Prevalence and Risk Factors for Refractory and Untreated Chronic Cough in the Canadian Longitudinal Study of Aging (CLSA)

Chronic cough affects many adults, with ∼4% having refractory or untreated disease. Most cases resolve over time, especially with smoking cessation or stopping ACE inhibitors, highlighting the importance of addressing treatable traits. Chronic cough (CC), defined as a persistent cough lasting >8 weeks, affects 16% of Canadian adults in the community. Chronic cough can be classified as refractory chronic cough (RCC) when cough persists despite treatment of any identifiable underlying condition. The prevalence of RCC is unclear, but also those who despite having a persistent cough, remain untreated. This prospective cohort study included 26 606 adults aged 45–85 from the Canadian Longitudinal Study of Aging (CLSA) with available chronic cough data at baseline and first follow-up at 3 years. Chronic cough was defined by self-reported daily cough for ≥12 months. In this cohort, 4,059 participants had a cough at baseline. Among them, 26.2% had RCC on medications, 27.4% had RCC without medication who we considered untreated CC, 19.3% had resolution with medication, and 27.1% resolved without medication. Overall, the prevalence of RCC on medication was 4.0% (1063/26 606) in this population and was 4.2% for the untreated CC group. RCC was more common in males, persistent smokers, and those with asthma, COPD, migraine, and inflammatory bowel disease (IBD) or irritable bowel syndrome (IBS). Smoking cessation and discontinuing ACE inhibitors were associated with resolution of cough. Despite guideline-recommended therapies, neuromodulators were infrequently prescribed by physicians. This population-based study was able to explore the outcomes of chronic cough over 3 years and identify risk factors with its development. Nearly one-third of cases resolved without new medication, but with likely targeting treatable traits such as smoking and stopping ACE-Inhibitor use.