Uses and Limitations of the Restricted Mean Survival Time: Illustrative Examples From Cardiovascular Outcomes and Mortality Trials in Type 2 Diabetes

Multimorbidity frailty index and clinical outcomes among 42,989 older heart failure patients directly discharged from emergency departments: A nationwide retrospective cohort study

AIMS

Frailty, a common and clinically significant condition in older adults with heart failure (HF), is often overlooked in emergency department (ED) settings. This study aims to evaluate the impact of frailty on clinical outcomes in older adults directly discharged from the ED due to HF.

METHODS AND RESULTS

This retrospective cohort study used data from Taiwan's National Health Insurance (NHI) database, identifying older adults (≥65 years) discharged from the ED due to HF between 2017 and 2021. Frailty was assessed using a 38-item multimorbidity frailty index (mFI) derived from ICD-10-CM codes, stratifying patients into fit, mild-to-moderately frail, and severely frail. Outcomes included all-cause mortality, all-cause readmissions, and HF-related readmissions. Cox regression and Fine and Gray models estimated the impact of frailty on these outcomes. Among 42,989 older HF patients (mean age 80.7 ± 8.2 years, 55.5 % female), 57.8 % were frail (46.4 % mild-to-moderately frail and 11.4 % severely frail). Six-month mortality rates were 12.0 % in fit, 16.0 % in mild-to-moderately frail, and 19.4 % in severely frail patients. Readmission rates showed similar patterns. The severely frail group had higher risks of mortality (aHR 1.44, 95 % CI 1.33-1.55), all-cause readmissions (sHR 1.69, 95 % CI 1.62-1.76), and HF-related readmissions (sHR 1.59, 95 % CI 1.48-1.71).

CONCLUSION

Frailty is prevalent among older adults directly discharged from the ED due to HF and significantly elevates risks of mortality and readmissions. These findings highlight the need for frailty assessment in ED settings for older HF patients to optimize care planning, and improve outcomes.

Effect of Lactated Ringer Administration on Survival Outcomes in Critically Ill Patients With Acute Kidney Injury: A Retrospective Cohort Study

Background: Although lactated Ringer's (LR) solution is widely used in managing patients with acute kidney injury (AKI), its specific impact on mortality remains unclear. This retrospective cohort study aimed to evaluate the effects of LR administration on survival outcomes in severely ill patients with AKI. Methods: Critically ill patients with AKI were identified using data from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database. Propensity score matching (PSM) was employed to address baseline discrepancies between patients who received LR and those who did not. The association of LR administration with survival, duration of hospitalization and intensive care unit (ICU) stay, requirement for renal replacement therapy (RRT), renal function recovery, and hyperkalemia was analyzed using restricted mean survival time (RMST), logistic regression, and linear regression models. Results: A total of 5620 patients with AKI were included. Following PSM, LR administration was associated with prolonged survival at 28 and 90 days compared to non-LR use (28-day survival increase: 1.12 days, 95% confidence interval [CI] 0.62-1.63, p < 0.001; 90-day survival increase: 3.73 days, 95% CI 1.70-5.76, p < 0.001). The survival benefit became more pronounced, with higher LR use linked to more remarkable 90-day survival. However, LR administration did not significantly affect renal function recovery or hyperkalemia incidence. Conclusion: Administering LR to critically ill patients with AKI was associated with improved survival at both 28 and 90 days.

Prostate-specific Membrane Antigen Positron Emission Tomography Before Reaching the Phoenix Criteria for Biochemical Recurrence of Prostate Cancer After Radiotherapy: Earlier Detection of Recurrences

BACKGROUND AND OBJECTIVE

Biochemical recurrence (BCR) of prostate cancer (PCa) after curative radiotherapy (RT) is defined according to the Phoenix criteria, which is a prostate-specific antigen (PSA) rise of ≥2.0 ng/ml above the PSA nadir. Prostate-specific membrane antigen (PSMA)-based positron emission tomography/computed tomography (PET/CT) can identify PCa recurrences at very low PSA values. Our aim was to investigate the detection rate and extent of PCa recurrences using PSMA PET/CT after curative RT among patients with a PSA rise of ≥2.0 ng/ml above the nadir (Phoenix positive, Ph+) and patients not reaching this threshold (Phoenix negative, Ph-) and to compare therapeutic management and clinical outcomes in terms of time to androgen deprivation therapy (ADT) and castration-resistance PCa (CRPC), as well as overall survival.

METHODS

We conducted a retrospective analysis of the Prostate Cancer Network Amsterdam (2015-2023) cohort of 568 patients who received curative-intent RT for PCa. Data on PSMA PET/CT outcomes, therapeutic management, and clinical follow-up were collected, including (re)initiation of ADT, progression to CRPC, and survival. Results were compared between groups using logistic regression and survival analyses.

KEY FINDINGS AND LIMITATIONS

The study cohort comprised 222 patients (39.1%) classified as Ph- and 346 (60.9%) classified as Ph+. PSMA-avid lesions were detected in 170 Ph- patients (76.6%) and 322 (93.1%) Ph+ patients. In these groups, 75.9% of Ph- patients and 45.0% of Ph+ patients were eligible for local salvage therapy (odds ratio [OR 3.84]; p < 0.001). Distant metastases were less frequent in the Ph- group (n = 37, 21.8%) than in the Ph+ group (n = 157, 48.8%; OR 0.29; p < 0.001). Survival analyses revealed longer times to ADT (re)initiation and progression to CRPC, as well as lower overall mortality, in the Ph- group (log-rank p < 0.001). The retrospective study design is the main limitation.

CONCLUSIONS AND CLINICAL IMPLICATIONS

For patients with PCa recurrence, PSMA PET/CT can detect this recurrence in the majority of cases not meeting the Phoenix criteria for BCR. Early imaging detects recurrences at a less advanced disease stage, allowing potential salvage treatments. In addition, early PSMA PET/CT is associated with longer times to ADT (re)initiation and progression to CRPC, as well as longer overall survival. These positive clinical implications warrant confirmation of our results in prospective studies to reduce potential leadtime bias.

PATIENT SUMMARY

We investigated early use of a special type of scan called PSMA PET (prostate-specific membrane antigen positron emission tomography) in patients with suspicion of recurrence of their prostate cancer after radiotherapy. Early scans can detect recurrence before the cancer progresses to a more advanced stage.

Improved Measurement of Treatment Effect in Multiple Sclerosis Clinical Trials

This decision analytical model study applies restricted mean survival time as a measure of treatment effect in 2 randomized clinical trials assessing disease-modifying treatments vs placebo in patients with progressive multiple sclerosis.

Changes in Sex Related Mortality after Revascularisation for Chronic Limb Threatening Ischaemia: A National Observational Study 1994 - 2018

OBJECTIVE

The aim of this study was to compare all cause mortality across three time periods with a focus on sex differences after revascularisation for chronic limb threatening ischaemia between 1994 and 2013 in Sweden.

METHODS

In this observational registry study, patients registered in the Swedish vascular registry (Swedvasc), revascularised between 1994 and 2013 with open or endovascular infra-inguinal procedures, were divided into three time periods: 1994 - 1999, 2000 - 2006, and 2007 - 2013. Patients were followed for five years. Poisson regression was used to compare 30 day mortality, presented as adjusted relative risk ratio (aRR). Adjusted restricted mean survival time (aRMST) differences at five years were compared with a generalised linear model. The analyses were adjusted for age, comorbidities, and endovascular or open surgery. Comparison with the general Swedish population was also conducted with age adjusted standardised mortality ratios. Results are presented with the 95% confidence interval (CI).

RESULTS

The study showed increasing 30 day mortality, with an aRR of 1.47 (95% CI 1.31 - 1.65) for women and aRR of 1.20 (95% CI 1.06 - 1.35) for men, per time period. In women, the five year RMST decreased from the first to the third period, with an aRMST of -45 (95% CI -59 - -32) days per period. In men, the aRMST increased 32 (95% CI 18 - 47) days per period. When comparing sexes, women showed lower 30 day mortality and higher five year survival than men in the first time period, but a significantly worse development over time periods than for men. Corresponding findings were observed in comparison with the general Swedish population.

CONCLUSION

This study showed an increased 30 day mortality in women and men across the periods, most evident in women. Men showed an increased five year survival across the periods, whereas opposite findings were recorded for women. The dismal trend over time for women could not be explained by increased age or a higher prevalence of comorbidities.

Predicting survival in bladder cancer with a novel apoptotic gene-related prognostic model

BACKGROUND

Apoptosis and apoptotic genes play a critical role in the carcinogenesis and progression of bladder cancer. However, there is no prognostic model established by apoptotic genes.

METHODS

Messenger RNA (mRNA), Expression data, and related clinical data were obtained from The Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) database. After extracting the apoptosis-related genes, the survival-related apoptosis genes were screened by univariate Cox regression analysis in the TCGA cohort. Following the Least Absolute Shrinkage and Selection Operator (LASSO) regression method, these genes were modeled by multivariate Cox analysis. The predictive abilities of the Apoptosis-Related Gene Model (ARGM) for overall survival (OS) rate, disease-specific survival (DSS) measures, and progression-free survival (PFS) were verified by the Kaplan-Meier(K-M)survival analysis and time-dependent Receiver Operating Characteristic (ROC) curve. Functional enrichment analyses were performed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG). CIBERSORT and Single-Sample Gene Set Enrichment Analysis (ssGSEA) were used to calculate the type of immune cell infiltration and immune functions. The model's predictive ability for immunotherapy were evaluated using Tumor Immune Dysfunction and Exclusion (TIDE) and the Imvigor210 study.The single-cell sequencing was used to display the expression level of the ARGM.Finally,qRT-PCR was executed to validate the expression level of ARGM.

RESULTS

Several apoptosis genes were identified through the model, including ANXA1, CASP6, CD2, F2, PDGFRB, SATB1, and TSPO. The prognostic value of the model for OS, DSS, and PFS were verified using the TCGA and GEO cohort. The model can predict patient response to immunotherapy treatment as established through the model's score which was linked to different types of immune cell infiltration and identified significant differences in the signal pathways between high-risk and low-risk groups. Nomogram variables, prompted from ARGM and clinical parameters, also generate a high predictive value for patient survival.

CONCLUSION

Ourestablished apoptosis-related gene model (ARGM) has a substantial predictive value for prognosis and immunotherapy of bladder cancer. It may help with clinical consultation, clinical stratification, and treatment selection. The immune infiltration status and signal pathway of different risk groups also provide direction for further research.

Estimating individualized treatment rules by optimizing the adjusted probability of a longer survival

Individualized treatment rules inform tailored treatment decisions based on the patient's information, where the goal is to optimize clinical benefit for the population. When the clinical outcome of interest is survival time, most of current approaches typically aim to maximize the expected time of survival. We propose a new criterion for constructing Individualized treatment rules that optimize the clinical benefit with survival outcomes, termed as the adjusted probability of a longer survival. This objective captures the likelihood of living longer with being on treatment, compared to the alternative, which provides an alternative and often straightforward interpretation to communicate with clinicians and patients. We view it as an alternative to the survival analysis standard of the hazard ratio and the increasingly used restricted mean survival time. We develop a new method to construct the optimal Individualized treatment rule by maximizing a nonparametric estimator of the adjusted probability of a longer survival for a decision rule. Simulation studies demonstrate the reliability of the proposed method across a range of different scenarios. We further perform data analysis using data collected from a randomized Phase III clinical trial (SWOG S0819).

Safety and Efficacy of Atezolizumab/Bevacizumab in Patients with Hepatocellular Carcinoma and Impaired Liver Function: A Systematic Review and Meta-Analysis

BACKGROUND

Safety and outcome of atezolizumab/bevacizumab in Child-Pugh B patients with hepatocellular carcinoma (HCC) have not been completely characterized.

OBJECTIVES

In this study, we aimed at addressing safety and efficacy of atezolizumab/bevacizumab in Child-Pugh B patients by reviewing the available data and analyzing them by meta-analysis.

METHODS

We compared the safety and efficacy of atezolizumab/becavizumab treatment in patients with unresectable HCC and various degrees of liver dysfunction. A total of 8 retrospective, non-randomized, cohort studies were included in this meta-analysis, for a total of 1,071 Child-Pugh A and 225 Child-Pugh B patients. The albumin-bilirubin (ALBI) grade was also used to assess liver function, when available.

RESULTS

Grade ≥3 adverse events were observed in 11.8% of Child-Pugh class A and 26.8% class B patients (p = 0.0001), with an odds ratio (OR) of 0.43 (confidence interval [CI] 0.21-0.90; p = 0.02). Progression-free survival (PFS) at both 6 months (4.90 ± 2.08 vs. 4.75 ± 2.08 months; p = 0.0004) and 12 months (8.83 ± 2.32 vs. 7.26 ± 2.33 months; p = 0.002) was lower in Child-Pugh class B patients. A trend toward a higher objective response rate (ORR) was observed in Child-Pugh class A patients (219/856, 25.6%) as compared to Child-Pugh class B patients (25/138, 18.1%; p = 0.070), while the probability of obtaining an ORR was significantly greater in Child-Pugh A patients (OR 1.79, CI 1.12-2.86; p = 0.02). Median overall survival (OS) was 16.8 ± 2.0 and 6.8 ± 3.2 months in Child-Pugh A and B patients, respectively (mean difference 9.06 months, CI 7.01-11.1, p < 0.0001). Lastly, OS was longer in patients with ALBI grades 1-2 than in those with grade 3 (8.3 ± 11.4 vs. 3.3 ± 5.0 months, p = 0.0008).

CONCLUSIONS

Oncological efficacy of atezolizumab/bevacizumab is moderate in Child-Pugh class B patients, and the shorter PFS and OS associated with the greater likelihood of experiencing treatment-related adverse events observed in these patients suggest great caution and individualization of treatment, possibly with the support of the ALBI grade.

Evaluation of Overall Survival by Restricted Mean Survival Time of Advanced Biliary Tract Cancer treated with Immunotherapy: A Systematic Review and Meta-Analysis

BACKGROUND

For biliary tract cancer (BTC), the addition of immunotherapy (durvalumab or pembrolizumab) to gemcitabine and cisplatin (GemCis) significantly improved overall survival (OS) in phase 3 clinical trials (RCTs). However, the interpretation and magnitude of the treatment effect is challenging because OS Kaplan-Meier curves violate the proportional hazards (PH) assumption. Analysis using restricted mean survival time (RMST) allows quantification of the benefits in the absence of PH. This systematic review and meta-analysis aims to assess the benefit of immunotherapy-based regimens for OS at 24 months using RMST analysis.

METHODS

A systematic review was conducted using studies published up to 8 November 2023. Only phase 3 RCTs evaluating the use of anti-PD-1/PD-L1 combined with GemCis and reporting OS were included. KM curves for OS were digitized, and the data were reconstructed. A meta-analysis for OS by RMST at 24 months was performed.

RESULTS

A total of 1754 participants from the TOPAZ-1 and KEYNOTE-966 trials were included. In TOPAZ-1, RMSTs at 24 months were 13.52 (7.92) and 12.21 (7.22) months with GemCis plus durvalumab and GemCis alone, respectively. In KEYNOTE-966, RMSTs at 24 months were 13.60 (7.76) and 12.45 (7.73) months with GemCis plus pembrolizumab and GemCis alone, respectively. Immunotherapy-based regimens showed a mean OS difference at 24 months by an RMST of 1.21 months [(95% CI: 0.49-1.93), p < 0.001, I2 = 0%].

CONCLUSIONS

Immunotherapy-based regimens improve OS in advanced BTC. Given this magnitude of benefit, it is essential to weigh up individual patient factors, preferences, and potential risks. RMST analysis provides valuable information to patients and physicians, facilitating decision-making in a value-based medical environment.

Optimal Donor Selection Across Multiple Outcomes For Hematopoietic Stem Cell Transplantation By Bayesian Nonparametric Machine Learning

Allogeneic hematopoietic cell transplantation (HCT) is one of the only curative treatment options for patients suffering from life-threatening hematologic malignancies; yet, the possible adverse complications can be serious even fatal. Matching between donor and recipient for 4 of the HLA genes is widely accepted and supported by the literature. However, among 8/8 allele matched unrelated donors, there is less agreement among centers and transplant physicians about how to prioritize donor characteristics like additional HLA loci (DPB1 and DQB1), donor sex/parity, CMV status, and age to optimize transplant outcomes. This leads to varying donor selection practice from patient to patient or via center protocols. Furthermore, different donor characteristics may impact different post transplant outcomes beyond mortality, including disease relapse, graft failure/rejection, and chronic graft-versus-host disease (components of event-free survival, EFS). We develop a general methodology to identify optimal treatment decisions by considering the trade-offs on multiple outcomes modeled using Bayesian nonparametric machine learning. We apply the proposed approach to the problem of donor selection to optimize overall survival and event-free survival, using a large outcomes registry of HCT recipients and their actual and potential donors from the Center for International Blood and Marrow Transplant Research (CIBMTR). Our approach leads to a donor selection strategy that favors the youngest male donor, except when there is a female donor that is substantially younger.

Individualized survival prediction and surgery recommendation for patients with glioblastoma

Background

There is a lack of individualized evidence on surgical choices for glioblastoma (GBM) patients.

Aim

This study aimed to make individualized treatment recommendations for patients with GBM and to determine the importance of demographic and tumor characteristic variables in the selection of extent of resection.

Methods

We proposed Balanced Decision Ensembles (BDE) to make survival predictions and individualized treatment recommendations. We developed several DL models to counterfactually predict the individual treatment effect (ITE) of patients with GBM. We divided the patients into the recommended (Rec.) and anti-recommended groups based on whether their actual treatment was consistent with the model recommendation.

Results

The BDE achieved the best recommendation effects (difference in restricted mean survival time (dRMST): 5.90; 95% confidence interval (CI), 4.40-7.39; hazard ratio (HR): 0.71; 95% CI, 0.65-0.77), followed by BITES and DeepSurv. Inverse probability treatment weighting (IPTW)-adjusted HR, IPTW-adjusted OR, natural direct effect, and control direct effect demonstrated better survival outcomes of the Rec. group.

Conclusion

The ITE calculation method is crucial, as it may result in better or worse recommendations. Furthermore, the significant protective effects of machine recommendations on survival time and mortality indicate the superiority of the model for application in patients with GBM. Overall, the model identifies patients with tumors located in the right and left frontal and middle temporal lobes, as well as those with larger tumor sizes, as optimal candidates for SpTR.

Translating trial results into interpretable risk estimates: Systematic analysis of cardiorenal outcome trials of glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors

BACKGROUND AND AIMS

In a randomised controlled trial (RCT), the between-arm difference in the average probability of an event per unit of time (i.e., yearly incidence risk difference, YIRD) is an easy-to-interpret treatment effect metric. We aimed to quantify the YIRD in cardiorenal RCTs of GLP-1RAs or SGLT-2is.

METHODS AND RESULTS

We digitally searched for RCTs published up to March 1st, 2023, including subjects with type 2 diabetes randomised to GLP-1RAs or SGLT-2is and investigating cardiorenal outcomes or death. We extracted information from Kaplan-Meier (KM) plots to obtain time-to-event individual data and estimate within-arm yearly incidence risk and YIRD. Data from 19 RCTs (28 kM plots) were analysed: comparing treatment to placebo, in GLP-1RA RCTs the YIRD ranged from 0.2 % (95 % CI: -0.7 %, 1.1 %) to -1.9 % (-3.1, -0.7), for primary outcome; and from -0.2 % (-0.5, 0.2) to -0.4 % (-0.7 %, -0.0 %), for mortality. With the exception of SOLOIST-WHF (YIRD 11.9 % for primary outcome), corresponding estimates in SGLT-2is RCTs were: from -0.1 % (-0.4, 0.1) to -5.0 % (-7.7, -2.6), for primary outcome; and from -0.1 % (-0.2, 0.1) to -1.9 % (-4.4 %, 0.6 %), for mortality.

CONCLUSION

The YIRD metric complements other relative treatment effect estimates and helps quantify the absolute benefit of GLP-1RAs and SGLT-2is.

Questioning a Sensible Result

Contemporary data collection strategies, storage capabilities, and modern statistical methodology have made retrospective analyses of observational databases commonplace. Such databases afford opportunities to learn about the effectiveness and risks of interventions or health behaviors that generally cannot be randomized. In this issue of NEJM Evidence, Cho et al.1 assemble survey data and cohort data from four countries to quantify the association between age-sex-specific smoking cessation and mortality. The authors conclude that smoking cessation at any age is associated with lower excess overall mortality risk and lower death from diseases made more common by smoking. It is difficult to argue with this conclusion - to question the magnitude of the associations is not.

Optimizing adjuvant treatment options for patients with glioblastoma

Background

This study focused on minimizing the costs and toxic effects associated with unnecessary chemotherapy. We sought to optimize the adjuvant therapy strategy, choosing between radiotherapy (RT) and chemoradiotherapy (CRT), for patients based on their specific characteristics. This selection process utilized an innovative deep learning method.

Methods

We trained six machine learning (ML) models to advise on the most suitable treatment for glioblastoma (GBM) patients. To assess the protective efficacy of these ML models, we employed various metrics: hazards ratio (HR), inverse probability treatment weighting (IPTW)-adjusted HR (HRa), the difference in restricted mean survival time (dRMST), and the number needed to treat (NNT).

Results

The Balanced Individual Treatment Effect for Survival data (BITES) model emerged as the most effective, demonstrating significant protective benefits (HR: 0.53, 95% CI, 0.48-0.60; IPTW-adjusted HR: 0.65, 95% CI, 0.55-0.78; dRMST: 7.92, 95% CI, 7.81-8.15; NNT: 1.67, 95% CI, 1.24-2.41). Patients whose treatment aligned with BITES recommendations exhibited notably better survival rates compared to those who received different treatments, both before and after IPTW adjustment. In the CRT-recommended group, a significant survival advantage was observed when choosing CRT over RT (p < 0.001). However, this was not the case in the RT-recommended group (p = 0.06). Males, older patients, and those whose tumor invasion is confined to the ventricular system were more frequently advised to undergo RT.

Conclusion

Our study suggests that BITES can effectively identify GBM patients likely to benefit from CRT. These ML models show promise in transforming the complex heterogeneity of real-world clinical practice into precise, personalized treatment recommendations.

Heterogeneous Treatment Effects of Intensive Glycemic Control on Kidney Microvascular Outcomes and Mortality in ACCORD

SIGNIFICANCE STATEMENT

Identifying and quantifying treatment effect variation across patients is the fundamental challenge of precision medicine. Here we quantify heterogeneous treatment effects of intensive glycemic control in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial, considering three outcomes of interest-a composite kidney outcome (driven by macroalbuminuria), all-cause mortality, and first assisted hypoglycemic event. We demonstrate that the effects of intensive glycemic control vary with risk of kidney failure, as predicted by the kidney failure risk equation (KFRE). Participants at highest risk of kidney failure gain the largest absolute kidney benefit of intensive glycemic control but also experience the largest absolute risk of death and hypoglycemic events. Our findings illustrate the value of identifying clinically meaningful treatment heterogeneity, particularly when treatments have different effects on multiple end points.

OBJECTIVE

Clear criteria to individualize glycemic targets in patients with type II diabetes are lacking. In this post hoc analysis of the ACCORD, we evaluate whether the KFRE can identify patients for whom intensive glycemic control confers more benefit in preventing kidney microvascular outcomes.

RESEARCH DESIGN AND METHODS

We divided the ACCORD trial population into quartiles on the basis of 5-year kidney failure risk using the KFRE. We estimated conditional treatment effects within each quartile and compared them with the average treatment effect in the trial. The treatment effects of interest were the 7-year restricted mean survival time (RMST) differences between intensive and standard glycemic control arms on ( 1 ) time-to-first development of severely elevated albuminuria or kidney failure and ( 2 ) all-cause mortality.

RESULTS

We found evidence that the effect of intensive glycemic control on kidney microvascular outcomes and all-cause mortality varies with baseline risk of kidney failure. Patients with elevated baseline risk of kidney failure derived the most from intensive glycemic control in reducing kidney microvascular outcomes (7-year RMST difference of 114.8 [95% confidence interval 58.1 to 176.4] versus 48.4 [25.3 to 69.6] days in the entire trial population) However, this same patient group also experienced a shorter time to death (7-year RMST difference of -56.7 [-100.2 to -17.5] v. -23.6 [-42.2 to -6.6] days).

CONCLUSIONS

We found evidence of heterogenous treatment effects of intensive glycemic control on kidney microvascular outcomes in ACCORD as a function of predicted baseline risk of kidney failure. Patients with higher kidney failure risk experienced the most pronounced reduction in kidney microvascular outcomes but also experienced the highest risk of all-cause mortality.

Effect of glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors on time to outcome in type 2 diabetes cardiorenal outcome trials

INTRODUCTION

In randomized controlled trials (RCTs), treatment effects are commonly reported as hazard ratio, a measure often misinterpreted as a relative risk reduction. The acceleration factor (AF) indicates the extent to which a treatment increases/decreases the time before the occurrence of an outcome and gives useful insights in the interpretation of trials' results.

METHODS

Using individual time-to-event data reconstructed from Kaplan-Meier plots, we estimated AFs for the primary outcomes (POs) and all-cause mortality in glucagon-like peptide-1 receptor agonists (GLP1-RAs) or sodium-glucose cotransporter-2 inhibitors (SGLT2-is) cardiorenal outcome trials in subjects with type 2 diabetes.

RESULTS

AFs were estimated from 28 Kaplan-Meier plots of 19 RCTs. Compared to placebo, most GLP1-RAs increased the time before the onset of POs (from 9 % to 59 %) and all-cause mortality (from 8 to 13 %). Similarly, SGLT2-is increased time before the onset of POs (from 19 % to 87 %) and all-cause mortality (from 13 % to 42 %).

CONCLUSIONS

The AFs provide a complementary and easier-to-interpret measure of treatment effect that could be useful to improve the shared decision-making.

Adequate versus deep response to ursodeoxycholic acid in primary biliary cholangitis: To what extent and under what conditions is normal alkaline phosphatase level associated with complication-free survival gain?

BACKGROUND AND AIMS

Normal alkaline phosphatase (ALP) levels in ursodeoxycholic acid (UDCA)-treated patients with primary biliary cholangitis (PBC) are associated with better long-term outcome. However, second-line therapies are currently recommended only when ALP levels remain above 1.5 times the upper limit of normal (×ULN) after 12-month UDCA. We assessed whether, in patients considered good responders to UDCA, normal ALP levels were associated with significant survival gains.

APPROACH AND RESULTS

We performed a retrospective cohort study of 1047 patients with PBC who attained an adequate response to UDCA according to Paris-2 criteria. Time to liver-related complications, liver transplantation, or death was assessed using adjusted restricted mean survival time (RMST) analysis. The overall incidence rate of events was 17.0 (95% CI: 13.7-21.1) per 1000 out of 4763.2 patient-years. On the whole population, normal serum ALP values (but not normal gamma-glutamyl transpeptidase (GGT), alanine aminotransferase (ALT), or aspartate aminotransferase (AST); or total bilirubin < 0.6 ×ULN) were associated with a significant absolute complication-free survival gain at 10 years (mean 7.6 months, 95% CI: 2.7 - 12.6 mo.; p = 0.003). In subgroup analysis, this association was significant in patients with a liver stiffness measurement ≥ 10 kPa and/or age ≤ 62 years, with a 10-year absolute complication-free survival gain of 52.8 months (95% CI: 45.7-59.9, p < 0.001) when these 2 conditions were met.

CONCLUSIONS

PBC patients with an adequate response to UDCA and persistent ALP elevation between 1.1 and 1.5 ×ULN, particularly those with advanced fibrosis and/or who are sufficiently young, remain at risk of poor outcome. Further therapeutic efforts should be considered for these patients.

The analgesic efficacy of ultrasound-guided erector spinae plane block versus ultrasound-guided caudal epidural block for abdominal surgery in pediatric patients - A patient and assessor-blind, randomized controlled study

Background

Literature on the efficacy and safety of erector spinae plane block (ESPB) in pediatric patients is limited. Hence, we aimed to compare ESPB versus caudal epidural block (CEB) in children undergoing abdominal surgery.

Methods

In this patient and assessor-blind study, fifty-two ASA I-II patients, between 1 to 9 years of age, were randomized into groups of 26 each. ESPB group received unilateral or bilateral ultrasound (USG)-guided ESPB with 0.5 ml/kg of 0.25% bupivacaine per side. CEB group received USG-guided CEB with 1 ml/kg of 0.25% bupivacaine. The primary objective was to estimate the proportion of patients requiring postoperative rescue analgesia. The secondary objectives were to assess postoperative Face, Legs, Activity, Cry and Consolability (FLACC) scale scores, duration of analgesia, and consumption of rescue analgesic drugs.

Results

More patients in the ESPB group (88.4%), compared to the CEB group (42.3%), required rescue analgesics (P value <0.001). FLACC scores in the ESPB group, though satisfactory, were inferior, to the CEB group. The duration of postoperative analgesia was shorter in the ESPB group by 9.54 h (95% CI: 4.51 to 14.57 h, P value <0.001). The median (IQR) consumption of rescue paracetamol was significantly higher in the ESPB group (20 mg/kg (10,20) compared to the CEB group (0.0 mg/kg (0.0,10) P value <0.001)). No adverse effects were reported.

Conclusion

In children undergoing abdominal surgery, both ESPB and CEB were safe and efficacious. CEB provided a longer duration and better quality of analgesia. ESPB may be considered when CEB is contraindicated or difficult.

Effect of SGLT2 inhibitors versus DPP4 inhibitors on major and non-major osteoporotic fracture risks among general and high-risk type 2 diabetes patients: A nationwide retrospective cohort study

AIMS

To retrospectively analyze the association of sodium-glucose cotransporter-2 inhibitors (SGLT2is) versus dipeptidyl peptidase-4 inhibitors (DPP4is) with a range of major and non-major fracture events, and explore heterogeneous treatment effect among high-risk patient subgroups.

METHODS

Newly stable SGLT2i or DPP4i users in 2017 were identified in Taiwan's National Health Insurance Research Database and followed up until a fracture occurred, loss of follow-up, death, or December 31, 2018, whichever came first. Outcomes included composite major and non-major fractures and individual components in major fractures. Cox model and restricted mean survival time (RMST) analyses were utilized to assess the treatment effect on fractures.

RESULTS

21,155 propensity-score-matched SGLT2i and DPP4i users were obtained. Over 2 years, the hazard ratio and RMST difference for major fracture with SGLT2i versus DPP4i use were 0.89 (95% CI, 0.80, 1.00) and 1.51 (-0.17, 3.17) days, respectively, and those for non-major fracture with SGLT2i versus DPP4i use were 0.89 (0.81, 0.98) and 2.44 (0.47, 4.37) days, respectively. A 180-day lag time analysis for fracture outcomes showed consistent results with primary findings. A SGLT2is-associated harmful effect on major fractures (but not on non-major fractures) was observed among female patients and those with a diabetes duration of ≥ 8 years, prior fractures, and established osteoporosis.

CONCLUSION

This study adds supporting real-world evidence for SGLT2is-associated bone safety for a wide range of fractures, which promotes the rational use of SGLT2is in routine care and highlights the importance of the close monitoring of patients with high fracture risks to maximize treatment benefits while reducing undesirable effects.

Impact of Second-Line Combination Treatment for Type 2 Diabetes Mellitus on Disease Control: A Population-Based Cohort Study

BACKGROUND

Type 2 diabetes mellitus is a chronic disease affecting millions of people worldwide. Achieving and maintaining glycemic control is essential to prevent or delay complications and different strategies are available as second-line treatment options for patients with type 2 diabetes who do not achieve glycemic control with metformin monotherapy.

OBJECTIVE

The aim of this work is to describe the impact of initiating a combination treatment to reduce glycated hemoglobin in patients with type 2 diabetes with insufficient glycemic control.

METHODS

We included patients with a type 2 diabetes diagnosis between 2015 and 2020 at the Information System for Research in Primary Care (SIDIAP) database in Catalonia, Spain. The primary outcome was the time to glycated hemoglobin control (≤ 7%) during the first 720 days, expressed as the restricted mean survival time. Adjusted differences of the restricted mean survival time were compared to analyze the performance of each treatment versus the combination with a sulfonylurea. Adherence was calculated as the medication possession ratio using an algorithm to model treatment exposure.

RESULTS

A total of 28,425 patients were analyzed. The most frequent combinations were those with sulfonylureas and dipeptidyl peptidase-4 inhibitors. All treatments reduced glycated hemoglobin and the restricted mean survival time for the sulfonylurea treatment was 455 (451-459) days although combinations with glucagon-like peptide-1 and insulin reached glycemic control earlier, - 126 days (- 152 to - 100, p < 0.001) and - 69 days (- 88 to - 50, p < 0.001), respectively. Adherence was high in all groups apart from the insulin combination and had a significant effect in reducing glycated hemoglobin except in sodium-glucose cotransporter type 2 inhibitors and insulin. Glucagon-like peptide-1 and sodium-glucose cotransporter type 2 inhibitors showed significant reductions in weight.

CONCLUSIONS

Patients achieved the glycated hemoglobin goal with second-line treatments. Glucagon-like peptide-1 and insulin combinations achieved the goal earlier than sulfonylurea combinations. Adherence significantly reduced the time to glycated hemoglobin control except for the combination with sodium-glucose cotransporter type 2 inhibitors.

Interatrial Block Association With Adverse Cardiovascular Outcomes in Patients Without a History of Atrial Fibrillation

BACKGROUND

Interatrial block (IAB) is associated with thromboembolism and atrial arrhythmias. However, prior studies included small patient cohorts so it remains unclear whether IAB predicts adverse outcomes particularly in context of atrial fibrillation (AF)/atrial flutter (AFL).

OBJECTIVES

This study sought to determine whether IAB portends increased stroke risk in a large cohort in the presence or absence of AFAF/AFL.

METHODS

We performed a 5-center retrospective analysis of 4,837,989 electrocardiograms (ECGs) from 1,228,291 patients. IAB was defined as P-wave duration ≥120 ms in leads II, III, or aVF. Measurements were extracted as .XML files. After excluding patients with prior AF/AFL, 1,825,958 ECGs from 458,994 patients remained. Outcomes were analyzed using restricted mean survival time analysis and restricted mean time lost.

RESULTS

There were 86,317 patients with IAB and 355,032 patients without IAB. IAB prevalence in the cohort was 19.6% and was most common in Black (26.1%), White (20.9%), and Hispanic (18.5%) patients and least prevalent in Native Americans (9.2%). IAB was independently associated with increased stroke probability (restricted mean time lost ratio coefficient [RMTLRC]: 1.43; 95% CI: 1.35-1.51; tau = 1,895), mortality (RMTLRC: 1.14; 95% CI: 1.07-1.21; tau = 1,924), heart failure (RMTLRC: 1.94; 95% CI: 1.83-2.04; tau = 1,921), systemic thromboembolism (RMTLRC: 1.62; 95% CI: 1.53-1.71; tau = 1,897), and incident AF/AFL (RMTLRC: 1.16; 95% CI: 1.10-1.22; tau = 1,888). IAB was not associated with stroke in patients with pre-existing AF/AFL.

CONCLUSIONS

IAB is independently associated with stroke in patients with no history of AF/AFL even after adjustment for incident AF/AFL and CHA2DS2-VASc score. Patients are at increased risk of stroke even when AF/AFL is not identified.

Inequalities in the impact of having a chronic disease on entering permanent paid employment: a registry-based 10-year follow-up study

BACKGROUND

This study aimed to investigate among unemployed persons (1) the impact of having a chronic disease on entering paid employment and obtaining a permanent contract and (2) whether these associations differed by educational attainment.

METHODS

Register data from Statistics Netherlands on employment status, contract type, medication and sociodemographic characteristics were linked. Dutch unemployed persons between 18 and 64 years (n=667 002) were followed up for 10 years (2011-2020). Restricted mean survival time analyses (RMSTs) were used to investigate differences in average months until entering paid employment and until obtaining a permanent contract between persons with and without cardiovascular diseases, inflammatory conditions, diabetes, respiratory illness, common mental disorders and psychotic disorders. Interaction terms were included for education.

RESULTS

One-third of the unemployed persons at baseline entered paid employment during follow-up. Persons with chronic diseases spent more months in non-employment compared with persons without chronic diseases (difference ranging from 2.50 months (95% CI 1.97 to 3.03 months) to 10.37 months (95% CI 9.98 to 10.77 months)), especially for persons with higher education. Conditional on entering paid employment, the time until a permanent contract was longer for persons with cardiovascular diseases (4.42 months, 95% CI 1.85 to 6.99 months), inflammatory conditions (4.80 months, 95% CI 2.02 to 7.59 months) and diabetes (8.32 months, 95% CI 4.26 to 12.37 months) than for persons without these diseases. These latter differences were similar across educational attainment.

CONCLUSIONS

Having a chronic disease is a barrier to entering permanent paid employment. The findings underline the need to prevent chronic diseases and promote an inclusive workforce.

Incidence of diabetes following COVID-19 vaccination and SARS-CoV-2 infection in Hong Kong: A population-based cohort study

BACKGROUND

The risk of incident diabetes following Coronavirus Disease 2019 (COVID-19) vaccination remains to be elucidated. Also, it is unclear whether the risk of incident diabetes after Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection is modified by vaccination status or differs by SARS-CoV-2 variants. We evaluated the incidence of diabetes following mRNA (BNT162b2), inactivated (CoronaVac) COVID-19 vaccines, and after SARS-CoV-2 infection.

METHODS AND FINDINGS

In this population-based cohort study, individuals without known diabetes were identified from an electronic health database in Hong Kong. The first cohort included people who received ≥1 dose of COVID-19 vaccine and those who did not receive any COVID-19 vaccines up to September 2021. The second cohort consisted of confirmed COVID-19 patients and people who were never infected up to March 2022. Both cohorts were followed until August 15, 2022. A total of 325,715 COVID-19 vaccine recipients (CoronaVac: 167,337; BNT162b2: 158,378) and 145,199 COVID-19 patients were 1:1 matched to their respective controls using propensity score for various baseline characteristics. We also adjusted for previous SARS-CoV-2 infection when estimating the conditional probability of receiving vaccinations, and vaccination status when estimating the conditional probability of contracting SARS-CoV-2 infection. Hazard ratios (HRs) and 95% confidence intervals (CIs) for incident diabetes were estimated using Cox regression models. In the first cohort, we identified 5,760 and 4,411 diabetes cases after receiving CoronaVac and BNT162b2 vaccines, respectively. Upon a median follow-up of 384 to 386 days, there was no evidence of increased risks of incident diabetes following CoronaVac or BNT162b2 vaccination (CoronaVac: 9.08 versus 9.10 per 100,000 person-days, HR = 0.998 [95% CI 0.962 to 1.035]; BNT162b2: 7.41 versus 8.58, HR = 0.862 [0.828 to 0.897]), regardless of diabetes type. In the second cohort, we observed 2,109 cases of diabetes following SARS-CoV-2 infection. Upon a median follow-up of 164 days, SARS-CoV-2 infection was associated with significantly higher risk of incident diabetes (9.04 versus 7.38, HR = 1.225 [1.150 to 1.305])-mainly type 2 diabetes-regardless of predominant circulating variants, albeit lower with Omicron variants (p for interaction = 0.009). The number needed to harm at 6 months was 406 for 1 additional diabetes case. Subgroup analysis revealed no evidence of increased risk of incident diabetes among fully vaccinated COVID-19 survivors. Main limitations of our study included possible misclassification bias as type 1 diabetes was identified through diagnostic coding and possible residual confounders due to its observational nature.

CONCLUSIONS

There was no evidence of increased risks of incident diabetes following COVID-19 vaccination. The risk of incident diabetes increased following SARS-CoV-2 infection, mainly type 2 diabetes. The excess risk was lower, but still statistically significant, for Omicron variants. Fully vaccinated individuals might be protected from risks of incident diabetes following SARS-CoV-2 infection.

Heterogeneous treatment effects of intensive glycemic control on kidney microvascular outcomes in ACCORD

Objective

Clear criteria to individualize glycemic targets are lacking. In this post-hoc analysis of the Action to Control Cardiovascular Risk in Diabetes trial (ACCORD), we evaluate whether the kidney failure risk equation (KFRE) can identify patients who disproportionately benefit from intensive glycemic control on kidney microvascular outcomes.

Research design and methods

We divided the ACCORD trial population in quartiles based on 5-year kidney failure risk using the KFRE. We estimated conditional treatment effects within each quartile and compared them to the average treatment effect in the trial. The treatment effects of interest were the 7-year restricted-mean-survival-time (RMST) differences between intensive and standard glycemic control arms on (1) time-to-first development of severely elevated albuminuria or kidney failure and (2) all-cause mortality.

Results

We found evidence that the effect of intensive glycemic control on kidney microvascular outcomes and all-cause mortality varies with baseline risk of kidney failure. Patients with elevated baseline risk of kidney failure benefitted the most from intensive glycemic control on kidney microvascular outcomes (7-year RMST difference of 115 v. 48 days in the entire trial population) However, this same patient group also experienced shorter times to death (7-year RMST difference of -57 v. -24 days).

Conclusions

We found evidence of heterogenous treatment effects of intensive glycemic control on kidney microvascular outcomes in ACCORD as a function of predicted baseline risk of kidney failure. Patients with higher kidney failure risk experienced the most pronounced benefits of treatment on kidney microvascular outcomes but also experienced the highest risk of all-cause mortality.

Comparative Effectiveness and Safety of Seizure Prophylaxis Among Adults After Acute Ischemic Stroke

BACKGROUND

Older adults occasionally receive seizure prophylaxis in an acute ischemic stroke (AIS) setting, despite safety concerns. There are no trial data available about the net impact of early seizure prophylaxis on post-AIS survival.

METHODS

Using a stroke registry (American Heart Association's Get With The Guidelines) individually linked to electronic health records, we examined the effect of initiating seizure prophylaxis (ie, epilepsy-specific antiseizure drugs) within 7 days of an AIS admission versus not initiating in patients ≥65 years admitted for a new, nonsevere AIS (National Institutes of Health Stroke Severity score ≤20) between 2014 and 2021 with no recorded use of epilepsy-specific antiseizure drugs in the previous 3 months. We addressed confounding by using inverse-probability weights. We performed standardization accounting for pertinent clinical and health care factors (eg, National Institutes of Health Stroke Severity scale, prescription counts, seizure-like events).

RESULTS

The study sample included 151 patients who received antiseizure drugs and 3020 who did not. The crude 30-day mortality risks were 219 deaths per 1000 patients among epilepsy-specific antiseizure drugs initiators and 120 deaths per 1000 among noninitiators. After standardization, the estimated mortality was 251 (95% CI, 190-307) deaths per 1000 among initiators and 120 (95% CI, 86-144) deaths per 1000 among noninitiators, corresponding to a risk difference of 131 (95% CI, 65-200) excess deaths per 1000 patients. In the prespecified subgroup analyses, the risk difference was 52 (95% CI, 11-72) among patients with minor AIS and 138 (95% CI, 52-222) among moderate-to-severe AIS patients. Similarly, the risk differences were 86 (95% CI, 18-118) and 157 (95% CI, 57-219) among patients aged 65 to 74 years and ≥75 years, respectively.

CONCLUSIONS

There was a higher risk of 30-day mortality associated with initiating versus not initiating seizure prophylaxis within 7 days post-AIS. This study does not support the role of seizure prophylaxis in reducing 30-day poststroke mortality.

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

BACKGROUND AND OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Incidence and Trends in the Use of Palliative Care among Patients with Reduced, Middle-Range, and Preserved Ejection Fraction Heart Failure

Background: Clinical practice guidelines recommend integrating palliative care (PC) into the care of patients with heart failure (HF) to address their many palliative needs. However, the incidence rates of PC use among HF subtypes are unknown. Methods: We conducted a retrospective cohort study of patients with the following HF subtypes in the Department of Veterans Affairs: reduced ejection fraction (HFrEF), mid-range ejection fraction (HFmEF), and preserved ejection fraction (HFpEF). Patients were included at the time of HF diagnosis from 2011 to 2015 and followed until a minimum of five years or death. Incidence rates of receipt of PC (primary outcome) were calculated using generalized estimating equations. We evaluated the time to incident PC by HF subtype with Kaplan-Meier analyses and with adjusted restricted mean survival time. Results: Of the 113,555 patients, 69% were ≥65 years, 98% were male, 73% White, and 18% Black; 58% had HFrEF, 7% HFmEF, and 34% HFpEF. Twenty percent received PC during follow-up, and 66% died. Adjusted PC incidence rates were higher among patients with HFrEF (47 per 1000 person-years, confidence interval [95% CI] 43-52) than for HFmEF and HFpEF (42 per 1000 person-years, CI 38-47 for both). Restricting follow-up to five years, patients with HFrEF received PC six weeks earlier than patients with HFpEF. There was no significant difference in time to PC between patients with HFmEF versus HFpEF. Conclusion: About 1 in 20 patients with HFrEF and 1 in 25 patients with HFmEF and HFpEF receive PC annually. Patients with HFrEF receive PC sooner than patients with HFmEF and HFpEF.

Restricted Mean Survival Time Analysis to Estimate SGLT2i-Associated Heterogeneous Treatment Effects on Primary and Secondary Prevention of Cardiorenal Outcomes in Patients With Type 2 Diabetes in Taiwan

IMPORTANCE

Increasing numbers of post hoc analyses have applied restricted mean survival time (RMST) analysis on the aggregated-level data from clinical trials to report treatment effects, but studies that use individual-level claims data are needed to determine the feasibility of RMST analysis for quantifying treatment effects among patients with type 2 diabetes in routine clinical settings.

OBJECTIVES

To apply RMST analysis for assessing sodium-glucose cotransporter-2 inhibitor (SGLT2i)-associated cardiovascular (CV) events and estimating heterogenous treatment effects (HTEs) on CV and kidney outcomes in routine clinical settings.

DESIGN, SETTING, AND PARTICIPANTS

This comparative effectiveness study of Taiwan's National Health Insurance Research Database examined 21 144 propensity score (PS)-matched pairs of patients with type 2 diabetes with SGLT2i and dipeptidyl peptidase-4 inhibitor (DPP4i) treatment for assessing CV outcomes, and 19 951 PS-matched pairs of patients with type 2 diabetes with SGLT2i and DPP4i treatment for assessing kidney outcomes. Patients were followed until December 31, 2018. Statistical analysis was performed from August 2021 to April 2022.

EXPOSURES

Newly stable SGLT2i or DPP4i use in 2017.

MAIN OUTCOMES AND MEASURES

Study outcomes were CV events including hospitalization for heart failure (HHF), 3-point major adverse CV events (3P-MACE: nonfatal myocardial infarction [MI], nonfatal stroke, and CV death), 4-point MACE (4P-MACE: HHF and 3P-MACE), and all-cause death, and chronic kidney disease (CKD). RMST and Cox modeling analyses were applied to estimate treatment effects on study outcomes.

RESULTS

After PS matching, the baseline patient characteristics were comparable between 21 144 patients with stable SGLT2i use (eg, mean [SD] age: 58.3 [10.7] years; 11 990 [56.7%] male) and 21 144 patients with stable DPP4i use (eg, mean [SD] age: 58.1 [11.6] years; 12 163 [57.5%] male) for assessing CV outcomes, and those were also comparable between 19 951 patients with stable SGLT2i use (eg, mean [SD] age: 58.1 [10.7] years; 11 231 [56.2%] male) and 19 951 patients with stable DPP4i use (eg, mean [SD] age: 57.9 [11.5] years; 11 340 [56.8%] male) for assessing kidney outcome. The 2-year difference in RMST between patients with SGLT2i use and patients with DPP4i use was 4.99 (95% CI, 3.56-6.42) days for HHF, 4.12 (95% CI, 2.72-5.52) days for 3P-MACE, 7.72 (95% CI, 5.83-9.61) days for 4P-MACE, 1.26 (95% CI, 0.47-2.04) days for MI, 2.70 (95% CI, 1.57-3.82) days for stroke, 0.69 (95% CI, 0.28-1.11) days for CV death, 6.05 (95% CI, 4.89-7.20) days for all-cause death, and 14.75 (95% CI, 12.99-16.52) days for CKD. Directions of hazard ratios from Cox modeling analyses were consistent with RMST estimates. No association was found between study treatment and the negative control outcome (dental visits for tooth care). Consistent results across sensitivity analyses using high-dimensional PS-matched and PS-weighting approaches supported the validity of primary analysis results. Largest difference in RMST of SGLT2i vs DPP4i use for HHF and CKD was found among patients with established heart failure (30.80 [95% CI, 5.08-56.51] days) and retinopathy (40.43 [95% CI, 31.74-49.13] days), respectively.

CONCLUSIONS AND RELEVANCE

In this comparative effectiveness study, RMST analysis was feasible for translating treatment effects into more clinical intuitive estimates and valuable for quantifying HTEs among diverse patients in routine clinical settings.

Intensive Versus Standard Blood Pressure Lowering and Days Free of Cardiovascular Events and Serious Adverse Events: a Post Hoc Analysis of Systolic Blood Pressure Intervention Trial

BACKGROUND

Communication of the benefits and harms of blood pressure lowering strategy is crucial for shared decision-making.

OBJECTIVES

To quantify the effect of intensive versus standard systolic blood pressure lowering in terms of the number of event-free days DESIGN: Post hoc analysis of the Systolic Blood Pressure Intervention Trial PARTICIPANTS: A total of 9361 adults 50 years or older without diabetes or stroke who had a systolic blood pressure of 130-180 mmHg and elevated cardiovascular risk INTERVENTIONS: Intensive (systolic blood pressure goal <120 mmHg) versus standard blood pressure lowering (<140 mmHg) MAIN MEASURES: Days free of major adverse cardiovascular events (MACE), serious adverse events (SAE), and monitored adverse events (hypotension, syncope, bradycardia, electrolyte abnormalities, injurious falls, or acute kidney injury) over a median follow-up of 3.33 years KEY RESULTS: The intensive treatment group gained 14.7 more MACE-free days over 4 years (difference, 14.7 [95% confidence interval: 5.1, 24.4] days) than the standard treatment group. The benefit of the intensive treatment varied by cognitive function (normal: difference, 40.7 [13.0, 68.4] days; moderate-to-severe impairment: difference, -15.0 [-56.5, 26.4] days; p-for-interaction=0.009) and self-rated health (excellent: difference, -22.7 [-51.5, 6.1] days; poor: difference, 156.1 [31.1, 281.2] days; p-for-interaction=0.001). The mean overall SAE-free days were not significantly different between the treatments (difference, -14.8 [-35.3, 5.7] days). However, the intensive treatment group had 28.5 fewer monitored adverse event-free days than the standard treatment group (difference, -28.5 [-40.3, -16.7] days), with significant variations by frailty status (non-frail: difference, 38.8 [8.4, 69.2] days; frail: difference, -15.5 [-46.6, 15.7] days) and self-rated health (excellent: difference, -12.9 [-45.5, 19.7] days; poor: difference, 180.6 [72.9, 288.4] days; p-for-interaction <0.001).

CONCLUSIONS

Over 4 years, intensive systolic blood pressure lowering provides, on average, 14.7 more MACE-free days than standard treatment, without any difference in SAE-free days. Whether this time-based effect summary improves shared decision-making remains to be elucidated.

TRIAL REGISTRATION

ClinicalTrials.gov Registration: NCT01206062.

Absolute treatment effects for the primary outcome and all-cause mortality in the cardiovascular outcome trials of new antidiabetic drugs: a meta-analysis of digitalized individual patient data

AIMS

Treatment effects from the large cardiovascular outcome trials (CVOTs) of new antidiabetic drugs are almost exclusively communicated as hazard ratios, although reporting guidelines recommend to report treatment effects also on an absolute scale, e.g. as numbers needed to treat (NNT). We aimed to analyse NNTs in CVOTs comparing dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, or sodium-glucose cotransporter-2 (SGLT2) inhibitors to placebo.

METHODS

We digitalized individual time-to-event information for the primary outcome and all-cause mortality from 19 CVOTs that compared DPP-4 inhibitors, GLP-1 receptor agonists, or SGLT2 inhibitors to placebo. We estimated Weibull models for each trial and outcome and derived monthly NNTs. NNTs were summarized across all trials and within drug classes by random effects meta-analysis methods.

RESULTS

Treatment effects in the CVOTs appear smaller if they are reported as NNTs: Overall, 100 (95%-CI: 60, 303) patients have to be treated for 29 months (the median follow-up time across all trials) to avoid a single event of the primary outcome, and 128 (95%-CI: 85, 265) patients have to be treated for 39 months to avoid a single death. NNT time courses are very similar for GLP-1 receptor agonists and SGLT2 inhibitors, whereas treatment effects with DPP-4 inhibitors are smaller.

CONCLUSIONS

We found that the respective treatment effects look less impressive when communicated on an absolute scale, as numbers needed to treat. For a valid overall picture of the benefit of new antidiabetic drugs, trial authors should also report treatment effects on an absolute scale.

Non-inferiority and clinical superiority of glucagon-like peptide-1 receptor agonists and sodium-glucose co-transporter-2 inhibitors: Systematic analysis of cardiorenal outcome trials in type 2 diabetes

AIMS

Most trials leading to the approval of glucagon-like peptide receptor agonists (GLP-1RAs) and sodium-glucose co-transporter-2 inhibitors (SGLT2is) were primarily designed to confirm their non-inferiority to placebo (commonly using an upper 95% confidence limit threshold of 1.3) and, if confirmed, superiority (threshold 1): this asymmetry of margins (1 vs. 1.3) favours the active intervention. We aimed to quantify the probability of clinical superiority of the active treatment by applying the same threshold used to claim non-inferiority.

MATERIALS AND METHODS

We searched PubMed and Cochrane CENTRAL for cardiorenal outcome trials in subjects with type 2 diabetes published before 5 December 2021, to reconstruct from Kaplan-Meier plots individual-level data for the primary outcome or all-cause mortality. We calculated Bayesian posterior densities to obtain the probability for a treatment effect (hazard ratio) <0.769, which is symmetric to the 1.3 threshold (i.e. its reciprocal 1/1.3), emulating a scenario where the active treatment is placebo and placebo is the active treatment.

RESULTS

We extracted data from 27 Kaplan-Meier plots (18 for the primary outcome, nine for mortality). Probabilities of clinical superiority to placebo varied significantly: for GLP-1RAs, from a minimum of 0% to a maximum of 69% for the primary outcome and from 0% to 8% for mortality; corresponding estimates for SGLT2is were 0% to 96% and 0% to 93%. Probabilities were on average greater for SGLT2is, particularly in trials investigating kidney or heart failure outcomes.

CONCLUSIONS

The probability of clinical superiority to placebo varies widely across trials previously reported as showing superiority of GLP-1RAs or SGLT2is compared with placebo. These results showed within- and between-class differences, highlight the drawbacks of a binary interpretation of the results, particularly in the context of the current designs of non-inferiority trials, and have implications for decision makers and future clinical recommendations.

The time-varying cardiovascular benefits of glucagon-like peptide-1 receptor agonist therapy in patients with type 2 diabetes mellitus: Evidence from large multinational trials

AIMS

To evaluate the time-varying cardio-protective effect of glucagon-like peptide-1 receptor agonists (GLP-1RAs) using pooled data from eight contemporary cardiovascular outcome trials using the difference in the restricted mean survival time (ΔRMST) as the effect estimate.

MATERIAL AND METHODS

Data from eight multinational cardiovascular outcome randomized controlled trials of GLP-1RAs for type 2 diabetes mellitus were pooled. Flexible parametric survival models were fit from published Kaplan-Meier plots. The differences between arms in RMST (ΔRMST) were calculated at 12, 24, 36 and 48 months. ΔRMST values were pooled using an inverse variance-weighted random-effects model; heterogeneity was tested with Cochran's Q statistic. The endpoints studied were: three-point major adverse cardiovascular events (MACE), all-cause mortality, stroke, cardiovascular mortality and myocardial infarction.

RESULTS

We included eight large (3183-14 752 participants, total = 60 080; median follow-up range: 1.5 to 5.4 years) GLP-1RA trials. Among GLP-1RA recipients, we observed an average delay in three-point MACE of 0.03, 0.15, 0.37 and 0.63 months at 12, 24, 36 and 48 months, respectively. At 48 months, while cardiovascular mortality was comparable in both arms (pooled ΔRMST 0.163 [-0.112, 0.437]; P = 0.24), overall survival was higher (ΔRMST = 0.261 [0.08-0.43] months) and stroke was delayed (ΔRMST 0.22 [0.15-0.33]) in patients receiving GLP-1RAs.

CONCLUSIONS

Glucagon-like peptide-1 receptor agonists may delay the occurrence of MACE by an average of 0.6 months at 48 months, with meaningfully larger gains in patients with cardiovascular disease. This metric may be easier for clinicians and patients to interpret than hazard ratios, which assume a knowledge of absolute risk in the absence of treatment.

Effectiveness of pembrolizumab in patients with urothelial carcinoma receiving proton pump inhibitors

BACKGROUND

The association of concurrent proton pump inhibitor (PPI) use with treatment outcome of metastatic urothelial carcinoma (UC) remains controversial.

MATERIALS AND METHODS

We retrospectively analyzed the records of 227 patients with platinum-treated metastatic UC treated with pembrolizumab. The primary outcome was overall survival (OS). Immune progression-free survival (iPFS) and objective response per immune response evaluation criteria in solid tumors were also compared. Inverse probability of treatment weighting (IPTW)-adjusted multivariable Cox regression models and an IPTW-adjusted multivariable logistic regression model were used to evaluate the oncological outcomes. Furthermore, the heterogeneity of the treatment effect on OS was examined using interaction terms within the IPTW-adjusted univariate Cox regression models.

RESULTS

Overall, 86 patients (37.9%) used PPIs. After weighting, no significant differences in patient characteristics were observed between PPI users and non-users. PPI use was significantly associated with a shorter OS (hazard ratio [HR]: 2.02, 95% confidence interval [CI]: 1.28-3.18, P = 0.003) and iPFS (HR: 1.70, 95% CI: 1.23-2.35, P = 0.001). Although not statistically significant, PPI use was associated with objective response as well (OR: 0.61, 95% CI: 0.36-1.02, P = 0.06). The interaction analyses showed that the effect of PPI significantly decreased with age (HR: 0.97, 95% CI: 0.93-1.00, P[interaction] = 0.048) and was increased in males (HR: 2.97, 95% CI: 1.10-8.05, P[interaction] = 0.032).

CONCLUSIONS

PPI use was significantly associated with worse survival of patients with metastatic UC treated with pembrolizumab. Furthermore, the results suggested that its effects decreased with age and was increased in males.

Resident-Driven Dysphagia Screening Protocol for Expedited Antithrombotic Delivery in Acute Ischemic Stroke

Background

We implemented a multi-disciplinary process improvement intervention at our Comprehensive Stroke Center with speech/language pathologists to expedite oral medication delivery in stroke patients. Following a failed nursing dysphagia screen, trained neurology physicians screened dysphagia further to approve use of oral medications. We analyzed the safety and efficacy of this intervention.

Methods

We analyzed retrospectively collected data for hospital course, timing of first screen, first oral medication use, and complications (e.g., aspiration pneumonia) in consecutive ischemic stroke patients (9/2019-07/2021). Patients were included if they passed a dysphagia assessment by physicians (Ph), nurses (RN), or speech/language pathologists (SLP). Arrival-to-dysphagia screen and arrival-to-antithrombotic were assessed using restricted mean survival time (RMST).

Results

Of the 789 included patients, 673 were passed by RN, 104 by SLP, and 12 by Ph. Compared to patients passed by SLP, those passed by Ph were younger and had less severe deficits ( P < .01 for both). Patients were screened more quickly by Ph than RN or SLP (median 38 vs 182 vs 1330-min post-arrival, P = .0001; 299-min RMST difference vs RN [95%CI 22-575, P = .03]; 470-min RMST difference vs SLP [95%CI 175-765, P = .002]). This translated to faster oral antithrombotic use for Ph-passed patients (138-min RMST difference vs RN [95%CI 59-216]; 332-min RMST difference vs SLP [95%CI 253-411]). No patients passed by Ph experienced aspiration pneumonia (0%).

Conclusions

We safely conducted a physician-driven dysphagia screening paradigm which led to faster oral antithrombotic delivery without signal of patient harm. Physician availability to complete dysphagia screens in acute stroke patients was a limitation.

Stratified Restricted Mean Survival Time Model for Marginal Causal Effect in Observational Survival Data

Time to event outcomes is commonly encountered in epidemiologic research. Multiple papers have discussed the inadequacy of using the hazard ratio as a causal effect measure due to its noncollapsibility and the time-varying nature. In this paper, we further clarified that the hazard ratio might be used as a conditional causal effect measure, but it is generally not a valid marginal effect measure, even under randomized design. We proposed to use the restricted mean survival time (RMST) difference as a causal effect measure, since it essentially measures the mean difference over a specified time horizon and has a simple interpretation as the area under survival curves. For observational studies, propensity score adjustment can be implemented with RMST estimation to remove observed confounding bias. We proposed a propensity score stratified RMST estimation strategy, which performs well in our simulation evaluation and is relatively easy to implement for epidemiologists in practice. Our stratified RMST estimation includes two different versions of implementation, depending on whether researchers want to involve regression modeling adjustment, which provides a powerful tool to examine the marginal causal effect with observational survival data.

Timing of dialysis initiation to reduce mortality and cardiovascular events in advanced chronic kidney disease: nationwide cohort study

OBJECTIVE

To identify the optimal estimated glomerular filtration rate (eGFR) at which to initiate dialysis in people with advanced chronic kidney disease.

DESIGN

Nationwide observational cohort study.

SETTING

National Swedish Renal Registry of patients referred to nephrologists.

PARTICIPANTS

Patients had a baseline eGFR between 10 and 20 mL/min/1.73 m2 and were included between 1 January 2007 and 31 December 2016, with follow-up until 1 June 2017.

MAIN OUTCOME MEASURES

The strict design criteria of a clinical trial were mimicked by using the cloning, censoring, and weighting method to eliminate immortal time bias, lead time bias, and survivor bias. A dynamic marginal structural model was used to estimate adjusted hazard ratios and absolute risks for five year all cause mortality and major adverse cardiovascular events (composite of cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke) for 15 dialysis initiation strategies with eGFR values between 4 and 19 mL/min/1.73 m2 in increments of 1 mL/min/1.73 m2. An eGFR between 6 and 7 mL/min/1.73 m2 (eGFR6-7) was taken as the reference.

RESULTS

Among 10 290 incident patients with advanced chronic kidney disease (median age 73 years; 3739 (36%) women; median eGFR 16.8 mL/min/1.73 m2), 3822 started dialysis, 4160 died, and 2446 had a major adverse cardiovascular event. A parabolic relation was observed for mortality, with the lowest risk for eGFR15-16. Compared with dialysis initiation at eGFR6-7, initiation at eGFR15-16 was associated with a 5.1% (95% confidence interval 2.5% to 6.9%) lower absolute five year mortality risk and 2.9% (0.2% to 5.5%) lower risk of a major adverse cardiovascular event, corresponding to hazard ratios of 0.89 (95% confidence interval 0.87 to 0.92) and 0.94 (0.91 to 0.98), respectively. This 5.1% absolute risk difference corresponded to a mean postponement of death of 1.6 months over five years of follow-up. However, dialysis would need to be started four years earlier. When emulating the intended strategies of the Initiating Dialysis Early and Late (IDEAL) trial (eGFR10-14 v eGFR5-7) and the achieved eGFRs in IDEAL (eGFR7-10 v eGFR5-7), hazard ratios for all cause mortality were 0.96 (0.94 to 0.99) and 0.97 (0.94 to 1.00), respectively, which are congruent with the findings of the randomised IDEAL trial.

CONCLUSIONS

Very early initiation of dialysis was associated with a modest reduction in mortality and cardiovascular events. For most patients, such a reduction may not outweigh the burden of a substantially longer period spent on dialysis.

Lymph Node Ratio after Neoadjuvant Chemotherapy for Stage II/III Breast Cancer: Prognostic Value Measured with Gini's Mean Difference of Restricted Mean Survival Times

Restricted mean survival time (RMST), recommended for reporting survival, lacks a tool to evaluate multilevel factors. The potential of the Gini’s mean difference of RMSTs (Δ) is explored in a comparison of a lymph node ratio-based classification (LNRc) versus a number-based classification (ypN) applied to stage II/III breast cancer patients who received neoadjuvant chemotherapy and underwent axillary dissection. Number of positive nodes (npos) classified patients into ypN0, npos = 0, ypN1, npos = [1,3], ypN2, npos = [4,9], and ypN3, npos ⩾ 10. Ratio npos/(number of nodes examined) of 0, (0,0.20], (0.20,0.65], and >0.65, classified patients into Lnr0 to Lnr3, respectively. Unadjusted and Cox-adjusted RMSTs were computed for the ypN and LNRc’s. At a follow-up time horizon of 72 months for 114 node-negative and 254 node-positive patients, unadjusted ypN0-ypN3 RMSTs were 62.4-41.4 months, Δ = 11.9 months (95%CI: 7.4-16.9), and Lnr0-Lnr3 62.4 to 36.3 months, Δ = 14.0 months (95%CI: 10.1-18.1). Cox models’ ypN1-ypN3 hazard ratios were 1.81-3.30, and Lnr1-Lnr3 1.52-4.39. Δ from Cox-fitted survival were ypN 8.1 months (95%CI: 5.9-10.5), LNRc 10.5 months (95%CI: 8.4-12.8). In conclusion, Gini’s mean difference is applicable to well established data in keeping with the literature on LNRc. It provides an alternative view on the improvement gained with a lymph node ratio-classification over using a number-classification.

Intensive versus standard blood pressure control in type 2 diabetes: a restricted mean survival time analysis of a randomised controlled trial

BACKGROUND

Restricted mean survival time analysis offers an intuitive and robust summary of treatment effect compared with HRs.

OBJECTIVE

To examine the effect of intensive versus standard blood pressure (BP) control on death or cardiovascular events in type 2 diabetes.

DESIGN

Secondary analysis of the Action to Control Cardiovascular Risk in Diabetes Blood Pressure trial.

SETTING

77 sites in the USA and Canada.

PARTICIPANTS

4733 adults with type 2 diabetes at high risk for cardiovascular events.

INTERVENTIONS

Systolic BP target <120 mm Hg (n=2371) versus <140 mm Hg (n=2362).

MEASUREMENTS

Composite endpoint of death, non-fatal myocardial infarction or non-fatal stroke.

RESULTS

The mean event-free survival time over 5 years (1825 days) was similar between intensive and standard BP control (1716 vs 1714 days; mean difference, 1.3 (95% CI -18.1 to 20.7) days). However, intensive BP treatment was more beneficial for those assigned to standard glycaemic control (1725 vs 1697 days; mean difference, 28.1 (95% CI 0.4 to 55.9) days), but not for those assigned to intensive glycaemic control (1706 vs 1731 days; mean difference, -25.2 (95% CI -52.3 to 1.9) days) (p=0.008 for interaction). In subgroup analysis, the mean event-free survival time difference between intensive and standard BP treatment was -76.0 (95% CI -131.8 to -20.3) days for those with cognitive impairment and 21.8 (95% CI -24.0 to 67.5) days for those with normal cognitive function (p=0.008 for interaction). The effect was not different by age, sex and baseline cardiovascular disease status.

CONCLUSIONS

Intensive BP treatment may reduce death and cardiovascular events among patients with type 2 diabetes receiving standard glycaemic treatment and without cognitive impairment.

TRIAL REGISTRATION NUMBER

NCT00000620; Post-results.

Cardiovascular effects of sodium-glucose co-transporter-2 inhibitors and glucagon-like peptide-1 receptor agonists: The P value and beyond

Despite growing awareness of the dangers of a dichotomous interpretation of trial results based on the 'statistical significance' of a treatment effect, the uptake of new approaches has been slow in diabetes medicine. We showcase a number of ways to interpret the evidence for a treatment effect applied to the cardiovascular outcome trials of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose co-transporter-2 inhibitors (SGLT-2is): the P value function (or confidence curves), which depicts the treatment effect across the whole spectrum of confidence levels; the counternull value, which is the hazard ratio (i.e. treatment effect size) supported by the same amount of evidence as the null value (i.e. no treatment effect); and the S value, which quantifies the strength of the evidence against the null hypothesis in terms of the number of coin tosses yielding the same side. We show how this approach identifies potential treatment effects, highlights similarities among trials straddling the threshold of statistical significance, and quantifies differences in the strength of the evidence from trials reporting statistically significant results. For example, while REWIND, CANVAS and CREDENCE failed to reach statistical significance at the .05 level for all-cause mortality, their counternull values indicate that reduced death rates by 19%, 24% and 31%, respectively, are supported by the same amount of evidence as that indicating no treatment effect. Moreover, similarities among results emerge in trials of GLP-1RAs (REWIND, EXSCEL and LEADER) lying closely around the threshold of 'statistical significance'. Lastly, several S values, such as for the primary outcome in HARMONY Outcomes (S value 10.9) and all-cause death in EMPAREG-OUTCOME (S value 15.0), stand out compared with values for other outcomes and other trials, suggesting much larger differences in the evidence between these studies and several others that cluster around the .05 significance threshold. P value functions, counternull values and S values should complement the standard reporting of the treatment effect to help interpret clinical trials and make decisions among competing glucose-lowering medications.

Effectiveness of angiotensin-neprilysin inhibitor treatment versus renin-angiotensin system blockade in older adults with heart failure in clinical care

OBJECTIVE

To evaluate the effectiveness of angiotensin receptor-neprilysin inhibitor (ARNI) versus renin-angiotensin system (RAS) blockade alone in older adults with heart failure with reduced ejection fraction (HFrEF).

METHODS

We conducted a cohort study using US Medicare fee-for-service claims data (2014-2017). Patients with HFrEF ≥65 years were identified in two cohorts: (1) initiators of ARNI or RAS blockade alone (ACE inhibitor, ACEI; or angiotensin receptor blocker, ARB) and (2) switchers from an ACEI to either ARNI or ARB. HR with 95% CI from Cox proportional hazard regression and 1-year restricted mean survival time (RMST) difference with 95% CI were calculated for a composite outcome of time to first worsening heart failure event or all-cause mortality after adjustment for 71 pre-exposure characteristics through propensity score fine-stratification weighting. All analyses of initiator and switcher cohorts were conducted separately and then combined using fixed effects.

RESULTS

51 208 patients with a mean age of 76 years were included, with 16 193 in the ARNI group. Adjusted HRs comparing ARNI with RAS blockade alone were 0.92 (95% CI 0.84 to 1.00) among initiators and 0.79 (95% CI 0.74 to 0.85) among switchers, with a combined estimate of 0.84 (95% CI 0.80 to 0.89). Adjusted 1-year RMST difference (95% CI) was 4 days in the initiator cohort (-1 to 9) and 12 days (8 to 17) in the switcher cohort, resulting in a pooled estimate of 9 days (6 to 12) favouring ARNI.

CONCLUSION

ARNI treatment was associated with lower risk of a composite effectiveness endpoint compared with RAS blockade alone in older adults with HFrEF.

Quantile regression on inactivity time

The inactivity time, or lost lifespan specifically for mortality data, concerns time from occurrence of an event of interest to the current time point and has recently emerged as a new summary measure for cumulative information inherent in time-to-event data. This summary measure provides several benefits over the traditional methods, including more straightforward interpretation yet less sensitivity to heavy censoring. However, there exists no systematic modeling approach to inferring the quantile inactivity time in the literature. In this paper, we propose a semi-parametric regression method for the quantiles of the inactivity time distribution under right censoring. The consistency and asymptotic normality of the regression parameters are established. To avoid estimation of the probability density function of the inactivity time distribution under censoring, we propose a computationally efficient method for estimating the variance-covariance matrix of the regression coefficient estimates. Simulation results are presented to validate the finite sample properties of the proposed estimators and test statistics. The proposed method is illustrated with a real dataset from a clinical trial on breast cancer.

The Restricted Mean Survival Time as a Tool for Ranking Comparative Outcomes in a Narrative Review that Evaluates a Network of Randomized Trials: An Example Based on PCSK9 Inhibitors

INTRODUCTION

On the basis of two randomized trials, evolocumab and alirocumab have been approved in patients with cardiovascular disease. The evidence on these two agents has been studied through different methods of analysis that span from narrative approaches to network meta-analysis. In the present study, we assessed the performance of a narrative approach combined with the application of the restricted mean survival time (RMST).

METHODS

We studied the two pivotal placebo-controlled trials focused on evolocumab and alirocumab. Our original framework of comparative assessment employed the RMST. Our objective was to show that in the context of a narrative review, the RMST can be an efficient although simple tool to make indirect comparisons. The endpoint was event-free survival, expressed in months.

RESULTS

For each cohort of patients (13,784 patients administered evolocumab, 9462 patients administered alirocumab, 23,242 controls), we determined the RMST values with 95% confidence intervals (CI) [evolocumab: 33.60 months, 95% CI 33.46-33.74; alirocumab: 34.07 months, 95% CI 33.92-34.22]. These results, along with those of the control groups, were analyzed and interpreted narratively. Univariate statistics were conducted, but no network meta-analysis was performed.

CONCLUSION

The experience presented herein indicates that a framework of evidence assessment focused on the RMST is a worthwhile option. Our study is in line with the growing literature that has recently emphasized the methodological advantages of the RMST.

Restricted mean survival time versus conventional measures for treatment decision-making

BACKGROUND/OBJECTIVES

Restricted mean survival time (RMST) summarizes treatment effect in terms of a gain or loss in the event-free days. It remains uncertain whether communicating treatment benefit and harm using RMST-based summary is more effective than conventional summary based on absolute and relative risk reduction. We compared the effect of RMST-based approach and conventional approach on decisional conflict using an example of intensive versus standard blood pressure-lowering strategies.

DESIGN

On-line survey.

SETTING

A convenience sample of patients in the United States.

PARTICIPANTS

Two hundred adults aged 65 and older with hypertension requiring anti-hypertensive treatment (response rate 85.5%).

INTERVENTIONS

Participants were randomly assigned to either RMST-based summary or conventional summary about the benefit and harm of blood pressure-lowering strategies.

MEASUREMENTS

Decisional Conflict Scale (DCS), ranging from 0 (no conflict) to 100 (high conflict), and preference for intensive blood pressure-lowering strategy.

RESULTS

Participants assigned to RMST-based approach (n = 100) and conventional approach (n = 100) had similar age (mean [standard deviation, SD]: 72.3 [5.6] vs 72.8 [5.5] years) and proportions of female (50 [50.0%] vs 61 [61.0%]) and white race (92 [92.0%] vs 92 [92.0%]). The mean (SD) DCS score was 25.2 (15.0) for RMST-based approach and 25.6 (14.1) for conventional approach (p = 0.84). The number (%) of participants who preferred intensive strategy was 10 (10.0%) for RMST-based approach and 14 (14.0%) for conventional approach (p = 0.52). The results were consistent in subgroups defined by age, sex, education level, cardiovascular disease status, and predicted mortality risk categories.

CONCLUSION

In a sample of relatively healthy older adults with hypertension, RMST-based approach was as effective as conventional approach on decisional conflict about choosing a blood pressure-lowering strategy. This study provides proof-of-concept evidence that RMST-based approach can be used in conjunction with absolute and relative risk reduction for communicating treatment benefit and harm in a decision aid.

Model-free estimates that complement information obtained from the hazard ratio

Understand the limitations of the modeling of survival data, especially as pertains to the Cox proportional hazards model.An introduction to model-free estimates of survival, namely, the restricted mean survival time/restricted mean lost time.Use R (The R Foundation for Statistical Computing, Austria) or STATA® (The STATACorp, College Station, TX, USA) to perform analyses and obtain these parameters from a dataset.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-021-01167-4.

The restricted mean survival time as a replacement for the hazard ratio and the number needed to treat in long-term studies

Aims

We applied the restricted mean survival time (RMST) to analyse the survival data reported in the PARADIGM‐HT trial in which sacubitril + valsartan was studied in comparison with enalapril in patients with heart failure. The estimates of this parameter were compared with the published values of hazard ratio (HR).

Methods

Two endpoints were evaluated: a composite of death or hospitalization and cardiovascular death. Our analyses were performed by considering the original follow‐up of 41.4 months and on the basis of a lifetime perspective. All statistical calculations were carried out using specific packages developed under the R‐platform.

Results

According to our RMST analysis, the results for the composite endpoint in the comparison of sacubitril + valsartan vs. enalapril showed an improvement from 32.9 to 34.2 months (gain of 1.25 months). This result is based on a time horizon of 41.4 months. The results for the cardiovascular mortality endpoint showed a RMST of 37.2 months for sacubitril + valsartan vs. 36.2 for enalapril (gain of 0.96 months). In the two lifetime analyses, the improvements were much more relevant and yielded a gain of 25.8 months for the composite endpoint and 27.6 months for survival free from cardiovascular death.

Conclusions

Using the data of the PARADIGM‐HT trial, our analysis confirmed that the RMST has documented advantages over the HR, particularly when the clinical study is characterized by a long follow‐up. The number needed to treat (NNT) has a more specific methodological role and cannot be replaced by the RMST.

Estimating restricted mean survival time and expected life-years lost in the presence of competing risks within flexible parametric survival models

Background

Royston-Parmar flexible parametric survival models (FPMs) can be fitted on either the cause-specific hazards or cumulative incidence scale in the presence of competing risks. An advantage of modelling within this framework for competing risks data is the ease at which alternative predictions to the (cause-specific or subdistribution) hazard ratio can be obtained. Restricted mean survival time (RMST), or restricted mean failure time (RMFT) on the mortality scale, is one such measure. This has an attractive interpretation, especially when the proportionality assumption is violated. Compared to similar measures, fewer assumptions are required and it does not require extrapolation. Furthermore, one can easily obtain the expected number of life-years lost, or gained, due to a particular cause of death, which is a further useful prognostic measure as introduced by Andersen.

Methods

In the presence of competing risks, prediction of RMFT and the expected life-years lost due to a cause of death are presented using Royston-Parmar FPMs. These can be predicted for a specific covariate pattern to facilitate interpretation in observational studies at the individual level, or at the population-level using standardisation to obtain marginal measures. Predictions are illustrated using English colorectal data and are obtained using the Stata post-estimation command, standsurv.

Results

Reporting such measures facilitate interpretation of a competing risks analysis, particularly when the proportional hazards assumption is not appropriate. Standardisation provides a useful way to obtain marginal estimates to make absolute comparisons between two covariate groups. Predictions can be made at various time-points and presented visually for each cause of death to better understand the overall impact of different covariate groups.

Conclusions

We describe estimation of RMFT, and expected life-years lost partitioned by each competing cause of death after fitting a single FPM on either the log-cumulative subdistribution, or cause-specific hazards scale. These can be used to facilitate interpretation of a competing risks analysis when the proportionality assumption is in doubt.