Revision of the Lymphedema Functioning, Disability and Health Questionnaire for Upper Limb Lymphedema (Lymph-ICF-UL): Reliability and Validity.

Lymphedema is associated with significant physical and psychosocial problems. The Lymphedema Functioning, Disability and Health questionnaire for upper limb lymphedema is a valid and reliable tool quantifying the amount of problems in functioning in patients with breast cancer-related lymphedema. Patients suggested a revision of the scoring system to facilitate completion of the questionnaire. Therefore, adjustment of the questionnaire was carried out by implementing a numeric rating scale instead of the existing visual analog scale. Purpose of this study was to investigate reliability and validity of the revised Lymph-ICF, called the Lymph-ICF-UL. Reliability and validity of the Lymph-ICF-UL were examined in 56 participants with upper limb lymphedema. Intraclass correlation coefficients for test-retest reliability ranged from 0.79 to 0.95. Cronbach's alpha coefficients for internal consistency were higher than 0.80. Face and content validity were very good because the scoring system was clear for all participants (100%), questions were understandable for all participants (100%), and all complaints due to arm lymphedema were mentioned by 98% of the participants. Construct validity was good. Convergent validity was established since four out of five expected domains of the Lymph-ICF-UL showed a moderate correlation with expected domains of the 36-Item Short-Form Health Survey questionnaire. There was good divergent validity because seven out of nine hypotheses assessing divergent validity were accepted. The Lymph-ICF-UL is a reliable and valid questionnaire using a simplified and clearer scoring procedure to assess impairments in function, activity limitations, and participation restrictions of patients with breast cancer-related arm lymphedema.