Impact of timing of interstitial lung disease in patients with systemic sclerosis

Systemic sclerosis (SSc) is characterised by multiorgan fibrosis; interstitial lung disease (ILD) is the leading cause of death. ILD can precede SSc, and clinical implications including mortality are unknown. The objective of this study using a hospital system registry was to determine the risk of mortality based on the timing of ILD relative to SSc diagnosis. Multivariable Cox proportional hazard models examined the association between ILD before and after SSc. Among 303 patients with ILD, 171 (56.4%) were diagnosed after SSc and 132 (43.6%) prior. The ILD before SSc group had higher mortality (HR 2.7, 95% CI 1.5 to 4.9, p=0.0006).