3.1 | Demographic characteristics of the study population
The study sample was based on 758 eligible pre-treatment HIV infected patients. Demographic and clinical characteristics of the included patients are shown in Table 1. Patients were mainly male [565 (74.5%)], with a median age of 33 (24-71) years old. Regarding pre-treatment HIV-RNA level, 27.8% and 6.3% of patients, showed viremia ranging between 100,000-500,000 copies/mL, and ≥500,000 copies/mL, respectively. Most selected patients [338 (44.6%)] had baseline CD4 cell count between 200 and 350 cells/mm3. The most commonly used regimen was tenofovir disoproxil fumarate (TDF) + lamivudine (3TC) + efavirenz (EFV) [517 (68.2%)]. In those whose genetic testing were available, very few had significant resistance to their regimen [16/353 (4.5%)]. The median follow-up time of the study population was 144 (108-276) weeks.
Table 1 Demographic and clinical characteristics of the study population.
Demographic and clinical characteristics
|
N (%) or median (IQR)
|
Males
|
565 (74.5%)
|
Age (years)
|
33 (27-41)
|
Year of ART initiation
2009
2013-2015
|
240 (31.7%)
518 (68.3%)
|
Follow-up time (weeks)
|
144 (108-276)
|
Baseline viral load (copies/ml)
<100,000
≥100,000 and <500,000
≥500,000
|
499 (65.8%)
211 (27.8%)
48 (6.3%)
|
Mode of transmission
Homosexual
Heterosexual
Bisexual
Others†
Unknown
|
290 (38.3%)
378 (49.9%)
21 (2.8%)
15 (2.0%)
54 (7.1%)
|
Baseline CD4 level (cells/mm3)
<100
≥100 and <200
≥200 and <350
≥350
|
96 (12.7%)
143 (18.9%)
338 (44.6%)
181 (23.9%)
|
Subtype
AE
B/C/BC
Others
Unknown
|
224 (29.6%)
111 (14.6%)
17 (2.2%)
406 (53.6%)
|
Regimen
TDF+3TC+EFV
3TC+AZT+NVP
3TC+AZT+EFV
3TC+TDF+NVP
Other 2NRTIs+NNRTI
|
517 (68.2%)
78 (10.3%)
14 (1.8%)
7 (0.9%)
142 (18.7%)
|
Serum HBsAg status
Positive
Negative
|
89 (12.1%)
645 (87.9%)
|
Serum HCV-Ab status
Positive
Negative
|
29 (4.0%)
699 (96.0%)
|
Resistance
Low, Intermediate and High
Susceptible and Potential Low
|
16 (4.5%)
337 (95.5%)
|
†Includes blood transfusion, exposure to infected needles, etc.
3TC, lamivudine; AZT, zidovudine; EFV, efavirenz; HBsAg, surface antigen of the hepatitis B virus; HCV-Ab, hepatitis C antibody; IQR, interquartile ranges; NNRTI, non-nucleoside reverse transcriptase inhibitor; NRTI, nucleoside reverse transcriptase inhibitor; NVP, nevirapine; TDF, tenofovir disoproxil fumarate.
3.2 | Virological trajectories in patients with different levels of baseline HIV-RNA
Overall, 529 (69.8%) of the patients in the cohort had achieved virological suppression by week 24, and 671 (89.7%) patients achieved virological suppression by week 48. At week 24, only 18/48 (37.5%) patients with a baseline HIV-RNA over 500,000 copies/ml had achieved virological suppression, compared with 117/211(55.5%) in those with a baseline between 100,000 and 500,000 copies/ml. Figure 1 shows percentage of patients that achieved virological suppression in different baseline level groups at week 12, 24, 48, 72 and 96. The rates of virological suppression in those with higher pretreatment viral load remained all the way lower than those with lower pretreatment viral load except for the first 12 weeks. At week 96, 718 (94.7%) patients still remained in the sample cohort, and the percentage of virological suppressed patients in three groups by rising baseline HIV-RNA levels were 88.6%, 95.9% and 98.3%, respectively. Chi-square analysis suggested all the difference in percentage between each group at different time points were significant (p<0.001). In addition, the cumulative Kaplan–Meier estimation showed a significantly lower probability of virological suppression for higher HIV-RNA categories (log-rank p<0.001, Figure 2). After the treatment, the median CD4 cell count of all the patients in the cohort rose from 263 (165-245) cells/m3 at week 0 to 446 (319-545) cells/m3 at week 96. Table 1S shows the number of patients that remained in three groups and of those who achieved virological suppression in each follow-up.
Univariate and Multivariable Cox proportional hazard models were used to analyze factors associating with time to virological suppression (Table 2). Very high baseline HIV viremia over 500,000 copies/ml were found to be independently associated with delayed virological suppression, after adjusting for factors including sex, age, mode of transmission, HIV-subtype, pre-treatment CD4 cell count, sero-positivity of HBsAg and HCV-Ab [≥500,000 vs. <100,000, adjusted RH (aRH) (95% CI), 0.455 (0.319-0.648), p <0.001]. Male sex was shown to be another significant relevant factor of deterred virological suppression [male vs. female, aRH (95% CI), 0.755 (0.622-0.916), p <0.001]. None of age, pre-treatment CD4 cell count, mode of transmission, HIV-subtype, pre-treatment resistance, initial regimen, sero-positivity of HBsAg of HCV-Ab was significantly associated with delayed virological suppression.
3.3 | High baseline HIV-RNA is related to virological failure
In the sample cohort, 71/758 (9.4%) patients had incomplete viral suppression, among whom 21/71 (30.0%) had never achieved virological suppression. 23/758 (3.0%) patients had viral rebound, with 7/23 (30.4%) having additional blips, 1/23 (4.3%) having severe adverse effect and stopped the initial regimen in week 48. Of these patients, 3/94 (3.2%) were resistant to their initial regimen that was later proved by genetic analysis.
Table 2 Univariate and Multivariate Cox proportional hazard models of the time to virological suppression among 758 treatment-naïve patients initiating NNRTI-based ART. Variables were mutually adjusted in the multivariate model that included age.
Variable
|
Crude
|
Adjusted
|
RH
|
(95%CI)
|
p
|
RH
|
(95%CI)
|
p
|
Male Gender
|
0.757
|
(0.641-0.894)
|
0.001
|
0.755
|
(0.622-0.916)
|
0.004
|
Year of ART Initiation
|
0.981
|
(0.839-1.148)
|
0.812
|
-
|
-
|
-
|
Baseline RNA (copies/ml)
|
|
|
|
|
|
|
<100,000
|
1.000
|
-
|
-
|
1.000
|
-
|
-
|
100,000-
500,000
|
0.628
|
(0.532-0.741)
|
<0.001
|
0.602
|
(0.497-0.730)
|
<0.001
|
≥500,000
|
0.477
|
(0.349-0.652)
|
<0.001
|
0.455
|
(0.319-0.648)
|
<0.001
|
Baseline CD4 (cells/m3)
|
|
|
|
|
|
|
<100
|
1.000
|
-
|
-
|
1.000
|
-
|
-
|
100-200
|
1.057
|
(0.809-1.383)
|
0.684
|
0.970
|
(0.740-1.272)
|
0.826
|
200-350
|
1.227
|
(0.970-1.551)
|
0.088
|
1.046
|
(0.823-1.331)
|
0.712
|
>350
|
1.313
|
(0.016-1.697)
|
0.037
|
1.181
|
(0.931-1.532)
|
0.209
|
HBsAg (+)
|
0.928
|
(0.741-1.164)
|
0.520
|
-
|
-
|
-
|
HCV-Ab (+)
|
0.878
|
(0.605-1.275)
|
0.495
|
-
|
-
|
-
|
Mode of Transmission
|
0.910
|
(0.722-1.147)
|
0.
|
-
|
-
|
-
|
Others
|
1.000
|
-
|
-
|
|
|
|
Homosexual
|
1.093
|
(0.649-1.839)
|
0.738
|
-
|
-
|
-
|
Heterosexual
|
1.196
|
(0.713-2.006)
|
0.498
|
-
|
-
|
-
|
Bisexual
|
0.804
|
(0.408-1.582)
|
0.527
|
-
|
-
|
-
|
Regimen
Other 2NRTIs+NNRTI
|
1.000
|
-
|
-
|
-
|
-
|
-
|
3TC+TDF+EFV
|
0.963
|
(0.790-1.175)
|
0.711
|
-
|
-
|
-
|
3TC+AZT+NVP
|
0.923
|
(0.694-1.227)
|
0.581
|
-
|
-
|
-
|
3TC+TDF+NVP
|
0.669
|
(0.383-1.167)
|
0.157
|
-
|
-
|
-
|
3TC+AZT+EFV
|
0.742
|
(0.346-1.590)
|
0.443
|
-
|
-
|
-
|
HIV Subtype
|
0.991
|
(0.898-1.093)
|
0.858
|
-
|
-
|
-
|
Resistance (Low, Intermediate and High)
|
0.757
|
(0.450-1.274)
|
0.294
|
-
|
-
|
-
|
3TC, lamivudine; AZT, zidovudine; CI, confidence interval; EFV, efavirenz; HBsAg, surface antigen of the hepatitis B virus; HCV-Ab, hepatitis C antibody; NNRTI, non-nucleoside reverse transcriptase inhibitor; NRTI, nucleoside reverse transcriptase inhibitor; NVP, nevirapine; TDF, tenofovir disoproxil fumarate.
Binary Logistic regression models were built to evaluate factors related to incomplete viral suppression or viral rebound (Table 3 and Table 4). After adjusting with covariates including age, sex, HIV subtype, pre-treatment resistance, baseline CD4 level, sero-positivity of HBsAg or HCV-Ab, mode of transmission, Odds ratio (OR) to incomplete viral suppression were significantly higher in patients with baseline HIV-RNA levels ≥500,000 copies/ml [≥500,000 vs. <100,000, aOR (95% CI), 6.084 (2.761-13.407), p <0.001)]. After excluding patients with viral blips, baseline HIV viremia over 500,000 copies/ml were found to be independently associated with rebound (≥500,000 vs. <100,000, aOR (95% CI), 3.671 (1.009-13.355), p =0.048).
Table 3 Univariate and adjusted Logistic regression analysis of OR of incomplete suppression among 758 treatment-naïve patients initiating NNRTI-based ART.
Variable
|
Univariate Analysis
|
Adjusted Analysis †
|
OR
|
(95%CI)
|
P
|
OR
|
(95%CI)
|
P
|
Male Gender
|
1.608
|
(0.861-3.004)
|
0.136
|
1.533
|
(0.805-2.917)
|
0.193
|
Age
|
0.993
|
(0.969-1.018)
|
0.595
|
-
|
-
|
-
|
Year of ART Initiation
|
0.743
|
(0.448-1.230)
|
0.248
|
-
|
-
|
-
|
Baseline RNA
(copies/ml)
|
|
|
|
|
|
|
<100,000
|
1.000
|
-
|
-
|
1.000
|
-
|
-
|
100,000-500,000
|
2.937
|
(1.712-5.041)
|
<0.001
|
2.736
|
(1.577-4.747)
|
<0.001
|
≥500,000
|
6.458
|
(3.061-13.625)
|
<0.001
|
6.084
|
(2.761-13.407)
|
<0.001
|
Baseline CD4 (cells/m3)
|
|
|
|
|
|
|
<100
|
1.000
|
-
|
-
|
1.000
|
-
|
-
|
100-200
|
1.057
|
(0.809-1.383)
|
0.014
|
1.386
|
(0.633-3.307)
|
0.414
|
200-350
|
1.227
|
(0.970-1.551)
|
0.004
|
0.970
|
(0.457-2.059)
|
0.938
|
>350
|
1.313
|
(0.016-1.697)
|
0.120
|
0.478
|
(0.190-1.206)
|
0.118
|
HBsAg (+)
|
1.246
|
(0.612-2.536)
|
0.545
|
-
|
-
|
-
|
HCV-Ab (+)
|
1.197
|
(0.350-4.093)
|
0.774
|
-
|
-
|
-
|
Mode of Transmission
|
1.029
|
(0.734-1.444)
|
0.866
|
-
|
-
|
-
|
HIV Subtype
|
1.306
|
(0.631-2.705)
|
0.472
|
-
|
-
|
-
|
Resistance (Low, Intermediate and High)
|
1.543
|
(0.328-7.261)
|
0.583
|
-
|
-
|
-
|
Table 4 Univariate and adjusted Logistic regression analysis of OR of viral rebound after excluding blips among 758 treatment-naïve patients initiating NNRTI-based ART.
Variable
|
Univariate Analysis
|
Adjusted Analysis †
|
OR
|
(95%CI)
|
P
|
OR
|
(95%CI)
|
P
|
Male Gender
|
1.259
|
(0.461-3.440)
|
0.653
|
-
|
-
|
-
|
Age
|
0.976
|
(0.932-1.021)
|
0.286
|
-
|
-
|
-
|
Year of ART Initiation
|
0.551
|
(0.267-1.137)
|
0.107
|
-
|
-
|
-
|
Baseline RNA (copies/ml)
|
|
|
|
|
|
|
<100,000
|
1.000
|
-
|
-
|
1.000
|
-
|
-
|
100,000-
500,000
|
2.781
|
(1.113-6.950)
|
0.029
|
2.405
|
(0.943-6.133)
|
0.066
|
≥500,000
|
5.182
|
(1.529-17.555)
|
0.008
|
3.671
|
(1.009-13.355)
|
0.048
|
Baseline CD4 (cells/m3)
|
|
|
|
|
|
|
<100
|
1.000
|
-
|
-
|
1.000
|
-
|
-
|
100-200
|
0.781
|
(0.254-2.402)
|
0.666
|
0.936
|
(0.297-2.946)
|
0.910
|
200-350
|
0.318
|
(0.104-0.971)
|
0.044
|
0.469
|
(0.144-1.524)
|
0.208
|
>350
|
0.250
|
(0.061-1.024)
|
0.054
|
0.350
|
(0.082-1.494)
|
0.156
|
HBsAg (+)
|
2.049
|
(0.071-5.668)
|
0.167
|
-
|
-
|
-
|
HCV-Ab (+)
|
1.060
|
(0.138-8.148)
|
0.955
|
-
|
-
|
-
|
Mode of Transmission
|
1.054
|
(0.594-1.871)
|
0.858
|
-
|
-
|
-
|
HIV Subtype
|
3.168
|
(0.777-12.922)
|
0.108
|
-
|
-
|
-
|
Resistance (Low, Intermediate and High)
|
1.747
|
(0.210-14.501)
|
0.605
|
-
|
-
|
-
|
†Significance in Omnibus Test of Model Coefficients is <0.037. Significance in Hosmer and Lemeshow Test is 0.788.
CI, confidence interval; HBsAg, surface antigen of the hepatitis B virus; HCV-Ab, hepatitis C antibody