Prevalence and influencing factors of pulmonary nodules in hospitalized patients with diabetes.

Background: Pulmonary nodules are an early manifestation of many lung cancers, and patients with diabetes are at high risk for lung cancer. However, there is a lack of epidemiological data on pulmonary nodules in patients with diabetes. This study investigated the prevalence rate of pulmonary nodules in hospitalized patients with diabetes and analyzed its influencing factors, with the aim of generating data to inform the management of pulmonary nodules in patients with diabetes.

Methods: This retrospective study included 1,864 patients with diabetes admitted to the Department of Endocrinology and Metabolism in the North District of Suzhou City Hospital from January 2020 to November 2022. According to the chest computed tomography (CT) examination, the patients were divided into two groups: a no pulmonary nodules group and a pulmonary nodules group. The prevalence rate of pulmonary nodules was calculated, and the number, size, nature, and other imaging characteristics of pulmonary nodules were compared. The pulmonary nodule group was divided into three subgroups according to the following nodule diameters: <5, ≥5 and <10, and ≥10 and ≤30 mm. The clinical data, blood biochemistry, insulin resistance index, and serum tumor marker levels were recorded. A multinomial logistic regression model was used to analyze the influencing factors of pulmonary nodule in diabetic patients.

Results: Among the 1,864 hospitalized patients with diabetes, 1,407 were found to have pulmonary nodules, representing a total prevalence rate of 75.48%. Compared with the pulmonary nodules subgroups, the no pulmonary nodules group had a higher proportion of males, a lower smoking rate, and higher incidence of proteinuria (all P values <0.05). Compared with the group with a nodule diameter ≥5 and <10 mm and that with a nodule diameter ≥10 and ≤30 mm, the no pulmonary nodules group had a lower age, insulin use rate, and homocysteine (Hcy) levels but higher fasting and 2-hour postprandial C-peptide level, low-density lipoprotein cholesterol (LDL-C) level and insulin resistance index [Homeostatic Model Assessment for Insulin Resistance 2 (HOMA2IR)] (all P values <0.05). The usage rate of dipeptidyl peptidase 4 (DPP4) inhibitor in the no pulmonary nodules group was lower than that in the subgroup with a nodule diameter ≥5 and <10 mm (P<0.05). Multinomial logistic regression analysis showed that age, smoking, and use of DPP4 inhibitors were independent risk factors for pulmonary nodules. DPP4 inhibitors increased the risk of nodules ≥5 and <10 mm in size, while older age and smoking increased the risk of nodules ≥5 mm in size (all P values <0.05).

Conclusions: The prevalence of pulmonary nodules in hospitalized patients with diabetes is up to 75.48%. Older age, smoking, and use of DPP4 inhibitors were found to be independent risk factors for pulmonary nodule development in diabetic patients.