Factors associated with virological suppression among HIV-positive individuals on highly active antiretroviral therapy in a multi-site Canadian cohort.
OBJECTIVE
The aim of the study was to evaluate time to virological suppression in a cohort of individuals who started highly active antiretroviral therapy (HAART), and to explore the factors associated with suppression.


METHODS
Eligible participants were HIV-positive individuals from a multi-site Canadian cohort of antiretroviral-naïve patients initiating HAART on or after 1 January 2000. Viral load and CD4 measurements within 6 months prior to HAART initiation were assessed. Univariate and multivariate analyses were conducted using piecewise survival exponential models where time scale was divided into intervals (<10 months; ≥10 months). Virological suppression was defined as the time to the first of at least two consecutive viral load measurements <50 HIV-1 RNA copies/mL.


RESULTS
A total of 3555 individuals were included in the study, of median age 40 years [interquartile range (IQR) 34-47 years]. Eighty per cent were male, 18% had a history of injecting drug use (IDU), and 13% presented with an AIDS-defining illness at baseline. The median time to suppression was 4.55 months (IQR 2.99-7.89 months). In multivariate analyses, older age, male sex, treatment in Ontario rather than British Columbia, non-IDU history, and having an AIDS diagnosis at baseline predicted increased likelihood of suppression. Patients with low baseline viral load were more likely to have suppression [4-5 log(10) copies/mL, hazard ratio (HR) 1.27, 95% confidence interval (CI) 1.18-1.38; <4 log(10) copies/mL, HR 1.49, 95% CI 1.32-1.68] than patients with baseline viral load ≥5 log(10) copies/mL; however, this effect ceased after 18 months of follow-up. Suppression was more likely with nonnucleoside reverse transcriptase inhibitors and ritonavir-boosted HAART.


CONCLUSIONS
Identification of patients at risk for diminished likelihood of virological suppression will allow focusing of efforts and the utilization of resources to maximize the benefits of HAART.
British Columbia Centre for Excellence in HIV/AIDS, Vancouver, Canada.
A M
AM
Cescon
C
C
Cooper
K
K
Chan
A K
AK
Palmer
M B
MB
Klein
N
N
Machouf
M R
MR
Loutfy
J
J
Raboud
A
A
Rachlis
E
E
Ding
V D
VD
Lima
J S G
JS
Montaner
S B
SB
Rourke
M
M
Smieja
C
C
Tsoukas
R S
RS
Hogg
D000328:Adult; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods; D018791:CD4 Lymphocyte Count; D002170:Canada / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000187:drug effects / Q000276:immunology*; D016896:Treatment Outcome; D019562:Viral Load
D012367:RNA, Viral