohort study of Japanese older adults ≥65 years of age (n = 32,748). We analyzed social participation (1) as a baseline exposure from 2010 (approximating a one-time boost intervention) and (2) as a time-varying exposure from 2010 and 2013 (approximating a sustained intervention). We defined binary depressive symptoms in 2016 using the Geriatric Depression Scale. We used the doubly robust targeted maximum likelihood estimation to address time-dependent confounding.

RESULTS

The magnitude of the association between sustained participation and the lower prevalence of depressive symptoms was larger than the association observed for baseline participation only (e.g., prevalence ratio [PR] for participation in any activity = 0.83 [95% confidence interval = 0.79, 0.88] vs. 0.90 [0.87, 0.94]). For activities with a lower proportion of consistent participation over time (e.g., senior clubs), there was little evidence of an association between baseline participation and subsequent depressive symptoms, while an association for sustained participation was evident (e.g., PR for senior clubs = 0.96 [0.90, 1.02] vs. 0.88 [0.79, 0.97]). Participation at baseline but withholding participation in 2013 was not associated with subsequent depressive symptoms.

CONCLUSIONS

Sustained social participation may be more strongly associated with fewer depressive symptoms among older adults.

Hospitalization for Myocardial Infarction with Ticagrelor or Clopidogrel in Patients with Acute Coronary Syndrome: An On-Treatment Comparative Effectiveness Analysis

INTRODUCTION

Prescribing patterns and suboptimal adherence present methodological challenges for real-world head-to-head comparisons of ticagrelor and clopidogrel in intent-to-treat studies. The aim of this study was to compare ticagrelor and clopidogrel in an on-treatment population.

METHODS

This retrospective cohort study used the Optum™ Clinformatics™ database to identify patients with acute coronary syndrome (ACS) discharged on ticagrelor or clopidogrel between January 1, 2012 and September 30, 2019. The primary end point was hospitalization for myocardial infarction (MI); the secondary end point was hospitalization for major bleeding. The ticagrelor and clopidogrel cohorts were balanced by propensity score matching (PSM) 1:3 for demographic and clinical characteristics. Outcomes were ascertained from day 31 until day 365 or end of follow-up.

RESULTS

Of 339,387 patients with ACS, 14,110 ticagrelor- and 57,482 clopidogrel-treated patients met the study criteria. After PSM, 13,373 ticagrelor- and 29,656 clopidogrel-treated patients provided 4945 and 13,895 patient-years of data, respectively, for the primary end point. Hospitalization for MI was significantly lower in the ticagrelor compared to the clopidogrel cohort (2.22 vs. 3.52 per 100 patient-years; 36.8% relative risk reduction [RRR]; P < 0.0001). Hospitalization for major bleeding was similar in the ticagrelor and clopidogrel cohorts (2.04 vs. 2.06 per 100 patient-years; 1.1% RRR, P = 0.9214).

CONCLUSIONS

In this real-world on-treatment analysis, hospitalization for MI was significantly lower with ticagrelor compared to clopidogrel, with similar rates of hospitalization for major bleeding. Study findings underscore the importance of being on the appropriate guideline-recommended therapy and support the use of ticagrelor over clopidogrel.

Using marginal structural models to analyze randomized clinical trials with non-adherence and lost to follow up

BACKGROUND

In the presence of non-adherence and lost to follow up, results of an Intention to Treat (ITT) analysis may be biased as it is measuring the effect of assignment rather than the effect of treatment. Given that Marginal Structural Models (MSMs) adjust for such issues, this study examines the use of MSMs to assess the validity of ITT analyses in the presence of non-adherence and lost to follow up in an existing randomized clinical trial on asthma treatment.

METHODS

Inverse probability weights were obtained from a pooled logistic regression assessing the probability of staying on assigned treatment (adherence) and of remaining uncensored (censored) for subjects at each visit by treatment arm. Weights were then pooled into a MSM analysis using a Poisson generalized estimating equation with an independent correlation matrix.

RESULTS

Out of 488 participants, 174 (36%) did not adhere to the baseline assignment and 85 (17%) were lost to follow up by the end of the study. The adjusted relative risks (RR), and 95% confidence intervals (CI), obtained from the MSMs (theophylline vs. montelukast; RR=1.24; 95% CI: 0.83,1.84; theophylline vs. placebo: RR=1.01; 95% CI: 0.70,1.48; and montelukast vs. placebo: RR=0.83; 95% CI: 0.57,1.19) were nearly identical to that of the ITT analysis (theophylline vs. montelukast: RR=1.22; 95% CI: 0.82,1.86; theophylline vs. placebo: RR=0.99; 95% CI: 0.67,1.50; and montelukast vs. placebo: RR=0.82; 95% CI: 0.55,1.21).

CONCLUSION

Concordance between the results of ITT and MSMs indicate adherence and censoring may not invalidate ITT analysis. However, no adherence or censorship thresholds currently exist to assist researchers in determining when MSMs may be superior to ITT in the analysis of clinical trials with non-adherence or censorship issues, and therefore, MSMs should be conducted as a sensitivity analysis to the ITT approach in clinical trials.

A Framework for Extension Studies Using Real-World Data to Examine Long-Term Safety and Effectiveness

Understanding the long-term benefits and risks of treatments, devices, and vaccines is critically important for individual- and population-level healthcare decision-making. Extension studies, or ‘roll-over studies,’ are studies that allow for patients participating in a parent clinical trial to ‘roll-over’ into a subsequent related study to continue to observe and measure long-term safety, tolerability, and/or effectiveness. These designs are not new and are often used as an approach to satisfy regulatory post-approval safety requirements. However, designs using traditional clinical trial infrastructure can be expensive and burdensome to conduct, particularly, when following patients for many years post trial completion. Given the increasing availability and access of real-world data (RWD) sources, direct-to-patient technologies, and novel real-world study designs, there are more cost-efficient approaches to conducting extension studies while assessing important long-term outcomes. Here, we describe various fit-for-purpose design options for extension studies, discuss related methodological considerations, and provide scientific and operational guidance on practices when planning to conduct an extension study using RWD. This manuscript is endorsed by the International Society for Pharmacoepidemiology (ISPE).

Adolescent depressed mood and difficulties with emotion regulation: Concurrent trajectories of change

INTRODUCTION

Adolescent depression is a significant mental health concern. Emotion regulation difficulties have been associated with subsequent depressive symptoms, though different facets of emotion regulation are rarely compared. This study examined the degree to which trajectories of change in different facets of emotion regulation (goal-directed behavior, impulse control, and regulation strategies) and depressive symptoms were associated across twelve months in a clinical adolescent sample.

METHODS

Participants included 110 adolescents from the US who were enrolled in a randomized trial that tested a cognitive-behavioral treatment for youth with co-occurring mental health and substance use concerns (M_age = 15.71 years; 57.3% male). Assessments were conducted at baseline, 3-, 6-, and 12-month follow-ups. Three separate bivariate latent basis growth curve analyses were conducted. Correlations between latent intercepts and latent slopes, as well as overall model fit, were examined.

RESULTS

Impulse control and goal-directed behavior were each associated with depressive symptoms at baseline. Additionally, change in impulse control over time was significantly associated with change in depressive symptoms. However, the same was not true for goal-directed behavior. Overall fit indices for models of emotion regulation strategies were below acceptable levels and thus could not be interpreted.

CONCLUSIONS

Findings from the present study indicate that adolescents' depressive symptoms appear to improve as their perceived ability to control impulses improves. These results suggest that addressing impulse control difficulties may be an important step in treating adolescent depression and co-occurring disorders.

Sodium-glucose cotransporter-2 inhibitors and the risk of urinary tract infection among diabetic patients in Japan: Target trial emulation using a nationwide administrative claims database

AIM

To assess the risk of urinary tract infection (UTI) occurrence associated with sodium-glucose cotransporter-2 (SGLT2) inhibitor use relative to biguanide use in diabetes in a population-based cohort study using a target trial emulation framework.

METHODS

Using a Japanese nationwide administrative claims database, we constructed a cohort of patients aged ≥40 years who were dispensed SGLT2 inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors or biguanides between April 2014 and March 2015. For computational ease, we randomly sampled 100% of SGLT2 inhibitor users, 3% of DPP-4 inhibitor users, and 20% of biguanide users; new antidiabetic drug initiators were analysed. We estimated the intention-to-treat (ITT) hazard ratios (HRs) of UTI with inverse probability of treatment (IPT)-weighted Cox's proportional hazards models that ignored subsequent treatment changes. Treatment weights were computed using patient sex, age, medications, medical history and hospitalization history. We also estimated per-protocol (PP) HRs using IPT- and inverse probability of censoring-weighted Cox's models that adjusted for nonrandom treatment changes.

RESULTS

We analysed 11 364 SGLT2 inhibitor initiators, 9035 DPP-4 inhibitor initiators, and 10 359 biguanide initiators. When compared with biguanide initiators, SGLT2 inhibitor initiators had a crude HR of 1.14 (95% confidence interval [CI] 1.05-1.24), an ITT HR of 0.94 (95% CI 0.86-1.03), and a PP HR of 0.90 (95% CI 0.78-1.03); and DPP-4 inhibitor initiators had a crude HR of 1.13 (95% CI 1.04-1.23), an ITT HR of 0.85 (95% CI 0.77-0.94), and a PP HR of 0.83 (95% CI 0.71-0.95).

CONCLUSION

Use of SGLT2 inhibitors or DPP-4 inhibitors did not increase the risk of UTI compared with biguanide use. Accounting for treatment changes did not substantially influence the estimated effects.

Theoretical evidence explaining the relationship between socio-demographic and psychosocial barriers on access to oral health care among adults: A scoping review

OBJECTIVES

Current global models for oral health care are outdated. Out of pocket payments and exclusion from most national health systems has created a gap for access of services by socio-economically vulnerable adults. Our objective is to understand barriers to access and the causal associations between barriers to care.

DATA

All study designs with a theoretical/conceptual framework to explain access and barriers among adults were included.

SOURCES

6 electronic databases (PubMed, Medline (EBSCO), CINAHL, Embase, Web of Science) including grey literature searches (ProQuest) and expert consultation. The identified studies were then analysed using narrative synthesis and NVivo.

STUDY SELECTION/RESULTS

40 studies using a theoretical framework to explain access among adults were identified. Andersen's behavioural model was most used. Cost was the primary causal factor that perpetuated the effect of other barriers. Associations were found between age and education level, cost and need, cost and dental anxiety. Study design and analysis used to identify these associations had limitations in determining causality.

CONCLUSION

Oral health access research is based in theory, leading to the identification of socio-demographic and psychosocial barriers and their relationships. However, a lack of explanation of causal associations persists. This review recognises the importance of understanding the cause of barriers in addition to their nature. Appropriate study designs and analysis considering the impact of time varying factors on access is required. Empirical analysis needs to focus on the role of confounders and mediators to determine causality successfully. To achieve this a theory driven causal model has been proposed.

The impact of the Trauma Triage App on pre-hospital trauma triage: design and protocol of the stepped-wedge, cluster-randomized TESLA trial

BACKGROUND

Field triage of trauma patients is crucial to get the right patient to the right hospital within a particular time frame. Minimization of undertriage, overtriage, and interhospital transfer rates could substantially reduce mortality rates, life-long disabilities, and costs. Identification of patients in need of specialized trauma care is predominantly based on the judgment of Emergency Medical Services professionals and a pre-hospital triage protocol. The Trauma Triage App is a smartphone application that includes a prediction model to aid Emergency Medical Services professionals in the identification of patients in need of specialized trauma care. The aim of this trial is to assess the impact of this new digital approach to field triage on the primary endpoint undertriage.

METHODS

The Trauma triage using Supervised Learning Algorithms (TESLA) trial is a stepped-wedge cluster-randomized controlled trial with eight clusters defined as Emergency Medical Services regions. These clusters are an integral part of five inclusive trauma regions. Injured patients, evaluated on-scene by an Emergency Medical Services professional, suspected of moderate to severe injuries, will be assessed for eligibility. This unidirectional crossover trial will start with a baseline period in which the default pre-hospital triage protocol is used, after which all clusters gradually implement the Trauma Triage App as an add-on to the existing triage protocol. The primary endpoint is undertriage on patient and cluster level and is defined as the transportation of a severely injured patient (Injury Severity Score ≥ 16) to a lower-level trauma center. Secondary endpoints include overtriage, hospital resource use, and a cost-utility analysis.

DISCUSSION

The TESLA trial will assess the impact of the Trauma Triage App in clinical practice. This novel approach to field triage will give new and previously undiscovered insights into several isolated components of the diagnostic strategy to get the right trauma patient to the right hospital. The stepped-wedge design allows for within and between cluster comparisons.

TRIAL REGISTRATION

Netherlands Trial Register, NTR7243. Registered 30 May 2018, https://www.trialregister.nl/trial/7038.

Design of a pragmatic cluster-randomized trial comparing telehealth care and best practice clinic-based care for uncontrolled high blood pressure

BACKGROUND

Uncontrolled hypertension is the largest single contributor to all-cause and cardiovascular mortality in the U.S.

POPULATION

Nurse- and pharmacist-led team-based care and telehealth care interventions have been shown to result in large and lasting improvements in blood pressure (BP); however, it is unclear how successfully these can be implemented at scale in real-world settings. It is also uncertain how telehealth interventions impact patient experience compared to traditional clinic-based care.

AIMS/OBJECTIVES

To compare the effects of two evidence-based blood pressure care strategies in the primary care setting: (1) best-practice clinic-based care and (2) telehealth care with home BP telemonitoring and management by a clinical pharmacist. To evaluate implementation using mixed-methods supported by the RE-AIM framework and Consolidated Framework for Implementation Research.

METHODS

The design is a cluster-randomized comparative effectiveness pragmatic trial in 21 primary care clinics (9 clinic-based care, 12 telehealth care). Adult patients (age 18-85) with hypertension are enrolled via automated electronic health record (EHR) tools during primary care encounters if BP is elevated to ≥150/95 mmHg at two consecutive visits. The primary outcome is change in systolic BP over 12 months as extracted from the EHR. Secondary outcomes are change in key patient-reported outcomes over 6 months as measured by surveys. Qualitative data are collected at various time points to investigate implementation barriers and help explain intervention effects.

CONCLUSION

This pragmatic trial aims to inform health systems about the benefits, strengths, and limitations of implementing home BP telemonitoring with pharmacist management for uncontrolled hypertension in real-world primary care settings.

Interval-cohort designs and bias in the estimation of per-protocol effects: a simulation study

BACKGROUND

Randomized trials are considered the gold standard for making inferences about the causal effects of treatments. However, when protocol deviations occur, the baseline randomization of the trial is no longer sufficient to ensure unbiased estimation of the per-protocol effect: post-randomization, time-varying confounders must be sufficiently measured and adjusted for in the analysis. Given the historical emphasis on intention-to-treat effects in randomized trials, measurement of post-randomization confounders is typically infrequent. This may induce bias in estimates of the per-protocol effect, even using methods such as inverse probability weighting, which appropriately account for time-varying confounders affected by past treatment.

METHODS/DESIGN

In order to concretely illustrate the potential magnitude of bias due to infrequent measurement of time-varying covariates, we simulated data from a very large trial with a survival outcome and time-varying confounding affected by past treatment. We generated the data such that the true underlying per-protocol effect is null and under varying degrees of confounding (strong, moderate, weak). In the simulated data, we estimated per-protocol survival curves and associated contrasts using inverse probability weighting under monthly measurement of the time-varying covariates (which constituted complete measurement in our simulation), yearly measurement, as well as 3- and 6-month intervals.

RESULTS

Using inverse probability weighting, we were able to recover the true null under the complete measurement scenario no matter the strength of confounding. Under yearly measurement intervals, the estimate of the per-protocol effect diverged from the null; inverse probability weighted estimates of the per-protocol 5-year risk ratio based on yearly measurement were 1.19, 1.12, and 1.03 under strong, moderate, and weak confounding, respectively. Bias decreased with measurement interval length. Under all scenarios, inverse probability weighted estimators were considerably less biased than a naive estimator that ignored time-varying confounding completely.

CONCLUSIONS

Bias that arises from interval measurement designs highlights the need for planning in the design of randomized trials for collection of time-varying covariate data. This may come from more frequent in-person measurement or external sources (e.g., electronic medical record data). Such planning will provide improved estimates of the per-protocol effect through the use of methods that appropriately adjust for time-varying confounders.

Housing Disadvantage and Poor Mental Health: A Systematic Review

CONTEXT

This study reviews collective evidence on the longitudinal impact of housing disadvantage (based on tenure, precarity, and physical characteristics) on mental health. It is focused on temporally ordered studies where exposures preceded outcomes, a key criterion to establishing causal evidence.

EVIDENCE ACQUISITION

A systematic review of evidence on housing disadvantage and mental health was performed. The literature search used six electronic databases including MEDLINE (PubMed and Ovid platform), Embase, PsycINFO, Web of Science, SciELO, and Sociological Abstracts. Population-based longitudinal studies where exposure to housing disadvantage (excluding exposure to homelessness) preceded mental health were included. Methodologic quality of selected studies was examined using the Newcastle-Ottawa Quality Assessment Scale. Because of definitional and methodologic heterogeneity among studies, narrative synthesis rather than meta-analysis was used to summarize research findings.

EVIDENCE SYNTHESIS

Of the 1,804 unique titles identified in the literature search, 12 met the selection criteria for inclusion in the systematic review. Housing disadvantage was measured by overcrowding, mortgage delinquency, housing mobility, housing tenure, subjective perceptions of inadequate housing, eviction, and physical housing conditions. Mental health was measured as depression, psychological impairment, anxiety, allostatic load, mental strain, and psychological health. Study sample sizes ranged from 205 to 16,234 people, and the follow-up period ranged from within 1 year to 34 years. Each study indicated a positive association between housing disadvantage and mental health for at least one housing disadvantage measure and mental health outcome.

CONCLUSIONS

This systematic review confirms that prior exposure to housing disadvantage may impact mental health later in life.

The sirtuin1 gene associates with left ventricular myocardial hypertrophy and remodeling in two chronic kidney disease cohorts: a longitudinal study

BACKGROUND

Oxidative stress and inflammation are major drivers of myocardial hypertrophy in chronic kidney disease (CKD). The silent information regulator gene 1 (Sirt1) is a fundamental mediator of the response to oxidative stress and inflammation and promotes myocardial growth under stress conditions; therefore, it may contribute to myocardial hypertrophy and concentric remodeling of the left ventricle (LV) in CKD.

METHODS

We investigated the cross-sectional and longitudinal relationship between three candidate polymorphisms in the Sirt1 gene and LV parameters in two cohorts of CKD patients including 235 stage G5D patients and 179 stages G1-5 patients, respectively.

RESULTS

In both cohorts, the C allele of the Sirt1 rs7069102 polymorphism associated with the posterior wall thickness in separate and combined analyses (beta = 0.15, P = 2 × 10) but was unrelated with the LV volume and the LV mass index indicating a peculiar association of this allele with LV concentric remodeling. Accordingly, the same allele was linked with the LV mass-to-volume ratio in separate and combined (beta = 0.14, P = 2 × 10) analyses in the same cohorts. Furthermore, in longitudinal analyses patients harboring the C allele showed a more pronounced increase in LV mass-to-volume ratio over time than patients without such an allele (regression coefficient = 0.14, 95% confidence interval: 0.05-0.23; P = 3 × 10 in the combined analysis).

CONCLUSION

The rs7069102 polymorphism in the Sirt1 gene is associated with LV concentric remodeling in two independent cohorts of stages G5D and G1-5 CKD patients. These results offer a genetic basis to the hypothesis that the Sirt1 gene plays a causal role in myocardial hypertrophy and LV concentric remodeling in these patients.

Perspective: Fundamental Limitations of the Randomized Controlled Trial Method in Nutritional Research: The Example of Probiotics

Studies on the relation between health and nutrition are often inconclusive. There are concerns about the validity of many research findings, and methods that can deliver high-quality evidence-such as the randomized controlled trial (RCT) method-have been embraced by nutritional researchers. Unfortunately, many nutritional RCTs also yield ambiguous results. It has been argued that RCTs are ill-suited for certain settings, including nutritional research. In this perspective, we investigate whether there are fundamental limitations of the RCT method in nutritional research. To this end, and to limit the scope, we use probiotic studies as an example. We use an epistemological approach and evaluate the presuppositions that underlie the RCT method. Three general presuppositions are identified and discussed. We evaluate whether these presuppositions can be considered true in probiotic RCTs, which appears not always to be the case. This perspective concludes by exploring several alternative study methods that may be considered for future probiotic or nutritional intervention trials.

Analysis of randomised trials with long-term follow-up

Randomised trials with long-term follow-up can provide estimates of the long-term effects of health interventions. However, analysis of long-term outcomes in randomised trials may be complicated by problems with the administration of treatment such as non-adherence, treatment switching and co-intervention, and problems obtaining outcome measurements arising from loss to follow-up and death of participants. Methods for dealing with these issues that involve conditioning on post-randomisation variables are unsatisfactory because they may involve the comparison of non-exchangeable groups and generate estimates that do not have a valid causal interpretation. We describe approaches to analysis that potentially provide estimates of causal effects when such issues arise. Brief descriptions are provided of the use of instrumental variable and propensity score methods in trials with imperfect adherence, marginal structural models and g-estimation in trials with treatment switching, mixed longitudinal models and multiple imputation in trials with loss to follow-up, and a sensitivity analysis that can be used when trial follow-up is truncated by death or other events. Clinical trialists might consider these methods both at the design and analysis stages of randomised trials with long-term follow-up.

Epic Allies, a Gamified Mobile Phone App to Improve Engagement in Care, Antiretroviral Uptake, and Adherence Among Young Men Who Have Sex With Men and Young Transgender Women Who Have Sex With Men: Protocol for a Randomized Controlled Trial

Background

In the United States, young men who have sex with men (YMSM) and transgender women who have sex with men (YTWSM) bear a disproportionate burden of prevalent and incident HIV infections. Once diagnosed, many YMSM and YTWSM struggle to engage in HIV care, adhere to antiretroviral therapy (ART), and achieve viral suppression. Computer-based interventions, including those focused on behavior change, are recognized as effective tools for engaging youth.

Objective

The purpose of the study described in this protocol is to evaluate the efficacy of Epic Allies, a theory-based mobile phone app that utilizes game mechanics and social networking features to improve engagement in HIV care, ART uptake, ART adherence, and viral suppression among HIV-positive YMSM and YTWSM. The study also qualitatively assesses intervention acceptability, perceived impact, and sustainability.

Methods

This is a two-group, active-control randomized controlled trial of the Epic Allies app. YMSM and YTWSM aged 16 to 24 inclusive, with detectable HIV viral load are randomized 1:1 within strata of new to care (newly entered HIV medical care ≤12 months of baseline visit) or ART-nonadherent (first entered HIV medical care >12 months before baseline visit) to intervention or control conditions. The intervention condition addresses ART adherence barriers through medication reminders and adherence monitoring, tracking of select adherence-related behaviors (eg, alcohol and marijuana use), an interactive dashboard that displays the participant’s adherence-related behaviors and provides tailored feedback, encouragement messages from other users, daily HIV/ART educational articles, and gamification features (eg, mini-games, points, badges) to increase motivation for behavior change and app engagement. The control condition features weekly phone-based notifications to encourage participants to view educational information in the control app. Follow-up assessments are administered at 13, 26, and 39 weeks for each arm. The primary outcome measure is viral suppression. Secondary outcome measures include engagement in care, ART uptake, ART adherence, and psychosocial barriers to engagement in care and ART adherence, including psychological distress, stigma, and social support.

Results

Baseline enrollment began in September 2015 and was completed in September 2016 (n=146), and assessment of intervention outcomes continued through August 2017. Results for primary and secondary outcome measures are expected to be reported in ClinicalTrials.gov by April 30, 2018.

Conclusions

If successful, Epic Allies will represent a novel adherence intervention for a group disproportionately impacted by HIV in the United States. Adherent patients would require less frequent clinic visits and experience fewer HIV-related secondary infections, thereby reducing health care costs and HIV transmission. Epic Allies could easily be expanded and adopted for use among larger populations of YMSM and YTWSM, other HIV-positive populations, and for those diagnosed with other chronic diseases such as diabetes and hypertension.

Trial Registration

ClinicalTrials.gov NCT02782130; https://clinicaltrials.gov/ct2/show/NCT02782130 (Archived by Webcite at http://www.webcitation.org/6yGODyerk)

Comparative cardiovascular safety of nonsteroidal anti-inflammatory drugs in patients with hypertension: a population-based cohort study

AIMS

Previous studies have suggested that nonsteroidal anti-inflammatory drugs (NSAIDs) may be associated with higher cardiovascular risks. However, few have been active comparison studies that directly assessed the potential differential cardiovascular risk between NSAID classes or across individual NSAIDs. We compared the risk of major cardiovascular events between cyclooxygenase 2 (COX-2)-selective and nonselective NSAIDs in patients with hypertension.

METHODS

We conducted a cohort study of patients with hypertension who initiated COX-2-selective or nonselective NSAIDs in a population-based Taiwanese database. The outcomes included hospitalization for the following major cardiovascular events: ischaemic stroke, acute myocardial infarction, congestive heart failure, transient ischaemic attack, unstable angina or coronary revascularization. We followed patients for up to 4 weeks, based on the as-treated principle. We used inverse probability weighting to control for baseline and time-varying covariates, and estimated the on-treatment hazard ratios (HRs) and 95% conservative confidence interval (CIs).

RESULTS

We identified 2749 eligible COX-2-selective NSAID users and 52 880 eligible nonselective NSAID users. The HR of major cardiovascular events comparing COX-2-selective with nonselective NSAIDs after adjusting for baseline and time-varying covariates was 1.07 (95% CI 0.65, 1.74). We did not observe a differential risk when comparing celecoxib to diclofenac (HR 1.17; 95% CI 0.61, 2.25), ibuprofen (HR 1.36; 95% CI 0.58, 3.18) or naproxen (HR 0.75; 95% CI 0.23, 2.44). There was an increased risk with COX-2-selective NSAIDs, however, when comparing COX-2-selective NSAIDs with mefenamic acid (HR 2.11; 95% CI 1.09, 4.09).

CONCLUSIONS

Our results provide important information about the comparative cardiovascular safety of NSAIDs in patients with hypertension.

Effects of Exposure to the Communities That Care Prevention System on Youth Problem Behaviors in a Community-Randomized Trial: Employing an Inverse Probability Weighting Approach

Earlier intention-to-treat (ITT) findings from a community-randomized trial demonstrated effects of the Communities That Care (CTC) prevention system on reducing problem behaviors among youth. In ITT analyses, youth were analyzed according to their original study community's randomized condition even if they moved away from the community over the course of follow-up and received little to no exposure to intervention activities. Using inverse probability weights (IPWs), this study estimated effects of CTC in the same randomized trial among youth who remained in their original study communities throughout follow-up. Data were from the Community Youth Development Study, a community-randomized trial of 24 small towns in the United States. A cohort of 4,407 youth was followed from fifth grade (prior to CTC implementation) to eighth grade. IPWs for one's own moving status were calculated using fifth- and sixth-grade covariates. Results from inverse probability weighted multilevel models indicated larger effects for youth who remained in their study community for the first 2 years of CTC intervention implementation compared to ITT estimates. These effects included reduced likelihood of alcohol use, binge drinking, smokeless tobacco use, and delinquent behavior. These findings strengthen support for CTC as an efficacious system for preventing youth problem behaviors.

Biases in Randomized Trials: A Conversation Between Trialists and Epidemiologists

Trialists and epidemiologists often employ different terminology to refer to biases in randomized trials and observational studies, even though many biases have a similar structure in both types of study. We use causal diagrams to represent the structure of biases, as described by Cochrane for randomized trials, and provide a translation to the usual epidemiologic terms of confounding, selection bias, and measurement bias. This structural approach clarifies that an explicit description of the inferential goal-the intention-to-treat effect or the per-protocol effect-is necessary to assess risk of bias in the estimates. Being aware of each other's terminologies will enhance communication between trialists and epidemiologists when considering key concepts and methods for causal inference.

Causal inference from experiment and observation

Results from well-conducted randomised controlled studies should ideally inform on the comparative merits of treatment choices for a health condition. In the absence of this, one attempts to use evidence from the impact of treatment when administered according to decisions of the physicians and the patients (observational evidence). Naïve comparisons between treatment options using observational evidence will lead to biased results. Under certain conditions, however, it is possible to obtain valid estimates of the comparative merits of different treatments from observational data. Causal inference can be conceptualised as a framework aiming to provide valid information about causal effects of treatments using observational evidence. It can be viewed as a missing data problem in which each patient has two outcomes: the observed outcome under the treatment actually received and a counterfactual (unobserved) outcome had the patient received a different treatment. Methodological developments over the last decades clarified the appropriate conditions and methods to obtain valid comparisons. This article provides an introduction to some of these methods.