Effect of Agkistrodon halys antivenom in patients bit by green pit viper and the prognostic role of the disease – a retrospective cohort study

Figures & data

Figure 1. Flow chart of antivenom use.

Figure 2. Flow chart of patient selection.

Table 1. Baseline characteristics of GPUA and GPNUA.

	Total patients (n = 3456)	GPUA (n = 2031)	GPNUA (n = 1425)	p Value
Age (years)	38.43 ± 0.26	39.07 ± 0.35	37.51 ± 0.41	.004
Sex				.502
Male	2,092 (60.53)	1,239 (61.00)	853 (59.86)	–
Female	1364 (39.47)	792 (39.00)	572 (40.14)	–
Severity of the bite				<.001
Mild	2267 (65.60)	1103 (54.31)	1164 (81.68)	–
Moderate	73 (2.11)	17 (0.84)	56 (3.93)	–
Severe	1116 (32.29)	911 (44.85)	205 (14.39)	–
Pregnant women^a	33 (0.95)	18 (0.89)	15 (1.05)	.723
Geographical location of bite incident				<.001
Indoors	168 (4.86)	58 (2.86)	110 (7.72)	–
Outdoors	3288 (95.14)	1973 (97.14)	1315 (92.28)	–
Anatomical site of bite				<.001
Upper limb	2206 (63.83)	1734 (85.38)	472 (33.12)	–
Lower limb	1250 (36.17)	297 (14.62)	953 (66.88)	–
Underlying comorbidities
Respiratory disease	340 (9.84)	241 (11.87)	99 (6.95)	<.001
Cardiovascular disease	392 (11.34)	264 (13.00)	128 (8.98)	<.001
Kidney disease	328 (9.49)	186 (9.16)	142 (9.96)	.444
Liver disease	529 (15.31)	391 (19.25)	138 (9.68)	<.001
Hematological disease	155 (4.48)	86 (4.23)	69 (4.84)	.405
Endocrine and metabolic disease	485 (14.03)	349 (17.18)	136 (9.54)	<.001
Immunodeficiency or immunosuppressive disease	110 (3.18)	50 (2.46)	60 (4.21)	.006
Bite-to-hospital time (hours)	4.63 ± 0.13	4.37 ± 0.18	5.01 ± 0.18	.016
First coagulation profile	–	–	–	.299
Level 1	230 (6.66)	82 (4.04)	148 (10.39)	.589
Level 2	1071 (30.99)	628 (30.92)	362 (25.40)	.598
Level 3	1311 (37.93)	890 (43.82)	502 (35.23)	.592
Level 4	617 (17.85)	307 (15.12)	310 (21.75)	.748
Level 5	227 (6.57)	124 (6.11)	103 (7.23)	.703
Skin condition prior to treatment	–	–	–	.420
Level 1	14 (0.41)	2 (0.10)	12 (0.84)	.350
Level 2	1175 (34.00)	685 (33.73)	444 (31.16)	.632
Level 3	1631 (47.19)	950 (46.77)	681 (47.79)	.661
Level 4	427 (12.36)	262 (12.90)	211 (14.81)	.694
Level 5	209 (6.05)	132 (6.50)	77 (5.40)	.604
Positive antivenom skin test	–	381 (18.76)	–	–

GPUA: the group of patients who used antivenom; GPNUA: the group of patients who did not use antivenom.

^aComparison among women only.

Table 2. Primary and secondary outcomes of GPUA and GPNUA.

	Total patients (n = 3456)	GPUA (n = 2031)	GPNUA (n = 1425)	p Value
Normalization time of coagulation parameters (days)	6.03 ± 0.05	5.95 ± 0.07	6.15 ± 0.09	.066
Level 1	1076 (31.13)	598 (29.44)	478 (33.54)	.874
Level 2	1091 (31.57)	802 (39.49)	289 (20.28)	.452
Level 3	681 (19.70)	259 (12.75)	422 (29.61)	.728
Level 4	608 (17.59)	372 (18.32)	236 (16.56)	.746
Fresh frozen plasma dosage (mL)	78.76 ± 3.13	79.76 ± 4.30	77.33 ± 4.51	.703
Cryoprecipitate dosage (U)	0.76 ± 0.03	0.70 ± 0.04	0.84 ± 0.05	.027
Platelet dosage (10 U)	0.12 ± 0.01	0.05 ± 0.01	0.22 ± 0.02	<.001
Red cell suspension dosage (U)	0.01 ± 0.002	0.01 ± 0.003	0.01 ± 0.004	.860
Length of hospital stay (days)^a	6.19 ± 0.09	6.22 ± 0.10	6.05 ± 0.24	.494
Treatment cost (in Chinese RMB Yuan; US$1≈CN¥6.4)	2711.58 ± 73.05	3740.45 ± 105.70	1245.17 ± 78.32	<.001

GPUA: the group of patients who used antivenom; GPNUA: the group of patients who did not use antivenom.

^aComparison among inpatients only.

Table 3. Comparison of the risks of GPUA and GPNUA by multinomial and ordinal logistic regression analysis.

	GPUA	GPNUA	Crude OR (95% CI)	p Value	Adjusted OR (95% CI)	p Value
Overall analysis	2031 (100)	1425 (100)	–	–	–	–
Non-use of antivenom	–	–	1	–	1	–
Use of antivenom	–	–	0.86 (0.76–0.97)	.018	1.15 (0.99–1.34)	.077
Stratified analysis of first coagulation profile	–	–	–	–	–	–
Level 1	82 (4.04)	148 (10.39)	4.01 (2.33–6.90)	<.001	2.75 (1.44–5.24)	.002
Level 2	628 (30.92)	362 (25.40)	1.79 (1.41–2.27)	<.001	2.46 (1.85–3.27)	<.001
Level 3	890 (43.82)	502 (35.23)	0.73 (0.60–0.89)	.002	0.81 (0.60–1.09)	.172
Level 4	307 (15.12)	310 (21.75)	0.30 (0.22–0.40)	<.001	0.40 (0.24–0.67)	<.001
Level 5	124 (6.11)	103 (7.23)	0.36 (0.22–0.59)	<.001	1.54 (0.58–4.07)	.381

GPUA: the group of patients who used antivenom; GPNUA: the group of patients who did not use antivenom; OR: odds ratios; CI: confidence intervals.

Table 4. Independent risk factors in all patients bit by green pit vipers by multinomial and ordinal logistic regression analysis.

	Recovery time of coagulation parameters
	Crude OR (95% CI)	p Value	Adjusted OR (95% CI)	p Value
Usage of antivenom
Non-use	1	–	1	–
Use	0.86 (0.76–0.97)	.018	1.15 (0.99–1.34)	.077
Age (years)	0.99 (0.99–1.01)	.825	0.99 (0.99–1.01)	.656
Sex
Female	1	–	1	–
Male	0.90 (0.80–1.02)	.109	0.89 (0.78–1.01)	.058
Severity of the bite
Mild	1	–	1	–
Moderate	0.95 (0.65–1.38)	.783	1.11 (0.75–1.64)	.609
Severe	0.44 (0.39–0.51)	<.001	0.37 (0.32–0.44)	<.001
Anatomical site of snakebite
Lower limb	1	–	1	–
Upper limb	0.80 (0.71–0.91)	<.001	1.06 (0.91–1.23)	.453
Respiratory disease	0.89 (0.73–1.08)	.227	0.99 (0.80–1.23)	.971
Cardiovascular disease	0.94 (0.78–1.14)	.552	0.98 (0.80–1.20)	.845
Kidney disease	0.94 (0.77–1.15)	.558	1.02 (0.82–1.26)	.890
Liver disease	0.92 (0.78–1.09)	.317	0.91 (0.76–1.09)	.303
Hematological disease	0.79 (0.59–1.05)	.105	0.83 (0.61–1.11)	.217
Endocrine and Metabolic disease	0.93 (0.79–1.11)	.434	1.01 (0.84–1.22)	.901
Immunodeficiency or immunosuppressive disease	0.85 (0.60–1.20)	.350	0.83 (0.58–1.21)	.341
Bite-to-hospital time (hours)	0.99 (0.99–1.01)	0.494	0.99 (0.99–1.01)	.572
First coagulation profile
Level 1	1	–	1	–
Level 2	1.97 (1.52–2.56)	<.001	1.73 (1.31–2.29)	<.001
Level 3	3.75 (2.89–4.85)	<.001	3.25 (2.46–4.29)	<.001
Level 4	2.99 (2.26–3.96)	<.001	3.07 (2.27–4.16)	<.001
Level 5	3.05 (2.17–4.29)	<.001	4.32 (2.88–6.47)	<.001
Skin condition prior to treatment
Level 1	1	–	1	–
Level 2	2.05 (0.79–5.32)	.141	1.35 (0.51–3.57)	.540
Level 3	3.57 (1.38–9.27)	.009	2.23 (0.84–5.89)	.105
Level 4	2.83 (1.08–7.43)	.034	1.49 (0.55–3.98)	.432
Level 5	3.53 (1.33–9.41)	.012	1.78 (0.65–4.87)	.259
Fresh frozen plasma dosage (mL)	1.01 (1.01–1.02)	.043	1.01 (1.01–1.02)	<.001
Cryoprecipitate dosage (U)	0.99 (0.97–1.03)	.981	1.01 (0.97–1.04)	.703
Platelet dosage (10 U)	1.33 (1.16–1.53)	<.001	1.24 (1.08–1.42)	.003
Red cell suspension dosage (U)	1.61 (1.07–2.42)	.021	1.59 (1.06–2.37)	.024

GPUA: the group of patients who used antivenom; GPNUA: the group of patients who did not use antivenom; OR: odds ratios; CI: confidence intervals.