Risk Factors for Systemic Inflammatory Response Syndrome Induced by Flexible Ureteroscope Combined with Holmium Laser Lithotripsy

Table 1

Clinical characteristics of study population.

Variables	Mean (SD) or (%)
Patients ()	216
Age (years)
BMI (kg/m^2)
Stone size (cm)
Surgery time (min)
Gender ()
Male	104 (48.1)
Female	112 (51.9)
Hydronephrosis	87 (40.3)

BMI = body mass index; SD = standard deviation; stone size = the diameter of stone based on preoperative CT scanning.