Prevalence and burden of possible refractory chronic cough in four European countries.

Background: This cross-sectional study estimated prevalence and health-related burden of possible refractory or unexplained chronic cough (RCC).

Methods: This secondary analysis of survey data from France, Germany, Italy and Spain included respondents who self-reported current chronic cough (CC; cough ≥8 weeks) and no smoking/vaping, lung cancer history, interstitial lung disease or angiotensin-converting enzyme inhibitor/oral steroid use. Respondents who scored ≥4 (of 10) on a cough severity visual analogue scale and did not report "a great deal" of relief from ≥1 category of eligible medications for CC-associated conditions were included in the possible RCC group; of these, respondents who received ≥2 or 3 categories of eligible medications were also included in possible RCC subgroups 1 and 2, respectively. Remaining respondents were included in the non-RCC group. Demographics/clinical characteristics and cough/health-related burden were assessed.

Results: Of 591 respondents with CC, 165 (27.9%) were included in the possible RCC group; 56 (9.5%) and 11 (1.9%) also met criteria for possible RCC subgroups 1 and 2, respectively. The possible RCC group non-RCC group had a higher proportion of females (66.7% 57.3%; p=0.037), lower mean EuroQoL five-dimension, five-level health questionnaire index (0.72 0.80; p<0.001), lower mean Leicester Cough Questionnaire score (13.49 15.95; p<0.001) and more mean healthcare visits within the past 6 months (9.87 6.26; p<0.001).

Conclusion: Up to 27.9% of this European population with CC may have RCC and experience increased health-related burden relative to non-RCC.