Growth differentiation factor-15 is a predictor of important disease outcomes in patients with COPD

Abstract

Increased levels of growth differentiation factor-15 (GDF15) are associated with cachexia, cardiovascular disease and all-cause mortality. The role of GDF15 in chronic obstructive pulmonary disease (COPD) is unknown.The study included 413 patients with COPD from the Bergen COPD Cohort Study. All patients had a forced expiratory volume in 1 s (FEV₁) <80% predicted, a FEV₁ to forced vital capacity (FVC) ratio <0.7 and a history of smoking. Spirometry, fat free mass index, blood gases and plasma GDF15 were measured at baseline. Patients were followed for 3 years regarding exacerbations and changes in lung function, and 9 years for mortality. Yearly exacerbation rate, survival and yearly change in FEV₁/FVC were evaluated with regression models.Median plasma GDF15 was 0.86 ng·mL^-1 (interquartile range 0.64-1.12 ng·mL^-1). The distribution was not normal and GDF15 was analysed as a categorical variable. High levels of GDF15 were associated with a higher exacerbation rate (incidence rate ratio 1.39, 95% CI 1.1-1.74, p=0.006, adjusted values). Furthermore, high levels of GDF15 were associated with higher mortality (hazard ratio 2.07, 95% CI 1.4-3.1, p<0.001) and an increased decline in both FEV₁ (4.29% versus 3.25%) and FVC (2.63% versus 1.44%) in comparison to low levels (p<0.01 for both).In patients with COPD, high levels of GDF15 were independently associated with a higher yearly rate of exacerbations, higher mortality and increased decline in both FEV₁ and FVC.