Table 2. Factors associated with virologic failure to a switch regimen composed of NVP plus TDF plus FTC (or 3TC) (n = 341).
| Univariate | Multivariate | |||
|---|---|---|---|---|
| Variable | HR (95% CI) | p value | HR (95% CI) | p value |
| Age | 0.99 (0.96, 1.03) | 0.76 | ||
| Gender | 1.41 (0.72, 2.78) | 0.31 | ||
| Intravenous Drug Users | 1.98 (1.09, 3.58) | 0.02 | 1.51 (1.12, 2.04) | 0.01 |
| Hepatitis B or C Co-infection | ||||
| Hep C | 1.58 (0.87, 2.87) | 0.13 | ||
| Hep B | 0.90 (0.32, 2.52) | 0.85 | ||
| Nadir CD4 cell count | 0.98 (0.79, 1.22) | 0.86 | ||
| Baseline CD4 cell count | 0.80 (0.69, 0.92) | 0.00 | ||
| Time of HIV-1 infection | 1.00 (1.00, 1.00) | 0.92 | ||
| Longer time with undetectable VL | 0.98 (0.97, 1.00) | 0.01 | 0.98 (0.97, 0.99) | 0.01 |
| Prior Antiretroviral exposure | 1.01 (0.89, 1.13) | 0.93 | ||
| number of prior NRTI | 1.18 (0.97, 1.43) | 0.10 | 1.49 (1.15, 1.93) | 0.00 |
| number of prior NNRTI | 2.38 (1.49, 3.85) | 0.00 | 3.22 (1.64, 6.25) | 0.00 |
| number of prior PI | 1.03 (0.81, 1.31) | 0.82 | ||
| Prior NRTI mono and dual therapy | 1.14 (0.65, 2.01) | 0.65 | ||
| Prior VF documented | 1.76 (0.96, 3.25) | 0.07 | ||
| Prior NNRTI treatment interruption | 2.13 (1.20, 3.78) | 0.01 | ||
| Nevirapine interruptions | 1.72 (0.86, 3.45) | 0.13 | 1.54 (1.10, 2.17) | 0.01 |
| Efavirenz interruptions | 3.11 (1.23, 7.90) | 0.02 | 5.76 (1.11, 29.87) | 0.04 |
| VL at baseline <50 c/mL * | 0.22 (0.12, 0.39) | 0.00 | ||
| 3TC present in the last regimen | 0.72 (0.40, 1.30) | 0.27 | ||
| FTC present in the last regimen | 0.30 (0.04, 2.18) | 0.23 | ||
| TDF present in the last regimen | 1.01 (0.53, 1.95) | 0.97 | ||
| NVP present in the last regimen | 0.32 (0.18, 0.57) | 0.00 | 0.57 (0.43, 0.76) | 0.00 |
| 3TC (vs FTC) in the regimen | 2.48 (1.38, 4.46) | 0.00 | ||
* Some individuals in early calendar years had an undetectable viral load at baseline, but with tests using a threshold of 80 or 200 copies/mL.
VL: viral load; VF: virologic failures; NNRTI: non-nucleoside reverse transcriptase inhibitor; NRTI: nucleoside analogue reverse transcriptase inhibitor; PI: protease inhibitor.