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Assessing Quality of Life

Assessing quality of lifeA consistent finding in PR research has been an improvement in patients’ health-related quality of life. Enhancing quality of life is a central aim of PR programs and is highly valued by patients.

A measure of health-related quality of life should be included in the evaluation of a PR program.

Health-related quality of life can be measured with disease-specific or generic measures. Due to their widespread and thorough validation, the following questionnaires are recommended:

  1. Chronic Respiratory Disease Questionnaire (CRDQ or CRQ) – disease specific.
  2. St George’s Respiratory Questionnaire (SGRQ) – disease specific.
  3. Medical Outcomes Study Short Form 36 (MOS SF 36) – generic.


Compared to the generic questionnaires, the disease-specific questionnaires are more likely to be responsive to changes after PR and more sensitive to specific respiratory issues.  However, the disease-specific questionnaires are also limited by their specificity (i.e. when seeking to compare results to other illness groups).

Compared to the disease-specific questionnaires, the generic questionnaires provide a more global view of the respiratory patient’s quality of life, include a wider range of scales and can be readily compared with other illness groups.  However, the generic questionnaires do have lower responsiveness and sensitivity.

According to Lung Foundation Australia’s 2015 national survey of PR programs- the SGRQ and CAT are the most commonly used QoL questionnaires used.

It should also be noted that use of MOS SF 36 and CRDQ requires license use payments.

The important features of each of these questionnaires are summarised in the table below:

 St. George’s Respiratory Questionnaire (SGRQ)Chronic Respiratory Disease Questionnaire (CRDQ or CRQ)Medical Outcomes Study Short Form 36 (MOS SF-36)The COPD Assessment Test (CAT)
Practical considerations- 50 items

- 10-15 minutes

- Self-administered

Interviewer administered
- 20 questions divided into four domains

- 15-30 minutes

Self administered
- 20 questions divided into four domains

- 8-10 minutes

- 36 items

- 5-10 minutes

- Self- or interviewer- administered




Patient self-completed

Domains assessed - Symptoms (frequency and severity)

- Activity

- Impact (social functioning, psychological disturbances)

- Dyspnoea

- Fatigue

- Emotional function

- Mastery of disease

Standardized dyspnoea domain available:

1. Feeling emotional, such as angry or upset

2. Taking care of basic needs (bathing, showering, eating or dressing)

3. Walking

4. Performing chores (housework, shopping)

5. Participating in social activities

- Same scoring method for individual/standardized dyspnoea items

- 8 minutes to complete

- Physical functioning

- Role limitations due to physical health problems

- Bodily pain

- Social functioning

- General mental health

- Role limitations due to emotional problems

- Vitality, energy or fatigue

- General health perceptions

- Ability to calculate a Physical Component and Mental Component score

The questionnaire asks the patient to respond to eight questions by placing a mark (X) in one of 6 boxes that best describes their current situation (see below). The eight questions cover:


  • ‘I never cough’ (0) to ‘I cough all the time’ (5)

Phlegm/Mucus production

  • ‘I have no phlegm/mucus’ (0) to ‘My chest is completely full of phlegm/mucus’ (5)

Chest tightness

  • ‘My chest does not feel tight at all’ (0) to ‘My chest feels very tight’ (5)

Dyspnoea (breathlessness)

  • ‘When I walk up a hill or one flight of stairs I am not breathless’ (0) to ‘When I walk up a hill or one flight of stairs I am very breathless’ (5)


  • ‘I am not limited doing any activities at home’ (0) to ‘I am very limited doing activities at home’ (5)


  • ‘I am confident leaving my home despite my lung condition’ (0) to ‘I am not at all confident leaving my home because of my lung condition’ (5)


  • ‘I sleep soundly’ (0) to ‘I don’t sleep soundly because of my lung condition’ (5)


  • ‘I have lots of energy’ (0) to ‘I have no energy at all’ (5)

Features/ Remarks
- Disease-specific

- Total score can also be calculated from all three components, with 0 indicating no health impairment and 100 representing maximum impairment

- Sensitive and responsive to change after PR

- Measures clinically significant change (a change of 4 U has been identified as the minimum clinically significant change)

- Available in many languages

- Reliability and validity widely tested

- Disease-specific

- Total score can also be calculated from all four components

- Sensitive and responsive to change after PR (self administered more responsive)

- Measures clinically significant change (a change of 0.5 U has been identified as the minimum clinically significant change)

- The interviewer administered version is resource intensive

- Reliability and validity of interviewer and self administered versions widely tested

- Available in many languages

- Generic measure

- Scores on nine health concepts are transformed linearly to scales of 0 to 100, with 0 indicating maximal impairment and 100 indicating the minimal impairment,

- Validity and reliability widely tested

- Used with many populations

- Good discriminatory potency in interstitial diseases

- A clinically significant change in score has not been determined

- In COPD outpatients, floor and ceiling effects have been noted

- Can compare with other disease groups

- Disease Specific

- The scores from all eight questions are added up to give a Total score (out of 40). The higher the score the higher the impact of COPD on the patient.15

- Not a diagnostic tool

- The CAT score is sensitive to change. When reviewing the patient following the PR Program, the patient should be aiming for a CAT score lower than or equal to their initial one. A change in score of 2 units has been identified by experts involved in developing the test as being clinically relevant.16


Quality of life Questionnaires

When determining the effectiveness of a PR program (see Patient reassessment section), both statistical significance and clinical importance should be considered. The magnitude of change in the scores of some quality of life questionnaires is reflective of an important improvement (e.g. CRDQ, SGRQ). However, with some other instruments (e.g. SF-36), the magnitude of the change that reflects an important improvement has not been determined.

For the SGRQ, a decrease in the score reflects an improvement. The minimum important difference in the SGRQ has been reported to be a change of -4 points for the Total Score.

For the CRDQ, an increase in the score reflects an improvement. The minimum important difference in the CRDQ is 0.5 points per item within each domain. Therefore if all questions within a domain are answered then the clinically important difference for each domain is as follows:

PR has been shown to achieve clinically and statistically significant improvements in quality of life  using disease specific quality of life questionnaires. The use of generic quality of life questionnaires has detected statistically significant changes in quality of life following PR.

Instructions on how to obtain a copy of the recommended questionnaires and the software that can be used to help with scoring are available.