Table 1.
Sample characteristics [median (IQR)] and association with use of boosted double PI regimena.
| Boosted single PI | Boosted double PI | P valueb | |
|---|---|---|---|
| Continuous variables | |||
| Calendar date | 3/2002 (9/2000, 8/2003) | 7/2002 (6/2001, 5/2003) | 0.07 |
| Peak log10 viral load (log10 copies/ml) | 5.1 (4.5, 5.5) | 5.2 l (4.7, 5.5) | 0.39 |
| Baseline log10 viral load (log10 copies/ml) | 4.2 (3.3, 4.9) | 4.2 (3.4, 4.9) | 0.59 |
| Nadir CD4 cell count (cells/μl) | 90 (30, 189) | 67 (19, 168) | 0.03 |
| Baseline CD4 cell count (cells/μl) | 239 (117, 373) | 212 (99, 356) | 0.44 |
| Time from baseline viral load to treatment change (days) | 26 (13, 50) | 28 (10, 46) | 0.51 |
| Time from baseline CD4 cell count to treatment change (days) | 27 (13, 52) | 27 (10, 47) | 0.12 |
| Time from most recent genotype to treatment change (days) | 107 (24, 376) | 121 (30, 352) | 0.43 |
| PI drugs experienced (prior to treatment change) (n) | 2 (1, 4) | 3 (2, 4) | < 0.01 |
| NRTI drugs experienced (prior to treatment change) (n) | 4 (3, 5) | 4 (4, 5) | < 0.01 |
| NNRTI drugs experienced (prior to treatment change) (n) | 1 (0, 1) | 1 (1, 2) | < 0.01 |
| Major PI mutations (n) | 1 (0, 3) | 2 (0, 3) | 0.04 |
| NRTI mutations (n) | 4 (2, 6) | 5 (4, 7) | < 0.01 |
| NNRTI mutations (n) | 1 (0, 2) | 1 (0, 2) | < 0.01 |
| Date of first ART therapy | 9/1995 (1/1994, 3/1997) | 1/1995 (1/1994, 8/1996) | 0.05 |
| Drugs used for the first time in current regimen (n) | 2 (1, 3) | 2 (1, 3) | 0.37 |
| NRTI in current regimen (n) | 2 (2, 3) | 1 (2, 3) | 0.18 |
| Drugs switched in current regimen (n) | 3 (2, 4) | 3 (2, 4) | 0.19 |
| Genotypic susceptibility score for non-PI drugs in current regimen | 2.0 (1.8, 2.6) | 1.8 (1.5, 2.6) | 0.02 |
| Categorical variables | |||
| History of mono/dual NRTI treatment | 552 (67.2%) | 124 (79.0%) | 0.01 |
| Use of T20 prior to treatment change | 10 (1.9%) | 3 (1.2%) | 0.49 |
| Use of T20 in current regimen | 43 (5.2%) | 13 (8.3%) | 0.13 |
| Use of NNRTI for the first time in current regimen | 127 (15.4%) | 17 (10.8%) | 0.14 |
a
Among 822 boosted single PI and 157 boosted double PI regimens with outcome measured.
b
Robust P-value for unadjusted association (odds ratio) between covariate and use of boosted double PI regimen, based on univariable logistic regression using General Estimating Equations with exchangeable working covariate matrix.
IQR, Interquartile range; PI, protease inhibitor; NRTI, nucleoside reverse transcriptase inhibitor; NNRTI, non-nucleoside reverse transcriptase inhibitor; ART, antiretroviral therapy.