Minimal Clinically Important Differences in 6-Minute Walk Test in Patients With HFrEF and Iron Deficiency.

BACKGROUND

The 6-minute walk test (6MWT) is widely used to measure exercise capacity; however, the magnitude of change that is clinically meaningful for individuals is not well established in heart failure with reduced ejection fraction (HFrEF).

OBJECTIVE

To calculate the minimal clinically important difference (MCID) for change in exercise capacity in the 6MWT in iron-deficient populations with HFrEF.

METHODS

In this pooled secondary analysis of the FAIR-HF and CONFIRM-HF trials, mean changes in the 6MWT from baseline to weeks 12 and 24 were calculated and calibrated against the Patient Global Assessment (PGA) tool (clinical anchor) to derive MCIDs in improvement and deterioration.

RESULTS

Of 760 patients included in the 2 trials, 6MWT and PGA data were available for 680 (89%) and 656 (86%) patients at weeks 12 and 24, respectively. The mean 6MWT distance at baseline was 281 ± 103 meters. There was a modest correlation between changes in 6MWT and PGA from baseline to week 12 (r = 0.31; P < 0.0001) and week 24 (r = 0.43; P < 0.0001). Respective estimates (95% confidence intervals) of MCID in 6MWT at weeks 12 and 24 were 14 meters (5;23) and 15 meters (3;27) for a "little improvement" (vs no change), 20 meters (10;30) and 24 meters (12;36) for moderate improvement vs a "little improvement,", -11 meters (-32;9.2) and -31 meters (-53;-8) for a "little deterioration" (vs no change), and -84 meters (-144;-24) and -69 meters (-118;-20) for "moderate deterioration" vs a "little deterioration".

CONCLUSIONS

The MCID for improvement in exercise capacity in the 6MWT was 14 meters-15 meters in patients with HFrEF and iron deficiency. These MCIDs can aid clinical interpretation of study data.

Informations de copyright

Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.

Déclaration de conflit d'intérêts

Conflicts of Interest SDA has received research grants and personal fees from Vifor Int and Abbott Vascular (IIT/Trial steering committee work), personal fees from Bayer, Boehringer Ingelheim and Impulse Dynamics (Trial steering committee work), Novartis, Cardiac Dimensions and Occlutech (Adivsory committee work), and Servier (Registry Steering Committee). TF reports support for statistical consultancies and personal fees from Vifor for the present manuscript, consulting fees for statistical consultancies and personal fees from Bayer, CSL Behring, Galapagos, Minoryx, Vifor, Novartis, and LivaNova outside of the current work; payment for educational events from Fresenius Kabi outside of the current work; personal fees from Novartis, Eli Lilly, Bayer, BiosenseWebster, Janssen, Roche, and Enanta for participation on a Data Safety Monitoring Board. EAJ has received research grants and personal fees from Vifor Pharma (co-PI of the AFFIRM trial); personal fees from Bayer, Novartis, Abbott, Boehringer Ingelheim, Pfizer, Servier, AstraZeneca, Berlin Chemie, Cardiac Dimensions, Fresenius, Respicardia, Takeda, Swixx Biopharma, and Gedeon Richter; treasurer of the Executive Committee for the Heart Failure Association. MM has received personal fees from Vifor Pharma (Executive Committee member), Amgen (Executive Committee member and National PI), AstraZeneca, Abbott vascular, Bayer (participation in Advisory Boards), Boehringer Ingelheim (advisory board member), Servier (participation in Advisory Boards and speeches at sponsored symposia), Edwards Therapeutics (speeches at sponsored symposia), Actelion (DMC Member), LivaNova (Executive Committee member), and Windtree Therapeutics (Executive Committee member and Advisory Board). ILP reports personal fees from Boehringer Ingelheim outside of the submitted work. AJSC reports personal fees from AstraZeneca, Bayer, Boehringer Ingelheim, Menarini, Novartis, Nutricia, Servier, Vifor, Abbott, Actimed, Arena, Cardiac Dimensions, Corvia, CVRx, Enopace, ESN Cleer, Faraday, Gore, Impulse Dynamics, and Respicardia outside of the submitted work. BR, UMG and FD are full-time employees of Vifor Pharma. JCC reports unrestricted grants from Vifor Pharma and Novartis; consulting fees from Vifor Pharma, AstraZenica and Boehringer Ingelheim; and honoraria for conference activities from Vifor Pharma, AstraZenica and Boehringer Ingelheim. GSF reports grants from the European Commission; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Bayer and Boehringer Ingelheim; participation on a data safety monitoring board or advisory board from Bayer and Boehringer Ingelheim; leadership or fiduciary role in the Heart Failure Association; and other financial or nonfinancial interests as a committee member for Medtronic, Vifor Pharma, Amgen, Servier, and Novartis. PP reports participation in clinical trials for and grants and personal fees from Vifor Pharma during the conduct of the study; participation in clinical trials for and personal fees from Amgen, Bayer, Novartis, AbbottVascular, Boehringer Ingelheim, Pfizer, Servier, Astra Zeneca, Cibiem, BMS, and Impulse Dynamics outside of the submitted work; participation in clinical trials for Cardiac Dimensions outside of the submitted work; and personal fees from Berlin Chemie outside of the submitted work. JB reports personal consulting fees from Abbott, Adrenomed, Amgen, Applied Therapeutics, Array, AstraZeneca, Bayer, Boehringer Ingelheim, CVRx, G3 Pharma, Impulse Dynamics, Innolife, Janssen, LivaNova, Luitpold, Medtronic, Merck, Novartis, NovoNordisk, Relypsa, Sequana Medical, and Vifor Pharma, and payment for lectures, presentations, speakers’ bureaus, manuscript writing, and educational events from AstraZeneca, Eli-Lilly, Janssen, and Novartis. DJVV, GR and MSK have no conflicts of interest relating to the performance of this research or in the evaluation and publication process of the manuscript.