Table 2.

Estimated Proportions of Mortality, Location Parameters, Scale Parameters, and Median Ages at Death From Weibull Mixture Models Comparing the Pre- and Post-Highly Active Antiretroviral Therapy Eras^a Among Multicenter AIDS Cohort Study Participants^b, 1984–2008

Mortality Category	Proportion of Mortality, %	95% CI	Location Parameter	95% CI	Scale Parameter	95% CI	Median Age, yearsb
HIV-negative, 1984–2008	N/A	N/A	3.73	3.71, 3.75	0.25	0.24, 0.26	73.1
Pre-HAART era (reference)
Non-AIDS mortality	6	5, 8	2.84	2.63, 3.04	0.53	0.41, 0.66	49.0
AIDS mortality	94	92, 95	2.34	2.29, 2.40	0.83	0.79, 0.87	42.7
HAART era
Non-AIDS mortality	53*	48, 59	3.57*	3.52, 3.62	0.37*	0.34, 0.40	66.0*
AIDS mortality	47*	41, 52	2.86*	2.70, 3.01	0.75	0.68, 0.83	48.2*

Abbreviations: AIDS, acquired immune deficiency syndrome; CI, confidence interval; HAART, highly active antiretroviral therapy; HIV, human immunodeficiency virus; MACS, Multicenter AIDS Cohort Study; N/A, not applicable.

* P < 0.05 for difference relative to pre-HAART era.

^a Pre-HAART era: 1984–1995; HAART era: 1996–2008.

^b Time origin is age 35 years. For HIV-negative individuals, survival times were modeled as Weibull (β, σ). For HIV-positive individuals, survival times were modeled as a mixture with the proportion who died of non-AIDS causes (π) as Weibull (location (β)₁, scale (σ)₁) and the complement (1 − π) who died of AIDS as Weibull (β₂, σ₂).