Impact of surgical volume on nationwide hospital mortality after pancreaticoduodenectomy

Table 1 Patient and hospital characteristics by surgical volume

Characteristics	Very-low (n = 92)	Low (n = 20)	Medium (n = 10)	High (n = 3)	Very-high (n = 1)	P value
Age (mean ± SD) (yr)	62.2 ± 10.7	62.1 ± 10.2	62.1 ± 10.5	61.2 ± 9.9	59.9 ± 10.3	0.077
Sex ratio (M:F)	1.5	1.3	1.5	1.6	1.6	0.282
Admission route						< 0.001
Outpatient department (%)	803 (78.6)	774 (77.0)	788 (77.3)	901 (84.4)	593 (68.9)
Emergency room (%)	218 (21.4)	231 (23.0)	232 (22.7)	167 (15.6)	268 (31.1)
Charlson comorbidity score						0.193
< 3 (%)	683 (66.9)	651 (64.8)	680 (66.7)	667 (62.5)	554 (64.3)
≥ 3 (%)	338 (33.1)	354 (35.2)	340 (33.3)	401 (37.5)	307 (35.7)
Type of medical security						< 0.001
Health insurance (%)	919 (90.0)	925 (92.0)	955 (93.6)	1048 (98.1)	841 (97.7)
Medical aid (%)	102 (10.0)	80 (8.0)	65 (6.4)	20 (1.9)	20 (2.3)
Type of operation						< 0.001
CPD (%)	604 (59.2)	420 (41.8)	361 (35.4)	325 (30.4)	301 (35.0)
PPPD (%)	417 (40.8)	585 (58.2)	659 (64.6)	743 (69.6)	560 (65.0)
Average annual volume	< 10	10-18	19-35	54-111	215	9.91

¹Denotes average annual surgical volume of all hospitals. SD: Standard deviation; M: Male; F: Female; CPD: Classical pancreaticoduodenectomy; PPPD: Pylorus-preserving pancreaticoduodenectomy.

Table 2 Observed hospital mortality by patient characteristics

Characteristics	No. of patients	Mortality (%)	P value
Age			< 0.001
Live (%)	4869 (97.9)	61.4 (10.4)1
Dead (%)	106 (2.1%)	66.0 (8.6)1
Sex			0.193
Male (%)	2 989 (60.1)	1.9
Female (%)	1 986 (39.9)	2.5
Admission route			0.291
Outpatient department (%)	3 859 (77.6)	2.3
Emergency room (%)	1 116 (22.4)	1.7
Charlson comorbidity score			0.291
< 3 (%)	3 235 (65.0)	2.0
≥ 3 (%)	1 740 (35.0)	2.4
Type of medical security			0.015
Health insurance (%)	4 688 (94.2)	2.0
Medical aid (%)	287 (5.8)	4.9
Operation type			< 0.001
CPD (%)	2 011 (40.4)	3.0
PPPD (%)	2 964 (59.6)	1.5

¹Indicates average age (standard deviation) of survival group and mortality group. No: Number; CPD: Classical pancreaticoduodenectomy; PPPD: Pylorus-preserving pancreaticoduodenectomy.

Table 3 Logistic regression for hospital mortality

Characteristics	Odds ratio (95% CI)	P value
Surgical volume
Very-low	1.00
Low	0.59 (0.36-0.98)	0.042
Medium	0.61 (0.37-1.01)	0.056
High	0.13 (0.05-0.32)	< 0.001
Very-high	0.16 (0.06-0.41)	< 0.001
Age1	1.04 (1.02-1.06)	< 0.001
Sex		0.329
Male	1.00
Female	1.22 (0.82-1.80)
Type of medical security		0.120
Health insurance	1.00
Medical aid	1.60 (0.89-2.88)
Operation type		0.025
CPD	1.00
PPPD	0.64 (0.43-0.96)

¹Per year increase in age. CI: Confidence Interval; CPD: Classical pancreaticoduodenectomy; PPPD: Pylorus-preserving pancreaticoduodenectomy.