Atsuki Fukada, Yuzo Suzuki, Kazutaka Mori, Masato Kono, Hirotsugu Hasegawa, Dai Hashimoto, Koshi Yokomura, Shiro Imokawa, Yuko Tanaka, Yusuke Inoue, Hironao Hozumi, Masato Karayama, Kazuki Furuhashi, Noriyuki Enomoto, Tomoyuki Fujisawa, Yutaro Nakamura,Naoki Inui, Yoshihisa Fujino, Hidenori Nakamura, Takafumi Suda
Background Idiopathic pleuroparenchymal fibroelastosis (iPPFE) is a rare interstitial lung disease characterised by predominant upper lobe fibrosis involving the pleura and subpleural lung parenchyma. Despite its poor prognosis, there is no consensus on prognostic determinants of iPPFE to date. Because volume loss in the upper lobe is a distinct feature of iPPFE, we hypothesised that the lung volume of the bilateral upper lobes (upper lobe-volume) accurately indicates disease severity and mortality risk in iPPFE patients.
Methods This retrospective study assessed two cohorts of 132 patients with iPPFE (69 in Hamamatsu cohort; 63 in Seirei cohort) and 45 controls. Each lobe volume was quantitatively measured using three-dimensional computed tomography at the time of iPPFE diagnosis and standardised using predicted forced vital capacity.
Results The standardised upper lobe-volume was less than twice as small in iPPFE patients versus controls, whereas the lower lobe-volume did not decrease. iPPFE patients with lower standardised upper lobe-volume had significantly shorter survival rates than those with higher volume (median survival: 6.08 versus 2.48 years, p<0.001). In multivariate analysis, the lower standardised upper lobe-volume was significantly associated with increased mortality adjusting for age, sex and forced vital capacity [hazard ratio: 0.939].
A composite scoring model, including age, sex and standardised upper lobe volume, was associated with a better risk of death than the gender-age-physiology (GAP) model.
Conclusion Assessment of upper lobe-volume provides useful information for managing iPPFE by evaluating disease severity and mortality risk in clinical practice.
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Conflicts of interest: The authors declare that no competing interests exist.