Research Article

Trends in Decline of Antiretroviral Resistance among ARV-Experienced Patients in the HIV Outpatient Study: 1999–2008

Table 1

Characteristics of ARV-experienced patients who had genotypic testing performed at viral load >1000 copies/mL and while on ARVs in selected calendar years, and overall, the HIV Outpatient Study, 1999–2008.

199920042008Unique total§
N%N%N%N%
Had GT in this yr →11816463906

Age, years*†
 Median (IQR)40 (36, 47)43 (39, 48)41 (38, 51)43 (38, 49)
 <351815.21710.4914.311012.1
 35–497866.111067.13657.158364.4
 50+2218.63722.61828.621323.5

Gender
 Female2521.23622.02438.120823.0
 Male9378.812878.03961.969877.0

Race
 White7361.97545.72234.944849.4
 Black3025.46539.63047.633436.9
 Other/unknown1512.72414.61117.512413.7

HIV Risk
 Heterosexual3126.35332.32742.926629.4
 IDU1210.2159.1914.310211.3
 MSM7059.38551.82336.548753.8
 Other/unknown54.2116.746.4515.6

Insurance*†
 Private5445.85835.42133.338142.0
 Public4941.59356.73758.744449.0
 Other/unknown1512.7137.957.9818.9

CD4+ count, cells/mm3*
 Median (IQR)225.5(105, 360)272(163, 432)170(64, 325)267.5(124, 433)
 <2005445.85634.23657.134738.3
 200–3493227.14628.01117.522925.3
 350–4991613.63420.7711.116217.9
 500+1512.72615.8812.715016.6
 Missing10.821.211.6182.0

Nadir CD4+ count, cells/mm3*†
 Median (IQR)99 (34, 213)126(40, 247)55(20, 206)105(32, 247)
 <503832.25231.12946.027830.7
 50–1994437.35231.71828.630633.8
 200–3492420.33823.21219.018420.3
 350+97.62012.346.410111.2
 Missing32.531.800.0374.1

HIV RNA viral load, copies/mL*
 Median log (IQR)4.6(3.9, 5.0)4.2(3.6, 4.8)4.5(3.7, 5.0)4.3(3.6, 4.9)
 1,000–9,9993529.76539.62336.536840.6
 10,000–99,9995445.86942.12336.536340.1
 ≥100,0002924.63018.31727.017519.3

AIDS*9983.913381.15282.572880.4

Antiretroviral exposure*
 3TC/FTC exposed11093.215896.36298.485694.5
 NRTI exposed118100.0164100.063100.090599.9
 NNRTI exposed7866.112878.14774.665672.4
 PI exposed (any)10589.014487.85587.379988.2
 Ritonavir-boosted PI exposed75.910966.55181.047852.8
 Mono-dual NRTI exposed8874.69960.43352.451556.8
 Triple-class exposed (TCE)5546.69457.33250.849654.8
 Only cART exposed2218.65432.92438.129933.0
 Any exposure to all 3 classes of agents (NRTI, NNRTI, and PI)7160.210966.53961.956662.5

ARV exposure duration among those exposed with complete and evaluable ARV history, median months*nMediannMediannMediannMedian
 3TC/FTC exposed1102215843625885637
 NRTI exposed1184416471637390562
 NNRTI exposed781212819472365620
 PI exposed (any)1052814451555679943
 Ritonoavir-boosted PI exposed7510823513647721
 Mono-dual NRTI exposed8819981231750313
 Triple-class exposed (TCE)38117546295739438
 Only cART exposed11155436243929934

Number of ARVs exposed to date, median118616486379067

Duration of ARV exposure, years, median1184.01646.2636.29065.3

§ Total number of unique patients during 1999–2008.
*As of last eligible genotypic test in the year. (For clinical measurements, only values within 6 months prior through 2 weeks after the first eligible genotypic test were considered, the closest one chosen to characterize the patient at time of the GT.).
value for trend during 1999–2008 was <0.05.
IQR: interquartile range. GT: genotypic testing; cART: combination antiretroviral therapy; NRTI: nucleoside reverse transcriptase inhibitor; NNRTI: non-nucleoside reverse transcriptase inhibitor; PI: protease inhibitor; TCE: triple-class exposed; MSM: men who have sex with men; IDU: injection drug use.