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. Author manuscript; available in PMC: 2012 Sep 28.
Published in final edited form as: AIDS. 2007 Jul 31;21(12):1579–1589. doi: 10.1097/QAD.0b013e3281532b31

Table 4.

Multivariate analysis of change in CD4 cell count (cells/μl) one year after starting antiretroviral therapy.

Base case
 With propensity
 With adherence
Effect P value Effect P value Effect P value
Nevirapine based −17 0.091 −15 0.139 −22 0.038
Single protease inhibitor based −22 0.003 −20 0.006 −21 0.008
Boosted protease inhibitor baseda −31 0.005 −30 0.007 −23 0.043
Triple nucleoside based −22 0.047 −20 0.069 −31 0.009
Other based −32 0.003 −31 0.004 −33 0.003
Current illicit drug use, compared with none −18 0.002 −17 0.004 −15 0.013
African-American, compared with Caucasian −8 0.133 −9 0.109 −1 0.856
Hispanic, compared with Caucasian −27 0.006 −34 0.001 −28 0.007
Other, compared with Caucasian 2 0.831 −1 0.924 11 0.237
Baseline log RNA, per log unit 14 <0.001 13 <0.001 13 <0.001
Baseline CD4 cell count, per 100 cells/μl −6 <0.001 −6 <0.001 −5 <0.001
Start in 1998, compared with ≤1997 11 0.074 7 0.289 10 0.131
Start in 1999, compared with ≤1997 25 0.001 −1 0.952 25 0.001
Start in 2000, compared with ≤1997 21 0.008 −19 0.406 17 0.050
Start in ≥2001, compared with ≤1997 14 0.075 −23 0.270 7 0.404
Stavudine/lamivudine backbone, compared with zidovudine/lamivudine −7 0.155 −7 0.172 −7 0.187
Other backbone, compared with zidovudine/lamivudine −16 0.011 −16 0.016 −14 0.033
Propensity score NAb 97 0.062 NAb
Adherence 60–80%, compared with 80–100% NAc NAc −5 0.428
Adherence 40–60%, compared with 80–100% −21 0.001
Adherence 20–40%, compared with 80–100% −66 <0.001
Adherence 0–20%, compared with 80–100% −104 <0.001

Efavirenz-based therapy is the referent category. Positive numbers represent higher elevations in the CD4 cell count, and are therefore more favorable. Results from three different models are displayed; the first does not adjust for the likelihood of being prescribed efavirenz nor levels of adherence (Base case), the second uses propensity scores to adjust for confounding by treatment selection (With propensity), and the third adjusts for the level of medication regimen adherence (With adherence).

a

Older boosted protease inhibitors (PI): −27, P=0.028 (base case), −26, P=0.036 (with propensity), −17, P=0.179 (with adherence). Newer boosted PI: −44, P=0.030 (base case), −42, P=0.036 (with propensity), −43, P=0.043 (with adherence).

b

Not applicable because analysis did not attempt to control for propensity.

c

Not applicable because analysis did not attempt to control for adherence.