分類できない特発性間質性肺炎の急性増悪：特発性肺線維症との比較．

Acute exacerbation of unclassifiable idiopathic interstitial pneumonia: comparison with idiopathic pulmonary fibrosis.

• Noriyuki Enomoto
• Hyogo Naoi
• Yuya Aono
• Mineo Katsumata
• Yasuoki Horiike
• Hideki Yasui
• Masato Karayama
• Hironao Hozumi
• Yuzo Suzuki
• Kazuki Furuhashi
• Tomoyuki Fujisawa
• Naoki Inui
• Yutaro Nakamura
• Takafumi Suda

抄録

背景:

特発性肺線維症（AE-IPF）の急性増悪は，その臨床経過において生命を脅かす病態としてよく知られている．しかし，分類不能特発性間質性肺炎（AE-UCIIP）のAEにおける臨床的特徴や予後については，未だ解明されていない。本研究の目的は，AE-UCIIP の臨床的特徴と予後を AE-IPF と比較して明らかにすることであった．

BACKGROUND: Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) is well known as a life-threatening condition during its clinical course. However, the clinical features and prognosis in AE of unclassifiable idiopathic interstitial pneumonia (AE-UCIIP) remain to be elucidated. The aim of this study was to clarify the clinical features and prognosis of AE-UCIIP compared with those of AE-IPF.

方法:

当院で診断・治療を受けたUCIIPまたはIPF患者187例、AE-UCIIPまたはAE-IPF患者64例を対象に、レトロスペクティブに評価した。

METHODS: In 187 patients with UCIIP or IPF, 64 patients with AE-UCIIP or AE-IPF, who were diagnosed and treated at our hospital, were retrospectively evaluated.

結果:

AE-UCIIP 患者 24 例は，AE-IPF 患者 40 例よりも有意に高齢（=0.011）であり，女性（<0.001）および非喫煙者（<0.001）が多く含まれ，高分解能コンピュータ断層撮影（=0.006）での肺病変の発現が少なかった．AE-UCIIPの発症率は10.29％/年で，AE-IPFと比較して有意に高かった（Gray's test，=0.008）．予後は，AE-UCIIPの予後はAE-IPFと同様に不良であった（log-rank，=0.681）．予測強制生命維持能力（％FVC）［ハザード比（HR）0.934，=0.045］，AE 前 12 カ月以内の GAP ステージ（HR 3.530，=0.023），および AE 時の分圧動脈酸素／触発酸素分率（PaO/FiO）比（HR 0.998，=0.016）は有意な予後因子であったが，これらの値は AE-IPF と比較して有意ではなかった．最後に，入院後 2 日以内にポリミキシン B 固定化ファイバーカラム（PMX-DHP）による長時間（"Sm_2A7E"12h）直接血流灌流を開始すると，AE-UCIIP の生存率が有意に改善し（log-rank，=0.038），有意な予後因子（HR 0.175，=0.0039）となった．長時間投与のPMX-DHPは、AE-UCIIPまたはAE-IPFとの併用群においても良好な治療効果を示した（log-rank =0.002、HR 0.328、=0.006）。

RESULTS: A total of 24 patients with AE-UCIIP were significantly older ( = 0.011), included more women ( < 0.001) and never-smokers ( < 0.001), and showed fewer lung lesions on high-resolution computed tomography ( = 0.006) than 40 patients with AE-IPF. Incidence of AE-UCIIP was 10.29%/year and was significantly higher than in AE-IPF (Gray's test,  = 0.008). Prognosis of AE-UCIIP was as poor as that of AE-IPF (log-rank,  = 0.681). Percent-predicted forced vital capacity (%FVC) [hazard ratio (HR) 0.934,  = 0.045], and GAP stage within 12 months before AE (HR 3.530,  = 0.023), and partial pressure arterial oxygen/fraction of inspired oxygen (PaO/FiO) ratio at AE (HR 0.998,  = 0.016) were significant prognostic factors. Finally, commencement of long-duration (⩾12 h) direct hemoperfusion with a polymyxin B-immobilised fibre column (PMX-DHP) within 2 days after admission significantly improved survival (log-rank,  = 0.038) and was a significant prognostic factor (HR 0.175,  = 0.0039) in AE-UCIIP. Long-duration PMX-DHP showed favourable treatment effects even in the combined group of patients with AE-UCIIP or AE-IPF (log-rank  = 0.002; HR 0.328,  = 0.006).

結論:

AE-UCIIP 患者は，AE-IPF 患者に比べて高齢であり，女性や非喫煙者が多かった．予後は，AE-UCIIP の予後は AE-IPF と同様に不良であった．

CONCLUSIONS: Patients with AE-UCIIP were older and included more women and never-smokers than those with AE-IPF. Prognosis of AE-UCIIP was as poor as that of AE-IPF.