Table 2 Univariable and multivariable analysis of postoperative SIRS

Age

0.991 (0.977, 1.005)

0.213

Sex

0.698 (0.471, 1.036)

0.073

Body mass index

0.994 (0.968, 1.022)

0.676

Diabetes

1,217 (0.719, 2.062)

0.464

Other chronic diseases

 No

Ref

 Yes

0.879 (0.493, 1.565)

0.660

Preoperative infection history

2.365 (1.597, 3.503)

< 0.001

0.867 (0.513, 1.465)

0.593

Positive preoperative urine culture

3.018 (1.844, 4.940)

< 0.001

2.224 (1.172, 4.220)

0.014

History of operation on affected side stones

1.478 (1.001, 2.183)

0.049

0.905 (0.607, 1.351)

0.627

Staghorn calculi

2.991 (1.934, 4.626)

< 0.001

1.624 (0.987, 2.696)

0.061

Stone long diameter

1.184 (1.033, 1.357)

0.015

0.914 (0.758, 1.101)

0.343

Stone location

 Limited to the kidney

0.595 (0.410, 0.863)

0.006

1.287 (0.845, 1.960)

0.240

 Involving the ureter

Ref

Ref

Bilateral stones

 No

Ref

 Yes

0.995 (0.694, 1.427)

0.979

Degree of hydronephrosis

 Severe

0.909 (0.607, 1.362)

0.645

 Non-severe

Ref

Anatomical abnormality

1.267 (0.797, 2.013)

0.371

Solitary kidney

0.411 (0.052, 3.268)

0.385

Operative methods

 Percutaneous nephrolithotomy

1.174 (1.073,3.490)

0.001

2.590(1.152,5.820)

0.021

 Flexible ureteroscopy

1.097 (0.988,1.219)

0.083

1.893(0.799,4.485)

0.147

 Ureteroscopy

Ref

Simultaneous bilateral surgery, n (%)

 No

Ref

 Yes

0.834 (0.314, 2.264)

0.735

Operation time

1.009 (1.003, 1.014)

0.020

1.006 (1.000, 1.012)

0.065

Percutaneous nephroscope channel

1.079 (1.015, 1.147)

0.015