Objectives. In a multi-centre study, we sought to determine whether extent of disease on high-resolution
CT (HRCT) lung, reported using a simple grading system, is predictive of decline and mortality in
SSc-related interstitial lung disease (SSc-ILD), independently of pulmonary function tests (PFTs) and
other prognostic variables.
Methods. SSc patients with a baseline HRCT performed at the time of ILD diagnosis were identified. All
HRCTs and PFTs performed during follow-up were retrieved. Demographic and disease-related data were
prospectively collected. HRCTs were graded according to the percentage of lung disease: >20%: extensive;
<20%: limited; unclear: indeterminate. Indeterminate HRCTs were converted to limited or extensive
using a forced vital capacity threshold of 70%. The composite outcome variable was deterioration (need
for home oxygen or lung transplantation), or death.
Results. Among 172 patients followed for mean (S.D.) of 3.5 (2.9) years, there were 30 outcome events.
In Weibull multivariable hazards regression modelling, baseline HRCT grade was independently predictive
of outcome, with an adjusted hazard ratio (aHR) = 3.0, 95% CI 1.2, 7.5 and P = 0.02. In time-varying
covariate models (based on 1309 serial PFTs and 353 serial HRCTs in 172 patients), serial diffusing
capacity of the lung for carbon monoxide by alveolar volume ratio (ml/min/mmHg/l) (aHR = 0.4; 95% CI
0.3, 0.7; P = 0.001) and forced vital capacity (dl) (aHR = 0.9; 95% CI 0.8, 0.97; P = 0.008), were also strongly
predictive of outcome.
Conclusion. Extensive disease (>20%) on HRCT at baseline, reported using a semi-quantitative grading
system, is associated with a three-fold increased risk of deterioration or death in SSc-ILD, compared with
limited disease. Serial PFTs are informative in follow-up of patients.
- Interstitial lung diseases
- Systemic scleroderma
- X-ray computed tomography