A nomogram based on lymphocyte percentage for predicting hospital mortality in exertional heatstroke patients: a 13-year retrospective study

doi:10.5847/wjem.j.1920-8642.2023.101

Abstract

Abstract:

BACKGROUND: Exertional heatstroke (EHS) is a life-threatening disease without ideal prognostic markers for predicting hospital mortality.

METHODS: This is a single-center retrospective study. Clinical data from EHS patients admitted to the Intensive Care Unit (ICU) of the General Hospital of Southern Theatre Command between January 1, 2008, and December 31, 2020, were recorded and analyzed. Univariate and multivariate logistic regression were used to identify the factors for mortality. The prediction model was developed with the prognostic markers, and a nomogram was established.

RESULTS: The study ultimately enrolled 156 patients, and 15 (9.6%) of patients died before discharge. The lymphocyte count (Lym) and percentage (Lym%) were significantly lower in non-survivors (P<0.05). The univariate and multivariate logistic regression analyses indicated that Lym% at the third day of admission (Lym% D3) (OR=0.609, 95%CI: 0.454-0.816) and hematocrit (HCT) (OR=0.908, 95%CI: 0.834-0.988) were independent protective factors for hospital mortality. A nomogram incorporating Lym% D3 with HCT was developed and demonstrated good discrimination and calibration ability. The comparison between the prediction model and scoring systems revealed that the prediction model had the largest area under the curve (AUC) (0.948, 95%CI: 0.900-0.977), with 100.00% sensitivity and 83.69% specificity, and a greater clinical net benefit.

CONCLUSION: Severe EHS patients had a higher risk of experiencing prolonged lymphopenia. A nomogram based on Lym% D3 and HCT was developed to facilitate early identification and timely treatment of patients with potentially unfavorable prognoses.

Key words: Exertional heatstroke, Lymphopenia, Nomogram, Prognosis

Jiale Yang, Fanghe Gong, Xuezhi Shi, Fanfan Wang, Jing Qian, Lulu Wan, Yi Chen, Huaisheng Chen, Huasheng Tong. A nomogram based on lymphocyte percentage for predicting hospital mortality in exertional heatstroke patients: a 13-year retrospective study[J]. World Journal of Emergency Medicine, 2023, 14(6): 434-441.

Figures/Tables 10

Figure 1.

Table 1.

Baseline characteristics of exertional heatstroke (EHS) patients in survival and non-survival groups

Variables	Total (n=156)	Survivors (n=141)	Non-survivors (n=15)	P-value
Age, years	29 (21-48)	29 (21-47)	28 (21-49)	0.890
Gender				1.000
Male	149 (95.5)	134 (95.0)	15 (100.0)
Female	7 (4.5)	7 (5.0)	0 (0.0)
Onset month				0.557
June	41 (26.3)	38 (27.0)	3( 20.0)
July	38 (24.4)	36 (25.5)	2 (13.3)
August	30 (19.2)	26 (18.4)	4 (26.7)
Other	47 (30.1)	41 (29.1)	6 (40.0)
Admission temperature, ℃	37.2 (36.8-38.0)	37.1 (36.7-38.0)	37.8 (37.0-39.5)	0.015
HR, beats/min	86 (75-114)	84 (74-103)	121 (103-127)	<0.001
MAP, mmHg	87±15	87±14	87±23	0.949
Lym D1, ×10⁹/L	1.27 (0.69-2.11)	1.37 (0.78-2.15)	0.40 (0.23-1.37)	0.002
Lym D3, ×10⁹/L	1.33±0.73	1.44±0.68	0.36±0.27	<0.001
Lym% D1	10.6 (5.0-23.6)	11.4 (5.7-24.0)	4.1 (2.2-16.1)	0.006
Lym% D3	16.4±11.0	17.7±10.7	3.4±2.2	<0.001
Neu D1, ×10⁹/L	8.86 (5.95-12.58)	8.94 (5.97-12.57)	8.59 (5.92-13.08)	0.993
Neu D3, ×10⁹/L	6.68 (4.34-9.37)	6.20 (4.32-8.77)	9.66 (6.88-13.43)	0.002
Neu% D1	83.8 (71.4-88.8)	83.0 (70.6-87.8)	91.3 (77.3-93.6)	0.007
Neu% D3	78.1 (67.0-87.1)	75.7 (65.8-85.4)	94.8 (87.4-96.3)	<0.001
Mono D1, ×10⁹/L	0.49 (0.30-0.78)	0.49 (0.32-0.76)	0.48 (0.24-0.80)	0.395
Mono D3, ×10⁹/L	0.44 (0.35-0.60)	0.46 (0.35-0.61)	0.40 (0.13-0.53)	0.059
Mono% D1	4.6 (3.2-6.3)	4.6 (3.3-6.3)	4.9 (2.0-6.0)	0.672
Mono% D3	5.5 (4.1-6.9)	5.6 (4.2-6.8)	2.1 (0.9-7.6)	0.010
WBC D1, ×10⁹/L	11.25 (8.21-15.35)	11.36 (8.24-15.50)	9.81 (7.60-14.08)	0.482
WBC D3, ×10⁹/L	8.72 (6.52-10.91)	8.60 (6.38-10.73)	10.23 (8.44-13.95)	0.051
Hb, g/L	139±28	142±26	113±36	0.007
HCT, %	41.0±7.8	41.8±7.2	33.7±10.1	0.008
Plt, ×10⁹/L	178 (90-232)	185 (112-235)	65 (33-92)	<0.001
APTT, s	32.9 (25.8-40.4)	32.3 (25.7-39.3)	52.0 (30.7-99.0)	0.013
PT, s	14.7 (12.6-18.4)	14.3 (12.5-17.6)	22.9 (15.2-38.4)	<0.001
INR	1.19 (1.06-1.56)	1.16 (1.06-1.47)	2.09 (1.32-3.81)	<0.001
D-dimer, μg/mL	0.94 (0.39-5.38)	0.81 (0.36-3.52)	9.49 (4.41-20.0)	<0.001
Fib, g/L	2.4 (2.0-3.0)	2.5 (2.1-3.0)	1.8 (1.0-3.2)	0.009
Scr, μmol/L	132 (98-180)	130 (95-172)	184 (153-258)	0.005
AST, U/L	63 (28-172)	51 (28-130)	260 (86-2,095)	0.001
CK, U/L	595 (242-2,125)	521 (239-1,249)	4,637 (985-7,021)	0.002
DIC	29 (18.6)	19 (13.5)	10 (66.7)	<0.001
Rhabdomyolysis	55 (35.3)	44 (31.2)	11 (73.3)	0.001
Vasoactive drugs	15 (9.6)	9 (6.4)	6 (40.0)	<0.001
Underlying diseases*	30 (19.2)	26 (18.4)	4 (26.7)	0.672
GCS score	15 (7-15)	15 (8-15)	6 (3-8)	<0.001
SIRS score	1 (1-2)	1 (0-2)	2 (2-3)	0.002
APACHE II score	9 (5-17)	7 (5-15)	20 (17-27)	<0.001
SOFA score	4 (2-7)	3 (2-6)	9 (7-11)	<0.001
ISTH score	2 (0-4)	2 (0-3)	5 (3-7)	<0.001
Length of ICU stay, d	4 (2-7)	4 (2-7)	10 (5-15)	<0.001
Length of hospital stay, d	8 (4-15)	8 (4-15)	11 (7-17)	0.182

Table 1.

Table 2.

Table 3.

Figure 2.

Figure 3.

Figure 4.

Table 4.

Figure 5.

Figure 6.

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Variables	OR	95%CI	P-value
Admission temperature	1.602	1.131-2.271	0.008
HR	1.033	1.015-1.052	<0.001
Hb	0.966	0.947-0.985	<0.001
HCT	0.888	0.830-0.949	<0.001
Plt	0.986	0.978-0.994	<0.001
APTT	1.046	1.022-1.069	<0.001
D-dimer	1.047	1.011-1.084	0.011
Rhabdomyolysis	6.062	1.829-20.099	0.003
DIC	12.842	3.957-41.682	<0.001
Vasoactive drug	9.778	2.846-33.589	<0.001
GCS score	0.775	0.678-0.886	<0.001
Lym D3	0.637	0.498-0.816	<0.001
Lym% D1	0.386	0.168-0.890	0.026
Lym% D3	0.014	0.002-0.107	<0.001
Neu D3	1.175	1.053-1.310	0.004
Neu% D1	1.069	1.003-1.140	0.041
Neu% D3	1.282	1.134-1.450	<0.001
Mono% D3	0.755	0.586-0.973	0.030

Models	AIC	AUC	95%CI	P-value	Cut-off	SEN (%)	SPE (%)	YI
HCT+Lym% D3	55.711	0.948	0.900-0.977	<0.0001	0.097	100.00	83.69	0.8369
SOFA	69.958	0.912	0.856-0.952	<0.0001	6	93.33	81.56	0.7489
APACHE II	79.930	0.838	0.770-0.892	<0.0001	12	93.33	67.38	0.6071
SIRS	93.560	0.737	0.660-0.804	0.0001	1	86.67	60.28	0.4695

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