Table 2.

Risk factors for GBM in primary cohort.

	Model 1			Model 2			Model 3
Intercept and variable	β	Adjusted OR	P	β	Adjusted OR	P	β	Adjusted OR	P
		(95% CI)			(95% CI)			(95% CI)
Intercept	−5.40	–	–	−6.33	–	–	−7.36	–	–
Age	0.07	1.07 (1.04–1.11)	<0.01	0.07	1.07 (1.04–1.11)	<0.01	0.07	1.07 (1.04–1.11)	<0.01
pKPS	−2.47	0.09 (0.02–0.31)	<0.01	−2.18	0.11 (0.30–0.44)	<0.01	−2.22	0.11 (0.03–0.38)	<0.01
pEO	−1.87	0.15 (0.05–0.50)	<0.05	−2.01	0.13 (0.04–0.45)	<0.01	–	–	–
SIRI	–	–	–	0.48	1.62 (1.10–2.39)	<0.05	0.43	1.53 (1.06–2.22)	<0.01
Tumor volume	0.07	1.08 (1.05–1.11)	<0.01	0.07	1.08 (1.04–1.11)	<0.01	0.07	1.07 (1.04–1.10)	<0.01
Annular enhancement	1.62	5.03 (1.79–14.14)	<0.01	1.64	5.17 (1.80–14.83)	<0.01	1.39	4.02 (1.53–10.54)	<0.01
PTE	0.02	1.02 (1.01–1.03)	<0.05	0.02	1.02 (1.01–1.04)	<0.05	0.02	1.02 (1.01–1.03)	<0.05
Tumor necrosis volume	0.09	1.09 (1.03–1.17)	<0.01	0.09	1.09 (1.03–1.16)	<0.05	0.09	1.09 (1.03–1.15)	<0.01
		C1-index	0.114		C2-index	0.244		C3-index	0.471
Primary cohort		0.815			0.894			0.839
Internal validation cohort		0.824			0.899			0.879
External validation cohort		0.793			0.915			0.851
		AIC1			AIC2			AIC3
		179.63			173.71			182.51
			IDI (2 vs. 1)				IDI (2 vs. 3)
			<0.01			<0.05
			11.89%				9.14%

pKPS, preoperative Karnofsky performance status; pEO, preoperative epilepsy occurrence; SIRI, systemic inflammation response index; P is obtained from the multivariable logistic regression; β is regression coefficient; PTE, peritumoral edema; OR, odds ratio; AIC, the Akaike information criterion; C-index, the concordance index (the area under curve in logistic regression analysis); IDI, the integrated discrimination improvement (model 2 vs. model 1, model 2 vs. model 3).