Table 2.

Description of core explanatory variable and control variables

Variable Type	Variable	Definition
Core explanatory variable (X)	Annual outpatient reimbursement ratio	It is a percentage which is equal to the annual expenditure of the basic medical insurance funds on outpatient services for a diabetes patient divided by his or her annual outpatient expenses
Control variable (Ui)	Age	——
	Nervous system disease	Whether a diabetes patient utilized any medical services because of nervous system disease within one year (Yes = 1, No = 0)
	Musculoskeletal system and connective tissue disease	Whether a diabetes patient utilized any medical services because of musculoskeletal system or connective tissue disease within one year (Yes = 1, No = 0)
	Circulatory system disease	Whether a diabetes patient utilized any medical services because of circulatory system disease within one year (Yes = 1, No = 0)
	Benign tumor	Whether a diabetes patient utilized any medical services because of benign tumor within one year (Yes = 1, No = 0)
	Malignant tumor	Whether a diabetes patient utilized any medical services because of malignant tumor within one year (Yes = 1, No = 0)
	Digestive system disease	Whether a diabetes patient utilized any medical services because of digestive system disease within one year (Yes = 1, No = 0)
	Eye and adnexal disease	Whether a diabetes patient utilized any medical services because of eye or adnexal disease within one year (Yes = 1, No = 0)
	Endocrine, nutritional and metabolic disease	Whether a diabetes patient utilized any medical services because of endocrine, nutritional or metabolic disease within one year (Yes = 1, No = 0)