Interstitial Lung Disease in Systemic Sclerosis A Simple Staging System

Rationale: In interstitial lung disease complicating systemic sclerosis (SSc-ILD), the optimal prognostic use of baseline pulmonary function tests (PFTs) and high-resolution computed tomography (HRCT) is uncertain.Objectives: To construct a readily applicable prognostic algorithm in SSc-ILD, integrating PFTs and HRCT.Methods: The prognostic value of baseline PFT and HRCT variables was quantified in patients with SSc-ILD (n = 215) against survival and serial PFT data.Measurements and Main Results: Increasingly extensive disease on HRCT was a powerful predictor of mortality (P < 0.0005), with an optimal extent threshold of 20%. In patients with HRCT extent of 10–30% (termed indeterminate disease), an FVC threshold of 70% was an adequate prognostic substitute. On the basis of these observations, SSc-ILD was staged as limited disease (minimal disease on HRCT or, in indeterminate cases, FVC ⩾ 70%) or extensive disease (severe disease on HRCT or, in indeterminate cases, FVC < 70%). This system (hazards ratio [H...