Construct validity and test-retest reliability of the walking questionnaire in people with a lower limb amputation.

Objective: To investigate the construct validity and test-retest reliability of the Walking Questionnaire, a patient-reported measure of activity limitations in walking in people with a lower limb amputation.

Design: Cross-sectional study.

Setting: Outpatient department of a rehabilitation center.

Participants: People with a lower limb amputation (N=172; mean age ± SD, 65±12y; 71% men; 82% vascular cause) participated in the study, 33 of whom also participated in the reliability study.

Interventions: Not applicable.

Main Outcome Measures: Construct validity was investigated by testing 11 hypotheses: limitations in walking according to the Walking Questionnaire will be greater in people with a lower limb amputation who (1) are older, (2) have a bilateral amputation, (3) have a higher level of amputation, (4) underwent their rehabilitation treatment in a nursing home, (5) walk less (in terms of time), and (6) walk shorter distances. Furthermore, limitations in walking will be positively related to activity limitations according to the (7) Locomotor Capabilities Index, (8) "distance walked" question on the Prosthetic Profile of the Amputee Questionnaire, (9) Questionnaire Rising and Sitting Down, (10) Climbing Stairs Questionnaire, and (11) Special Interest Group on Amputation Medicine/Dutch Working Group on Amputations and Prosthetics mobility scale. Construct validity was quantified by using the Mann-Whitney U test and Spearman correlation coefficient. Test-retest reliability was assessed with a 3-week interval and quantified using the intraclass correlation coefficient.

Results: Construct validity (10 of 11 hypotheses not rejected) and test-retest reliability were good (intraclass correlation coefficient =.73; 95% confidence interval, .43-.88).

Conclusions: The Walking Questionnaire has good construct validity and test-retest reliability in people with a lower limb amputation.