ObjectiveTo investigate the relationship between clinicopathologic characteristics of patients with papillary thyroid carcinoma (PTC) and diabetes mellitus (DM), and to provide basis for individualized diagnosis and treatment.MethodsThe patients who underwent the first thyroid surgery in the Renmin Hospital of Wuhan University from January 1, 2017 to September 15, 2020 and were pathologically diagnosed as PTC were collected. According to the presence or absence of DM, the clinical features were compared.ResultsThere were 2859 patients without DM and 133 patients with DM in 2992 patients. In patients with or without DM, there were no differences in lymph node metastasis, multiple, bilateral tumors, and extrathyroid invasion between the two groups (P>0.05). However, compared with the PTC patients without DM, the proportion of women with DM was lower (58.65% versus 76.71%, P<0.01), the proportions of age >55 years old (92.48% versus 66.32%, P<0.01) and capsule invasion (67.21% versus 63.11%, P=0.04) with DM were higer. After adjusting for age and gender, the multivariate analysis showed that the risks of larger tumor and capsular invasion in the patients with DM was 1.51 times [95%CI (1.06, 2.16), P=0.02] and 1.75 times [95%CI (1.16, 2.64), P<0.01] respectively as compared with in the patients without DM.ConclusionsIn PTC patients with DM, proportion of women is lower, proportions of elderly population (age >55 years old) and patients with capsular invasion are higer, tumor is larger. Therefore, patients with DM must not neglect regular examination of thyroid morphology and function, and PTC patients should also pay attention to control of blood glucose.