Table 1. Matched study clinic pairs (As of December 1, 2006, prior to study commencement).

Study clinic	Study arm	Duration of operation (months)	Number of adult patients on ART*	Probability of survival at 18 months (95%CI)†
Matero Ref.	Intervention	28.0	2,375	0.86 (0.85, 0.88)
Kanyama	Control	31.1	2,728	0.88 (0.86, 0.89)
Chipata	Intervention	21.9	1,151	0.82 (0.80, 0.85)
Chawama	Control	9.0	775	0.92 (0.90, 0.95)
George	Intervention	28.0	1,460	0.87 (0.85, 0.89)
Chilenje	Control	27.0	1,097	0.85 (0.83, 0.87)
Mtendere	Intervention	31.1	1,044	0.85 (0.83, 0.87)
Bauleni	Control	23.4	456	0.82 (0.78, 0.86)
Kabwata	Intervention	8.5	297	0.95 (0.90, 0.99)
Matero Main	Control	4.0	227	0.91 (0.85, 0.96)
Ngombe‡	Intervention	0	0	na
Makeni‡	Control	0	0	na

*Excludes former patients classified as deceased or lost to follow-up.

^†Kaplan-Meier estimate of the proportion of adult patients surviving at 18 months post-ART initiation.

^‡Ngombe and Makeni clinics opened in March 2007.