An updated approach to determine minimal clinically important differences in idiopathic pulmonary fibrosis.
Pubmed ID: 34671666
Pubmed Central ID: PMC8521018
Journal: ERJ open research
Publication Date: 10/18/2021
Affiliation: Emory University School of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Atlanta, GA, USA.
Authors: Martin GS, Kang M, Veeraraghavan S, Kempker JA
Cite As: Kang M, Veeraraghavan S, Martin GS, Kempker JA. An updated approach to determine minimal clinically important differences in idiopathic pulmonary fibrosis. ERJ Open Res 2021 Oct 18;7. (4). doi: 10.1183/23120541.00142-2021. eCollection 2021 Oct.
- Idiopathic Pulmonary Fibrosis Network (IPFnet) AntiCoagulant Effectiveness in Idiopathic Pulmonary Fibrosis (ACE IPF)
- Idiopathic Pulmonary Fibrosis Network (IPFnet) Prednisone, Azathioprine, and N-Acetylcysteine: A Study That Evaluates Response in Idiopathic Pulmonary Fibrosis (PANTHER IPF)
- Idiopathic Pulmonary Fibrosis Network (IPFnet) Sildenafil Trial of Exercise Performance in Idiopathic Pulmonary Fibrosis (STEP IPF)
Introduction: Current medications for idiopathic pulmonary fibrosis (IPF) have not been shown to impact patient-reported outcome measures (PROMs), highlighting the need for accurate minimal clinically important difference (MCID) values. Recently published consensus standards for MCID studies support using anchor-based over distribution-based methods. The aim of this study was to estimate MCID values for worsening in IPF using only an anchor-based approach. Methods: We conducted secondary analyses of three randomised controlled trials with different inclusion criteria and follow-up intervals. The health transition question in the 36-Item Short-Form Health Survey (SF-36) questionnaire was used as the anchor. We used receiver operating curves to assess responsiveness between the anchor and 10 variables (four physiological measures and six PROMs). We used an anchor-based method to determine the MCID values of variables that met the responsiveness criteria (area under the curve ≥0.70). Results: 6-min walk distance (6MWD), the St George's Respiratory Questionnaire (SGRQ), physical component score (PCS) of SF-36 and University of California, San Diego, Shortness of Breath Questionnaire (UCSD SOBQ) met the responsiveness criteria. The MCID value for 6MWD was -75 m; the MCID value for SF-36 PCS was -7 points; the MCID value for SGRQ was 11 points; and the MCID value for the UCSD SOBQ was 11 points. Conclusions: The MCID estimates of 6MWD, SGRQ, SF-36 and UCSD SOBQ using only anchor-based methods were considerably higher compared to previously proposed values. A single MCID value may not be applicable across all classes of disease severity or durations of follow-up time.