Prevalence of Chronic Rhinosinusitis with Nasal Polyps in Catalonia (Spain): a retrospective, large-scale population-based study

Background: Studies on the prevalence of chronic rhinosinusitis (CRS) with nasal polyps (NP) in general-based populations are scarce in Europe and worldwide. We performed a retrospective population-based observational cohort study of 30,189 adult patients diagnosed with NP in Catalonia (Spain). Methodology: Adult individuals (>= 18 years old) with a diagnosis of NP established by medical records at different health care levels (primary, hospital, and emergency) from the Catalan Health System (CHS) were included. Socio-demographic characteristics, prevalence, overall and by age and gender, disease severity, multi-morbidities, and biomarkers of type-2 inflammation were evaluated, together with appropriate medical treatment (AMT) and Endoscopic Sinus Surgery (ESS). Results: In general population and severity sub-populations, the overall diagnosed NP prevalence was 0.49% and higher for males than females (0.60% vs 0.39%, p<0.0016). The prevalence for the severe NP population was 0.12%. The NP prevalence increased with age, the highest being at >= 60 years old for both gender and severity groups. Asthma (40.1%), acute rhinosinusitis (41.1%), and allergic rhinitis (32.1%) were among the most frequent comorbid respiratory diseases. ESS was performed in 15.4% of NP patients. Type 2 inflammation was present in 83.8% of the NP population and was more frequent in severe than non-severe (87.1% vs 82.7%, p<0.0001) patients and in those with respiratory multi-morbidities (91%). Conclusions: This is the first large-scale population-based NP epidemiology study conducted in Spain, including severity based on undergoing medical and surgical treatment and type 2 inflammation. Although the prevalence data are lower than in previous European studies, the large NP cohort studied represents an essential strength of the results.