Rhinosinusitis in morbidity registrations in Dutch General Practice: A retro-spective case-control study Epidemiology and research methodology in primary care

Background: There is only limited accurate data on the epidemiology of rhinosinusitis in primary care. This study was conducted to assess the incidence of acute and chronic rhinosinusitis by analysing data from two Dutch general practice registration projects. Several patient characteristics and diseases are related to the diagnosis rhinosinusitis. Methods: The Continuous Morbidity Registration (CMR) and the Transitionproject (TP) are used to analyse the data on rhinosinusitis in primary practice. Both registries use codes to register diagnoses. Results: In the CMR 3244 patients are registered with rhinosinusitis and in the TP 5424 CMR: The absolute incidence of (acute) rhinosinusitis is 5191 (18.8 per 1000 patient years). Regarding an odds ratio of 5.58, having nasal polyps is strongest related to rhinosinusitis compared to the other evaluated comorbidities. A separate code for chronic rhinosinusitis exists, but is not in use. TP: Acute and chronic rhinosinusitis are coded as one diagnosis. The incidence of rhinosinusitis is 5574 or 28.7 per 1000 patient years. Patients who visit their general practitioner with "symptoms/complaints of sinus", allergic rhinitis and "other diseases of the respiratory system" have the highest chances to be diagnosed with rhinosinusitis. Medication is prescribed in 90.6 % of the cases. Conclusions: Rhinosinusitis is a common diagnosis in primary practice. In the used registries no difference could be made between acute and chronic rhinosinusitis, but they give insight in comorbidity and interventions taken by the GP in case of rhinosinusitis