Cross-cultural adaptation and validation of the Norwegian version of the Leicester Cough Questionnaire in chronic obstructive pulmonary disease

ABSTRACT

Background

Cough is a common symptom among patients with chronic obstructive pulmonary disease (COPD), but there are currently no patient-reported outcome measures (PROM) for subjective cough symptoms in Norwegian.

Objective

The objective was to translate and validated the most widely used PROM for chronic cough, the Leicester Cough Questionnaire (LCQ) from English to Norwegian (NLCQ) using established guidelines.

Methods

Forward and backward translations were performed using external translators. All phases were discussed in an expert workgroup until consensus was achieved. Ten patients were interviewed about the pre-final version to assess understandability and ease to complete. The final NLCQ was externally proofread and tested for content and construct validity, internal consistency, test–retest reliability and measurement error.

Results

Mean (SD) age was 67 (7.9) years, and 62% of the sample were female (n = 56/89). According to GOLD stages, 10% had mild, 27% moderate, 35% severe and 22% very severe COPD, respectively. GOLD stages were missing for five patients (6%). The NLCQ showed acceptable accordance with the original, acceptable understandability and ease to complete, satisfactory content reliability, total score construct validity, internal consistency and test–retest reliability. Test–retest bias was low, but measurement error was larger than previously reported. The standard error of measurement and smallest detectable change were 1.56 and 4.32, respectively. Construct validity and factor analysis raised concerns regarding the three subdomains.

Conclusion

The present cross-cultural adaptation of the NLCQ showed satisfactory reliability and overall validity. Due to concerns for the validity of the three domains, we suggest use should be restricted to the NLCQ total score until these are reassessed.

KEYWORDS:

• Cough
• surveys and questionnaires
• cross-cultural adaptation
• chronic obstructive pulmonary disease
• validation

Disclosure statement

The authors have no competing interests to declare.

Additional information

Funding

The present project received funding from Østfold Hospital Trust.