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.

Clinical Validation of Novel Digital Measures: Statistical Methods for Reliability Evaluation.

Background: Assessment of reliability is one of the key components of the validation process designed to demonstrate that a novel clinical measure assessed by a digital health technology tool is fit-for-purpose in clinical research, care, and decision-making. Reliability assessment contributes to characterization of the signal-to-noise ratio and measurement error and is the first indicator of potential usefulness of the proposed clinical measure. Summary: Methodologies for reliability analyses are scattered across literature on validation of PROs, wet biomarkers, etc., yet are equally useful for digital clinical measures. We review a general modeling framework and statistical metrics typically used for reliability assessments as part of the clinical validation. We also present methods for the assessment of agreement and measurement error, alongside modified approaches for categorical measures. We illustrate the discussed techniques using physical activity data from a wearable device with an accelerometer sensor collected in clinical trial participants. Key Messages: This paper provides statisticians and data scientists, involved in development and validation of novel digital clinical measures, an overview of the statistical methodologies and analytical tools for reliability assessment.

Blood Pressure and Cardiorenal Outcomes With Finerenone in Chronic Kidney Disease in Type 2 Diabetes.

BACKGROUND: Chronic kidney disease is frequently associated with hypertension and poorly controlled blood pressure can lead to chronic kidney disease progression. Finerenone, a nonsteroidal mineralocorticoid receptor antagonist, significantly improves cardiorenal outcomes in patients with chronic kidney disease and type 2 diabetes. This analysis explored the relationship between office systolic blood pressure (SBP) and cardiorenal outcomes with finerenone in FIDELIO-DKD trial (Finerenone in Reducing Kidney Failure and Disease Progression in Diabetic Kidney Disease). METHODS: Patients with type 2 diabetes, urine albumin-to-creatinine ratio 30 to 5000 mg/g, and estimated glomerular filtration rate of 25 to <75 mL/min per 1.73 m2 receiving optimized renin-angiotensin system blockade, were randomized to finerenone or placebo. For this analysis, patients (N=5669) were grouped by baseline office SBP quartiles. RESULTS: Finerenone reduced office SBP across the baseline office SBP quartiles, including patients with baseline office SBP of >148 mm Hg. Overall, patients with lower baseline office SBP quartile and greater declines from baseline in SBP were associated with better cardiorenal outcomes. The risk of primary kidney and key secondary cardiovascular composite outcomes was consistently reduced with finerenone versus placebo irrespective of baseline office SBP quartiles (P for interaction 0.87 and 0.78, respectively). A time-varying analysis revealed that 13.8% and 12.6% of the treatment effect with finerenone was attributed to the change in office SBP for the primary kidney composite outcome and the key secondary cardiovascular outcome, respectively. CONCLUSIONS: In FIDELIO-DKD, cardiorenal outcomes improved with finerenone irrespective of baseline office SBP. Reductions in office SBP accounted for a small proportion of the treatment effect on cardiorenal outcomes. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02540993.