title: Impact of drug classes and treatment availability on the rate of antiretroviral treatment change in the TREAT Asia HIV Observational Database (TAHOD).
abstract: BACKGROUND
  It is critical to understand the pattern of antiretroviral treatment (ART) prescription in different regions of the world as ART procurement needs to be anticipated. We aimed at exploring rates and predictors of ART combination changes in clinical practice in Treat Asia HIV Observational Database (TAHOD).
  
  
  METHODS
  Rates of ART changes were examined in patients who started first line triple or more ART combination in TAHOD, and had at least one follow-up visit. Rates of ART changes were summarised per follow-up year, and factors associated with changes assessed using random-effect Poisson regression. The Kaplan-Meier method was used to determine durations of patients in their first, second and third regimen.
  
  
  RESULTS
  A total of 1846 patients initiated an ART combination with at least three drugs. Median follow up time for the first treatment was 3.2 years. The overall rate of ART change was 29 per 100-person-year. In univariate analyses, rate of treatment change was significantly associated with exposure category, the country income category, the drug class combination, calendar year and the number of combinations. In multivariate analysis, compared to d4T/3TC/NVP, starting ART with another NNRTI-containing regimen, with PI only or with a triple NRTI regimen was associated with a higher risk of combination change (relative risk (RR) 1.6 (95% CI 1.64 - 1.96), p < 0.001, RR 3.39 (2.76 - 4.16) p < 0.001, RR 6.37 (4.51 - 9.00), p < 0.001). Being on a second or a third combination regimen was also associated with a decreased rate of ART change, compared with first ART combination (RR 0.82 (0.68 - 0.99), p = 0.035, RR 0.77 (0.61 - 0.97), p = 0.024). Sites with fewer than 12 drugs used had an increased rate of treatment changes (1.31 (1.13 - 1.51), p < 0.001). Injecting drug users, and other/unknown exposure was found to increase rate of treatment change (1.24 (1.00 - 1.54), p = 0.055). Percentages of patients who stopped treatment due to adverse events were 31, 27 and 32 in 1st, 2nd and 3rd treatment combinations, respectively.
  
  
  CONCLUSIONS
  Our study suggests that drug availability impacts on ART prescription patterns. Our data, reflecting real clinic use in Asia, suggest that around half of all patients require second combination ART by 3 years after treatment initiation.
authors.affiliation: The National Centre in HIV Epidemiology and Clinical Research (NCHECR), University of New South Wales, Sydney, NSW, Australia.
authors.forename: Preeyaporn
authors.initials: P
authors.lastname: Srasuebkul
authors.affiliation: St Vincent's Hospital, Sydney, Australia.|Division des Maladies infectieuses, unite VIH/SIDA, Hopital universitaire de Geneve, Switzerland.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Calmy
authors.affiliation: The National Centre in HIV Epidemiology and Clinical Research (NCHECR), University of New South Wales, Sydney, NSW, Australia.
authors.forename: Jialun
authors.initials: J
authors.lastname: Zhou
authors.affiliation: YRG Centre for AIDS Research and Education, Chennai, India.
authors.forename: Nagalingeswaran
authors.initials: N
authors.lastname: Kumarasamy
authors.affiliation: The National Centre in HIV Epidemiology and Clinical Research (NCHECR), University of New South Wales, Sydney, NSW, Australia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Law
authors.affiliation: Tan Tock Seng Hospital, Singapore.
authors.forename: Poh Lian
authors.initials: PL
authors.lastname: Lim