Table 2.

Assignment methods for independent variables.

Variables	Value assignment approach
Age	50∼70 = 1 71∼80 = 2 >80 = 3
Medical insurance statue	urban employees = 1 urban residents = 2
Fontaine stage	Ⅱa stage = 1 Ⅱb stage = 2 Ⅲ stage = 3 Ⅳ stage = 4
Number of comorbidities	0 = 1 1∼3 = 2 >3 = 3
ADL	Self-care = 1 Mild = 2 Moderate = 3 Severe = 4
Social support	Low level = 1 Moderate level = 2 High level = 3
HGB	Plugging in the original values