A Prediction Model for Rapid Identification of Ischemic Stroke: Application of Serum Soluble Corin

Figures & data

Figure 1 A flowchart illustrating the selection of study participants and analytical plan.

Notes: A mixture population including patients with ischemic stroke, patients with hemorrhagic stroke, and healthy individuals were randomly divided into training and testing samples. The diagnostic model of ischemic stroke was developed using backward stepwise logistic regression in the training sample and validated in the testing sample. The discrimination, calibration, and utility of the constructed model were assessed in both samples by ROC curve analysis, calibration curve analysis, and decision curve analysis, respectively.

Abbreviation: ROC, receiver operating characteristics.

Table 1 Clinical Characteristics of Study Participants

Characteristics	Training Sample	Testing Sample	P value
No. of participants	1547	1548	–
Age, years	54.6±11.0	54.5±10.9	0.708
Male, men (%)	662 (42.79)	684 (44.19)	0.456
Cigarette smoking, n (%)	419 (27.08)	408 (26.36)	0.677
Alcohol consumption, n (%)	322 (21.81)	308 (19.90)	0.556
Family history of stroke, n (%)	184 (11.89)	171 (11.05)	0.494
History of CHD, n (%)	19 (1.23)	38 (2.45)	0.016
Hypertension, n (%)	751 (48.55)	735 (47.48)	0.578
Diabetes mellitus, n (%)	113 (7.30)	124 (8.01)	0.502
Systolic blood pressure, mmHg	134.7±20.1	133.9±20.5	0.316
Diastolic blood pressure, mmHg	85.4±10.35	85.62±10.75	0.566
Total cholesterol, mg/dL	199.6±38.49	200.75±83.21	0.634
Triglycerides, mg/dL	137.62±154.98	127.34±116.87	0.043
LDL cholesterol, mg/dL	116.29±30.33	116.11±30.35	0.873
HDL cholesterol, mg/dL	56.41±19.2	57.01±19.49	0.402
Fasting plasma glucose, mmol/L, Median (IQR)	5.2 (4.8–5.9)	5.3 (4.8–5.9)	0.575
Serum uric acid, mmol/L, Median (IQR)	273 (217–342)	271 (215–340)	0.525
Serum corin, pg/mL, Median (IQR)	1686 (1378–2094)	1687 (1378–2094)	0.875

Note: All values are expressed with mean ± standard deviation unless otherwise noted.

Abbreviations: CHD, coronary heart disease; LDL, low-density lipoprotein; HDL, high-density lipoprotein; IQR, interquartile range.

Table 2 The Final Diagnostic Model Developed in the Training Sample

Predictors	β	OR (95% CI)	P value
Age, per year	0.078	1.08 (1.06–1.11)	<0.001
Sex
Female	Reference
Male	0.783	2.19 (1.16–4.11)	0.015
Cigarette smoking
No	Reference
Yes	0.675	1.96 (1.13–3.42)	0.018
Family history of stroke
No	Reference
Yes	1.228	3.41 (1.94–6.01)	<0.001
History of hypertension
No	Reference
Yes	−0.801	0.45 (0.27–0.76)	0.003
Systolic blood pressure, per mmHg	0.038	1.04 (1.03–1.05)	<0.001
Total cholesterol, per mg/dL	−0.006	0.99 (0.98–1.00)	0.036
HDL cholesterol, per mg/dL	−0.098	0.91 (0.89, 0.93)	<0.001
Fasting plasma glucose, per mmol/L	0.272	1.31 (1.18–1.45)	<0.001
Log-corin, per unit	−1.864	0.16 (0.08–0.32)	<0.001

Notes: Goodness of fit: Akaike information criterion=601, Brier score=0.058, Nagelkerke’s R²=50.5%. The probability of the diagnostic model is:

Abbreviations: HDL, high-density lipoprotein cholesterol; Log-corin, Log-transformed corin.

Figure 2 The receiver-operating characteristic curve illustrating the discrimination of the diagnostic model in the training (A) and testing (B) samples.

Notes: The area under the receiver-operating characteristic curve was 0.910 (95% CI: 0.884–0.936) and 0.907 (95% CI: 0.881–0.934) for the diagnostic model in the training and testing samples, respectively.

Abbreviation: AUC, area under the receiver-operating characteristic curve.

Figure 3 The calibration curve illustrating the agreement between the observed and predicted probability of ischemic stroke determined by the diagnostic model in the training (A) and testing (B) samples.

Notes: The diagonal line shows the ideal agreement between the observed and predicted probability. The dotted line shows the realistic agreement between the observed and predicted probability determined by the diagnostic model. The difference between the ideal and realistic agreements was not significant in both the training (P=0.619) and testing (P=0.157) samples, respectively, tested by the Spiegelhalter Z-test’s p value. The height of the bars indicates the number of participants with corresponding predicted probability of ischemic stroke.

Figure 4 The decision curve for the diagnostic model in the training (A) and testing (B) samples.

Notes: The red line represents the probability of being ischemic stroke predicted by the diagnostic model. The results suggest that the diagnostic model could be clinically applied if the risk threshold was 1–79% and 2–70% in the training and testing samples, respectively.

Figure 5 The nomogram for the probability of being ischemic stroke predicted by the diagnostic model.

Abbreviations: HDL, high-density lipoprotein cholesterol; Log-corin, Log-transformed corin.