Table 3.
Factors influencing atazanavir plasma concentration
| Change in drug concentration (% change in ng/mL) |
|||||||||
|---|---|---|---|---|---|---|---|---|---|
| univariable |
multivariable 1 |
multivariable 2 |
|||||||
| Parameter | effect | 95% CI | P | effect | 95% CI | P | effect | 95% CI | P |
| Age (per 10 years) | −6.0 | −18.2 to 7.9 | 0.38 | −2.6 | −13.1 to 9.2 | 0.65 | 0.1 | −11.2 to 12.5 | 0.99 |
| Gender (female versus male) | −6.1 | −29.8 to 25.6 | 0.67 | 0.5 | −26.5 to 37.5 | 0.97 | −3.3 | −29.9 to 33.2 | 0.84 |
| Ethnicity (black versus white) | −1.8 | −24.1 to 27.1 | 0.89 | −12.2 | −33.4 to 15.6 | 0.35 | −12.4 | −34.1 to 16.5 | 0.36 |
| Weight (per 10 kg) | −5.6 | −13.0 to 2.4 | 0.16 | −6.3 | −12.1 to −0.1 | 0.047 | −6.3 | −12.4 to 0.3 | 0.06 |
| Time on ATV (per 4 weeks) | 0.6 | −1.1 to 2.5 | 0.48 | 0.2 | −2.5 to 3.0 | 0.89 | 0.1 | −2.6 to 2.9 | 0.94 |
| Time on current regimen (per 4 weeks) | 1.1 | −0.9 to 3.2 | 0.28 | 0.6 | −2.5 to 3.8 | 0.70 | 0.7 | −2.5 to 4.0 | 0.68 |
| ATV regimen (versus 300 mg/r)a | |||||||||
| 400 mg/r | 35.2 | 8.8 to 67.9 | 0.007 | 29.3 | 6.4 to 57.1 | 0.010 | 40.3 | 13.7 to 73.1 | 0.002 |
| 400 mg | −75.0 | −82.8 to −63.7 | <0.001 | −69.4 | −78.0 to −57.5 | <0.001 | −66.8 | −76.7 to −52.7 | <0.001 |
| On zidovudine (yes versus no) | −0.7 | −28.6 to 38.0 | 0.97 | 19.8 | −9.8 to 59.1 | 0.21 | |||
| On lamivudine (yes versus no) | −26.2 | −41.1 to −7.5 | 0.009 | −17.4 | −33.5 to 2.7 | 0.09 | |||
| On stavudine (yes versus no) | −0.7 | −40.7 to 66.2 | 0.98 | 17.0 | −22.5 to 76.7 | 0.45 | |||
| On tenofovir DF (yes versus no) | 40.1 | 11.3 to 76.3 | 0.004 | 7.1 | −14.0 to 33.4 | 0.54 | |||
| On didanosine (yes versus no) | −4.1 | −24.3 to 21.4 | 0.73 | −4.0 | −22.1 to 18.3 | 0.70 | |||
| On abacavir (yes versus no) | −13.8 | −32.3 to 9.8 | 0.23 | −5.7 | −23.6 to 16.4 | 0.59 | |||
| On efavirenz (yes versus no) | −8.3 | −36.9 to 33.2 | 0.65 | −32.3 | −50.6 to −7.1 | 0.016 | |||
| On nevirapine (yes versus no) | −19.9 | −47.4 to 22.0 | 0.30 | −15.0 | −40.4 to 21.5 | 0.37 | |||
| On emtricitabine (yes versus no) | 48.7 | 7.3 to 106.1 | 0.017 | −0.4 | −27.1 to 36.1 | 0.98 | |||
| On saquinavir (yes versus no) | −2.9 | −36.8 to 49.4 | 0.89 | 6.6 | −26.7 to 55.0 | 0.74 | |||
| On lopinavir (yes versus no) | −15.1 | −47.8 to 37.9 | 0.51 | −11.3 | −40.3 to 31.8 | 0.55 | |||
ATV, atazanavir; /r, ritonavir boosted; DF, disoproxil fumarate.
Multivariable model 1: concomitant antiretroviral drugs not considered.
Multivariable model 2: considering concomitant antiretroviral drugs.
Both multivariable models are adjusted for hours since last atazanavir intake.
All results with P < 0.05 are shown in bold.
aOverall P value for all three models <0.001.