Definitions of antiretroviral treatment failure for measuring quality outcomes.
OBJECTIVE
Our aim was to compare three different definitions of treatment failure and discuss their use as quality outcome measures for a clinical service.


METHODS
Data for treatment-naïve patients who attended the Melbourne Sexual Health Centre (MSHC) between 1 January 2000 and 31 December 2008 were analysed. Definition 1 was the strict Food and Drug Administration (FDA) definition of treatment failure as determined using the time to loss of virological response (TLOVR) algorithm. Definition 2 defined treatment failure as occurring in those whose viral load never fell to <400 HIV-1 RNA copies/mL or who developed two consecutive viral loads > or =400 copies/mL on any treatment (switching or stopping treatment with a viral load <400 copies/mL was permitted). Definition 3 was the same as definition 2 except that individuals were also deemed to have failed if they stopped treatment for 6 months or longer.


RESULTS
There were 310 antiretroviral-naïve patients who started treatment in the study period. Of these, 156 [50.3%; 95% confidence interval (CI) 42.1-53.3%] experienced treatment failure under definition 1, 10 (3.2%; 95% CI 1.5-5.8%) experienced treatment failure under definition 2, and 16 (4.5%; 95% CI 2.5-7.4%) experienced treatment failure under definition 3 over the 108 months of follow-up. The probability of failing definition 1 was statistically different from the probability of failing definition 2 or 3 (P=0.01).


CONCLUSIONS
There were significant differences in treatment failure for the three definitions. If definition 1 were used, the outcomes would be sufficiently common to enable clinics to be compared but would be less meaningful. If definition 2 or 3 were used, the events would be too rare to enable clinics to be compared, but it would be possible to set a benchmark level of success that clinics could aim to reach.
Samaranayake
A
A
Melbourne Sexual Health Centre, Australia.
Chen
M Y
MY
McNeil
J
J
Read
T R H
TR
Hocking
J S
JS
Bradshaw
C S
CS
Fairley
C K
CK
D000328:Adult; D000368:Aged; D000465:Algorithms; D044966:Anti-Retroviral Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D019985:Benchmarking; D003153:Community Health Services / Q000592:standards*; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care / Q000592:standards*; D019984:Quality Indicators, Health Care / Q000592:standards; D013997:Time Factors; D017211:Treatment Failure; D019562:Viral Load / Q000187:drug effects*
D044966:Anti-Retroviral Agents