Propensity Score Stratification Research Articles

Prophylactic anticoagulation in children receiving home parenteral nutrition: An international prospective multicenter study.

Catheter-related thrombosis (CRT) is a serious complication associated with home parenteral nutrition (HPN) in children with chronic intestinal failure (CIF). Guidelines on pediatric HPN state that there is insufficient evidence to advocate the prophylactic use of CRT. Aim is to evaluate the efficacy and safety of prophylactic anticoagulation in preventing CRT in children on HPN. We performed a prospective, international, multicenter study across three expertise centers. Children aged 0-18 years on HPN were included and divided into two groups: 1) primary/secondary prophylaxis- and 2) non-prophylaxis group. Participants were followed for 24 months and screened for CRT using ultrasonography annually. Primary outcomes included total incidence of CRT per 1000 catheter days, and association between prophylactic anticoagulation and CRT. Propensity score stratification and logistic regression were used to evaluate the association between prophylactic anticoagulation and CRT, adjusting for significant covariates differing between groups. Balance was visually assessed before and after stratification, and statistical significance (p<0.05) was determined. Secondary outcomes included incidence of catheter-related bloodstream infections (CRBSI) and bleeding events per 1000 catheter days. A total of 115 children, mean age of 6,9 years (SD 4,6), were included. Fifty-seven patients were receiving prophylactic anticoagulation (50%). The overall incidence of CRT was 0.17 per 1000 catheter days in 13 patients (11%), with no significant difference between the prophylaxis (n=6) and non-prophylaxis group (n=7) (odds ratio 0.64, 95% CI: 0.12-3.4, p=0.60). Incidence rate of CRBSIs was 0.34/1000 catheter days (n=25). Patients with CRT during follow up were significantly more likely to have a CRBSI (54%) compared to those without (14%) (p=0.010). Two minor bleeding events were reported in the prophylaxis group, resulting in an incidence of 0,03/1000 catheter days. Our study shows that prophylactic anticoagulation does not significantly reduce the incidence of CRT in children on HPN. Our results do underline the clinical importance of optimal catheter care and infection prevention as CRBSIs were more likely to occur in patients with CRT, and emphasize the need for larger multicenter trials to establish evidence-based recommendations for the use of prophylactic anticoagulation in children on HPN.

A comparison of time-varying propensity score vs sequential stratification approaches to longitudinal matching with a time-varying treatment

BackgroundMethods for matching in longitudinal cohort studies, such as sequential stratification and time-varying propensity scores, facilitate causal inferences in the context of time-dependent treatments that are not randomized where patient eligibility or treatment status changes over time. The tradeoffs in available approaches have not been compared previously, so we compare two methods using simulations based on a retrospective cohort of patients eligible for weight loss surgery, some of whom received it.MethodsThis study compares matching completeness, bias, coverage, and precision among three approaches to longitudinal matching: (1) time-varying propensity scores (tvPS), (2) sequential stratification that matches exactly on all covariates used in tvPS (SS-Full) and (3) sequential stratification that exact matches on a subset of covariates (SS-Selected). These comparisons are made in the context of a deep sampling frame (50:1) and a shallow sampling frame (5:1) of eligible comparators. A simulation study was employed to estimate the relative performance of these approaches.ResultsIn 1,000 simulations each, tvPS retained more than 99.9% of treated patients in both the deep and shallow sampling frames, while a smaller proportion of treated patients were retained for SS-Full (91.6%) and SS-Selected (98.2%) in the deep sampling frame. In the shallow sampling frame, sequential stratification retained many fewer treated patients (73.9% SS-Full, 92.0% SS-Selected) than tvPS yet coverage, precision and bias were comparable for tvPS, SS-Full and SS-Selected in the deep and shallow sampling frames.ConclusionTime-varying propensity scores have comparable performance to sequential stratification in terms of coverage, bias, and precision, with superior match completeness. While performance was generally comparable across methods, greater match completeness makes tvPS an attractive option for longitudinal matching studies where external validity is highly valued.

Metformin is associated with lower risks of incident cancers compared to sulphonylurea use: a population-based study with competing risk analyses

Abstract Objective To investigate the effects of sulphonylurea compared to metformin on the risks new-onset cancers and mortality in patients with type 2 diabetes mellitus. Methods This is a retrospective population-based cohort study of patients with type 2 diabetes mellitus between 1st January and 31st December 2009 with follow-up until 31st December 2019. Propensity score matching (1:2 ratio) between metformin and sulphonylurea users was performed. The primary outcome is new diagnosis of any cancer. The secondary outcomes are cancer, cardiovascular, or all-cause mortality. Cox regression was used to identify significant predictors. Competing risks were considered using cause-specific or subdistribution hazard models. Propensity score stratification, inverse probability weighting, and high-dimensional propensity score adjustment were also used. Results In the matched cohort, 36487 sulphonylurea and 71306 metformin users were included. Univariable Cox regression showed that compared to metformin users, sulphonylurea users had a higher risks of any new cancer diagnosis (hazard ratio [HR]: 2.26, 95% confidence interval [CI]: 2.18-2.34, P&amp;lt;0.0001), including pancreatic (HR: 4.03 [3.37, 4.82], P&amp;lt;0.0001), colorectal (HR: 2.12 [1.97, 2.27], P &amp;lt;0.0001), genitourinary (HR: 1.73 [1.57, 1.90], P&amp;lt;0.0001), breast (HR: 1.36 [1.22, 1.51], P&amp;lt;0.0001) and lung cancer (HR: 3.37 [3.11, 3.65], P&amp;lt;0.0001) cancers. Sulphonylurea users also had higher risks of cancer-related (HR: 2.38, 95% CI: 1.87-3.03; P&amp;lt;0.0001) and all-cause mortality (HR: 1.92, 95% CI: 1.78 -2.08; P&amp;lt;0.0001). Conclusion Metformin use was associated with lower risks of new diagnosis of any cancer, cancer-related and all-cause mortality in patients with type 2 diabetes mellitus.Figure 1.Study flow diagram.FIgure 2.New diagnosis of cancer.

Effectiveness of bivalent HPV vaccination against genital HPV DNA-positivity of a catch-up campaign at age 13–16 years compared to routine vaccination at age 12 years: a biennial repeated cross-sectional study

BackgroundThe Netherlands is one of few countries worldwide which has used the bivalent HPV vaccine for girls-only for over a decade. This allows assessment of vaccine effectiveness (VE) against female genital HPV DNA-positivity of this vaccine in an observational post-licencing real-world setting. Additionally, it is unclear whether catch-up vaccination campaigns result in similar VE as routine vaccination. Therefore, type-specific and grouped VE were assessed and compared for women who had been eligible for catch-up vaccination at 13–16 years with those who had been eligible for routine vaccination at 12 years.MethodsPASSYON is a Dutch biennial repeated cross-sectional (2011–2021) study among sexual health clinic clients aged 16–24 years old. Women provided self-collected vaginal samples, questionnaires on demographics and sexual behaviour were administered, and women self-reported HPV vaccination status. Samples were analysed using a PCR-based assay (SPF10-LiPA25). Type-specific and grouped VE estimates, adjusted with propensity score stratification, were assessed against genital positivity for 14 HPV types. VE for targeted and non-targeted genotypes were compared between women who had been eligible for the catch-up and those who had been eligible for routine vaccination.ResultsThe study included 4488 female participants who had been eligible for HPV vaccination and provided genital swabs (1561 eligible for catch-up, 2927 for routine vaccination). Very high VE against genital HPV-16 and HPV-18 was observed (resp. 93.5% and 89.5%) and significant cross-protection against six other genotypes (HPV-31/33/35/45/52/58), varying from 18.0% (HPV-52) to 79.6% (HPV-45). VE estimates were comparable between women who had been eligible for the catch-up campaign and those eligible for routine vaccination: VE HPV-16/HPV-18: 92.2% (95%CI: 87.9–94.9) vs. 91.8% (95%CI: 86.0–95.2).ConclusionsIn real-world settings, the VE of bivalent vaccine is high against targeted genotypes, with cross-protection against 6 other genotypes. Catch-up campaigns up to age 16 years can be as effective as routine vaccination at age 12, although it is recommendable to provide HPV vaccination at an age at which most are likely not sexually active yet. This may inform countries considering catch-up campaigns when introducing or extending the use of HPV vaccination within their national immunisation programmes.

8527 The Role Of SGLT2 Inhibitors In Outcomes After LVAD Implantation

Abstract Disclosure: L. Carafone: None. S. McNitt: None. I. Goldenberg: None. J. Alexis: None. Introduction: Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are important medications in the treatment of diabetes mellitus, however they offer several additional benefits, including improved heart failure outcomes in patients with and without diabetes. The role of SGLT2i in heart failure outcomes for patients who receive left ventricular assist device (LVAD) implantation is not known. Right heart failure, in particular, is a frequent complication and major contributor to morbidity and mortality after LVAD implantation. SGLT2i have been increasingly used in patients who undergo LVAD implantation, however it is unknown whether right heart failure events post-LVAD implantation are meaningfully impacted by SGLT2i use. Objective: The purpose of this study was to evaluate the role of SGLT2i in outcomes after LVAD implantation. The primary endpoint was the onset of a first right heart failure (RHF) event following LVAD implantation. Secondary endpoints included recurrent RHF, first and recurrent hospitalization for RHF, and all-cause mortality. Methods: The study population comprised all consecutive patients who received a HeartMate 3 LVAD implantation at the medical center from 9/25/2015 through 9/1/2023 who are included in the institution’s LVAD Database. Both patients who received and did not receive a SGLT2i were included. A time-dependent model was used to evaluate treatment with SGLT2i as a time-dependent variable. Multivariable propensity score matching was used in the analysis of outcomes. Results: A total of 399 patients were analyzed, which included 175 patients who received SGLT2i and 224 patients who did not receive SGLT2i. Cox proportional hazards regression, employing propensity score stratification, demonstrated SGLT2i use was not associated with a statistical significant effect in the primary endpoint of a first occurrence of RHF event (HR = 1.41, 95% CI = 0.77-2.61, p = 0.268). Similarly, SGLT2i use was not associated with secondary outcomes, including recurrent RHF (HR = 1.28, 95% CI = 0.76-2.16, p = 0.360), first or recurrent hospitalization for RHF (HR = 0.38, 95% CI = 0.11-1.33, p = 0.131 and HR = 0.63, 95% CI = 0.27-1.46, p = 0.285, respectively), and all-cause mortality (HR = 0.90, 95% CI = 0.44-1.83, p = 0.771). Presence or absence of diabetes diagnosis did not significantly impact outcomes. Conclusions: The observational data in this study suggest no incremental benefit of SGLT2i for right heart failure or mortality outcomes after LVAD implantation, however large-scale prospective studies are needed to evaluate the role of SGLT2i in this setting. Further elucidating the role of these medications in LVAD outcomes will be critical in clinical decision-making regarding use of SGLT2i in this population. Presentation: 6/1/2024

Perbandingan Propensity Score Stratification dan Propensity Score Matching dengan Pendekatan Multivariate Adaptive Regression Spline

Research on complications of Diabetes Mellitus (DM) is multifactorial, where the risk factors causing DM complications are interrelated, leading to confounding bias, which results in inaccurate research findings. Confounding bias can be reduced using the propensity score method. This study aims to compare the performance of the Propensity Score Stratification (PSS) and Propensity Score Matching (PSM) methods with the Multivariate Adaptive Regression Spline (MARS) approach in estimating treatment effects on DM complication cases. The data used is the medical records of type-2 DM patients at Hospital X. The results showed that the PSS method with the MARS approach is not suitable for small data sets, as it can lead to treatment or control groups lacking members, making it impossible to calculate the p-value in balance testing or the Percent Bias Reduction (PBR). The estimated Average Treatment Effect (ATE) using the PSS method was 0.487 with a PBR of 35.1%, whereas the estimated Average Treatment for Treated (ATT) using the PSM method was 0.531 with a PBR of 99.46%. These PBR values indicate that the best method for estimating treatment effects and the one that can reduce the most bias in this case is the PSM method with MARS. The analysis also showed that serum uric acid levels significantly affect the peripheral diabetic neuropathy (PDN) status of DM patients.

Clinical outcomes of COVID-19 infection in patients with osteoporosis: a nationwide cohort study in Korea using the common data model

Many older patients with COVID-19 likely have co-morbid osteoporosis. We investigated the clinical outcomes of COVID-19 patients with osteoporosis. This was a retrospective cohort study using national claims data from Korea encoded in the common data model. Patients aged ≥ 50 years diagnosed with COVID-19 infection between January 2020 and April 2022 were included and stratified into two groups according to a history of osteoporosis. Clinical outcomes of COVID-19 infection were analyzed using logistic regression analysis after large-scale propensity score stratification. Of the 597,011 patients with COVID-19 included in the study, 105,172 had a history of osteoporosis. In patients with a history of osteoporosis, the odds of mortality decreased (odds ratio [OR] 0.82, P < 0.002), whereas most clinical outcomes of COVID-19 did not exhibit differences compared to those without such a history. Osteoporosis patients with a history of fractures showed increased odds of pneumonia, hospitalization, major adverse cardiac events, venous thromboembolism, and mortality, compared to patients without osteoporosis (ORs 1.34–1.58, P < 0.001 to P = 0.001). Our study suggests that patients with severe osteoporosis who have experienced fractures have an elevated risk of severe complications with COVID-19, while osteoporosis patients without fractures who have sought medical attention have a lower risk of mortality.

Semiparametric efficiency gains from parametric restrictions on propensity scores

Abstract We explore how much knowing a parametric restriction on propensity scores improves semiparametric efficiency bounds in the potential outcome framework. For stratified propensity scores, considered as a parametric model, we derive explicit formulas for the efficiency gain from knowing how the covariate space is split. Based on these, we find that the efficiency gain decreases as the partition of the stratification becomes finer. For general parametric models, where it is hard to obtain explicit representations of efficiency bounds, we propose a novel framework that enables us to see whether knowing a parametric model is valuable in terms of efficiency even when it is high dimensional. In addition to the intuitive fact that knowing the parametric model does not help much if it is sufficiently flexible, we discover that the efficiency gain can be nearly zero even though the parametric assumption significantly restricts the space of possible propensity scores.

Propensity score matching for comparative studies: a tutorial with R and Rex.

Recently, there has been considerable progress in developing new technologies and equipment for the medical field, including minimally invasive surgeries. Evaluating the effectiveness of these treatments requires study designs like randomized controlled trials. However, due to the nature of certain treatments, randomization is not always feasible, leading to the use of observational studies. The effect size estimated from observational studies is subject to selection bias caused by confounders. One method to reduce this bias is propensity scoring. This study aimed to introduce a propensity score matching process between two groups using a practical example with R. Additionally, Rex, an Excel add-in graphical user interface statistical program, is provided for researchers unfamiliar with R programming. Further techniques, such as matching with three or more groups, propensity score weighting and stratification, and imputation of missing values, are summarized to offer approaches for more complex studies not covered in this tutorial.

One- versus three-month dual antiplatelet therapy in high bleeding risk patients undergoing percutaneous coronary intervention for non-ST-segment elevation acute coronary syndromes.

A short dual antiplatelet therapy (DAPT) duration has been proposed for patients at high bleeding risk (HBR) undergoing drug-eluting coronary stent (DES) implantation. Whether this strategy is safe and effective after a non-ST-segment elevation acute coronary syndrome (NSTE-ACS) remains uncertain. We aimed to compare the impact of 1-month versus 3-month DAPT on clinical outcomes after DES implantation among HBR patients with or without NSTE-ACS. This is a prespecified analysis from the XIENCE Short DAPT programme involving three prospective, international, single-arm studies evaluating the safety and efficacy of 1-month (XIENCE 28 USA and Global) or 3-month (XIENCE 90) DAPT among HBR patients after implantation of a cobalt-chromium everolimus-eluting stent. Ischaemic and bleeding outcomes associated with 1- versus 3-month DAPT were assessed according to clinical presentation using propensity score stratification. Of 3,364 HBR patients (1,392 on 1-month DAPT and 1,972 on 3-month DAPT), 1,164 (34.6%) underwent DES implantation for NSTE-ACS. At 12 months, the risk of the primary endpoint of death or myocardial infarction was similar between 1- and 3-month DAPT in patients with (hazard ratio [HR] 1.09, 95% confidence interval [CI]: 0.71-1.65) and without NSTE-ACS (HR 0.88, 95% CI: 0.63-1.23; p-interaction=0.34). The key secondary endpoint of Bleeding Academic Research Consortium (BARC) Type 2-5 bleeding was consistently reduced in both NSTE-ACS (HR 0.57, 95% CI: 0.37-0.88) and stable patients (HR 0.84, 95% CI: 0.61-1.15; p-interaction=0.15) with 1-month DAPT. Among HBR patients undergoing implantation of an everolimus-eluting stent, 1-month, compared to 3-month DAPT, was associated with similar ischaemic risk and reduced bleeding at 1 year, irrespective of clinical presentation.

Evaluating the comparability of osteoporosis treatments using propensity score and negative control outcome methods in UK and Denmark electronic health record databases.

Evidence on the comparative effectiveness of osteoporosis treatments is heterogeneous. This may be attributed to different populations and clinical practice, but also to differing methodologies ensuring comparability of treatment groups before treatment effect estimation and the amount of residual confounding by indication. This study assessed the comparability of denosumab vs oral bisphosphonate (OBP) groups using propensity score (PS) methods and negative control outcome (NCO) analysis. A total of 280 288 women aged ≥50yr initiating denosumab or OBP in 2011-2018 were included from the UK Clinical Practice Research Datalink (CPRD) and the Danish National Registries (DNR). Balance of observed covariates was assessed using absolute standardized mean difference (ASMD) before and after PS weighting, matching, and stratification, with ASMD >0.1 indicating imbalance. Residual confounding was assessed using NCOs with ≥100 events. Hazard ratio (HR) and 95%CI between treatment and NCO were estimated using Cox models. Presence of residual confounding was evaluated with 2 approaches (1) >5% of NCOs with 95% CI excluding 1, (2) >5% of NCOs with an upper CI <0.75 or lower CI >1.3. The number of imbalanced covariates before adjustment (CPRD 22/87; DNR 18/83) decreased, with 2%-11% imbalance remaining after weighting, matching, or stratification. Using approach 1, residual confounding was present for all PS methods in both databases (≥8% of NCOs), except for stratification in DNR (3.8%). Using approach 2, residual confounding was present in CPRD with PS matching (5.3%) and stratification (6.4%), but not with weighting (4.3%). Within DNR, no NCOs had HR estimates with upper or lower CI limits beyond the specified bounds indicating residual confounding for any PS method. Achievement of covariate balance and determination of residual bias were dependent upon several factors including the population under study, PS method, prevalence of NCO, and the threshold indicating residual confounding.

More Likely to Pay but Less Engaged: The Effects of Switching Online Courses from Scheduled to On-Demand Release on User Behavior

Following trends in entertainment streaming services, online educational platforms are increasingly offering users flexible “on-demand” content options. It is important to understand how the timing of content release affects learning behaviors and firm revenue drivers. The current research studies over 67,000 users taking a marketing course before versus after a natural experiment in which the platform switched the course from a scheduled weekly-release format to an on-demand format with all content immediately available. The switch to on-demand positively impacted short-term firm revenue by increasing the number and proportion of certificate-paying users, suggesting that on-demand content can attract a broader set of consumers who value flexibility. On the downside, the switch resulted in users exhibiting lower lecture completion rates and quiz performance and taking fewer additional business courses on the platform, representing a long-term cost. The results were robust to propensity score matching and stratification. The analyses also revealed that on-demand content enabled learning patterns that deviated from a standard evenly paced schedule, including “strategic” binge learning and stretching out engagement past the recommended course period. Thus, while on-demand formats can boost revenues by bringing in more paying users, managers must consider new strategies for maintaining performance and engagement levels within these environments.

Editor's Choice – Comparison of Open Surgery and Endovascular Techniques for Juxtarenal and Complex Neck Aortic Aneurysms: The UK COMPlex AneurySm Study (UK-COMPASS) – Peri-operative and Midterm Outcomes

Treatment of juxtarenal and complex neck abdominal aortic aneurysms (AAAs) is now commonly by endovascular rather than open surgical repair (OSR). Published comparisons show poor validity and scientific precision. UK-COMPASS is a comparative cohort study of endovascular treatments vs. OSR for patients with an AAA unsuitable for standard on label endovascular aneurysm repair (EVAR). All procedures for AAA in England (November 2017 to October 2019) were identified, AAA anatomy assessed in a Corelab, peri-operative risk scores determined, and propensity scoring used to identify patients suitable for either endovascular treatment or OSR. Patients were stratified by aneurysm neck length (0 - 4 mm, 5 - 9 mm, or ≥ 10 mm) and operative risk; the highest quartile was considered high risk and the remainder standard risk. Death was the primary outcome measure. Endovascular treatments included fenestrated EVAR (FEVAR) and off label standard EVAR (± adjuncts). Among 8 994 patients, 2 757 had AAAs that were juxtarenal, short neck, or complex neck in morphology. Propensity score stratification and adjustment method comparisons included 1 916 patients. Widespread off label use of standard EVAR devices was noted (35.6% of patients). The adjusted peri-operative mortality rate was 2.9%, lower for EVAR (1.2%; p= .001) and FEVAR (2.2%; p= .001) than OSR (4.5%). In standard risk patients with a 0 - 4 mm neck, the mortality rate was 7.4% following OSR and 2.3% following FEVAR. Differences were smaller for patients with a neck length ≥ 5 mm: 2.1% OSR vs. 1.0% FEVAR. At 3.5 years of follow up, the overall mortality rate was 20.7% in the whole study population, higher following FEVAR (27.6%) and EVAR (25.2%) than after OSR (14.2%). However, in the 0 - 4 mm neck subgroup, overall survival remained equivalent. The aneurysm related mortality rate was equivalent between treatments, but re-intervention was more common after EVAR and FEVAR than OSR. FEVAR proves notably safer than OSR in the peri-operative period for juxtarenal aneurysms (0 - 4 mm neck length), with comparable midterm survival. For patients with short neck (5 - 9 mm) and complex neck (≥10mm) AAAs, overall survival was worse in endovascularly treated patients compared with OSR despite relative peri-operative safety. This warrants further research and a re-appraisal of the current clinical application of endovascular strategies, particularly in patients with poor general survival outlook owing to comorbidity and age.

The effects of overseas exhibition games on consumer interest: the case of the English Premier League

ABSTRACT Research question This paper attempts to disentangle the impact of overseas exhibition games, a strategic marketing tool frequently implemented by professional sports clubs in their endeavors to expand into foreign markets, on demand. As such, it contributes to the recently growing literature examining the internationalization processes of leagues and clubs. Research methods We implement two different studies. Study 1 analyzes the effects of games played by English Premier League (EPL) clubs in the US in summer 2015 on US residents’ willingness to pay (WTP) for add-on football packages on television. In doing so, we exploit the panel structure of geocoded data collected in two representative surveys and use inverse-probability-weighted regression adjustment estimators. Study 2 focuses on regional audience data on EPL games televised in the US. We account both for summer 2014 and 2015 exhibition games by implementing propensity score stratification. Results and findings Overall, we find that exhibition games played by EPL clubs have a positive effect on both the WTP for TV subscription packages as well as viewership. Further analysis reveals that these effects are primarily driven by top brands traveling abroad (though also some spillover benefits on EPL-wide demand emerge) and dissipate over time. Implications Facilitating the organization of overseas exhibition games seems reasonable from a commercial point of view for league management. For broadcasters, requiring certain top brands to participate in preseason tours in their national markets might be essential if they seek to improve their return on investment.

Exploring the efficacy and beneficial population of preimplantation genetic testing for aneuploidy start from the oocyte retrieval cycle: a real-world study

BackgroundPreimplantation genetic testing for aneuploidy (PGT-A) is widely used as an embryo selection technique in in vitro fertilization (IVF), but its effectiveness and potential beneficiary populations are unclear.MethodsThis retrospective cohort study included patients who underwent their first oocyte retrieval cycles at CITIC-Xiangya between January 2016 and November 2019, and the associated fresh and thawed embryo transfer cycles up to November 30, 2020. PGT-A (PGT-A group) and intracytoplasmic sperm injection (ICSI)/IVF (non-PGT-A group) cycles were included. The numbers of oocytes and embryos obtained were unrestricted. In total, 60,580 patients were enrolled, and baseline data were matched between groups using 1:3 propensity score matching. Sensitivity analyses, including propensity score stratification and traditional multivariate logistic regression, were performed on the original unmatched cohort to check the robustness of the overall results. Analyses were stratified by age, body mass index, ovarian reserve/responsiveness, and potential indications to explore benefits in subgroups. The primary outcome was cumulative live birth rate (CLBR). The other outcomes included live birth rate (LBR), pregnancy loss rate, clinical pregnancy rate, pregnancy complications, low birth weight rate, and neonatal malformation rate.ResultsIn total, 4195 PGT-A users were matched with 10,140 non-PGT-A users. A significant reduction in CLBR was observed in women using PGT-A (27.5% vs. 31.1%; odds ratio (OR) = 0.84, 95% confidence interval (CI) 0.78–0.91; P < 0.001). However, women using PGT-A had higher first-transfer pregnancy (63.9% vs. 46.9%; OR = 2.01, 95% CI 1.81–2.23; P < 0.001) and LBR (52.6% vs. 34.2%, OR = 2.13, 95% CI 1.92–2.36; P < 0.001) rates and lower rates of early miscarriage (12.8% vs. 20.2%; OR = 0.58, 95% CI 0.48–0.70; P < 0.001), preterm birth (8.6% vs 17.3%; P < 0.001), and low birth weight (4.9% vs. 19.3%; P < 0.001). Moreover, subgroup analyses revealed that women aged ≥ 38 years, diagnosed with recurrent pregnancy loss or intrauterine adhesions benefited from PGT-A, with a significant increase in first-transfer LBR without a decrease in CLBR.ConclusionPGT-A does not increase and decrease CLBR per oocyte retrieval cycle; nonetheless, it is effective in infertile populations with specific indications. PGT-A reduces complications associated with multiple gestations.

Comparison of Propensity Score Weighting Methods to Remove Selection Bias in Average Treatment Effect Estimates

In this Monte Carlo simulation study, the performance of six different propensity score methods implemented through weighting cases was investigated: inverse probability of treatment weighting, truncated inverse probability of treatment weighting, propensity score stratification, marginal mean weighting through propensity score stratification, optimal full propensity score matching, and marginal mean weighting through optimal full propensity score matching. These methods aim to reduce selection bias in estimates of the average treatment effect (ATE) in observational studies. For the estimation of standard errors of the ATE with weights, three methods were compared: weighted least squares (WLS), Taylor series linearization (TSL), and jackknife (JK). Results indicated that covariance adjustment extensions of the investigated propensity score methods, in combination with TSL and JK standard error estimation methods, remove the selection bias appropriately and provide the most accurate standard errors under the simulated conditions.

Stratified analysis in comparative effectiveness studies that emulate randomized trials.

For observational cohort studies that employ matching by propensity scores (PS), preliminary stratification by consequential predictors of outcome better emulates stratified randomization and potentially reduces variance and bias through relaxed dependence on modeling assumptions. We assessed the impact of pre-stratification in two real-life examples. For both, prior evidence from placebo-controlled randomized clinical trials (RCTs) suggested small or no risk reduction, but observational analysis suggested protection, presumably the result of confounding bias. The study populations consisted of Medicare beneficiaries (2014-18) with type 2 diabetes initiating either (i) empagliflozin versus dipeptidyl peptidase-4 inhibitors (DPP-4i) or (ii) empagliflozin versus glucagon-like peptide-1 receptor agonists (GLP-1RA). The outcome was myocardial infarction or stroke. We estimated hazard ratios (HR) and rate differences (RD) after controlling for 143 pre-exposure covariates via 1:1 PS matching after (1) PS estimation in the total cohort (total-cohort PS-matching) and (2) PS estimation separately by baseline cardiovascular disease (stratified PS matching). Stratified PS matching resulted in HRs that exceeded those from total-cohort PS-matching by 13% and 9%, respectively, for the comparisons of empagliflozin to DPP-4i and GLP-1RA. Against both comparators, HRs and RDs after stratified PS matching were closer to the null, with slightly higher variances (2%-3%) than those after total-cohort PS matching. Stratified PS matching produced effect estimates closer to the expected trial findings than total-cohort PS matching. The price paid in increased variance was minimal.

Long-Term Clinical Implications of Atrial Fibrillation on Mortality in Patients Hospitalized with COVID-19: A Nationwide Cohort Study.

Atrial fibrillation (AF) increases the risk of long-term mortality in patients hospitalized with Coronavirus Disease 2019 (COVID-19), but the evidence is limited. This study used data from the Common Data Model of the Health Insurance Review and Assessment Service of Korea collected between 1 January 2020 and 30 April 2022. A total of 107,247 patients hospitalized with COVID-19 were included in this study. They were divided into two groups according to a history of AF. The primary outcome was all-cause mortality. After propensity score stratification, 1919 patients with a history of AF and 105,328 patients without a history of AF who were hospitalized with COVID-19 were analyzed to determine long-term mortality. The primary outcome occurred in 99 of 1919 patients (5.2%) with a history of AF and in 1397 of 105,328 patients (1.3%) without a history of AF (hazard ratio, 1.49; 95% confidence interval 1.20-1.82; p < 0.01). A history of AF was also associated with an increased risk of within 30-day mortality. A history of AF was associated with an increased risk of long-term mortality in patients hospitalized with COVID-19. Our findings indicate the necessity for physicians to reevaluate the optimal management of patients with AF following discharge.

1- or 3-Month DAPT in Patients With HBR With or Without Oral Anticoagulant Therapy After PCI

BackgroundThe optimal duration of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) in patients on long-term oral anticoagulation (OAC) therapy is still uncertain. ObjectivesThe aim of this analysis was to assess the effects of 1- vs 3-month DAPT in patients with and those without concomitant OAC included in the XIENCE Short DAPT program. MethodsThe XIENCE Short DAPT program enrolled patients with high bleeding risk who underwent successful PCI with a cobalt-chromium everolimus-eluting stent. DAPT was discontinued at 1 or 3 months in patients free from ischemic events and adherent to treatment. The effect of 1- vs 3-month DAPT was compared in patients with and those without OAC using propensity score stratification. The primary endpoint was all-cause death or any myocardial infarction (MI). The key secondary endpoint was Bleeding Academic Research Consortium (BARC) types 2 to 5 bleeding. Outcomes were assessed from 1 to 12 months after index PCI. ResultsAmong 3,364 event-free patients, 1,462 (43%) were on OAC. Among OAC patients, the risk for death or MI was similar between 1- and 3-month DAPT (7.4% vs 8.8%; adjusted HR: 0.74; 95% CI: 0.49-1.11; P = 0.139), whereas BARC types 2 to 5 bleeding was lower with 1-month DAPT (adjusted HR: 0.71; 95% CI: 0.51-0.99; P = 0.046). These effects were consistent in patients with and those without OAC (P for interaction = NS). ConclusionsBetween 1 and 12 months after PCI, 1-month compared with 3-month DAPT was associated with similar rates of all-cause death or MI and a reduced rate of BARC types 2 to 5 bleeding, irrespective of OAC treatment.

Estimating causal effects in observational studies for survival data with a cure fraction using propensity score adjustment.

In observational studies, covariates are often confounding factors for treatment assignment. Such covariates need to be adjusted to estimate the causal treatment effect. For observational studies with survival outcomes, it is usually more challenging to adjust for the confounding covariates for causal effect estimation because of censoring. The challenge becomes even thornier when there exists a nonignorable cure fraction in the population. In this paper, we propose a causal effect estimation approach in observational studies for survival data with a cure fraction. We extend the absolute treatment effects on survival outcomes-including the restricted average causal effect and SPCE-to survival outcomes with cure fractions, and construct the corresponding causal effect estimators based on propensity score stratification. We prove the asymptotic properties of the proposed estimators and conduct simulation studies to evaluate their performances. As an illustration, the method is applied to a stomach cancerstudy.