title: Regional changes over time in initial virologic response rates to combination antiretroviral therapy across Europe.
abstract: BACKGROUND
  Changes in virologic response to initial combination antiretroviral therapy (cART) over calendar time may indicate improvements in cART or emergence of primary resistance. Regional variations may identify differences in available antiretroviral drugs or patient management.
  
  
  METHODS
  Virologic response (viral load < 500 copies/mL) 6 to 12 months after starting cART was analyzed in antiretroviral-naive EuroSIDA patients. Analyses were stratified by region (south, central west, north, east) or time started cART (early, 1996-1997; mid, 1998-1999; late, 2000-1904).
  
  
  RESULTS
  Virologic suppression was achieved by 60% of 2102 patients: 57% south (n = 560), 61% central west (n = 466), 63% north (n = 606), 58% east (n = 470) (P = 0.091). An increase was observed over time: 52% early cART, 56% mid cART, 69% late cART (P < 0.001). Overall, there were significant effects of region (P = 0.026) and time (P < 0.001) on virologic response after adjustment for confounders. Stratified by period, regional differences were less evident (early cART, P = 0.967; mid cART, P = 0.291; late cART, P = 0.163). Stratified by region, temporal changes were observed (south, P = 0.061; central west, P < 0.001; north: P = 0.070; east, P = 0.001).
  
  
  CONCLUSIONS
  There was some evidence of regional differences in initial virologic response to cART. Improvements over time were observed, suggesting that so far, the effect of primary resistance has not been of sufficient magnitude to prevent increasing suppression rates.
authors.affiliation: Department of Primary Care and Population Sciences, Royal Free and University College Medical School, London, UK. w.bannister@pcps.ucl.ac.uk
authors.forename: Wendy P
authors.initials: WP
authors.lastname: Bannister
authors.forename: Ole
authors.initials: O
authors.lastname: Kirk
authors.forename: Jose M
authors.initials: JM
authors.lastname: Gatell
authors.forename: Brygida
authors.initials: B
authors.lastname: Knysz
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Viard
authors.forename: Helene
authors.initials: H
authors.lastname: Mens
authors.forename: Antonella D'Arminio
authors.initials: AD
authors.lastname: Monforte
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Phillips
authors.forename: Amanda
authors.initials: A
authors.lastname: Mocroft
authors.forename: Jens D
authors.initials: JD
authors.lastname: Lundgren
mesh_terms: D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D024882:Drug Resistance, Viral; D005060:Europe / Q000453:epidemiology; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology* / Q000821:virology; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D008297:Male; D013997:Time Factors; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents