Longitudinal follow-up of fibrosing interstitial pneumonia: relationship between physiologic testing, computed tomography changes, and survival rate.
OBJECTIVE
The aim of this study was to evaluate the prognostic implications of computed tomography (CT) and physiologic variables at baseline and on sequential evaluation in patients with fibrosing interstitial pneumonia.


METHODS
We identified 72 patients with fibrosing interstitial pneumonia (42 with idiopathic disease, 30 with collagen vascular disease). Pulmonary function tests and CT were performed at the time of diagnosis and at a median follow-up of 12 months, respectively. Two chest radiologists scored the extent of specific abnormalities and overall disease on baseline and follow-up CT. Rate of survival was estimated using the Kaplan-Meier method. Three Cox proportional hazards models were constructed to evaluate the relationship between CT and physiologic variables and rate of survival: model 1 included only baseline variables, model 2 included only serial change variables, and model 3 included both baseline and serial change variables.


RESULTS
On follow-up CT, the extent of mixed ground-glass and reticular opacities (P<0.001), pure reticular opacity (P=0.04), honeycombing (P=0.02), and overall extent of disease (P<0.001) was increased in the idiopathic group, whereas these variables remained unchanged in the collagen vascular disease group. Patients with idiopathic disease had a shorter rate of survival than those with collagen vascular disease (P=0.03). In model 1, the extent of honeycombing on baseline CT was the only independent predictor of mortality (P=0.02). In model 2, progression in honeycombing was the only predictor of mortality (P=0.005). In model 3, baseline extent of honeycombing and progression of honeycombing were the only independent predictors of mortality (P=0.001 and 0.002, respectively). Neither baseline nor serial change physiologic variables, nor the presence of collagen vascular disease, was predictive of rate of survival.


CONCLUSIONS
The extent of honeycombing at baseline and its progression on follow-up CT are important determinants of rate of survival in patients with fibrosing interstitial pneumonia.
Hwang
Jeong-Hwa
JH
Division of Radiology, National Jewish Health, Denver, CO 80206, USA.
Misumi
Shigeki
S
Curran-Everett
Douglas
D
Brown
Kevin K
KK
Sahin
Hakan
H
Lynch
David A
DA
D000328:Adult; D000368:Aged; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D008137:Longitudinal Studies; D017563:Lung Diseases, Interstitial / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012720:Severity of Illness Index; D015996:Survival Rate; D014057:Tomography, X-Ray Computed