Table 4.

Comparison of Immunologic Failure Definitions for True-Positive Versus False-Positive Groups

	Immunologic and virologic failure (true positives)		Immunologic failure only (false positives)
Immunologic (CD4) failure definitiona	No.	Row %b	No.	Row %b	χ2P value
1 only	222	33.4	442	66.6
2 only	275	26.8	751	73.2
3 only	48	42.5	65	57.5
1 and 2	227	36.6	394	63.4
2 and 3	162	72.6	61	27.4
1 and 3	24	46.2	28	53.8
1, 2, and 3	267	63.1	156	36.9
Total	1225		1897		<.0001
All def. 1 failures	740	42.0	1020	58.0	<.0001
All def. 2 failures	931	40.6	1362	59.4	<.0001
All def. 3 failures	501	61.8	310	38.2	<.0001

^aCD4 failure definitions: 1, fall of CD4 count to, or below, pretherapy baseline; 2, 50% fall from on-treatment peak value; 3, persistent CD4 levels <100 cells/mm³ after at least 12 months on antiretroviral therapy.

^bRow percentage describes the proportion of individuals among either the true-positive or false-positive group meeting any 1 (or combination of) CD4 failure criteria, over all individuals meeting the same criteria. This provides a quick assessment as to which criteria more commonly contribute to true-positive versus false-positive results.