Table 4. Sensitivity analysis for effectiveness of IPT with or without ART using Cox proportional hazards model among patients on ART assuming those who were lost to follow-up and dead developed TB in SNNP region, Ethiopia, September 2007 to August 2010.

Category	Sub-category	Incident TB+lost+dead	Person-years	Incidence rate per 100 person-years	Unadjusted HR (95% CI)	Adjusted HR (95% CI)
IPT and/or ART *	No intervention	93	1018	9.1	1	1
	IPT only	9	370	2.4	0.36 (0.18–0.71)	0.40 (0.20–0.80)
	IPT before ART	15	682	2.2	0.42 (0.24–0.74)	0.45 (0.25–0.80)
	ART only	266	3832	6.9	0.93 (0.73–1.19)	0.69 (0.53–0.89)
	IPT & ART Simultaneously	14	558	2.5	0.39 (0.22–0.70)	0.35 (0.20–0.62)
	IPT after ART	41	2713	1.5	0.30 (0.20–0.46)	0.22 (0.15–0.34)

*Controlled for sex, WHO stage, cotrimoxazole use, and baseline CD4; HR-Hazard Ratio; CI- Confidence Interval; IPT-Isoniazid Preventive Therapy; ART-antiretroviral therapy; WHO-World Health Organization; HIV-Human Immunodeficiency virus.