Baseline health status and setting impacted Minimal Clinically Important Differences in COPD: an explorative study

Harma Alma, Corina de Jong, Danijel Jelusic, Michael Wittmann, Michael Schuler, B.J. Kollen, Robbert Sanderman, Janwillem Kocks, Konrad Schultz, Thys van der Molen

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OBJECTIVE: Minimal Clinically Important Differences (MCIDs) are used as fixed numbers in the interpretation of clinical trials. Little is known about its dynamics. This study aims to explore the impact of baseline score, study setting and patient characteristics on health status MCIDs in Chronic Obstructive Pulmonary Disease (COPD).

STUDY DESIGN AND SETTING: Baseline and follow-up data on the COPD Assessment Test (CAT), Clinical COPD Questionnaire (CCQ) and St. George's Respiratory Questionnaire (SGRQ) were retrospectively analysed from Pulmonary Rehabilitation (PR) and Routine Clinical Practice (RCP). Anchor- and distribution-based MCID estimates were calculated, and tested between settings, gender, age, GOLD classification, co-morbidities and baseline health status.

RESULTS: In total, 658 patients were included with 2299 change measurements. MCID estimates for improvement and deterioration ranged for all subgroups 0.50-6.30 (CAT); 0.10-0.84 (CCQ); 0.33-12.86 (SGRQ). Larger MCID estimates for improvement and smaller ones for deterioration were noted in patients with worse baseline health status, females, elderly, GOLD I/II patients, and patients with less co-morbidities. Estimates from PR were larger.

CONCLUSION: Baseline health status and setting affected MCID estimates of COPD health status questionnaires. Patterns were observed for gender, age, spirometry classification and co-morbidity levels. These outcomes would advocate the need for tailored MCIDs.

Original languageEnglish
Pages (from-to)49-61
Number of pages13
JournalJournal of Clinical Epidemiology
Early online date27-Jul-2019
Publication statusPublished - Dec-2019


  • 0.5SD
  • 12 months follow-up
  • 3 months follow-up
  • 3 weeks follow-up
  • 6 months follow-up
  • 9 months follow-up
  • Area Under the Curve
  • Baseline
  • CAT
  • CCQ
  • Chronic Obstructive Pulmonary Disease
  • Chronic Obstructive Pulmonary Disease (COPD)
  • CI
  • Clinical COPD Questionnaire
  • Clinical COPD Questionnaire (CCQ)
  • Confidence Interval
  • COPD
  • COPD Assessment Test
  • COPD Assessment Test (CAT)
  • False Discovery Rate
  • FDR
  • FEV1%Pred
  • Forced Expiratory Volume in one second % Predicted
  • Global initiative for Obstructive Lung Disease
  • Global Rating of Change scale
  • GOLD
  • GRC
  • Half Standard Deviation: AUC
  • Health Status
  • ICC
  • IMT
  • Inspiratory Muscle Training
  • Inter-Quartile Range
  • Intraclass Correlation Coefficient
  • IQR
  • MCID
  • Minimal Clinically Important Difference
  • Minimal Clinically Important Difference (MCID)
  • mMRC
  • modified Medical Research Council dyspnea scale
  • N
  • Number of Patients
  • PR
  • Proportion of the variance of the dependent factor explained by independent factors
  • Pulmonary Rehabilitation
  • QoL
  • Quality of Life
  • R(2)
  • RCP
  • Receiver Operating Characteristics
  • ROC
  • Routine Clinical Practice
  • Routine Inspiratory Muscle Training within COPD Rehabilitation
  • SD
  • SGRQ
  • St. George Respiratory Questionnaire
  • St. George’s Respiratory Questionnaire (SGRQ)
  • Standard Deviation
  • T0
  • T1
  • T2
  • T3
  • T4
  • T5
  • UMCG
  • University Medical Center Groningen
  • aged
  • area under the curve
  • article
  • chronic obstructive lung disease
  • clinical practice
  • comorbidity
  • controlled study
  • correlation coefficient
  • deterioration
  • dyspnea
  • female
  • follow up
  • forced expiratory volume
  • gender
  • health status
  • human
  • major clinical study
  • male
  • medical research
  • minimal clinically important difference
  • muscle
  • pulmonary rehabilitation
  • quality of life
  • questionnaire
  • receiver operating characteristic
  • retrospective study
  • spirometry
  • university hospital
  • gold

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