Table 3.

The threshold effect of HCV-Ab and biochemical indicators on HCV infection was analyzed using a two-stage phased regression model

Variables	Models	Adjusted OR (95% CI)	P
HCV-Ab (S/CO)	Model 1 Fitting model by standard linear regression	1.30 (1.20-1.42)	< .001
	Model 2 Fitting model by two-piecewise linear regression
	Inflection point	11.17
	< 11.17	2.04 (1.34-3.10)	< .001
	≥ 11.17	0.77 (0.59-1.01)	0.057
	P for likelihood test		< .001
ALT (U/L)	Model 1 Fitting model by standard linear regression	1.04 (1.03-1.06)	< .001
	Model 2 Fitting model by two-piecewise linear regression
	Inflection point	54.00
	< 54.00	1.09 (1.04-1.14)	< .001
	≥ 54.00	1.02 (1.00-1.04)	0.112
	P for likelihood test		0.017
AST (U/L)	Model 1 Fitting model by standard linear regression	1.05 (1.03-1.07)	< .001
	Model 2 Fitting model by two-piecewise linear regression
	Inflection point	39.00
	< 39.00	1.16 (1.05-1.28)	0.004
	≥ 39.00	1.02 (1.00-1.04)	0.086
	P for likelihood test		0.007
mAST (U/L)	Model 1 Fitting model by standard linear regression	1.06 (1.01-1.11)	0.016
	Model 2 Fitting model by two-piecewise linear regression
	Inflection point	7.00
	< 7.00	1.56 (1.14-2.13)	0.006
	≥ 7.00	1.00 (0.93-1.07)	0.983
	P for likelihood test		0.005
GGT (U/L)	Model 1 Fitting model by standard linear regression	1.00 (1.00-1.01)	0.026
	Model 2 Fitting model by two-piecewise linear regression
	Inflection point	28.00
	< 28.00	1.14 (0.99-1.30)	0.071
	≥ 28.00	1.00 (1.00-1.01)	0.290
	P for likelihood test		0.017

OR, odds ratio; CI, confidence interval; HCV-Ab, hepatitis C antibody; ALT, alanine aminotransferase; AST, aspartate aminotransferase; mAST, mitochondrial aspartate aminotransferase isoenzyme; GGT, gamma-glutamyl transferase.