Background Idiopathic pulmonary fibrosis (IPF) is an age-related, progressive and irreversible lung disease.1 The diagnosis of IPF is made using clinical history, pulmonary function testing (PFT), and radiological appearances of Usual Interstitial Pneumonia (UIP) on High Resolution CT (HRCT) Scanning provided other appearances have been excluded. The diagnosis is frequently made at MDT where the images are categorised into Definite UIP, Possible UIP, or Inconsistent with UIP using HRCT criteria.2 In the west of Scotland, patients demonstrating definite or possible UIP patterns on HRCT with a FVC < 80% are considered for antifibrotic therapy. The aim of this study was to assess whether response to antifibrotic therapy in IPF is correlated with the aforementioned categories. The presence of pleural plaques was also considered.
Methods We retrospectively divided 170 patients into three categories: definite UIP pattern, possible UIP pattern, and UIP with pleural plaques. Serial pulmonary function test results were obtained and the change in FVC calculated. Treatment failure was defined as a change in FVC% predicted of >10% per year. The rate of treatment failure, overall mortality, 6-month and 12-month survival was compared between the three groups.
Results 116 patients out of 170 were started on antifibrotic therapy. The average duration of therapy was 256 days. There was a trend towards higher treatment failure in possible (n = 3 of 12 25%) versus definite UIP patterns (n = 6 of 55 11%), this was not statistically significant. Overall mortality rates were similar between possible and definite UIP patterns at 6- and 12-months (Figure 1). 5 patients with UIP and pleural plaques were started on therapy.
Conclusions Mortality at 12 months was similar in possible UIP and UIP groups; there was a trend towards higher levels of treatment failure in patients with possible UIP. A different disease process may exist in some patients with possible UIP which is non-responsive to antifibrotic treatment. Numbers are relatively small and further observation is warranted.