Development of the Qualeffo–31, an osteoporosis-specific quality-of-life questionnaire

Abstract

Introduction

Vertebral deformities are a common consequence of osteoporosis and are known to decrease quality of life. The Qualeffo–41 is a quality-of-life questionnaire especially developed for measuring quality of life in patients with vertebral deformities. It consists of 41 questions arranged in five domains: pain, physical function, social function, general health perception, and mental function. The objectives of this study were: (1) to develop a shorter version of the Qualeffo–41 by removing redundant questions; and (2) to investigate the scale characteristics, reliability, and validity of this shorter version.

Methods

The study was performed using data from the Qualeffo validation study and the Multiple Outcomes of Raloxifene Evaluation (MORE) study. The analyses were performed in patients with vertebral deformities (n=579). Factor analysis on polychoric correlations and an item response theory (IRT) model, i.e., the generalized partial credit model (GPCM), were used to create a shorter version of Qualeffo–41. Using GPCM, scoring weights were computed for all items.

Results

Three items were removed from the data set because of too many missing values. Factor analysis identified three instead of five domains: (1) pain, (2) physical function, and (3) mental function. Five items had factor loadings <0.4 and were not included in the GPCM. After excluding several items, the domains pain (four items), physical function (18 items), and mental function (nine items) showed a good, reasonable, and excellent fit, respectively. This indicates that the mental function domain and the pain domain are more unidimensional than the physical function domain. All three domains showed a very high correlation (r ≥0.95) with the corresponding domains of the Qualeffo–41.

Conclusions

Qualeffo–31 was developed, consisting of three domains with a reasonable to excellent fit to the GPCM. Although the fit to the GPCM supports the construct validity of the Qualeffo–31, validation in a new study should be performed before using it in practice.

Appendix

Pain

The four questions in this section regard the situation in the last week.

Question 1 (1)	Possible response
How often have you had back pain in the last week?	○ Never
	○ 1 day per week or less
	○ 2–3 days per week
	O 4–6 days per week
	○ every day
Question 2 (2)
If you have had back pain, for how long did you have back pain in the daytime?	○ Never
	○ 1–2 hours
	○ 3–5 hours
	○ 6–10 hours
	○ All day
Question 3 (3+4)
How severe is your back pain usually?	○ No back pain
	○ Mild
	○ Moderate
	○ Severe
	○ Unbearable
Question 4 (5)
Has the back pain disturbed your sleep in the last week?	○ Less than once per week
	○ Once a week
	○ Twice a week
	○ Every other night
	○ Every night

Physical function

The next 18 questions regard the present situation.

Question 1 (6)	Possible response
Do you have problems with dressing?	○ No difficulty
	○ A little difficulty
	○ Moderate difficulty
	○ May need some help
	○ Impossible without help
Question 2 (7)
Do you have problems with taking a bath or shower?	○ No difficulty
	○ A little difficulty
	○ Moderate difficulty
	○ May need some help
	○ Impossible without help
Question 3 (8)
Do you have problems with getting to or operating a toilet?	○ No difficulty
	○ A little difficulty
	○ Moderate difficulty
	○ May need some help
	○ Impossible without help
The next 5 questions also regard the present situation. If someone else does these things in your house, please answer as though you were responsible for them.
Question 4 (10)
Can you do the cleaning?	○ Without difficulty
	○ With a little difficulty
	○ With moderate difficulty
	○ With great difficulty
	○ Impossible
Question 5 (11)
Can you prepare meals?	○ Without difficulty
	○ With a little difficulty
	○ With moderate difficulty
	○ With great difficulty
	○ Impossible
Question 6 (12)
Can you wash the dishes?	○ Without difficulty
	○ With a little difficulty
	○ With moderate difficulty
	○ With great difficulty
	○ Impossible
Question 7 (13)
Can you do your day to day shopping?	○ Without difficulty
	○ With a little difficulty
	○ With moderate difficulty
	○ With great difficulty
	○ Impossible
Question 8 (14)
Can you lift a heavy object of 20 lb (e.g., a crate of 12 bottles of milk, or a one-year-old child) and carry it for at least 10 yards?	○ Without difficulty
	○ With a little difficulty
	○ With moderate difficulty
	○ With great difficulty
	○ Impossible
Question 9 (15)
Can you get up from a chair?	○ Without difficulty
	○ With a little difficulty
	○ With moderate difficulty
	○ With great difficulty
	○ Only with help
Question 10 (16)
Can you bend down?	○ Easily
	○ Fairly easily
	○ Moderately
	○ Very little
	○ Impossible
Question 11 (17)
Can you kneel down?	○ Easily
	○ Fairly easily
	○ Moderately
	○ Very little
	O Impossible
Question 12 (18)
Can you climb stairs to the next floor of a house?	○ Without difficulty
	○ With a little difficulty
	○ With at least one rest
	○ With help only
	○ Impossible
Question 13 (19)
Can you walk 100 yards?	○ Fast without stopping
	○ Slowly without stopping
	○ Slowly with at least one stop
	○ Only with help
	○ Impossible
Question 14 (20)
How often have you been outside in the last week?	○ Every day
	○ 5–6 days/week
	○ 3–4 days/week
	○ 1–2 days/week
	○ Less than once/week
Question 15 (21)
Can you use public transport?	○ Without difficulty
	○ With a little difficulty
	○ With moderate difficulty
	○ With great difficulty
	○ Only with help
Question 16 (24)
Can you do your gardening?	○ Yes
	○ Yes with restrictions
	○ Not at all
	○ Not applicable
Question 17 (26)
Can you visit a cinema, theatre, etc.?	○ Yes
	○ Yes with restrictions
	○ Not at all
	○ No cinema, or theatre within a reasonable distance
Question 18 (27)
How often did you visit friends or relatives during the last 3 months?	○ Once a week or more
	○ Once or twice a month
	○ Less than once a month
	○ Never

Mental function

The next 9 questions regard the situation in the last week.

Question 1 (31)	Possible response
How would you rate your overall quality of life during the last week?	○ Excellent
	○ Good
	○ Satisfactory
	○ Fair
	○ Poor
Question 2 (33)
Do you tend to feel tired?	○ In the morning
	○ In the afternoon
	O Only in the evening
	○ After strenuous activity
	○ Almost never
Question 3 (34)
Do you feel downhearted?	○ Almost every day
	○ Three to five days a week
	○ One or two days a week
	O Once in a while
	○ Almost never
Question 4 (35)
Do you feel lonely?	○ Almost every day
	○ Three to five days a week
	○ One or two days a week
	○ Once in a while
	○ Almost never
Question 5 (36)
Do you feel full of energy?	○ Almost every day
	○ Three to five days a week
	O One or two days a week
	O Once in a while
	○ Almost never
Question 6 (37)
Are you hopeful about your future?	○ Never
	○ Rarely
	○ Sometimes
	O Quite often
	○ Always
Question 7 (38)
Do you get upset over little things?	○ Never
	○ Rarely
	○ Sometimes
	O Quite often
	○ Always
Question 8 (39)
Do you find it easy to make contact with people?	O Never
	○ Rarely
	○ Sometimes
	O Quite often
	○ Always
Question 9 (40)
Are you in good spirits most of the day?	○ Never
	○ Rarely
	○ Sometimes
	○ Quite often
	○ Always