Predictive value of serial high-resolution computed tomography analyses and concurrent lung function tests in systemic sclerosis.
OBJECTIVE
Systemic sclerosis (SSc) carries a high risk of progressive interstitial lung disease (ILD), but tools for stratifying individual risk are scarce. The purpose of this study was to assess detailed data from serial lung fibrosis measurements and paired pulmonary function tests (PFTs) as outcome prediction tools in a prospective cohort of SSc patients.


METHODS
Paired PFTs and high-resolution computed tomography (HRCT) scans were obtained at baseline and at followup in 305 SSc patients who met the American College of Rheumatology/European League Against Rheumatism 2013 classification criteria. The extent of fibrosis was scored on 10 sections from every HRCT scan and expressed as the percentage of the total lung volume.


RESULTS
Baseline HRCT analyses revealed 3 SSc subgroups: those with >20% lung fibrosis (n = 40), those with 1-20% fibrosis (n = 157), and those with no fibrosis (n = 108). At followup HRCT (mean of 3.1 years later), all 108 group 3 patients were still free of fibrosis. In group 2 patients, 146 continued to have 1-20% fibrosis (group 2a), whereas 11 (marked by short disease duration of 1.3 years) had experienced progression to >20% fibrosis (group 2b). The annual fibrosis progression rate differed across the 4 groups: 0.9% in group 1, 0.7% in group 2a, 5.9% in group 2b, and 0% in group 3. The annual fibrosis progression rate correlated with the total decline in the forced vital capacity (FVC) (7.1%, 5.7%, 8.7%, and 2.9% in groups 1, 2a, 2b, and 3, respectively), but not the diffusing capacity for carbon monoxide (DLco) (8.4%, 7.7%, 7.7%, and 8.6%, respectively). Multivariate analyses identified anticentromere antibodies (odds ratio [OR] 4.7) and baseline DLco (OR 1.04) as predictors of no fibrosis at followup and baseline fibrosis (OR 1.3) and FVC (OR 0.96) as predictors of >20% fibrosis at followup.


CONCLUSIONS
These prospective cohort data suggest that HRCT performed at baseline predicts the development of fibrosis, the rate of progression of fibrosis, and the decline in pulmonary function in SSc.
Oslo University Hospital, Rikshospitalet, and University of Oslo, Oslo, Norway.
Anna-Maria
AM
Hoffmann-Vold
Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Trond M
TM
Aaløkken
Oslo University Hospital, Rikshospitalet, Oslo, Norway.
May Brit
MB
Lund
Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Torhild
T
Garen
Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Øyvind
Ø
Midtvedt
Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Cathrine
C
Brunborg
Oslo University Hospital, Rikshospitalet, and University of Oslo, Oslo, Norway.
Jan Tore
JT
Gran
Oslo University Hospital, Rikshospitalet, and University of Oslo, Oslo, Norway.
Øyvind
Ø
Molberg
D000328:Adult; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D011653:Pulmonary Diffusing Capacity; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D012129:Respiratory Function Tests; D012595:Scleroderma, Systemic / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed; D014797:Vital Capacity