Onset of symptoms in idiopathic pulmonary fibrosis: A case-control study

Abstract

Background: The incidence of idiopathic pulmonary fibrosis (IPF) is increasing, but little is known about the onset of its symptoms. These may be mistaken for manifestations of chronic obstructive pulmonary disease (COPD) and heart failure. Aims and Objectives: To determine for how long IPF cases are symptomatic, in terms of presentation to their general practitioner, before a diagnosis is made. Methods: Incident cases of IPF were identified in The Health Improvement Network (THIN) database and assigned four controls matched on sex, age and general practice. The frequency of symptoms of IPF was assessed amongst cases and controls, within each of the 5 years before cases were diagnosed. Additional diagnoses of COPD and heart failure were also examined. Conditional logistic regression was used to assess differences between cases and controls and obtain odds ratios. Results: Within the year before their IPF diagnosis, breathlessness presented as the most common symptom amongst cases (43%) followed by cough (31%). Cases were significantly more likely than controls to experience breathlessness and/or cough within all annual time periods, from 0-5 years prior to diagnosis (p Conclusions: Some patients with IPF may be symptomatic for more than five years before their diagnosis, whilst others may be misdiagnosed with COPD or heart failure. The index of suspicion of IPF needs elevating in primary care.