Does delaying ureteral stent placement lead to higher rates of preoperative acute pyelonephritis during pregnancy?

Table 1 Patient characteristics associated with early and delayed time to ureteral stent placement

Demographic data/clinical parameters	Total (n = 100)	Early TTU (n = 42)	Delayed TTU (n = 58)	P value
Age (yr), mean ± SD	30 ± 4.55	31 ± 4.87	29 ± 4.19	0.06
BMI (kg/cm2), mean ± SD	23.05 ± 3.06	23.38 ±3.28	22.81 ± 2.89	0.36
Gestation (wk), mean ± SD	22 (18, 27)	22 ± 7.83	22 ± 5.02	0.99
History of stones, n (%)	26 (76)	14 (53.8)	12 (46.2)	0.16
WBC count (× 109/L), mean ± SD	13.48 ± 3.49	14.19 ± 4.12	12.97 ± 2.87	0.10
CRP (mg/dL), median (Q1, Q3)	2.64 (1.04, 4.35)	4.25 (1.9, 5.89)	1.77 (0.98, 4.0)	0.12
Stone size (mm), median (Q1, Q3)	8.25 (4.28, 14)	9.98 (4.5, 12)	9.07 (0, 15)	0.59
< 10 mm, n (%)	55 (55)	21 (38.2)	34 (61.8)	0.39
≥ 10 mm, n (%)	45 (45)	21 (46.7)	24 (53.3)
Hydronephrosis (mm), median (Q1, Q3)	26.5 (15, 62)	47 (15, 80)	34 (15, 42)	0.30
None/light, n (%)	62 (62)	21 (40.4)	31 (59.6)	0.73
Moderate/severe, n (%)	38 (38)	21 (43.8)	27 (56.3)
Stone location, n (%)				0.09
None	24 (24)	11 (45.8)	13 (54.2)
Ureter	48 (48)	24 (50)	24 (50)
Kidney	28 (28)	7 (25)	21 (75)
Urology consultation time (h), median (Q1, Q3)	27 (19, 52)	19 (13, 23)	48 (24, 90)	0.001
≤ 24 h, n (%)	53 (53)	34 (64.2)	19 (35.8)	0.00
> 24 h, n (%)	47 (47)	8 (17)	39 (83)
Preoperative fetal complications, n (%)	12 (12)	6 (50)	6 (50)	0.55
PANP, n (%)	32 (32)	15 (46.9)	17 (53.1)	0.50
UTI after surgery, n (%)	22 (22)	11 (50)	11 (50)	0.39
LOS (d), mean ± SD	7 ± 3.56	6 ± 3.03	8 ± 3.60	0.001
Total cost (Yuan in RMB), mean ± SD	12382.79 ± 5665.26	10448.95 ± 2412.28	13783.16 ± 6841.61	0.001
Newborn weight (g), mean ± SD	2893.30 ± 542.10	2891.67 ± 509.18	2894.48 ± 569.15	0.98
Cesarean section rate, n (%)	38 (38)	17 (44.7)	21 (55.3)	0.66
Preterm delivery, n (%)	8 (8)	6 (75)	2 (25)	0.07

TTU: Time to ureteral stent placement; PANP: Preoperation acute pyelonephritis; UTI: Urinary tract infection; LOS: Length of stay.

Table 2 Associations between preoperative characteristics and preoperative acute pyelonephritis

Demographic data/clinical parameters	PANP (n = 32)	No-PANP (n = 68 )	P value
Age (yr), mean ± SD	29 ± 5.01	30 ± 4.04	0.53
BMI (kg/cm2), mean ± SD	21.66 ± 2.44	23.30 ± 2.97	0.007
Gestation (wk), median (Q1, Q3)	20 (19, 25)	23 (20, 28)	0.04
History of stones, n (%)	12 (46.2)	14 (53.8)	0.07
Pain to surgery (h), median (Q1, Q3)	114.5 (70, 140)	84.5 (61, 120)	0.00
< 96 h, n (%)	9 (17.6)	42 (82.4)	0.002
≥ 96 h, n (%)	23 (46.9)	26 (53.1)
Admission to surgery (h), median (Q1, Q3)	53 (24, 160)	50 (36, 90)	0.81
< 48 h, n (%)	15 (35.7)	27 (64.3)	0.81
≥ 48 h, n (%)	17 (29.3)	41 (70.7)
Pain to admission (h), median (Q1, Q3)	90 (50, 120)	24 (12, 48)	0.00
< 48 h, n (%)	3 (6.1)	46 (93.6)	0.00
≥ 48 h, n (%)	29 (56.9)	22 (43.1)
WBC count (× 109/L), mean ± SD	14.59 ± 4.40	12.96 ± 2.84	0.06
CRP (mg/dL), median (Q1, Q3)	3.20 (1.47, 6.32)	2.23 (0.97, 3.86)	0.01
Stone location, n (%)			0.00
None	6 (25)	18 (75)
Ureter	8 (16.7)	40 (83.3)
Kidney	18 (64.3)	10 (35.7)
Stone size (mm), median (Q1, Q3)	8.25 (4.5, 17)	8 (0, 12)	0.25
< 10 mm, n (%)	18 (32.7)	37 (67.3)	0.86
≥ 10 mm, n (%)	14 (31.1)	31 (68.9)
Hydronephrosis (mm), median (Q1, Q3)	31 (20, 60)	19.5 (14, 62)	0.05
None/light, n (%)	12 (23.1)	40 (76.9)	0.05
Moderate/severe, n (%)	20 (41.7)	28 (58.3)
Urology consultation time (h), median (Q1, Q3)	23 (13, 68)	34 (20, 53)	0.23
≤ 24 h, n (%)	16 (30.2)	37 (69.8)	0.68
> 24 h, n (%)	16 (34)	31 (66)
Total cost (Yuan in RMB), mean ± SD	16522.59 ± 8871.61	10236.07 ± 3281.16	0.001
Preoperative fetal complications, n (%)	6 (50)	6 (50)	0.27
UTI after surgery, n (%)	12 (54.5)	10 (45.5)	0.01
LOS (d), mean ± SD	11 ± 5.34	7 ± 2.98	0.001
Newborn weight (g), mean ± SD	2706.56 ± 649.47	2978.97 ± 460.58	0.02
Cesarean section rate, n (%)	14 (36.8)	24 (63.2)	0.42
Preterm delivery, n (%)	6 (75)	2 (25)	0.02

PANP: Preoperation acute pyelonephritis, UTI: Urinary tract infection, LOS: Length of stay.

Table 3 Multivariate analysis of preoperative acute pyelonephritis

Variable	OR (95%CI)	P value
Pain to admission (h)	22.10 (5.31-91.91)	0.000
Stone location		0.003
None	1.0
Ureter	6.61 (1.48-29.53)
Kidney	9.91 (2.56-38.42)

Table 4 Comparison of outcomes in time to ureteral stent placement patients before and after surgery

Variable	Before surgery (n = 100)	After surgery (n = 100)	P value
WBC count (× 109/L), mean ± SD	13.48 ± 3.48	9.96 ± 1.95	< 0.01
CRP (mg/dL), median (Q1, Q3)	2.64 (1.04, 4.35)	1.35 (0.54, 2.36)	< 0.01
Hydronephrosis (mm), median (Q1, Q3)	26.50 (15.00, 75.00)	10.50 (0, 18)	< 0.01