Risk of malignant tumors in chinese patients with type 2 diabetes mellitus: A retrospective cohort study based on diabetes management data in Jiaxing city, Zhejiang province / 肿瘤

ABSTRACT

Objective: To estimate the risk of malignant tumors in Chinese patients with type 2 diabetes mellitus (T2DM), and to evaluate the possible impact of using anti-diabetic agent on the risk. Methods: A retrospective cohort study was designed to include registered T2DM patients in the diabetes management system of Nanhu, Xiuzhou and Haining Districts in Jaxing City, Zhejiang Province. A record linkage was conducted for those patients diagnosed from January 1st, 2009 to December 31st, 2016 with the Cancer Registry System and the Vital Statics using ID number to obtain the information on cancer incidence and all-cause deaths up to December 2016. The incidence and the standardized incidence ratio (SIR) of malignant tumors in the patients with T2DM were calculated by gender. COX regression model was applied to estimate hazard ratio (HR) and 95% confidence interval (CI) of using anti-diabetic agents with the risk of cancer. Results: Within 1 year of diabetes diagnosis, a small peak of overall cancer incidence was observed in a total of 52 911 patients with T2DM. After controlling the potential detection bias by excluding events and person-years in the first year of observation, the lower risks of overall cancer (SIR = 0.89, 95% CI 0.83-0.95), esophageal cancer (SIR = 0.56, 95% CI 0.37-0.81), stomach cancer (SIR = 0.60, 95% CI 0.44-0.79) and lung cancer (SIR = 0.73, 95% CI 0.62-0.84) were observed in men as compared with their counterparts in general population, and the higher risks were observed for kidney cancer (SIR = 1.67, 95% CI 1.02-2.57) and pancreas cancer (SIR = 1.36, 95% CI 1.02-1.78). In women, a lower risk of stomach cancer (SIR = 0.56, 95% CI 0.34-0.87) and a higher risk of pancreas cancer (SIR = 1.77, 95% CI 1.34-2.31) were found as compared with general population. The patients using oral anti-diabetic agents only had lower risk of overall cancer, with SIR (95% CI) being 0.78 (0.69-0.89) in men and 0.79 (0.69-0.91) in women. However, no significant association was observed between the use of anti-diabetes agents and the risk of cancer in diabetes patients after adjusting the possible confounding factors with COX risk regression model. Conclusion: The incidences of overall, esophageal, stomach and lung cancers in male patients with T2DM in Jiaxing City are lower than those in general population, while those of kidney and pancreas cancers are higher. The incidence of stomach cancer in fremale patients with T2DM is lower than that in general population, while that of pancreas cancer is higher. Use of anti-diabetic agents, particularly metformin and sulfonylurea may decrease the risk of cancer in the patients with T2DM.