Predicting hemorrhage and obstruction in the elderly population using thromboelastographic indices

Figures & data

Table 1 Comparison of general information and clinical features between patients in different groups

Variable	Outcome			χ^2 or F
	Normal (%)	Hemorrhage (%)	Obstruction (%)
Number of subjects	300	25	78
Age (mean ± SD)	82.2 ± 7.4	86.9 ± 7.7	84.9 ± 5.7	8.467ΔΔ
Sex
Male	279 (93.0)	23 (92.0)	71 (91.0)	0.3622
Female	21 (7.0)	2 (8.0)	7 (9.0)
Long-term bed resta
No	281 (93.7)	6 (24.0)	52 (66.7)	105.894ΔΔ
Yes	19 (6.3)	19 (76.0)	26 (33.3)
Taking anticoagulant drugsb
No	59 (19.7)	2 (8.0)	10 (12.8)	3.698
Yes	241 (80.3)	23 (92.0)	68 (87.2)
History of obstructive diseasec
No	202 (67.3)	18 (72.0)	34 (43.6)	15.8972ΔΔ
Yes	98 (32.7)	7 (28.0)	44 (56.4)
Baseline TEG index value
R (mean ± SD)	6.8 ± 2.0	7.3 ± 2.3	6.3 ± 1.6	3.592Δ
K (mean ± SD)	1.9 ± 0.8	2.0 ± 0.7	1.7 ± 0.6	2.981Δ
MA (mean ± SD)	60.2 ± 5.7	59.8 ± 7.7	61.7 ± 6.9	2.055
ANGLE (mean ± SD)	59.1 ± 10.4	61.7 ± 8.4	62.2 ± 8.8	3.295Δ

Notes:

a Long-term bed rest refers to cases in which duration of bed rest was longer than half a year;

b anticoagulant drugs taken included aspirin, clopidogrel, heparin sodium, low molecular weight heparin sodium, argatroban, warfarin sodium, enteric-coated lumbrokinase capsules;

c history of obstructive diseases included history of old lacunar infarction and old myocardial infarction;

Δ between-group comparison P < 0.05;

ΔΔ between-group comparison P < 0.01.

Abbreviations: ANGLE, solidification angle; K, coagulation formation time; MA, maximum amplitude; R, coagulation reaction time; SD, standard deviation; TEG, thromboelastography.

Table 2 Predicting obstruction in elderly population using ROC curves and currently adopted cutoff values for different TEG indices

Positive criteria	Obstruction		Sensitivity (%)	Specificity (%)	Positive predictive value (%)	Negative predictive value (%)	Accuracy (%)	AUC
	Yes	No
R
≤2	0	0	0	100	0	79.4	79.4	0.5000
>2	78	300
K
≤1	4	15	5.1	95	21.1	79.4	76.5	0.5006
>1	74	285
MA
≥69	11	18	14.1	94	37.9	80.8	77.5	0.5405
<69	67	282
ANGLE
≥78	0	1	0	99	0	79	79.1	0.5000
<78	78	299

Notes: Sensitivity is the proportion of true positives that are correctly identified by TEG test; it shows how good the test is at detecting a disease. Specificity is the proportion of the true negatives correctly identified by TEG test; it suggests how good the test is at identifying normal (negative) condition. Positive predictive value is the probability that the disease is present when the TEG test is positive. Negative predictive value accuracy is the probability that the disease is not present when the TEG test is negative. Accuracy is the proportion of true results, either true positive or true negative, in a population; it measures the degree of veracity of a diagnostic test on a condition.

Abbreviations: ANGLE, solidification angle; AUC, area under the curve; K, coagulation formation time; MA, maximum amplitude; R, coagulation reaction time; ROC, receiver-operating characteristics; TEG, thromboelastography.

Table 3 Predicting obstruction in elderly population using ROC curves and optimal cutoff values for different TEG indices

Positive criteria	Obstruction		Sensitivity (%)	Specificity (%)	Positive predictive value (%)	Negative predictive value (%)	Accuracy (%)	AUC
	Yes	No
R
≤7	61	174	78.2	42	26	88.1	49.5	0.5936a
>7	17	126
K
≤1.5	39	89	50	70.3	30.5	84.4	66.1	0.5987b
>1.5	39	211
MA
≥63.5	37	75	47.4	75	33.1	84.6	69.3	0.5825c
<63.5	41	225
ANGLE
≥67.1	29	69	37.2	77	29.6	82.5	68.8	0.5743d
<67.1	49	231

Notes: Sensitivity is the proportion of true positives that are correctly identified by TEG test; it shows how good the test is at detecting a disease. Specificity is the proportion of the true negatives correctly identified by TEG test; it suggests how good the test is at identifying normal (negative) condition. Positive predictive value is the probability that the disease is present when the TEG test is positive. Negative predictive value accuracy is the probability that the disease is not present when the TEG test is negative. Accuracy is the proportion of true results, either true positive or true negative, in a population; it measures the degree of veracity of a diagnostic test on a condition. Compared to AUC using currently adopted cutoff values to predict obstruction,

a P = 0.002;

b P = 0.0011;

c P = 0.014;

d P = 0.022.

Abbreviations: ANGLE, solidification angle; AUC, area under the curve; K, coagulation formation time; MA, maximum amplitude; R, coagulation reaction time; ROC, receiver-operating characteristics; TEG, thromboelastography.

Figure 1 Receiver-operating characteristics (ROC) curve of joint index and obstruction occurrence.

Abbreviation: C, area under the curve of ROC.

Table 4 Predicting hemorrhage in elderly population using ROC curves and currently adopted cutoff values for different TEG indices

Positive criteria	Hemorrhage		Sensitivity (%)	Specificity (%)	Positive predictive value (%)	Negative predictive value (%)	Accuracy (%)	AUC
	Yes	No
R
≥8	9	69	36	77	11.5	93.5	73.8	0.5650
<8	16	231
K
≥3	2	19	8	93.7	9.5	92.4	87.1	0.5083
<3	23	281
MA
≤51	5	16	20	94.6	23.8	93.4	88.9	0.5733
>51	20	284
ANGLE
≤55	21	220	84	26.7	8.7	95.2	34.2	0.5443
>55	4	80

Notes: Sensitivity is the proportion of true positives that are correctly identified by TEG test; it shows how good the test is at detecting a disease. Specificity is the proportion of the true negatives correctly identified by TEG test; it suggests how good the test is at identifying normal (negative) condition. Positive predictive value is the probability that the disease is present when the TEG test is positive. Negative predictive value accuracy is the probability that the disease is not present when the TEG test is negative. Accuracy is the proportion of true results, either true positive or true negative, in a population; it measures the degree of veracity of a diagnostic test on a condition.

Abbreviations: ANGLE, solidification angle; AUC, area under the curve; K, coagulation formation time; MA, maximum amplitude; R, coagulation reaction time; ROC, receiver-operating characteristics; TEG, thromboelastography.

Table 5 Predicting hemorrhage in elderly population using ROC curves and optimal cutoff values for different TEG indices

Positive criteria	Hemorrhage		Sensitivity (%)	Specificity (%)	Positive predictive value (%)	Negative predictive value (%)	Accuracy (%)	AUC
	Yes	No
R
≥7.8	12	80	48	73.3	13	94.4	71.4	0.5656a
<7.8	13	220
K
≥2.3	10	66	40	78	13.2	94.0	75.1	0.5618b
<2.3	15	234
MA
≤50.5	5	13	20	95.7	27.8	93.5	89.8	0.5783c
>50.5	20	287
ANGLE
≤53.7	23	228	92	24	9.2	97.4	29.2	0.5479d
>53.7	2	72

Notes: Sensitivity is the proportion of true positives that are correctly identified by TEG test; it shows how good the test is at detecting a disease. Specificity is the proportion of the true negatives correctly identified by TEG test; it suggests how good the test is at identifying normal (negative) condition. Positive predictive value is the probability that the disease is present when the TEG test is positive. Negative predictive value accuracy is the probability that the disease is not present when the TEG test is negative. Accuracy is the proportion of true results, either true positive or true negative, in a population; it measures the degree of veracity of a diagnostic test on a condition. Compared to AUC using currently adopted cutoff values to predict hemorrhage,

a P = 0.1796;

b P = 0.0081;

c P = 0.822;

d P = 0.5662.

Abbreviations: ANGLE, solidification angle; AUC, area under the curve; K, coagulation formation time; MA, maximum amplitude; R, coagulation reaction time; ROC, receiver-operating characteristics; TEG, thromboelastography.

Figure 2 Receiver-operating characteristics (ROC) curve of joint index and hemorrhage occurrence.

Abbreviation: C, area under the curve of ROC.

Table 6 Multi-factor Cox regression analysis on predicting obstruction occurrence

Item	RR value	95% CI	P-value
Age	1.022	0.982–1.063	0.2859
Sex	0.986	0.442–2.197	0.9721
Long-term bed rest	4.285	2.526–7.267	<0.0001ΔΔ
Taking anticoagulant drugs	0.925	0.461–1.856	0.8262
History of obstructive diseases	2.040	1.270–3.276	0.0032ΔΔ
R ≤ 7	1.565	0.854–2.869	0.1473
K ≤ 1.5	0.955	0.443–2.602	0.9073
MA ≥ 63.5	1.629	0.873–3.040	0.0092ΔΔ
ANGLE ≥ 67.1	1.162	0.626–2.159	0.6337

Notes:

Δ P < 0.05;

ΔΔ P < 0.01. Relative risk value is the risk of an event (developing obstruction or hemorrhage events) related to exposure.

Abbreviations: ANGLE, solidification angle; CI, confidence interval; K, coagulation formation time; MA, maximum amplitude; R, coagulation reaction time RR, relative risk.

Table 7 Multi-factor Cox regression analysis on predicting hemorrhage occurrence

Item	RR value	95% CI	P-value
Age	1.064	0.985–1.148	0.1132
Sex	4.220	0.721–24.709	0.1104
Long-term bed rest	37.171	13.414–103.005	<0.0001ΔΔ
Taking anticoagulant drugs	0.819	0.169–3.969	0.8042
History of obstructive diseases	0.934	0.372–2.347	0.8845
R ≥ 7.8	3.008	1.090–8.301	0.0335Δ
K ≥ 2.3	2.060	0.577–7.350	0.2653
MA ≤ 50.5	8.110	1.836–35.837	0.0058ΔΔ
ANGLE ≤ 53.7	0.228	0.052–1.004	0.0506

Notes:

Δ P < 0.05;

ΔΔ P < 0.01. Relative risk (RR) value is the risk of an event (developing obstruction or hemorrhage events) related to exposure.

Abbreviations: ANGLE, solidification angle; CI, confidence interval; K, coagulation formation time; MA, maximum amplitude; R, coagulation reaction time RR, relative risk.