Body mass index and its association with clinical outcomes in acute liver failure

Table 1 Baseline demographic and clinical characteristics of patients with acute liver failure by outcome, n (%)

Baseline characteristics	Overall (n = 196)	Spontaneous and transplant-free survival (n = 94)	Liver transplantation or death (n = 102)	P value
Age (years), median (IQR)	43.5 (30-56.5)	40.5 (30-53)	46.5 (31-59)	0.05
Sex, female	124 (63.3)	62 (66.0)	62 (60.8)	0.45
Ethnicity, non-Hispanic	189 (96.4)	91 (96.8)	98 (96.1)	1.00
Race
White	117 (59.7)	54 (57.4)	63 (61.8)	0.20
African American	59 (30.1)	32 (34)	27 (26.5)
Asian	7 (3.6)	1 (1.1)	6 (5.9)
Type of insurance
Medicaid	4 (2)	4 (4.3)	0 (0)	0.27
Medicare	26 (13.3)	12 (12.8)	14 (13.7)
Private	81 (41.3)	36 (38.3)	45 (44.1)
Uninsured	34 (17.3)	15 (16)	19 (18.6)
Unknown	51 (26)	27 (28.7)	24 (23.5)
Body mass index (kg/m2), mean (SD)	28.19 (7.78)	26.59 (7.53)	29.64 (7.75)	0.008
Charlson comorbidity score
0	32 (16.3)	20 (21.3)	12 (11.8)	0.07
1–3	122 (62.2)	59 (62.8)	63 (61.8)
> 3	42 (21.4)	15 (16)	27 (26.5)
Etiology of acute liver failure
Viral hepatitis	17 (8.7)	9 (9.6)	8 (7.8)	< 0.001
Acetaminophen toxicity	89 (45.4)	53 (56.4)	36 (35.3)
Drug-related hepatitis	21 (10.7)	13 (13.8)	8 (7.8)
Other	69 (35.2)	19 (20.2)	50 (49)
Symptom at the time of admission
Jaundice	55 (28.1)	22 (23.4)	33 (32.4)	0.043
Hepatomegaly	2 (1)	2 (2.1)	0 (0)
Nausea/vomiting	14 (7.1)	8 (8.5)	6 (5.9)
Ascites	7 (3.6)	1 (1.1)	6 (5.9)
Abdominal pain	53 (27)	31 (33)	22 (21.6)
Fever	8 (4.1)	2 (2.1)	6 (5.9)
Diarrhea	3 (1.5)	2 (2.1)	1 (1)
GI bleed	2 (1)	1 (1.1)	1 (1)
None	26 (13.3)	15 (16)	11 (10.8)
Grade of hepatic encephalopathy
I-II	84 (42.9)	59 (62.8)	25 (24.5)	< 0.001
III-IV	112 (57.1)	35 (37.2)	77 (75.5)
Vital signs, median (IQR)
Pulse	96.5 (81-112)	96 (78-110)	98 (84-114)	0.41
Respiratory rate	21 (17-26)	20 (17-24)	21 (16.5-27)	0.32
Mean arterial pressure	82 (70-97)	84.5 (73.5-100)	80 (69-96)	0.14
Temperature	36.9 (36.4-37.4)	36.8 (36.4-37.3)	37 (36.4-37.6)	0.23
CT abdomen
Presence of fatty liver	32 (16.3)	15 (16)	17 (16.7)	0.89
CT/magnetic resonance imaging of the brain
Presence of cerebral/brain edema	84 (42.9)	27 (28.7)	57 (55.9)	< 0.001
Alpha-fetoprotein (ng/mL)	3.75 (2-8.25)	5 (2.3-9)	3 (0.9-6)	0.03
Lactate (mmol/L)	2.8 (1.9-5.4)	2.1 (1.3-3.1)	4.6 (2.4-10.3)	< 0.001
Phosphate (mg/dL)	3.2 (2.3-5.6)	2.7 (2-3.8)	4.2 (2.7-6.5)	< 0.001
Organ support
Vasopressors	21 (17.2)	11 (28.9)	10 (11.9)	0.001
Renal replacement therapy	13 (10.7)	7 (18.4)	6 (7.1)
Mechanical ventilation	32 (16.6)	8 (8.8)	24 (23.5)
Blood products
Platelets	17 (20)	5 (19)	12 (21)	0.14
Fresh frozen plasma	38 (46)	9 (33)	29 (52)
Packed red blood cells	28 (34)	13 (48)	15 (27)
Prognostic scores, median (IQR)
KCC (acetaminophen)	0 (0-2)	0 (0-1)	1.5 (0-2)	< 0.001
KCC (non-acetaminophen)	2 (1-2)	2 (1-2)	2 (1-2)	0.84
MELD	28 (21-36.5)	23.5 (19.00-29)	33.5 (25-39)	< 0.001
MELD-Na	29 (22-37.5)	25 (21.00-30)	33.5 (26-39)	< 0.001
Admission to death, days, median (IQR)	10 (3-241)	20 (2-649)	9.00 (4-34)	0.79

CT: Computed tomography; IQR: Interquartile range; KCC: King's college criteria; MELD: Model for end-stage liver disease.

Table 2 Biochemical comparison between groups stratified by body mass index, n (%)

Baseline characteristics	Overall (n = 196)	Normal weight1 (n = 69)	Overweight1 (n = 62)	Obese1 (n = 65)	P value
Age (years), median (IQR)	44 (29-57)	36 (25-51)	45 (37-60)	48 (33-57)	0.006
Sex, female	124 (63.3)	49 (71)	36 (58.1)	39 (60)	0.36
Ethnicity	189 (96.4)	70 (100)	50 (88.7)	60 (92.3)	0.004
Non-Hispanic	189 (96.4)	70 (100)	50 (88.7)	60 (92.3)	0.004
Race
White	117 (59.7)	41(59.4)	39 (62.9)	37(59.9)	0.60
African American	59 (30.1)	24 (34.8)	13 (21.1)	22 (33.8)
Asian	7 (3.6)	2 (2.9)	2 (3.2)	3 (4.6)
Etiology of acute liver failure
Viral hepatitis	17 (8.7)	6 (8.7)	5 (8.1)	6 (9.2)	0.85
Acetaminophen toxicity	89 (45.4)	30 (49.3)	26 (45.2)	24 (41.5)
Drug-related hepatitis	21 (10.7)	8 (11.6)	5 (8.1)	8 (12.3)
Other	69 (35.2)	25 (36.2)	19 (31)	25 (38.5)
Charlson comorbidity score
0	32 (16.3)	12 (17.4)	9 (14.5)	11 (16.9)	0.94
1–3	122 (62.2)	47 (68.1)	37 (60.1)	39 (60)
> 3	42 (21.4)	14 (20.3)	13 (21)	15 (23.1)
Grade of hepatic encephalopathy
I-II	84 (42.9)	36 (52.2)	29 (46.8)	19 (29.2)	0.04
III-IV	112 (57.1)	34 (49.3)	33 (51.6)	46 (70.2)
Liver chemistries, median (IQR)
Alanine aminotransferases (IU/L)	1983 (353-4497)	2115 (753-4560)	2571 (809-5691)	703 (108-2920)	0.001
Aspartate aminotransferase (IU/L)	2436 (453-5383)	3100 (1007-6223)	3090 (675-7400)	989 (208-3321)	0.003
Alkaline phosphatase (IU/L)	134 (88-208)	134 (88-204)	148 (97-236)	122 (86-206)	0.45
Total bilirubin (mg/dL)	3.9 (1.6-10.8)	3.5 (1.7-9.9)	4.6 (2.2-8.6)	4.5 (1.2-16.6)	0.81
Albumin (g/dL)	3.1 (2.6-3.7)	3.4 (2.7-4)	3.2 (3-3.7)	2.7 (2.3-3.1)	< 0.001
Total protein (g/dL)	5.5 (4.6-6.2)	5.8 (4.6-6.5)	5.5 (4.9-6.2)	5 (4.2-5.7)	0.007
Ammonia (μmol/L)	64 (45.5-105)	56 (44-98)	62 (51-116)	67.5 (45-115)	0.41
Coagulation test, median (IQR)
prothrombin time	21.4 (16.1-34.3)	21.4 (15.1-38.1)	20.4 (16.3-27.5)	21.4 (16.8-31.5)	0.78
Activated partial thromboplastin time	34.8 (29.2-45.2)	34.5 (28.1-45.4)	34.1 (28.7-41.9)	35.3 (29.8-47.7)	0.76
International normalized ratio	2.2 (1.7-3.6)	2.20 (1.70-3.82)	2.4 (1.7-3.2)	2.1 (1.7-3.2)	0.90
Renal function tests, median (IQR)
Creatinine (mg/dL)	1.6 (0.9-3.1)	1.1 (0.6-1.8)	1.7 (1-3.1)	2.1 (1-3.31)	0.005
Blood urea nitrogen (mg/dL)	19 (9-39)	15 (8-39)	21 (11-34)	24 (10-43)	0.19
Estimated glomerular filtration rate (mL/minute/1.73 m2)	49 (21-60)	60 (38-60)	46 (22-60)	30 (18-60)	0.004
Fasting glucose (mg/dL)	108 (88-150)	109 (93-150)	105 (89-134)	108 (88-153)	0.71
Alpha-fetoprotein (ng/mL)	3.2 (2-8)	3.5 (0.9-9)	3.6 (2-7)	3.2 (2-7.3)	0.97
Lactate (mmol/L)	2.8 (1.9-5.4)	2.8 (1.6-5.3)	2.8 (2.2-8)	2.75 (1.8-4.8)	0.41
CT abdomen
Presence of fatty liver	32 (16.3)	10 (14.5)	12 (19.2)	10 (15.3)	0.84
CT/magnetic resonance imaging brain
Presence of cerebral/brain edema	84 (42.9)	24 (34.8)	25 (40.2)	35 (53.8)	0.11
Organ support
Vasopressors	21 (17.2)	8 (25)	4 (12.5)	9 (18.4)	0.02
Renal replacement therapy	13 (10.7)	3 (9.4)	5 (15.6)	5 (10.2)
Mechanical ventilation	32 (16.6)	10 (31.3)	5 (15.6)	5 (15.6)
Prognostic scores
KCC (Acetaminophen)	1 (0-2)	0.5 (0-1.5)	0 (0-2)	1 (0-2)	0.55
KCC (non-acetaminophen)	2 (1-2)	1 (1-2)	1 (1-2)	2 (1-2)	0.11
MELD	28 (21-36)	25 (21-34)	26 (22-36)	30 (23-38)	0.15
MELD-Na	29 (22-37)	27 (22-34)	28 (24-36)	31 (23-38)	0.22
Overall survival
< 21 days	69 (35.2)	13 (20)	24 (45.3)	27 (44.3)	0.004
Outcome
Spontaneous survival	94 (48)	39 (56.5)	26 (41.9)	29 (44.6)	0.004
Liver transplantation or death	102 (52)	29 (42)	34 (54.8)	39 (60)
Length of hospital stay (days), median (IQR)	7 (4-19)	8 (4-19)	5 (3-13)	9 (4-23)	0.08

¹Based on the World Health Organization criteria used for body mass index (BMI) categories: (1) Normal weight: BMI between 18.5 kg/m² and 24.9 kg/m²; (2) Overweight: BMI between 25.0 kg/m² and 29.9 kg/m²; and (3) Obese: BMI ≥ 30 kg/m².

CT: Computed tomography; IQR: Interquartile range; KCC: King's college criteria; MELD: Model for end-stage liver disease.

Table 3 Adjusted Cox proportional hazards model to predict the relationship of body mass index to outcome in acute liver failure

Parameters	Hazard ratio1	95%CI	P value
Age	1.01	0.99-1.02	0.83
Sex
Male	Reference
Female	0.84	0.55-1.31	0.44
Ethnicity
Hispanic	Reference
Not Hispanic	1.79	0.62-5.23	0.28
Race
White	Reference
African American	0.73	0.43-1.24	0.24
Other	1.26	0.47-3.38	0.64
Unknown	0.47	0.17-1.32	0.15
Body mass index categories2
Normal weight	Reference
Overweight	2.20	1.23-3.92	0.007
Obese	2.00	1.15-3.38	0.001
Etiology of acute liver failure
Viral hepatitis	Reference
Acetaminophen toxicity	1.34	0.52-3.57	0.56
Drug-related hepatitis	0.92	0.26-3.24	0.90
Other	2.98	1.15-7.73	0.02

¹Age, gender, ethnicity, race, body mass index, etiology of acute liver failure, underlying comorbidities, lactate, phosphate, alpha-fetoprotein, model for end-stage liver disease, and grades of hepatic encephalopathy, use of renal replacement therapy and vasopressors were adjusted as confounders in the Multivariable Cox proportional hazards model.

²Based on the World Health Organization criteria used for body mass index (BMI) categories: (1) Normal weight: BMI between 18.5 kg/m² and 24.9 kg/m²; (2) Overweight: BMI between 25.0 kg/m² and 29.9 kg/m²; and (3) Obese: BMI ≥ 30 kg/m².