The walking impairment questionnaire: an effective tool to assess the effect of treatment in patients with intermittent claudication.
OBJECTIVE
Assessment of walking distance by treadmill testing is the most commonly used method to evaluate the effect of treatment in patients with peripheral arterial disease. However, treadmill testing is time consuming, relatively expensive, and does not adequately reflect real life functional ability. We hypothesized that the Walking Impairment Questionnaire (WIQ) could be an alternative tool to assess objective improvement in functional walking ability of patients with intermittent claudication.


METHODS
This was a validation study. It was conducted through the outpatient clinic for vascular surgery. Patients with intermittent claudication were referred for supervised exercise therapy. Treadmill testing (absolute claudication distance [ACD]), WIQ, and quality of life questionnaires (RAND-36 and EuroQol) were administered at study onset and after 3 months of supervised exercise therapy. Responsiveness was determined by mean changes in and correlation coefficients of WIQ, ACD, and quality of life questionnaires. Patients were categorized into quartiles based on the increase in ACD, which were subsequently related to change in WIQ and quality of life.


RESULTS
The mean pre- and post-treatment total WIQ scores of 91 patients were 0.45 (0.22) and 0.58 (0.22), respectively. The correlation coefficient between the change in total WIQ score and ACD was 0.331 (P = .004). A 0.1 change in total WIQ score corresponded to a change of 345 meters in ACD. Analysis of the four quartiles compared to an increase in ACD showed that a greater increase in ACD corresponded with a greater increase in WIQ score, from 0.06 to 0.25 (P = .011).


CONCLUSIONS
These data indicate that the WIQ is a valid tool to detect improvement or deterioration in the daily walking ability of patients with intermittent claudication. Hence, the WIQ can be used as an alternative to treadmill testing for objective assessment of functional walking ability, both in daily practice and in clinical trials.
Nicolaï
Saskia P A
SP
Department of Surgery, Atrium Medical Centre Parkstad, Heerlen, The Netherlands.
Kruidenier
Lotte M
LM
Rouwet
Ellen V
EV
Graffius
Kirsten
K
Prins
Martin H
MH
Teijink
Joep A W
JA
D000368:Aged; D005080:Exercise Test; D005260:Female; D006801:Humans; D007383:Intermittent Claudication / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D016491:Peripheral Vascular Diseases / Q000150:complications / Q000175:diagnosis*; D011788:Quality of Life; D011795:Surveys and Questionnaires