Subjects were 78 patients with IPF who underwent CT on two occasions with one-year interval (38 consecutive patients treated with pirfenidone and 40 age-matched control). Changes in the fibrous lesion on sequential CTs were assessed as visual score by two radiologists. We measured the volume and change per year of fibrous pattern (F-pattern) quantitatively using a computer-aided system on sequential CTs.
The baseline vital capacity (%pred VC) was 74.0 卤 14.0% in the pirfenidone group and 74.6 卤 16.6% in controls (p = NS). Deterioration of respiratory status was defined as 10% or greater decline in %pred VC value after 12-month treatment. A significantly larger proportion of pirfenidone-treated patients showed stable respiratory status (21 of 38, 65.6%) than the control (15 of 40, 37.5%). The change in fibrous lesion was significantly smaller in the pirfenidone group than the control in both of visual score (p = 0.006) and computer analysis (p < 0.001). The decline in VC correlated significantly with the increase in fibrotic lesion (p < 0.001).
CT can be used to assess pirfenidone-induced slowing of progression of pulmonary fibrosis.