. Author manuscript; available in PMC: 2009 Sep 22.

Published in final edited form as: AIDS Res Hum Retroviruses. 2001 Jul 1;17(10):901–910. doi: 10.1089/088922201750290023

TABLE 4.

Multivariate Cox Regression Model for Female-to-Male and Male-to-Female Transmission

Variable	Adjusted risk ratio	95% CI	p Value
A. Female-to-Male Transmission
Viral load category (copies/ml)^a
Low (<10,000)	1.0
Medium (≥10,000 to <100,000)	4.1	1.2, 14.1	0.02
High (≥100,000)	7.6	2.3, 25.5	0.001
Log viral load (per log₁₀ increment)^b	2.5	1.5, 4.0	0.0002
B. Male-to-Female Transmission
Viral load category (copies/ml)^a,^c
Low (<10,000)	1.0
Medium (≥10,000 to ,100,000)	1.2	0.5, 3.4	0.67
High (≥100,000)	2.1	0.8, 5.6	0.12
Log viral load (per log₁₀ increment)^b,^d	1.8	1.2, 2.8	0.004

Log viral loads were used in all models.

Separate Cox models were constructed, utilizing log viral load as a continuous variable.

Number of unprotected sexual acts in the last 3 months, genital inflammation, and age were also independently predictive of transmission.

Genital inflammation was independently predictive of transmission.