. Author manuscript; available in PMC: 2010 Mar 1.

Published in final edited form as: J Acquir Immune Defic Syndr. 2009 Mar 1;50(3):259–266. doi: 10.1097/QAI.0b013e3181989a8b

Table 4.

Random Effects Model for Slope of CD4⁺ Cell Decline (square root transformed)^*

Parameter	Estimate	Std Err	95% CI	P-value
Baseline Log RNA	−1.61	0.77	[−3.12,−0.09]	0.04
Tropism [D/M Vs. R5]	−1.03	0.10	[−1.22,−0.85]	<0.01
CD4⁺ Slope (cells/μL/yr)	−0.79	0.36	[−1.49,−0.09]	0.03
Interaction Tropism^* Slope^**	−1.64	0.36	[−2.35,−0.94]	<0.01

Individual random effects included for intercept and slope. Fixed effect intercept term not shown

^**

The interaction term between time and presence of D/M-tropic virus represents the difference in slope of square-root transformed CD4⁺ between participants with D/M-tropic virus measured against those with R5-tropic virus represents an additional decline of −1.64 sqrt (cells/μL) per year over the reference slope of −0.79 square root (cells/μL) per year.