Trends of transmitted drug resistance of HIV-1 and its impact on treatment response to first-line antiretroviral therapy in Taiwan.
OBJECTIVE
To determine the impact of transmitted drug resistance (TDR) of HIV-1 on treatment outcome in areas where routine testing for drug resistance mutations may not be available before combination antiretroviral therapy (cART) is initiated.


METHODS
Genotypic resistance assays were performed on HIV isolates from archived blood samples obtained from 1349 antiretroviral-naive HIV-1-infected patients in Taiwan from 2000 to 2010. Resistance mutations were interpreted with the use of the HIVdb program of the Stanford University HIV Drug Resistance Database. The genotypic sensitivity score (GSS) of the regimens prescribed was calculated. A matched case-control study was conducted to assess the impact of TDR on treatment outcomes.


RESULTS
The overall prevalence of TDR to any antiretroviral agent was 8.0%, declining from 12.3% in 2003-06 to 5.1% in 2007-10. In the matched case-control study, 31 patients with high- or intermediate-level resistance, 16 with low-level resistance and 89 controls were enrolled. Compared with regimens with GSS >2.5, initiation of regimens with GSS ≤2.5 was associated with a higher treatment failure rate (39.3% versus 15.7%, P = 0.02) and shorter time to treatment failure (log-rank P < 0.001). In patients receiving regimens with GSS ≤2.5, protease inhibitor-based regimens were less likely to result in treatment failure, compared with non-nucleoside reverse-transcriptase inhibitor-based regimens (hazard ratio 0.26, 95% CI 0.06-1.12, P = 0.07).


CONCLUSIONS
In Taiwan the prevalence of TDR of HIV-1 strains declined and stabilized between 2007 and 2010. Receipt of antiretroviral regimens with GSS ≤2.5 was associated with poorer treatment responses than regimens with GSS >2.5.
Department of Internal Medicine,  Kaohsiung Medical University Hospital and Kaohsiung Medical University, Kaohsiung,  Taiwan.
Chung-Chih
CC
Lai
Chien-Ching
CC
Hung
Mao-Yuan
MY
Chen
Hsin-Yun
HY
Sun
Ching-Lan
CL
Lu
Yu-Tzu
YT
Tseng
Shu-Fang
SF
Chang
Yi-Ching
YC
Su
Wen-Chun
WC
Liu
Chia-Yin
CY
Hsieh
Pei-Ying
PY
Wu
Sui-Yuan
SY
Chang
Shan-Chwen
SC
Chang
D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage*; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods*; D024882:Drug Resistance, Viral; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects* / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D015995:Prevalence; D012367:RNA, Viral / Q000235:genetics; D013624:Taiwan / Q000453:epidemiology; D016896:Treatment Outcome
D019380:Anti-HIV Agents; D012367:RNA, Viral