Pre-COPD and PRISM: Wrong definitions with significant clinical impact

ABSTRACT

‘Pre-COPD’ is defined as a high-risk state in individuals with symptoms like cough with sputum production and dyspnea, physiological abnormalities like low FEV1, faster decline of FEV1, low DLCO etc and radiological abnormalities like airway abnormalities and emphysema, with a normal FeV1/ FVC ratio in the spirometry. The term ‘PRISM--Preserved Ratio Impaired Spirometry’ was also introduced as a subset of Pre-COPD with FEV1 < 80%, but with preserved or normal FEV1/ FVC ratio. If a person is symptomatic with lung function test, radiology and even histology suggestive of COPD, how can we call them ‘Pre-COPD’ just because the spiromteric FEV1/FVC ratio did not fall less than 70% or below the 5^th percentile. There are various reasons why we might fail to demonstrate an airway obstruction just by FeV1/ FVC ratio alone. Overdependence on spirometry to define clinical terminologies in COPD can have adverse effects on the disease management. In this article, we discuss the pit falls in the definitions of ‘Pre-COPD’ and ‘PRISM’ and also the need of better clinical definitions in detail.

Keywords: Pre-COPD, PRISM, Spirometry, Oscillometry, COPD