Fibrinogen-to-Albumin Ratio and Long-Term Mortality in Coronary Artery Disease Patients with Different Glucose Metabolism Status

Background: Abnormal glucose metabolism is present in most patients with coronary artery disease (CAD). Inflammation is considered to be a common risk factor for CAD and diabetes. Fibrinogen-to-albumin ratio (FAR), a novel inflammation biomarker, has been proposed as a predictor for cardiovascular disease. However, the relationship between the level of FAR and long-term mortality including all-cause, cardiovascular and cancer mortality, remains unknown in CAD patients, especially those with prediabetes. Methods: We enrolled 66,761 CAD patients from 2007 to 2020 from a multi-center registry cohort study. The primary outcomes were the all-cause, cardiovascular and cancer mortality. FAR was calculated using the following formula: Fibrinogen (g/L)/Albumin (g/L). Patients were divided into three groups by FAR tertile (low FAR (FAR-L), median FAR (FAR-M), high FAR (FAR-H)), and further categorized into 9 groups according to FAR and glucose metabolism status (normal glucose regulation (NGR), prediabetes mellitus (PreDM), diabetes mellitus (DM)). Cox regression models and competing risk models were used to examine the relationships between FAR and clinical outcomes. Results: 66,761 patients (63.1 ± 11.0 years, 75.3% male) were enrolled. During the follow-up, 10,534 patients died, including 4991 cardiovascular deaths and 1092 cancer deaths. After adjusting for confounders, higher FAR was associated with increased risk of all-cause and cause-specific mortality in CAD patients with NGR, PreDM and DM. The risk of all-cause and cardiovascular mortality was highest in FAR-H with DM (HR (95% CI) = 1.71 (1.58–1.86), 2.11 (1.86–2.38), respectively; p < 0.001). FAR-H with PreDM was significantly associated with the highest risk of cancer mortality (HR (95% CI) = 2.27 (1.70–3.02), p < 0.001). Adding FAR to the original model significantly improved the prediction of long-term mortality. Conclusions: Increased FAR was significantly associated with higher risk of all-cause and cause-specific mortality in CAD patients with NGR, PreDM and DM. Abnormal glucose metabolism augments the relationship between FAR and mortality. Clinical Trial Registration: ClinicalTrials.gov NCT05050877.