Patients with PRIS(m) have a high mortality in the longitudinal analysis over a period of 12 years – Results of the BACOP study

<bold>Background:</bold> The current classification system for airway obstruction, based on fixed spirometric values of FEV1 and FEV1/FVC < 0.70, ignores relevant aspects such as dynamic and static hyperinflation, airway resistance and disturbances of gas exchange and may not accurately reflect long-term outcome. BACOP is a large study of serial testing of lung function parameters that allows the identification of variables with robust predictive value for clinically important endpoints in COPD. <bold>Methods:</bold> Data of 11,247 in- and outpatients (over 40 years of age, smoking ≥20 pack-years, and a confirmed diagnosis of COPD) underwent at least one plethysmography at the Clinic of Respiratory Medicine of the University Hospital Basel, between 2008 and 2019. Information on mortality was obtained from relatives, general practitioners, hospital charts, insurance companies and death registries. Causes of death was provided by the central register of the death causes, Bern, Switzerland. <bold>Results:</bold> Mortality-hazard ratio using Cox regression (adjusted to age and sex) in patients who had undergone prebronchodilator pulmonary function tests revealed for the Preserved Ratio Impaired Spirometry (PRISm) defined as FEV1/FVC ≥ 70% and FEV1 < 80%pred a high mortality (hazard ratio [HR] 1.907; CI 1.709 to 2.218; p<0.001) in comparison to normal spirometry (for Gold 1 category HR 0.809; CI 0.654 to 1.000; p=0.05 and for Gold 2-4 HR 1,857; CI 1,678 to 2,055; p<0.001). <bold>Conclusion:</bold> Patients with PRIS(m) have a high mortality in the longitudinal analysis of lung function parameters over a period of 12 years.