Determinants of Increased Fibrinogen in COVID-19 Patients with and Without Diabetes and Impaired Fasting Glucose

Background: To investigate the factors associated with elevated fibrinogen (Fbg) levels in COVID-19 patients with and without diabetes (DM) and impaired fasting glucose (IFG). Methods: According to whether or not their glucose metabolism was impaired, COVID-19 patients were subdivided into 2 groups: 1) with DM and IFG, 2) control group. Their demographic data, medical history, signs and symptoms, laboratory results, and final clinical results were analyzed retrospectively. Results: 28 patients (16.3%) died during hospitalization, including 21 (29.2%) in group 1 and 7 (7.0%) in group 2 (P < 0.001). Fbg levels in groups 1 and 2 were higher than the normal range, at 5.6 g/L (IQR 4.5–7.2 g/L) and 5.0 g/L (IQR 4.0–6.1 g/L), respectively (P = 0.009). Serum ferritin levels, C-reactive protein (CRP), interleukin-6 (IL-6), IL-8, tumor necrosis factor-α (TNF-α), triglycerides (TG) were significantly increased in group 1 compared to those in the control. TG levels were 1.3 mmol/L in the control, while that in group 1 was 1.8 mmol/L. Multiple linear regression showed that the predicting factors of Fbg in the control group were serum ferritin and CRP, R2 = 0.295; in group 1, serum ferritin, CRP, and TG, R2 = 0.473. Conclusions: Fbg in all COVID-19 patients is related to serum ferritin and CRP involved in inflammation. Furthermore, in COVID-19 patients with insulin resistance, Fbg is linearly positively correlated with TG. This suggests that regulation of TG, insulin resistance, and inflammation may reduce hypercoagulability in COVID-19 patients, especially those with insulin resistance.