Characteristics of adults with potential refractory chronic cough identified using an algorithm designed for administrative claims databases: A descriptive study.

As population-based studies describing the characteristics of patients with refractory chronic cough (RCC) are sparse, the objective of this descriptive study was to identify and describe such patients using an algorithm developed for administrative claims databases and requiring validation in future. We identified adults with chronic cough (N = 782,121) from Optum Clinformatics™ Data Mart as individuals with a 'cough event' (primary cough event; based on ICD codes/relevant prescriptions) and ≥2 cough events in the 56-180 preceding days. We applied several exclusion criteria to identify potential RCC cases and stratified them into probable, possible, and unlikely RCC cohorts by the number of cough events during 1-year follow up (≥3, 1-2 or 0 events, respectively). Patient characteristics were described during the year before the primary cough event and follow up. 16.8% (n = 131,772) of patients with chronic cough were potential RCC cases: 25.8% probable, 35.9% possible and 38.3% unlikely. The majority were female (66.4-70.5%); median age was 53-60 years. The most common comorbidities and cough-associated complications at baseline were: allergic rhinitis (30.7-39.1%), hypertension (37.3-47.7%), gastro-oesophageal reflux disease (23.7-34.3%), asthma (18.1-27.3%), insomnia (6.3-8.3%) and stress incontinence (2.5-3.9%). Among probable RCC cases, use of several medications was higher during follow up versus baseline: 52.7% versus 49.0% (cough treatments), 73.3% versus 69.0% (respiratory drugs), 40.5% versus 34.2% (gastrointestinal drugs) and 58.8% versus 56.1% (psychotherapeutics). Our algorithm requires validation but provides a starting point to identify patients with RCC in claims databases in future studies.