title: HIV disease progression to CD4 count <200 cells/μL and death in Saskatoon, Saskatchewan.
abstract: OBJECTIVE
  To characterize and identify determinants of HIV disease progression among a predominantly injection drug use (IDU) HIV population in the highly active antiretroviral therapy era.
  
  
  METHODS
  The present retrospective study was based on 343 HIV patients diagnosed from 2005 to 2010 from two clinics in Saskatoon, Saskatchewan. Disease progression was defined as the time from diagnosis to immunological AIDS (CD4 count <200 cells/μL) and death. Uni- and multivariable Cox proportional hazards models were used.
  
  
  RESULTS
  Of the 343 patients, 79% had a history of IDU, 77% were hepatitis C virus (HCV) coinfected and 67% were of Aboriginal descent. The one-year and three-year immunological AIDS-free probabilities were 78% and 53%, respectively. The one-year and three-year survival probabilities were 97% and 88%, respectively. Multicollinearity among IDU, HCV and ethnicity was observed and, thus, separate models were built. HCV coinfection (HR 2.9 [95% CI 1.2 to 6.9]) was a significant predictor of progression to immunological AIDS when controlling for baseline CD4 counts, treatment, age at diagnosis and year of diagnosis. For survival, only treatment use was a significant predictor (HR 0.34 [95% CI 0.1 to 0.8]). HCV coinfection was marginally significant (P=0.067).
  
  
  CONCLUSIONS
  Baseline CD4 count, HCV coinfection, year of diagnosis and treatment use were significant predictors of disease progression. This highlights the importance of early treatment and the need for targeted interventions for these particularly vulnerable populations to slow disease progression.
authors.affiliation: Department of Community Health and Epidemiology, University of Saskatchewan, Saskatoon;
authors.forename: Stephanie
authors.initials: S
authors.lastname: Konrad
authors.affiliation: Department of Medicine, University of Saskatchewan, Saskatoon;
authors.forename: Stuart
authors.initials: S
authors.lastname: Skinner
authors.affiliation: First Nations & Inuit Health Branch, Saskatchewan Region, Health Canada, Regina, Saskatchewan.
authors.forename: Germain Bukassa
authors.initials: GB
authors.lastname: Kazadi
authors.affiliation: Department of Medicine, University of Saskatchewan, Saskatoon;
authors.forename: Kali
authors.initials: K
authors.lastname: Gartner
authors.affiliation: Department of Community Health and Epidemiology, University of Saskatchewan, Saskatoon;
authors.forename: Hyun June
authors.initials: HJ
authors.lastname: Lim
keywords: Aboriginal ethnicity; Disease progression; HIV/AIDS; Hepatitis C coinfection; Injection drug use; Survival