Then, we analysed the relationship between the FBG and complications in COVID-19 patients. The number of patients who had complications within 28 days in the groups with FBG <6.1 mmol/l, 6.1–6.9 mmol/l and ≥7.0 mmol/l was 86 (14.2%), 48 (7.9%) and 103 (17.0%), respectively. The number of patients without complications within 28 days in the groups with FBG <6.1 mmol/l, 6.1–6.9 mmol/l and ≥7.0 mmol/l was 243 (40.2%), 52 (8.6%), and 73 (12.1%), respectively (Table 1). Compared with patients with admission FBG <6.1 mmol/l, patients with admission FBG ≥7.0 mmol/l (OR 3.99 [95% CI 2.71, 5.88]) and 6.1–6.9 mmol/l (OR 2.61 [95% CI 1.64, 4.41]) had higher levels of in-hospital complications.