Table 1.

Variables in the research.

Variables	Variable assignment	Type of variable
Gender	1 = male, 2 = female	Nominal variables
Age	—	Continuous variables
Marital status	1 = unmarried, 2 = married, 3 = other	Nominal variables
Medical payment method	1 = Medical insurance, 2 = full public expense, 3 = full self-pay, 4 = other	Nominal variables
Hospitalization frequency	—	Continuous variables
Number of other diagnoses	—	Continuous variables
Major procedure*	1 = 38.93; 2 = 38.95; 3 = 39.27; 4 = 39.42; 5 = 39.95; 6 = 54.93; 7 = 55.23; 8 = 55.69; 9 = 87.03; 10 = 87.41; 11 = 88.01; 12 = 88.72; 13 = 88.75; 14 = 88.76; 15 = 88.77; 16 = 93.96; 17 = null	Nominal variables
Number of procedures	—	Continuous variables
Length of hospital stay	—	Continuous variables
Hospitalized expense	—	Continuous variables

^*38.93, Venous catheterization; 38.95, venous catheterization for renal dialysis; 39.27, arteriovenostomy for renal dialysis; 39.42, revision of arteriovenous shunt for renal dialysis; 39.95, hemodialysis; 54.93, creation of cutaneoperitoneal fistuna; 55.23, closed (percutaneous) (needle) biopsy of kidney; 55.69, other kidney transplantation; 87.03, computerized axial tomography of head; 87.41, computerized axial tomography of thorax; 88.01, computerized axial tomography of abdomen; 88.72, diagnostic ultrasound of heart; 88.75, diagnostic ultrasound of urinary; 88.76, diagnostic ultrasound of abdomen and retroperitoneum; 88.77, diagnostic ultrasound of peripheral vascular system; 93.96, other oxygen enrichment.