title: Additive or sequential nucleoside analogue therapy compared with continued zidovudine monotherapy in human immunodeficiency virus-infected patients with advanced disease does not prolong survival: an observational study.
abstract: To study the effect of sequential or additive use of zalcitabine or didanosine on survival in 308 human immunodeficiency virus-infected patients with advanced disease treated with zidovudine, an observational study using time-dependent Cox proportional hazards models was done. Changing to sequential or additive therapy was based on deterioration of a patient's health status, a significant drop in CD4 cell count, or intolerance for zidovudine. The median CD4 cell count at baseline was 110 x 10(6)/L; 42% of patients had AIDS. The median count before a change in therapy was 50 x 10(6)/L. Additive or sequential treatment was associated with an increased risk for death (relative hazard, 1.59; 95% confidence interval [CI], 1.01-2.49; and 1.58; 95% CI, 1.10-2.37, respectively). Adjustment of the models for prognostic factors failed to substantially affect this observation. Possibly the lack of benefit in this study is because patients switched therapy at advanced stages, whereas the switch may be more effective in early disease.
authors.affiliation: Academic Medical Center, University of Amsterdam, Department of Medicine, Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: van Leeuwen
authors.forename: G J
authors.initials: GJ
authors.lastname: Bonsel
authors.forename: P
authors.initials: P
authors.lastname: Reiss
authors.forename: S A
authors.initials: SA
authors.lastname: Danner
authors.forename: J M
authors.initials: JM
authors.lastname: Lange
mesh_terms: D000328:Adult; D000367:Age Factors; D019380:Anti-HIV Agents / Q000008:administration & dosage*; D016049:Didanosine / Q000008:administration & dosage; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D015658:HIV Infections / Q000188:drug therapy* / Q000401:mortality*; D015497:HIV-1; D006801:Humans; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D015996:Survival Rate; D016896:Treatment Outcome; D016047:Zalcitabine / Q000008:administration & dosage; D015215:Zidovudine / Q000008:administration & dosage
chemical_list: D019380:Anti-HIV Agents; D015215:Zidovudine; D016047:Zalcitabine; D016049:Didanosine