Chronic cough, defined as a cough lasting at least 8 weeks, affects approximately 5% of the European population, particularly older adults and individuals with a history of smoking. In some cases, cough is considered refractory or unexplained because it does not respond to treatment for underlying conditions such as asthma or gastroesophageal reflux disease or no clear cause is found.

These cases could be linked to hypersensitivity of the cough reflex, which can severely reduce the quality of life. Diagnosis is difficult and can only be confirmed after full evaluation.

A European survey found that approximately 28% of patients with chronic cough had refractory chronic cough. More than half of the patients reported that they had stopped seeking treatment. To better understand this group, researchers have conducted a large survey to identify what distinguishes patients with refractory cough from others.

Study Design

The secondary analysis of the survey data involved 5352 adults from Germany, Spain, France, and Italy who had a chronic cough within the past 12 months. Participants had no history of smoking, lung cancer, current interstitial lung disease (eg, idiopathic pulmonary fibrosis), current use of an angiotensin-converting enzyme inhibitor, and current regular use of oral steroids (daily, for more than 2 weeks) to treat chronic cough, asthma, or chronic obstructive pulmonary disease.

Respondents with a cough severity score of 4 or higher (on a 0-10 scale) who received at least one eligible medication but did not report “a great deal” of relief were classified as having possible refractory chronic cough. This group was divided into two overlapping subgroups: Subgroup 1 included those who did not report “a great deal” of relief with two or more medication categories, and subgroup 2 included those who did not report “a great deal” of relief with all three medication categories.

Comorbidity Burden

Overall, 27.9% of the participants had a refractory form, including 9.5% of patients who were classified as refractory. Patients with refractory vs nonrefractory cough were more often women (66.7% vs 57.3%; P = .037) and had higher Charlson comorbidity index scores (average, 1.03 and 1.07 for possibly and probably refractory cases, respectively, vs 0.43; P < .05).

Depression and anxiety scores were higher, and sleep disorders were more prevalent. Urinary incontinence was reported by 33.9%-42.9% of those with refractory cough compared with 24.4% of those with nonrefractory cough (P < .05). Asthma, allergies, and other cough-related conditions, such as chronic obstructive pulmonary disease, rhinitis, and chronic sinusitis, were also more common.

Quality Decline

Health-related quality of life was lower in the refractory group. Scores on the EuroQol five-dimension, five-level health questionnaire index. General health outcomes and health-related quality of life assessed using the Medical Outcomes Trust short-form 12-item health survey, version 2, were lower for in refractory cases than for nonrefractory cases. 

These validated instruments assess patients perceived physical and mental well-being and are widely used in clinical and population studies to quantify disease burden and treatment impact.

Patients with refractory cough had more frequent visits to healthcare professionals, averaging 9.87 visits to health professionals in the previous 6 months, compared with 6.26 visits among other patients.

They were also more likely to consult specialists such as allergists, ear, nose, and throat physicians, and pulmonologists.

Emergency visits were nearly twice as common (0.48 vs 0.24 on average). Eighty percent of the patients with refractory cough had at least one diagnostic test compared with 47.7% of those with nonrefractory cough.

Based on previous data describing the prevalence of chronic cough, this study suggests that a substantial proportion of affected individuals may have refractory forms.

The findings showed that these patients experienced impaired physical and mental health despite frequent consultations and diagnostic investigations, indicating that current treatments remain inadequate.

Moreover, 53.6% of respondents with refractory cough said they had stopped seeking medical care to relieve the symptoms compared with 37.3% of those with nonrefractory cough.

This story was translated from Univadis France.