Table 3.

The result of two-piecewise linear regression model

	OR (95% CI)	P value
Fitting model by standard linear regression	1.05 (1.02–1.08)	0.001
Fitting model by two-piecewise linear regression
Inflection point of virus positive duration (day)	8	-
< 8	1.35 (0.83–2.19)	0.228
≥ 8	1.04 (1.02–1.07)	0.002
P for log likelihood ratio test	-	0.286

We adjusted age, sex and other covariates presented in Table 1

CI confidence interval, OR odd ratio