Table 3.
Association Between the Key Exposures Nucleoside Reverse Transcriptase Inhibitor Resistance at Switch and Nonadherence at Switch and Our Outcome, Early Viral Suppression on Second-line Antiretroviral Therapy
| Key Exposures and Confounders | VL <400 copies/mL / Total (n = 121), No. (%) | Univariable Analysis |
Multivariable Analysis |
||||
|---|---|---|---|---|---|---|---|
| NRTI Resistance at Switch (n = 111) |
Nonadherence at Switch (n = 70) |
||||||
| RR (95% CI) | P Valuea | aRR (95% CI) | P Valuea | aRR (95% CI) | P Valuea | ||
| Key exposures | |||||||
| NRTI resistance at switch | n = 114 | ||||||
| None | 18/35 (51.4) | 1 | .04 | 1 | .02 | … | … |
| M184V/I only | 28/38 (73.7) | 1.43 (.98–2.09) | 1.61 (1.1–2.36) | … | … | ||
| 1–2 TAMsb | 19/23 (82.6) | 1.61 (1.1–2.33) | 1.79 (1.23–2.61) | … | … | ||
| Cross-resistanceb | 15/18 (83.3) | 1.62 (1.1–2.38) | 1.87 (1.24–2.84) | … | … | ||
| Nonadherence at switch | n = 72 | ||||||
| Therapeutic ARTc | 28/33 (84.8) | 1 | .02d | … | … | 1 | .01d |
| Subtherapeutic + DRM | 14/19 (73.7) | 0.87 (.64–1.18) | … | … | 0.85 (.6–1.2) | ||
| Subtherapeutic, no DRM | 10/20 (50.0) | 0.6 (.37–.94) | … | … | 0.53 (.32–.86) | ||
| Confounders | … | … | |||||
| Drug concentration at switch | n = 79 | ||||||
| Therapeutic ART | 29/35 (82.9) | 1 | .02 | … | … | ||
| Subtherapeutic ART | 26/44 (29.1) | 0.71 (.53–.95) | … | … | |||
| Sex | … | … | |||||
| Male | 36/60 (60.0) | 1 | .05 | 1 | .05 | ||
| Female | 47/61 (77.0) | 1.28 (1.0–1.65) | 1.39 (1.0–1.93) | ||||
| Age at switch | |||||||
| <35 y | 40/52 (76.9) | 1 | .15 | ||||
| 35–44 y | 28/41 (68.3) | 0.89 (.69–1.15) | |||||
| ≥45 y | 15/28 (53.6) | 0.7 (.48–1.01) | |||||
| Duration of viremia | n = 118 | ||||||
| <12 mo | 40/53 (75.5) | 1.2 (.94–1.52) | 1.36 (1.08–1.71) | 1.33 (.98–1.8) | |||
| ≥12 mo | 41/65 (63.1) | 1 | .15 | 1 | <.01 | 1 | .07 |
| Magnitude of viremia | |||||||
| Log10 ≤4 | 30/37 (81.1) | 1 | .06 | ||||
| Log10 VL >4–5 | 42/62 (67.7) | 0.83 (.66–1.05) | |||||
| Log10 VL >5 | 11/22 (50.0) | 0.62 (.39–.96) | |||||
| CD4 count at switch | |||||||
| <100 cells/µL | 22/37 (59.5) | 1 | .19 | ||||
| ≥100 cells/µL | 61/84 (72.6) | 1.22 (.91–1.64) | |||||
| Year at switch | |||||||
| ≤2007 | 34/51 (66.7) | 1 | .7 | ||||
| 2008 | 49/70 (70.0) | 1.05 (.82–1.34) | |||||
| Program | |||||||
| Workplace | 11/27 (40.7) | 1 | <.01 | ||||
| Community | 72/94 (76.6) | 1.88 (1.17–3.01) | |||||
| Transfers in on ART | n = 111 | ||||||
| No | 43/71 (60.6) | 1 | <.01 | ||||
| Yes | 35/40 (87.5) | 1.44 (1.16–1.8) | |||||
Abbreviations: aRR, adjusted relative risk; ART, antiretroviral therapy; CI, confidence interval; DRM, drug resistance mutation; NRTI, nucleoside reverse transcriptase inhibitor; RR, relative risk; TAM, thymidine analogue mutation; VL, viral load.
a Wald test.
b with or without M184V/I.
c All patients had major DRMs detected.
d Test for trend (departure from linear trend P > .5).