Risk-adjustment in hepatobiliarypancreatic surgery

Table 1 Diagnosis.

Organ	Number of patients (% of total)	Number of deaths (% mortality)
Hepatic	89 (50.3)	1 (1.1)
Liver primary	14 (7.9)	0
Colorectal secondaries	47 (26.6)	1 (2.1)
Other secondaries	5 (2.8)	0
Carcinoid tumors	10 (5.6)	0
Benign liver lesions	13 (7.3)	0
Biliary	63 (35.6)	4 (6.3)
Cholangiocarcinoma	24 (13.6)	4 (16.6)
Iatrogenic biliary strictures	24 (13.6)	0
Benign biliary strictures	15 (8.5)	0
Pancreatic	25 (14.1)	2 (8)
Pancreatic malignancy	18 (10.2)	2 (11)
Pancreatitis	7 (3.9)	0
Total	177 (100)	7 (3.95)

Table 2 Type of procedure and in-hospital mortality.

Procedure	Number of patients (% of total)	Number of deaths (% mortality)
Right hepatectomy	29 (16.4)	1 (3.4)
Left hepatectomy	15 (8.5)	0
Extended right hepatectomy	16 (9)	2 (12.5)
Extended left hepatectomy	5 (2.8)	1 (20)
Segmental liver resection	28 (15.8)	0
Hepaticojejunostomy	47 (26.6)	0
Pancreaticoduodenectomy	22 (12.4)	3 (13.6)
Total pancreatectomy	2 (1.1)	0
Distal pancreatectomy	2 (1.1)	0
Others	11 (6.2)	0
Total	177 (100)	7 (3.95)

Table 3 Patient characteristics and associated mortality and morbidity.

Demographics	Number (% of total)
Age (median, range)	54.6 (19, 80)
Female patients	96 (54.2)
Length of stay (median, range)
Hospital	15 (2-113)
ITU	0 (0-20)
HDU	0 (0-10)
Mortality (in-hospital)	7 (3.95)
Morbidity
No morbidity	97 (54.8)
Minor/intermediate	56 (31.6)
Major	24 (13.6)

Table 4 Types of morbidity.

System	Minor/intermediate1	Severe1
Respiratory	25 (14.1)	10 (5.6)
Gastrointestinal	23 (13.0)	12 (6.7)
Hematological	20 (11.3)	6 (3.4)
Wound	15 (8.5)	3 (1.7)
Intra-abdominal sepsis	15 (8.5)	2 (1.1)
Cardiac	9 (5.1)	3 (1.7)
Renal	8 (4.5)	3 (1.7)
Venous	2 (1.1)	2 (1.1)
Others	19 (10.7)	2 (1.1)
Total	56 (31.6)1	24 (13.6)1

¹A given patient may have complications of varying grade in one or more systems.

Table 5 Analysis of the separate risk scoring systems by unifactorial ordered logistic regression using sampling quartiles for continuous variables.

Risk score/factor	Group	Number of patients(% of total)	Minor/intermediate complications (%)	Major complications/death (%)	Unadjusted odds ratio1	95%CI1
POSSUM	12-13	62 (35.0)	13 (21)	7 (11.3)	1
Physiological	14-15	53 (29.9)	20 (37.7)	6 (11.3)	1.8	0.24, 3.77
Score12	16-17	31 (17.5)	13 (41.9)	3 (9.7)	1.9	0.81, 4.41
	18-31	31 (17.5)	10 (32.3)	8 (25.8)	3.12	1.32, 7.38
APACHE II	0-1	30 (16.9)	9 (30)	3 (10)	1
Acute	2-3	66 (37.3)	20 (30.3)	6 (9.1)	0.97	0.41, 2.28
Physiological	4-5	49 (27.7)	14 (28.6)	7 (14.3)	1.18	0.48, 2.89
Score13	6-13	32 (18.1)	13 (40.6)	8 (25)	2.86	1.09, 7.5
ASA	1	47 (26.6)	12 (25.5)	3 (6.4)	1
	2	77 (43.5)	27 (35.1)	8 (10.4)	1.73	0.15, 3.63
	3-4	31 (17.5)	17 (33.3)	12 (23.5)	3.16	1.41, 7.07
	Missing	2 (1.1)
Child-Pugh	A	145 (81.9)	49 (33.8)	16 (11)	1
	B	32 (18.1)	7 (21.9)	8 (25)	1.34	0.64, 2.94
	C	0
INR	<0.9	45 (25.4)	13 (28.9)	4 (8.9)	1
	0.9-1.1	119 (67.2)	36 (30.3)	16 (13.5)	1.32	0.67, 2.63
	>1.1	13 (7.3)	7 (53.9)	4 (30.7)	5.5	1.78, 17.5
Blood loss	<1	90 (50.9)	24 (26.7)	9 (10)	1
	1-2	38 (21.5)	11 (29.0)	2 (5.3)	0.85	0.39, 1.85
-	>2	49 (27.7)	21 (43.0)	13 (26.0)	4.1	1.49, 11.13

¹For illustration purposes all the scores (continuous variables) were grouped into meaningful quartiles. †Odds ratios and 95% confidence intervals (CI) calculated using unifactorial ordered logistic regression analysis.

²Theoretical range of values for the physiological score of POSSUM is 12-96.

³Theoretical range of values for the acute physiological score of APACHE II is 0-44.

Table 6 Multivariate ordered logistic regression analysis of risk factors for HPB surgery.

Factor	Category	Estimate (b)	Adjusted OR	CI 95%
Physiological	10-1 units increase		1.18	1.07, 1.31
score-
POSSUM
INR2	10-2 units increase		1.47	1.12, 1.94
Blood loss	< 2 L		1
	>2 L		4.1	1.49, 11.13
Procedure	Right hepatectomy		1
	Pancreaticoduodenectomy		3.27	1.07, 9.97
Sub-factors of
POSSUM3
Serum sodium1	10-1 units increase		0.89	0.82, 0.97
Serum creatinine	10-1 units increase		1.01	1.00, 1.02
Pulse rate (bpm)	10-1 units increase		1.04	1.01, 1.06

¹OR denotes that patients do worse with every unit decrease in sodium below the lower limit of normal range (130 mmol/L).

²OR denotes that patients do worse with every 0.1 unit increase in INR above 1.1.

³When the physiological score of the POSSUM variables are analyzed separately with multifactorial ordered logistic regression, the significant factors are sodium, creatinine and pulse rate which affect mortality and morbidity.