Table 3.

Multivariable Cox regression models to identify risk factors for CKD stage 3.

	MODEL 1	MODEL 2	MODEL 3	MODEL 4
Variables	Clinical AIC=1908.4	Clinical + Classification AIC= 1841.9	MODEL 2 + SCysC AIC=1720.0	MODEL 2 + pNGAL AIC=1774.6
(a)Age	2.4 (1.7–3.4)	2.3 (1.6 – 3.2)	2.1 (1.5 – 3.1)	2.2 (1.5 – 3.2)
CVD	1.9 (1.4–2.6)	1.5 (1.1 – 2.1)	1.7 (1.2 – 2.4)	1.5 (1.1 – 2.1)
(b) CCI	1.9 (1.4–2.6)	1.6 (1.2 – 2.2)	1.6 (1.1 – 2.2)	1.7 (1.2 – 2.3)
(c) Susceptibility	2.2 (1.5–3.0)	1.1 (0.7 – 1.5)	0.8 (0.5 – 1.3)	1.1 (0.7 – 1.6)
(d)Classification
AKI		5.7 (3.8 – 8.7)	4.7 (2.9 – 7.7)	5.6 (3.5 – 8.8)
TAz		2.4 (1.5 – 3.6)	2.3 (1.5 – 3.5)	2.3 (1.5 – 3.5)
SCys			1.5 (1.1 – 2.0)
(e)pNGAL				1.0 (0.7 – 1.5)

Results are expressed as hazard ratios (95% confidence interval); SCysC, serum cystatin C; pNGAL, plasma NGAL; AIC, Akaike’s Information Criterion; CVD, cardiovascular disease; CCI, Charlson Comorbidity Index; AKI, Acute Kidney Injury; TAz, Transient Azotemia.

^(a)The cut point 63 years for age was obtained by the analysis of Martingale residuals, age < 63 years old was considered as the reference category;

^(b)reference category: CCI≤3;

^(c)Susceptibility stage I–II considered as the reference category;

^(d)reference category: NF;

^(e)reference category: pNGAL ≤ 133 ng/mL.

Model 1: p<0.001 for all variables; Model 2: CVD p=0.007, CCI p=0.003, Susceptibility p=0.749, p<0.001 for the remaining variables; Model 3: CVD p=0.002, CCI p=0.011, Susceptibility p=0.399, SCysC p=0.011, p<0.001 for the remaining variables; Model 4: CVD p=0.010, CCI p=0.002, Susceptibility p=0.779, pNGAL p=0.809, p<0.001 for the remaining variables.