Interstitial Pneumonia Related to Undifferentiated Connective Tissue Disease: Pathologic Pattern and Prognosis.

Chest

PubMedID: 25211168

Kim HC, Ji W, Kim MY, Colby TV, Jang SJ, Lee CK, Han SB, Kim DS. Interstitial Pneumonia Related to Undifferentiated Connective Tissue Disease: Pathologic Pattern and Prognosis. Chest. 2015;147(1):165-72.
ABSTRACT
Background:Undifferentiated connective tissue disease (UCTD) involves conditions characterized by both having symptoms of connective tissue disease (CTD) and autoantibodies but they do not fulfill the criteria of a specific CTD. The frequency or prognosis of the usual interstitial pneumonia (UIP) pattern in UCTD is unknown, which may be confused with idiopathic pulmonary fibrosis (IPF). This study aimed to investigate the frequency of the UIP pattern in interstitial pneumonia related to UCTD and compare its prognosis with that of IPF and UCTD-nonspecific interstitial pneumonia (UCTD-NSIP). Methods:The medical records of 788 patients presumptively diagnosed with idiopathic interstitial pneumonia (IIP) at Asan Medical Center from January 2005 to December 2012 were retrospectively reviewed. UCTD was diagnosed according to the criteria by Corte et al1 and the prognoses were compared between UCTD-UIP and UCTD-NSIP and between UCTD-UIP and IPF. Results:Among 105 UCTD patients (13.3% of total subjects), 44 had an UIP pattern (by surgical lung biopsy: 24; by high-resolution computed tomography: 20), 29 had an NSIP pattern (by surgical lung biopsy), and 9 had an organizing pneumonia pattern (by biopsy). The overall survival of the UCTD-UIP group was shorter than that of the UCTD-NSIP group (P=0.021) but significantly better than that of the IPF group (P=0.042). Conclusions:A UIP pattern, which seems to be frequent in UCTD, showed a poorer prognosis than that of UCTD-NSIP. However, the prognosis of UCTD-UIP was significantly better than that of IPF, highlighting the importance of searching for underlying UCTD in suspected IPF cases.

Background
Undifferentiated connective tissue disease (UCTD) involves conditions characterized by both having symptoms of connective tissue disease (CTD) and autoantibodies but they do not fulfill the criteria of a specific CTD. The frequency or prognosis of the usual interstitial pneumonia (UIP) pattern in UCTD is unknown, which may be confused with idiopathic pulmonary fibrosis (IPF). This study aimed to investigate the frequency of the UIP pattern in interstitial pneumonia related to UCTD and compare its prognosis with that of IPF and UCTD-nonspecific interstitial pneumonia (UCTD-NSIP).

Methods
The medical records of 788 patients presumptively diagnosed with idiopathic interstitial pneumonia (IIP) at Asan Medical Center from January 2005 to December 2012 were retrospectively reviewed. UCTD was diagnosed according to the criteria by Corte et al1 and the prognoses were compared between UCTD-UIP and UCTD-NSIP and between UCTD-UIP and IPF.

Results
Among 105 UCTD patients (13.3% of total subjects), 44 had an UIP pattern (by surgical lung biopsy: 24; by high-resolution computed tomography: 20), 29 had an NSIP pattern (by surgical lung biopsy), and 9 had an organizing pneumonia pattern (by biopsy). The overall survival of the UCTD-UIP group was shorter than that of the UCTD-NSIP group (P=0.021) but significantly better than that of the IPF group (P=0.042).

Conclusions
A UIP pattern, which seems to be frequent in UCTD, showed a poorer prognosis than that of UCTD-NSIP. However, the prognosis of UCTD-UIP was significantly better than that of IPF, highlighting the importance of searching for underlying UCTD in suspected IPF cases.