Associations of circulating matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases with clinically relevant outcomes in idiopathic pulmonary fibrosis: Data from the IPF-PRO Registry

Introduction We assessed the prognostic utility of circulating levels of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in patients with idiopathic pulmonary fibrosis (IPF) in the IPF-PRO Registry. Methods MMP and TIMP concentrations were quantified by ELISA in plasma from 300 patients. A Cox proportional hazard regression model was used to assess associations between select MMPs and TIMPs and death and disease progression (absolute decline in forced vital capacity ≥10% predicted, death, or lung transplant). Results Over a median follow-up of 30.4 months, 98 patients died and 182 patients had disease progression. In unadjusted analyses, higher concentrations of MMPs 2, 3, 8 and 9 and TIMPs 1, 2 and 4 were associated with an increased risk of death. MMPs 2 and 8 and TIMP1 remained associated with death after adjustment for clinical factors. In unadjusted analyses, higher concentrations of MMPs 8 and 9 and TIMPs 1 and 4 were associated with an increased risk of disease progression. MMPs 8 and 9 and TIMP1 remained associated with progression after adjustment for clinical factors. Conclusion Circulating levels of MMP8 and TIMP1 may provide information on the risk of outcomes in patients with IPF not captured by clinical measures.