1. Health Status in Chronic Obstructive Pulmonary Disease: Measuring the Minimal Clinically Important Difference over Different Periods of Time
H.J. Alma, MSc; C. de Jong, PhD; D. Jelusic, MD; M. Wittmann, MD; M. Schuler, PhD; J.W.H. Kocks, MD, PhD; K. Schultz, MD; Prof. T. Van der Molen, MD, PhD
Presented by Harma Alma, MD-PhD Student
IPCRG 27th of May 2016
Harma Alma, PhD Student
IPCRG 27th of May 2016

2. Statement
I have no conflict of interest to declare

3. Background (1) Health status of major importance in COPD
Need to assess clinically relevant changes
Minimal (Clinically) Important Difference (MCID)
“The smallest difference in score in the domain of interest, which patients perceive as beneficial and which would mandate, in the absence of troublesome side effects and excessive costs, a change in the patient’s management”
GOLD, 2016; Jaeschke, 1989

4. Background (2) Various methods to determine MCID: Anchor-based
Global Rating of Change (GRC) – anchor question
Clinical event (e.g. exacerbation, hospital admission, doctor’s visit etc. )
Correlated questionnaire/test with known MCID
Distribution-based
Standard Error of Measurement (SEM)
Half Standard Deviation (0,5SD)
Beaton, 2002; Copay, 2007; Revicki, 2008

5. Research question Global Rating of Change (GRC) – anchor question
Scores of +/-2 and +/-3 are considered minimal clinical changes
Does the length of recall period affect the MCID of various health status tools used in COPD?

6. Methods Data analysis RIMTCORE Trial
RCT on impact of Inspiratory Muscle Training
Klinik Bad Reichenhall, Germany
Pulmonary rehabilitation, 3 weeks
Inclusion: COPD GOLD II-IV, signed IC
Exclusion: Respiratory failure, other respiratory co-morbidities, cognitive limitations, CI to IMT training
Baseline / 3 wk / 3 / 6 / 9 / 12 months follow-up
COPD Assessment Test (CAT), Clinical COPD Questionnaire (CCQ) and St. George’s Respiratory Questionnaire (SGRQ)
Change vs. Baseline
Global rating of change at follow-up moments
SF-36 anchor question at 12 months
MCID - mean changes scores (95% CI) for patients reporting a minimal change on the GRC
Jones, 1991; Jones, 2009; van der Molen, 2003

7. Patients (N=451) Table 2: N indicating minimal change 3 weeks + 196
3 months 36
6 months
+ 96 42
9 months
+ 80 37
12 months
+ 88 43
12 months SF-36
+ 81 71
Table 1: Baseline characteristics
Age (years)
57.87 ± 6.56
Gender (% male)
65.0
GOLD II (N (%))
227 (50.3)
GOLD III (N (%))
176 (39.0)
GOLD IV (N (%))
48 (10.6)
Smoking pack years
42.61 ± 23.47

8. Results - CCQ

9. Results - CAT

10. Results - SGRQ

11. Conclusions MCID ranges found: No specific pattern found
CCQ improvement 0,33-0,56
CCQ deterioration 0,42-0,66
CAT improvement 1,40-3,12
CAT deterioration 1,91-4,21
SGRQ improvement 7,58-10,28
SGRQ deterioration 5,01-7,52
No specific pattern found
Significant overlap in 95% confidence intervals
Recall bias seems of limited influence on the MCID of health status tools.

12. Questions?
Thank you for your attention!

13. Literature
Beaton DE, Boers M, Wells GA. Many faces of the minimal clinically important difference (MCID): a literature review and directions for future research. Curr Opin Rheumatol 2002 Mar;14(2):
Copay AG, Subach BR, Glassman SD, Polly DW,Jr, Schuler TC. Understanding the minimum clinically important difference: a review of concepts and methods. Spine J 2007 Sep-Oct;7(5):
Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global Strategy for the Diagnosis, Management and Prevention of COPD. 2016; Available at: Accessed 01/20, 2016.
Jaeschke R, Singer J, Guyatt GH. Measurement of health status. Ascertaining the minimal clinically important difference. Control Clin Trials 1989 Dec;10(4):
Jones PW, Quirk FH, Baveystock CM, Littlejohns P. A self-complete measure of health status for chronic airflow limitation. The St. George's Respiratory Questionnaire. Am Rev Respir Dis 1992 Jun;145(6):
Jones PW, Harding G, Berry P, Wiklund I, Chen WH, Kline Leidy N. Development and first validation of the COPD Assessment Test. Eur Respir J 2009 Sep;34(3):
Revicki D, Hays RD, Cella D, Sloan J. Recommended methods for determining responsiveness and minimally important differences for patient-reported outcomes. J Clin Epidemiol 2008 Feb;61(2):
Van der Molen T, Willemse BW, Schokker S, ten Hacken NH, Postma DS, Juniper EF. Development, validity and responsiveness of the Clinical COPD Questionnaire. Health Qual Life Outcomes 2003 Apr 28;1:13.