The Danish version of Lymphoedema Functioning, Disability and Health Questionnaire (Lymph-ICF) for breast cancer survivors: Translation and cultural adaptation followed by validity and reliability testing

ABSTRACT

Purpose: To translate and culturally adapt the Lymphoedema Functioning, Disability and Health Questionnaire (Lymph-ICF) for breast cancer survivors with arm lymphedema into Danish and examine its content validity and reliability. Methods: (1) Translation and cultural adaptation was performed in 10 steps following international guidelines (International Society for Pharmacoeconomics and Outcome Research); (2) cognitive interviewing (step 7) was conducted in 15 women with breast cancer related arm lymphedema to explore understandability, interpretation, and cultural relevance; (3) after adjustments, content validity (N = 52) was explored by interviews; and (4) reliability (N = 50) examined by intraclass correlation coefficients (ICC) statistics and Cronbach alpha analysis. Results: Cognitive interviewing lead to an adapted and improved version of the translated questionnaire. Content validity was supported. Internal consistency (α) for all questions was .98 and ranged for the different domains between 0.92 and 0.97. Test–retest reliability for the total score was highly satisfactory, ICC = 0.95, standard error of measurement (SEM) = 4.5 and smallest detectable change = 12.5. ICC values for the domains ranged from 0.84 to 0.94. SEM values differed for the domains, 6.4 (physical function), 5.7 (mobility activities), 7.09 (life and social activities), 9.1 (mental functions), and 10.2 (household activities). Conclusion: The translated and adjusted Lymph-ICF DK (Denmark) is reliable and valid, allowing for assessing self-reported impairments in function, activity limitations, and participation restrictions in Danish patients with breast cancer-related arm lymphedema.

KEYWORDS:

• Lymphedema
• breast cancer
• Lymphoedema Functioning, Disability and Health Questionnaire
• translation
• cognitive interviewing
• Danish version

Acknowledgments

The authors thank all the women with breast cancer-related lymphedema who willingly participated in this study. The authors would also like to thank the translators for their help, Lone G. Laursen, physiotherapist at Department of Physiotherapy and Occupational Therapy at Aalborg University Hospital, for data collection assistance, and associate professor Bo Grarup for coding a part of the cognitive interviews and for help with statistics. Finally, the corresponding author would like to thank Dr. Nele Devoogdt, who found time to discuss results of our research project. Her comments were of great value for us.

Declaration of interest

The authors report no declarations of interest.