Serum cholesterol levels predict the survival in patients with idiopathic pulmonary fibrosis: A long-term follow up study

Background: The relationship between serum lipid with idiopathic pulmonary fibrosis (IPF) required to be explored. We aim to evaluate the association of serum lipid levels with mortality in patients with IPF.

Materials and methods: This retrospective study included IPF patients with more than three years follow-up. We collected baseline demographics information, forced vital capacity (FVC)% predicted, carbon monoxide diffusion capacity (DLCO)% predicted, gender-age-physiology (GAP) index, and serum lipid levels, including Triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C). We evaluate the relationship between the serum lipid levels and the disease severity, and the mortality in IPF.

Results: This study enrolled 146 patients, with the three-year survival rate of 71.23%. The median follow-up time was 46.5 months. There was no significant difference in baseline lipid levels between the survival and non-survival group. TG levels were positively correlated with DLCO% predicted (r = 0.189, p = 0.022) and negatively correlated with GAP index (r=-0.186, p=0.025). After adjusting for GAP index, smoking history, body mass index and the use of antifibrotic and lipid-lowering drug, lower TC levels (HR: 0.74, 95% CI: 0.58-0.94, p=0.013) were identified as an independent risk factor for mortality.

Conclusion: This study demonstrated that lower TC levels were associated with increased mortality in IPF. More investigations are required to explore the role of lipid metabolism in the pathogenesis of pulmonary fibrosis.