AIDS Research and Treatment Self-report questionnaire (all three items)∗ 100% adherent At least one missed HAART dose Visual analog scale∗ 10 9 <9 Antiretroviral drug concentrations (ng/mL) ≥1000 for EFV or ≥3000 for NVP <1000 for EFV or <3000 for NVP Macrocytosis (MCV ≥100 fL)∗∗ Yes No Self-report questionnaire plus macrocytosis 100% adherent At least one mistake Self-report questionnaire plus drug assays 100% adherent At least one mistake N 223 34 184 62 11 241 18 229 23 200 50 209 48 1 1 1 1 1 1 1.21 [0.56–2.64] 0.98 [0.52–1.85] 0.54 [0.11–2.55] 2.94 [1.23–7] 1.44 [0.75–2.78] 2.05 [1.07–3.93] 7.67 [2.63 –22.40] <.0001 63 (28.2) 11 (32.3) 54 (29.3) 18 (29.1) 2 (18.2) 61 (25.3) 13 (72.2) 62 (27.1) 12 (52.1) 56 (28) 18 (36) 54 (25.8) 20 (41.7) P .62 .70 3 .015 .27 .031 Table 2: Association between the four measures of adherence and virological failure in the overall population. Virological failure: N (%) OR [95% CI] OR: odds ratio; CI: conﬁdence interval, ∗Available for 257 patients, ∗∗Available for 252 patients. the diﬀerent measures of adherence to predict virological failure. All statistical analyses were performed using Stata 8 software (Stata Corporation, College Station; Texas, USA); all tests were two-sided and P values <.05 were considered signiﬁcant. 3. Results Among the 259 patients evaluated, 151 (58%) were male. Median age was 35 years (interquartile range (IQR), 31–41). At inclusion in the program, the median CD4 cell count was 93/µL (IQR, 38–173); 158 patients (61%) were ARV- na¨ıve and 101 (39%) had already taken ARV before entry to the program (dual NRTI therapy in 63 cases and a ﬁxed- dose combination of D4T/3TC/NVP in 38 cases). At the time of the evaluation, HAART consisted of AZT/3TC/NVP in 183 (71%) patients, AZT/3TC/EFV in 46 patients (18%), d4T/3TC/NVP in 17 patients (6%), and d4T/3TC/EFV in 14 patients (5%). The median CD4 cell count increments at 6 and 12 months were, respectively, 54/µL (IQR, 18–105) and 92/µL (31–144). At the study visit, the median treatment duration was 16.1 months (IQR, 14.3–17.7). Viral load was below 400 HIV RNA copies/mL in 71.5% (n = 185) of the patients overall, and in 81% (n = 128) of the 158 ARV-na¨ıve patients. As shown in Table 1, the diﬀerent measurements showed that most patients were adherent. In particular, 241 patients (93%) had drug concentrations above the thresholds used to deﬁne nonadherence. The visual analog scale gave the lowest level of adherence (71%). The association between virological failure and the diﬀerent measures of adherence was ﬁrst investigated in all the patients (Table 2), and then in the previously ARV-na¨ıve patients only (Table 3). Except for the visual analog scale, the diﬀerent measures were associated with virological failure in univariate analysis, and the association was stronger in ARV- na¨ıve patients. In an attempt to improve the identiﬁcation of nonadherent patients, we tested various combinations of the measures of adherence. A patient was considered nonadherent if any single measure indicated they were nonadherent. When added to the self-report questionnaire, MCV and drug assay each strengthened the association with the virological response. After adjustment for sex and therapeutic status at entry to the ESTHER program, logistic regression showed that the results of the self-report questionnaire did not correlate with virological failure. Only the biological measures were associated with virological failure (Table 4). Exposure to ARV before entry to the ESTHER program was strongly associated with virological failure. 4. Discussion Resistance to NNRTI-based regimens emerges rapidly when adherence is poor. In our study, adherence was considered “perfect” in more than 90% of patients, whatever the method used to estimate it, and 81% of previously ARV-na¨ıve patients were virological responders. Similar good results have been obtained in Cambodia by an MSF team [32, 33], as well as in other low- to middle-income countries with similar regimens [10, 11]. Several factors could explain this good adherence. First, treatment was free of charge for all the patients, thanks to the ﬁnancial stability of the program. Second, good drug