# Cross-cultural validation and reliability of the Leicester Cough Questionnaire in a Danish population

## TL;DR

The study validated a Danish version of the Leicester Cough Questionnaire, showing it is reliable for measuring cough-related quality of life in Danish patients.

## Contribution

The study provides a cross-culturally validated Danish version of the LCQ for clinical and research use.

## Key findings

- The LCQ-DK showed excellent internal consistency with a Cronbach’s alpha of 0.96 for the total score.
- Test–retest reliability was high with an ICC of 0.90 for the total score.
- The questionnaire had no significant floor or ceiling effects for the total score.

## Abstract

Chronic cough markedly impairs health-related quality of life (HRQoL). The Leicester Cough Questionnaire (LCQ) is widely used to assess cough burden across physical, psychological, and social domains; however, no validated Danish version is available.

The LCQ was translated and culturally adapted into Danish in accordance with COSMIN guidelines and was approved by the original developers. Forty-two clinically stable patients with chronic cough (mean age 70.8 years; 67% male) completed baseline and retest questionnaires at a median of 28 days (IQR 21–42). Internal consistency was examined with Cronbach’s alpha. Test–retest reliability was assessed using intraclass correlation coefficients (ICC), standard error of measurement (SEM), and minimal detectable change (MDC).

The LCQ-DK demonstrated excellent internal consistency (Cronbach’s alpha = 0.96 total; 0.84–0.92 domains). Test–retest reliability was high (ICC = 0.90, 95% CI: 0.79–0.95 total; 0.86–0.89 domains). SEM was 1.14 points (8%) and MDC 3.16 points (23%) for the total score. No floor or ceiling effects were seen for the total score, though ceiling effects up to 12% occurred within domains.

The LCQ-DK demonstrates high reliability following cross-cultural adaptation and supports group-level assessment of HRQoL in Danish-speaking patients with chronic cough for clinical and research use.