Table 4.
Multivariable Cox proportional hazards models by calendar period of cART initiation for factors associated with achieving an undetectable HIV viral load test result* with the first cART regimen, the HIV Outpatient Study, 1996–2011 (N = 1,467; n = 996 [66%] achieved an undetectable viral load with the first cART regimen). Baseline characteristics listed in the table were included in all models except where noted.
| Calendar period of first cART initiation Number achieving undetectable viral load with first cART (%) |
1996–1999, N = 430 n = 227 (52.8%) |
2000–2003, N = 330 n = 190 (57.6%) |
2004–2007, N = 353 n = 265 (75.1%) |
2008–2011, N = 354 n = 284 (80.2%) |
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|---|---|---|---|---|---|---|---|---|
| Baseline Characteristic | aHR (95% CI) | p-value | aHR (95% CI) | p-value | aHR (95% CI) | p-value | aHR (95% CI) | p-value |
| Age in years < 40 (vs. ≥ 40 years) | 0.86 (0.65–1.12) | 0.26 | 0.98 (0.73–1.33) | 0.90 | 1.01 (0.79–1.31) | 0.92 | 1.05 (0.82–1.33) | 0.72 |
| Female sex (vs. male sex) | 0.88 (0.58–1.34) | 0.55 | 0.74 (0.51–1.09) | 0.13 | 1.11 (0.76–1.61) | 0.60 | 1.08 (0.79–1.49) | 0.62 |
| Black, non-Hispanic/Latino race/ethnicity (vs. other race/ethnicities) | 0.88 (0.63–1.23) | 0.44 | 0.57 (0.40–0.81) | 0.002 | 0.69 (0.49–0.95) | 0.024 | 1.22 (0.93–1.59) | 0.15 |
| IDU HIV transmission risk (vs. other HIV transmission risks) | 0.32 (0.17–0.62) | < 0.001 | 1.24 (0.68–2.24) | 0.48 | 1.58 (0.93–2.69) | 0.09 | 2.18 (0.98–4.86) | 0.06 |
| Public/no insurance (vs. private insurance) | 0.66 (0.49–0.89) | 0.006 | 0.95 (0.69–1.29) | 0.72 | 0.88 (0.65–1.20) | 0.42 | 0.86 (0.67–1.11) | 0.25 |
| Viral load (per 1 log10 c/ml)** | 0.91 (0.75–1.12) | 0.37 | 0.88 (0.72–1.09) | 0.24 | 0.75 (0.61–0.91) | 0.005 | 0.73 (0.61–0.87) | < 0.001 |
| Baseline CD4+ cell count < 200 cells/mm3 (vs. ≥ 200 cells/mm3) | 0.79 (0.59–1.08) | 0.14 | 0.74 (0.53–1.03) | 0.07 | 0.89 (0.67–1.17) | 0.39 | 0.78 (0.58–1.04) | 0.09 |
| Twice or more daily dosing (vs. once daily dosing) | n/a | n/a | 0.71 (0.53–0.95) | 0.022 | 1.23 (0.83–1.82) | 0.30 | ||
| Boosted PI-containing cART (vs. NNRTI cART) | 0.95 (0.45–2.00) | 0.89 | 0.82 (0.55–1.21) | 0.32 | 1.09 (0.83–1.42) | 0.55 | 1.04 (0.77–1.42) | 0.79 |
| Unboosted PI-containing cART (vs. NNRTI cART) | 0.77 (0.58–1.02) | 0.06 | 0.84 (0.56–1.27) | 0.42 | 0.46 (0.24–0.87) | 0.017 | 1.38 (0.69–2.76) | 0.36 |
| Integrase or entry inhibitor-containing cART (vs. NNRTI cART) | n/a | n/a | n/a | 1.17 (0.76–1.78) | 0.48 | |||
Abbreviations: aHR, adjusted hazard ratio; c/mL, copies per milliliter; CI, confidence interval; cART, combination antiretroviral therapy; IDU, injection drug use; PI, protease inhibitor, NNRTI, non-nucleoside reverse transcriptase inhibitor; n/a, not applicable (variable not included in the model because not relevant in the specific calendar period of interest).
Undetectable viral load was defined as one below the limit of detection for each given viral load assay
Values were imputed for patients with missing pre-cART viral load (also see Table 2).