Table 2.

Frequency of the Observed Disease State Transitions and the Estimated Average Annual Transition Probabilities During the First Antiretroviral Therapy Interruption Episode (N = 2212)^a

CD4 Strata at time t, cells/μL	CD4 Strata at Time t+1, Cells/μL
	≥500	200–499	<200	Deathb
	Observed CD4 Transitions
≥500	2073	446	19	13
200–499	0	5097	484	42
<200	0	0	2133	108
Model-Estimated Annual Transition Probabilities
≥500	0.49	0.41	0.08	0.02
200–499	0	0.70	0.26	0.04
<200	0	0	0.81	0.19

^aTransition probabilities were estimated using a 4-state continuous-time Markov model among individuals who had at least 2 observed disease status measurements (either CD4 measurements or death) during the first episode of antiretroviral therapy (ART) interruption.

^bOff-ART deaths, classified as such if they occurred during off-ART period, or within 90 days of reinitiating ART.