Determinants of Progression and Mortality in Lymphangioleiomyomatosis

Abstract

Background: Lymphangioleiomyomatosis is a progressive diffuse cystic lung disease with approximately 85% survival at 10 years. The determinants of disease progression and mortality after the introduction of sirolimus therapy and vascular endothelial growth factor D (VEGF-D) as a biomarker have not been well defined.

Research question: Which factors, including VEGF-D and sirolimus therapy, influence disease progression and survival prognosis in patients with lymphangioleiomyomatosis?

Study design and methods: The progression dataset and the survival dataset included 282 and 574 patients, respectively, from Peking Union Medical College Hospital, Beijing, China. A mixed-effects model was used to compute the rate of decline in FEV₁, and generalized linear models were used to identify variables affecting FEV₁ decline. A Cox proportional hazards model was used to explore the association between clinical variables and the outcomes of death or lung transplantation in patients with lymphangioleiomyomatosis.

Results: VEGF-D levels and sirolimus treatment were associated with FEV₁ changes and survival prognosis. Compared with patients with VEGF-D of < 800 pg/mL at baseline, patients with VEGF-D of ≥ 800 pg/mL lost FEV₁ faster (SE, -38.86 mL/y; 95% CI, -73.90 to -3.82 mL/y; P = .031). The 8-year cumulative survival rates of patients with VEGF-D of ≥ 2,000 pg/mL and < 2,000 pg/mL were 82.9% and 95.1%, respectively (P = .014). The generalized linear regression model also demonstrated the benefit of delaying the decline of FEV₁ by 65.56 mL/y (95% CI, 29.06-102.06 mL/y) in patients treated with sirolimus compared with those without sirolimus (P < .001). The 8-year risk of death was reduced by 85.1% (hazard ratio, 0.149; 95% CI, 0.075-0.299) after sirolimus treatment. After inverse treatment probability weighting, the risks of death in the sirolimus group were reduced by 85.6%. CT scan results of grade III severity were associated with worse progression than results of grades I or II severity. Patients with baseline FEV₁ of 70% predicted or St. George's Respiratory Questionnaire Symptoms domain 50 or higher predicted a higher risk of worse survival.

Interpretation: Serum VEGF-D levels, a biomarker of lymphangioleiomyomatosis, are associated with disease progression and survival. Sirolimus therapy is associated with slower disease progression and better survival in patients with lymphangioleiomyomatosis.

Trial registry: ClinicalTrials.gov; No.: NCT03193892; URL: www.

Clinicaltrials: gov.

Keywords: FEV(1); VEGF-D; lymphangioleiomyomatosis; mortality; prognosis; sirolimus.