title: Setting a minimum threshold CD4 count for initiation of highly active antiretroviral therapy in HIV-infected patients.
abstract: The aim of our study was to determine a minimum threshold CD4 count for highly active antiretroviral therapy (HAART) initiation in HIV-infected patients. A schema using longitudinal data from a clinical cohort was designed. The presenting CD4 counts of asymptomatic HIV-infected patients in Hong Kong were evaluated in relation to their progression to AIDS within 1 year of diagnosis of HIV infection. A graph was generated to depict the changes in the percentage of cumulative AIDS diagnoses for every 10 cell/microL increase in presenting CD4 count. Of 181 patients, 24 had developed AIDS within 1 year of diagnosis of HIV infection. Setting the CD4 count threshold at 150 cells/microL gave a good balance between the number of preventable AIDS-defining events and the number of non-AIDS patients initiating HAART. No extra AIDS-defining events occurred when the CD4 count threshold was reduced from 200 to 150 cells/microL, despite the addition of 13 more patients. In multivariate Cox regression analysis, presenting CD4 count was a significant predictor for AIDS occurrence. The relative hazard for AIDS occurrence of patients with presenting CD4 counts <or=150 cells/microL was 27-fold greater. We suggest a CD4 count of 150 cells/microL as the minimum threshold for HAART initiation in a cohort of Chinese HIV-infected patients. At this level, 20.8% of the AIDS-defining events could be prevented. While a cut-off of 200 cells/microL remains a standard for considering HAART initiation, the minimum threshold signifies a critical moment for timely intervention to be introduced.
authors.affiliation: Integrated Treatment Centre, Centre for Health Protection, Department of Health, Kowloon, Hong Kong SAR, Hong Kong. cfho@dhspp.net
authors.forename: Cf
authors.initials: C
authors.lastname: Ho
authors.forename: Ss
authors.initials: S
authors.lastname: Lee
authors.forename: Kh
authors.initials: Kh
authors.lastname: Wong
authors.forename: Ls
authors.initials: L
authors.lastname: Cheng
authors.forename: My
authors.initials: M
authors.lastname: Lam
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000517:prevention & control; D000293:Adolescent; D000328:Adult; D000368:Aged; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods*; D018791:CD4 Lymphocyte Count; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006678:HIV / Q000254:growth & development*; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology* / Q000821:virology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D019562:Viral Load