Design and Analysis of Studies Based on Hierarchical Composite Endpoints: Insights from the DARE-19 Trial

On approximate equality of Z-values of the statistical tests for win statistics (win ratio, win odds, and net benefit)

Dong et al. (2023) showed that the win statistics (win ratio, win odds, and net benefit) can complement each another to demonstrate the strength of treatment effects in randomized trials with prioritized multiple outcomes. This result was built on the connections among the point and variance estimates of the three statistics, and the approximate equality of Z-values in their statistical tests. However, the impact of this approximation was not clear. This Discussion refines this approach and shows that the approximate equality of Z-values for the win statistics holds more generally. Thus, the three win statistics consistently yield closely similar p-values. In addition, our simulations show an example that the naive approach without adjustment for censoring bias may produce a completely opposite conclusion from the true results, whereas the IPCW (inverse-probability-of-censoring weighting) approach can effectively adjust the win statistics to the corresponding true values (i.e. IPCW-adjusted win statistics are unbiased estimators of treatment effect).

Outcome improvement for anaemia and iron deficiency in ERAS hip and knee arthroplasty: a descriptive analysis

BACKGROUND AND PURPOSE

Preoperative anaemia including iron deficiency anaemia (IDA) is a well-established perioperative risk factor. However, most studies on iron therapy to treat IDA have been negative and few have been conducted within an enhanced recovery after surgery (ERAS) protocol. Furthermore, patients with IDA often have comorbidities not necessarily influenced by iron, but potentially influencing traditional study endpoints such as length of stay (LOS), morbidity, etc. The aim of this paper is to discuss patient-related challenges when planning outcome studies on the potential benefits of iron therapy in patients with IDA, based upon a large detailed prospective database in ERAS total hip (THA) and knee arthroplasty (TKA).

METHODS

A prospective observational cohort study in ERAS THA and TKA from 2022 to 2023. Detailed complete follow-up through questionnaires and electronic medical records.

RESULTS

Of 3655 included patients, 276 (7.6%) had IDA defined as a haemoglobin (Hb) of < 13.0 g/dL and transferrin saturation of 0.20, while 3379 had a Hb of ≥ 13.0. Patients with IDA were a median 5 years older than non-anaemics, with an increased fraction living alone (38.4% vs. 28.8%), using walking aids (54.3% vs 26.4%) and receiving home care (16.2% vs 4.7%). Fewer IDA patients were working (12.7% vs. 29.6%) and a median number of prescribed drugs was higher (10 vs. 6). Median LOS was 1 day in both IDA and non-anaemic patients, but a LOS of > 2 days occurred in 11.6% of patients with IDA vs. 4.3% in non-anaemics. The proportion with 30- or 90-day readmissions was 6.5% vs. 4.1% and. 13.4% vs6.0%, in patients with IDA and non-anaemics, respectively. However, potentially anaemia or iron deficiency-related causes of LOS > 2 days or 90-day readmissions were only 5.4% and 2.2% in patients with IDA and 1.9% and 1.0% in non-anaemics.

CONCLUSION

Conventional randomised trials with single or composite "hard" endpoints are at risk of being inconclusive or underpowered due to a considerable burden of other patient-related risk factors and with postoperative complications which may not be modifiable by correction of IDA per se. We will propose to gain further insights from detailed observational and mechanistic studies prior to initiating extensive randomised studies.

Development and Validation of a New Hierarchical Composite End Point for Clinical Trials of Kidney Disease Progression

SIGNIFICANCE STATEMENT

The established composite kidney end point in clinical trials combines clinical events with sustained large changes in GFR but does not weigh the relative clinical importance of the end point components. By contrast, a hierarchical composite end point (HCE) accounts for the clinical importance of the end point components. The authors developed and validated a kidney HCE that combines clinical kidney outcomes with longitudinal GFR changes (GFR slope). They demonstrate that in seven major placebo-controlled kidney outcome trials with different medications, treatment effect estimates on the HCE were consistently in similar directions and of similar magnitudes compared with treatment effects on the established kidney end point. The HCE's prioritization of clinical outcomes and ability to combine dichotomous outcomes with GFR slope make it an attractive alternative to the established kidney end point.

BACKGROUND

The established composite kidney end point in clinical trials combines clinical events with sustained large changes in GFR. However, the statistical method does not weigh the relative clinical importance of the end point components. A HCE accounts for the clinical importance of the end point components and enables combining dichotomous outcomes with continuous measures.

METHODS

We developed and validated a new HCE for kidney disease progression, performing post hoc analyses of seven major Phase 3 placebo-controlled trials that assessed the effects of canagliflozin, dapagliflozin, finerenone, atrasentan, losartan, irbesartan, and aliskiren in patients with CKD. We calculated the win odds (WOs) for treatment effects on a kidney HCE, defined as a hierarchical composite of all-cause mortality; kidney failure; sustained 57%, 50%, and 40% GFR declines from baseline; and GFR slope. The WO describes the odds of a more favorable outcome for receiving the active compared with the control. We compared the WO with the hazard ratio (HR) of the primary kidney outcome of the original trials.

RESULTS

In all trials, treatment effects calculated with the WO reflected a similar direction and magnitude of the treatment effect compared with the HR. Clinical trials incorporating the HCE would achieve increased statistical power compared with the established composite end point at equivalent sample sizes.

CONCLUSIONS

In seven major kidney clinical trials, the WO and HR provided similar direction of treatment effect estimates with smaller HRs associated with larger WOs. The prioritization of clinical outcomes and inclusion of broader composite end points makes the HCE an attractive alternative to the established kidney end point.

Validity and Utility of a Hierarchical Composite End Point for Clinical Trials of Kidney Disease Progression: A Review

Clinical trials in nephrology often use composite end points comprising clinical events, such as onset of ESKD and initiation of kidney function replacement therapy, along with a sustained large ( e.g. , ≥50%) decrease in GFR. Such events typically occur late in the disease course, resulting in large trials in which most participants do not contribute clinical events. In addition, components of the end point are considered of equal importance; however, their clinical significance varies. For example, kidney function replacement therapy initiation is likely to be clinically more meaningful than GFR decline of ≥50%. By contrast, hierarchical composite end points (HCEs) combine multiple outcomes and prioritize each patient's most clinically relevant outcome for inclusion in analysis. In this review, we consider the use of HCEs in clinical trials of CKD progression, emphasizing the potential to combine dichotomous clinical events such as those typically used in CKD progression trials, with the continuous variable of GFR over time, while ranking all components according to clinical significance. We consider maraca plots to visualize overall treatment effects and the contributions of individual components, discuss the application of win odds in kidney HCE trials, and review general design considerations for clinical trials for CKD progression with kidney HCE as an efficacy end point.

Use of Win Statistics to Analyze Outcomes in the DAPA-HF and DELIVER Trials

BACKGROUND: The primary end point in most heart failure (HF) trials is a composite of time to a first worsening HF event or cardiovascular death. Prevention of recurrent events and improvements in symptoms/quality of life are also important for patients but are usually analyzed separately. Win statistics can integrate all these outcomes into a single composite end point, which is analyzed in hierarchical order, reflecting the clinical importance of each component. METHODS: The Dapagliflozin and Prevention of Adverse Outcomes in Heart Failure (DAPA-HF, n=4744) and Dapagliflozin Evaluation to Improve the Lives of Patients with Preserved Ejection Fraction Heart Failure (DELIVER, n=6263) trials enrolled patients with New York Heart Association class II, III, or IV HF, elevated natriuretic peptides, and either an ejection fraction of 40% or less (DAPA-HF) or greater than 40% and left atrial enlargement/left ventricular hypertrophy (DELIVER). We examined the effects of dapagliflozin compared with placebo on a hierarchical composite outcome, including cardiovascular death, total (first and recurrent) HF hospitalizations, total urgent HF visits, and improvement/deterioration in Kansas City Cardiomyopathy Questionnaire total symptom score (KCCQ-TSS; range from 0 to 100, with a higher score indicating fewer symptoms and physical limitations) at 8 months. RESULTS: For this composite outcome, the win ratio was 1.30 (95% confidence interval [CI], 1.23 to 1.36) in the pooled cohort, 1.33 (95% CI, 1.23 to 1.43) in the DAPA-HF trial, and 1.27 (95% CI, 1.18 to 1.36) in the DELIVER trial. Win odds and net benefit in overall patients were 1.19 (95% CI, 1.14 to 1.24) and 8.7% (95% CI, 6.6 to 10.9%), respectively. In the overall pooled cohort, the majority of wins and losses were accounted for by KCCQ-TSS; 52.4% were settled by the KCCQ-TSS tier in the pooled cohort. CONCLUSIONS: In both the DAPA-HF and DELIVER trials, dapagliflozin led to a significant improvement in composite outcomes that incorporated patient-reported outcomes along with total HF events, as well as cardiovascular deaths. These analyses provided a comprehensive presentation of win statistics and illustrated the utility and flexibility of win statistics in describing the effects of dapagliflozin in two recent clinical trials in patients with HF. (Funded by British Heart Foundation Centre of Research Excellence and others; clinical trial registration numbers, NCT03036124 and NCT03619213.)

Anakinra authorized to treat severe coronavirus disease 2019; Sepsis breakthrough or time to reflect?

Introduction

The European Medicines Agency (EMA) and the United States Food and Drug Administration (FDA) announced conditions for using recombinant human interleukin-1 receptor antagonist (rhIL-1ra) to treat hospitalized patients with Coronavirus disease 2019 (COVID-19) and risk for progression. These decisions followed publication of the suPAR-guided Anakinra treatment for Validation of the risk and early Management OF seveRE respiratory failure by COVID-19 (SAVE- MORE) phase 3 clinical trial that yielded positive results.

Methods

We conducted a literature review and theoretical analysis of IL-1 blockade as a therapy to treat COVID-19. Using a stepwise analysis, we assessed clinical applicability of the SAVE-MORE results and evaluated conceptual support for interleukin-1 suppression as a suitable approach to COVID-19 treatment. This therapeutic approach was then examined as an example of inflammation-suppressing measures used to treat sepsis.

Results

Anakinra use as a COVID-19 therapy seems to rely on a view of pathogenesis that incorrectly reflects human disease. Since COVID-19 is an example of sepsis, COVID-19 benefit due to anti-inflammatory therapy contradicts an extensive history of unsuccessful clinical study. Repurposing rhIL-1ra to treat COVID-19 appears to exemplify a cycle followed by inflammation-suppressing sepsis treatments. A landscape of treatment failures is interrupted by a successful clinical trial. However, subsequent confirmatory study fails to replicate the positive data.

Discussion

We suggest further experimentation is not a promising pathway to discover game-changing sepsis therapies. A different kind of approach may be necessary.

The stratified win statistics (win ratio, win odds, and net benefit)

The win odds and the net benefit are related directly to each other and indirectly, through ties, to the win ratio. These three win statistics test the same null hypothesis of equal win probabilities between two groups. They provide similar p-values and powers, because the Z-values of their statistical tests are approximately equal. Thus, they can complement one another to show the strength of a treatment effect. In this article, we show that the estimated variances of the win statistics are also directly related regardless of ties or indirectly related through ties. Since its introduction in 2018, the stratified win ratio has been applied in designs and analyses of clinical trials, including Phase III and Phase IV studies. This article generalizes the stratified method to the win odds and the net benefit. As a result, the relations of the three win statistics and the approximate equivalence of their statistical tests also hold for the stratified win statistics.

The maraca plot: A novel visualization of hierarchical composite endpoints

BACKGROUND

Hierarchical composite endpoints are complex endpoints combining outcomes of different types and different clinical importance into an ordinal outcome that prioritizes the clinically most important (e.g. most severe) event of a patient. Hierarchical composite endpoint can be analysed with the win odds, an adaptation of win ratio to include ties. One of the difficulties in interpreting hierarchical composite endpoint is the lack of proper tools for visualizing the treatment effect captured by hierarchical composite endpoint, given the complex nature of the endpoint which combines events of different types.

METHODS

Hierarchical composite endpoints usually combine time-to-event outcomes and continuous outcomes into a composite; hence, it is important to capture not only the shift from more severe categories to less severe categories in the active group in comparison to the control group (as in any ordinal endpoint), but also changes occurring within each category. We introduce the novel maraca plot which combines violin plots (with nested box plots) to visualize the density of the distribution of the continuous outcome and Kaplan-Meier plots for time-to-event outcomes into a comprehensive visualization.

CONCLUSION

The novel maraca plot is suggested for visualization of hierarchical composite endpoints consisting of several time-to-event outcomes and a continuous outcome. It has a very simple structure and therefore easily communicates both the overall treatment effect and the effect on individual components.

Sarcoidosis: Updates on therapeutic drug trials and novel treatment approaches

Sarcoidosis is a systemic granulomatous inflammatory disease of unknown etiology. It affects the lungs in over 90% of patients yet extra-pulmonary and multi-organ involvement is common. Spontaneous remission of disease occurs commonly, nonetheless, over 50% of patients will require treatment and up to 30% of patients will develop a chronic progressive non-remitting disease with marked pulmonary fibrosis leading to significant morbidity and death. Guidelines outlining an immunosuppressive treatment approach to sarcoidosis were recently published, however, the strength of evidence behind many of the guideline recommended drugs is weak. None of the drugs currently used for the treatment of sarcoidosis have been rigorously studied and prescription of these drugs is often based on off-label” indications informed by experience with other diseases. Indeed, only two medications [prednisone and repository corticotropin (RCI) injection] currently used in the treatment of sarcoidosis are approved by the United States Food and Drug Administration. This situation results in significant reimbursement challenges especially for the more advanced (and often more effective) drugs that are favored for severe and refractory forms of disease causing an over-reliance on corticosteroids known to be associated with significant dose and duration dependent toxicities. This past decade has seen a renewed interest in developing new drugs and exploring novel therapeutic pathways for the treatment of sarcoidosis. Several of these trials are active randomized controlled trials (RCTs) designed to recruit relatively large numbers of patients with a goal to determine the safety, efficacy, and tolerability of these new molecules and therapeutic approaches. While it is an exciting time, it is also necessary to exercise caution. Resources including research dollars and most importantly, patient populations available for trials are limited and thus necessitate that several of the challenges facing drug trials and drug development in sarcoidosis are addressed. This will ensure that currently available resources are judiciously utilized. Our paper reviews the ongoing and anticipated drug trials in sarcoidosis and addresses the challenges facing these and future trials. We also review several recently completed trials and draw lessons that should be applied in future.