Measurement instruments

Description and comparison of samples of tests that are available to evaluate patients at the beginning, in the course of and at the end of pulmonary rehabilitation programs.

Instrument: Discriminative, i.e. that can discriminate along given characteristics (e.g.: incapacity);

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Instrument: Discriminative, i.e. that can discriminate along given characteristics (e.g.: incapacity);

Measurement Instrument	Use		Validation	Instrument		MCID	Comments
	Self	Prof.		Discriminative	Evaluative
Dyspnea
CRM Scale	√	√	√	√		Not avail.	Not very sensitive to changes but a good discriminative instrument (to distinguish the incapacity from one patient to another) and predictive (prognostic survival rate value).
BDI/TDI		√	√		√	1	Good comprehension and training required by the health professionnal using it
Chronic Respiratory Disease Questionnaire CRQ (dyspnea)	√	√	√	√	√	0.5	Widely validated questionnaire in various COPD populations. Well known clinical change value (MCID). There is a cost to use this questionnaire.
Quality of life
SF-36 (6 dimensions) (2 score summaries)	√	√	√	√	√	0.3	Generic questionnaire so less sensitive to changes than specific questionnaires (CRQ, SGRQ). The response to change in pulmonary rehab is less known. Mostly used in this category. Scale from 0.29 to 1.00; 1.00 indicates «perfect health». There are canadian normative values (health population). There is a cost to use this questionnaire.
Chronic Respiratory Disease Questionnaire CRQ (4 areas)	√	√	√	√	√	0.5	Widely validated questionnaire in various COPD french canadian populations. Scale from 0 to 7; 7 indicates «perfect health». Well known clinical change value (MCID). There is a cost to use this questionnaire
St. George Hospital Respiratory Questionnaire SGRQ (4 areas)	√	√	√	√	√	-4	Widely validated questionnaire in various COPD french canadian populations. Scale from 0 to 100; 0 indicates «perfect health». Well known clinical change value (MCID). Less sensitive to change than the CRQ. No charge to use this questionnaire. Program required in order to calculate the score (a little complicated).
COPD Assessment Test CAT (8 questions)		√	√ New	√	Unknown	Unknown	A study has shown that this questionnaire has discriminative values very similar to the SGRQ ones. Weaknesses: Reliability and validation results are based on American data only. The questionnaire’s psychometric values must be further evaluated before being able to use it routinely in practice and during clinical trials.
Hospital Anxiety and Depression Scale HADS		√	√	√	Unknown	Unknown	This instrument includes 7 items to measure anxiety (HAD-A) and 7 items to measure depression (HAD-D). A 0 to 7 score corresponds to normal; 8-10 indicates a possible case; 11-21 indicates a very likely case.
Physical Capacity
6 Minutes Walking Test 6MWT		√	√	√	√	43 m	Simple and easily achieved by patients, but requires the appropriate space which might be a constraint. Good prognostic instrument but not the best assessment tool because of its weak sensitivity to change
Shuttle Walk Distance Test		√	√	√	Unknown	Unknown	Results less influenced by patients’ motivation, provides better information on COPD patients’ physical capacity, can better reveal changes that happen during a pulmonary rehab program as the indicators are more sensitive.
Cardio Pulmonary Exercise Test CPET: 2 types of tests: 1) Incremental Exercise Test 2) Endurance Test		√	√	√	√	>10%	Specialized Test that must take place in a lab and done by experienced technician Individuals are asked why (main reason) they have stopped exercise. On the Borg scale, they are asked to score their discomfort (breathing and legs) felt at rest and during the exercise, at each minute until they reach maximal capacity. 2 types of laboratory exercise tests : 1) *Incremental Cycle Exercise Test*, limited by symptoms: This test will determine the maximal work capacity and will represent the highest work frequence that can be maintained at least 30 sec by the patient.This test also evaluates potential limits and/or possible cardiovascular events. 2) Stationnary bike Endurance Test, done at 80% of the maximum work capacity. This test evaluates the endurance time on the stationary bike, i.e. how much time can the patient pedal at 80% of his maximum work capacity.

* Use: Self = = « self-administrated »; Prof = « administrated by a health professionnal ».

Instrument: Discriminative, i.e. that can discriminate along given characteristics (p.e.: incapacity);
Evaluative, i.e. that is sensitive to change (p.e. the test will enable one to determine if there has been an improvement at the end of a rehabilitation program).

MCID: "Minimum Clinically Important Difference", i.e. the difference that corresponds to a change perceived by the patient as being clinically significant.

(French version translated to English by V. Chabot)

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Evaluative, i.e. that is sensitive to change (e.g.: the test will enable one to determine if there has been an improvement at the end of a rehabilitation program).

See the table

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Evaluative, i.e. that is sensitive to change (e.g.: the test will enable one to determine if there has been an improvement at the end of a rehabilitation program).

	Benefits	Limits and weaknesses
Activity diary	Easy to use and inexpensive; Gives details on daily physical activities ; Good for short period recall.	Can lead to misinterpretation Response is less than desired Difficulty to remember the time and the intensity of the activity Can lead people to change their habits in terms of physical activities High level of resources needed for data collection Level of energy expense might not be provided accurately Intensive effort
Pedometer	Measure direct movement Small and discret Inexpensive	Only walking activities may be recorded Do not differenciate between walking, running or going up the stairs Cannot evaluate effort or energetic expense No time-related information Not very precise at very low pace (severe COPD) or high speed walking
Accelerometer	Large memory capacity Gives time-related information Assess physical activity volume (frequency, intensity and length) Can estimate energy expense Fairly reliable and accurate	Expensive May cause discomfort after a long period of time May require frequent quality control tests Underestimates the energy expense from the upper body moves
Questionnaires Exemple : >CHAMPS	The most comprehensible Reflects the physical activity volume (frequency, intensity, lenght of time) and the type (work, recreational, etc.) Can estimate the level of energy expense > This instrument has shown strong psychometric values with seniors (including COPD) > developped to assess the seniors’ level of physical activity	Cost of implementation Quality Control Requires data collection Burden for patients >Validation presently taking place within a COPD population
Heart rate monitor	Small Inexpensive Easy to use Memory capacity (in days)	Different factors other than physical activity may cause heart rate changes Calibration curve based on simultaneous measurements of heart rate and VO2

*Source : Bourbeau, J. Activity of Life : The COPD patient. COPD: Journal of COPD, June 2009, p. 194.

(French version translated to English by V. Chabot)

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Step 4Post-program evaluation

Measurement instruments

Instrument: Discriminative, i.e. that can discriminate along given characteristics (e.g.: incapacity);

Instrument: Discriminative, i.e. that can discriminate along given characteristics (e.g.: incapacity);

Evaluative, i.e. that is sensitive to change (e.g.: the test will enable one to determine if there has been an improvement at the end of a rehabilitation program).

Evaluative, i.e. that is sensitive to change (e.g.: the test will enable one to determine if there has been an improvement at the end of a rehabilitation program).

Step 4
Post-program evaluation