Table 2.

Probability of HIV rebound above the lower limit of quantitation during continuous suppression

Initial CD4 count	Years of HIV suppression (year)	No. at start of Year	No. of rebounds	Yearly %Probability (95 % CI)	Cumulative  % Probability (95 % CI)
<300 cells/μl	0–1	248	99	54.1 (48.8–65.4)	43.6 (37.2–50.1)
	1–2	118	32	35.0 (31.0–49.2)	59.9 (53.1–66.4)
	2–3	65	16	31.1 (26.7–50.4)	70.9 (63.8–77.2)
	3–4	38	8	25.8 (21.6–51.3)	77.8 (70.5–83.7)
	4–5	24	6	30.8 (24.1–67.8)	83.5 (76.2–88.9)
	5–6	15	2	16.0 (12.8–63.7)	86.0 (78.5–91.1)
	6–7	10	0	0.0	86.0 (78.5–91.1)
>300 cells/μl	0–1	543	131	29.8 (28.3–35.2)	25.9 (22.2–29.8)
	1–2	337	68	24.2 (22.9–30.7)	41.9 (37.4–46.5)
	2–3	224	43	22.9 (21.3–30.8)	54.1 (49.2–58.9)
	3–4	152	13	9.7 (9.2–16.8)	58.4 (53.4–63.2)
	4–5	115	8	7.7 (7.3–15.3)	61.3 (56.2–66.2)
	5–6	94	5	6.5 (6.1–15.5)	63.7 (58.5–6.86)
	6–7	61	0	0.0	63.7 (58.5–68.6)
All combined	0–1	791	230	36.9 (32.5–41.9)	31.4 (28.1–34.8)
	1–2	455	100	26.9 (22.1–32.6)	47.5 (43.7–51.3)
	2–3	289	59	24.6 (19.1–31.7)	59.3 (55.2–63.2)
	3–4	190	21	12.8 (8.3–19.6)	64.2 (60.1–68.1)
	4–5	139	14	11.3 (6.7–19.0)	68.0 (63.8–71.9)
	5–6	109	7	7.8 (3.7–16.4)	70.3 (66.0–74.2)
	6–7	71	0	0.0	70.3 (66.0–74.2)

Estimates of yearly probability for HIV rebound determined by computing Hazard Rate via the Life Table method and cumulative probability by Kaplan–Meier (SAS 9.3, Cary, NC). Analysis restricted to the first sequence of each patient with consecutive viral loads less than the lower limit of quantitation. Sequences were right-censored 43 times because the testing interval exceeded 390 days and 317 times when the observation period ended 31 December 2011