PROGNOSTIC INDICATORS FOR AIDS AND INFECTIOUS-DISEASE DEATH IN HIV-INFECTED INJECTION-DRUG USERS - PLASMA VIRAL LOAD AND CD4(+) CELL COUNT

Context.-Plasma human immunodeficiency virus type 1 (HIV-1) viral load and CD4(+) cell count are used to predict prognosis of persons infect ed with HIV. However, whether combining these markers improves prognos tic accuracy and whether they predict prognosis for injection drug use rs (IDUs) and nonwhite persons infected with HIV has not been extensiv ely investigated. Objective.-To evaluate plasma viral load and CD4(+) cell count as prognostic indicators for the acquired immunodeficiency syndrome (AIDS) and infectious disease deaths. Design.-Cohort study in itiated in 1988 and 1989 with follow-up for up to 7.9 years. Participa nts.-Injection drug users infected with HIV recruited from the communi ty in Baltimore, Md. Main Outcome Measures.-Plasma HIV-1 RNA and CD4() cell count measured at baseline compared with time to first clinical AIDS diagnosis and death due to an infectious disease. Results.-Of 52 2 subjects, 96% were African American, 80% were male, 96% injected dru gs within the past 6 months, and the median age was 33 years. A total of 146 cases of AIDS and 119 infectious disease deaths were seen durin g a median follow-up period of 6.4 years. Time-fixed baseline levels o f viral load and CD4(+) cell count were independent predictors of prog ression to AIDS and infectious disease deaths, but in proportional haz ards models, viral load had better predictive value than CD4(+) cell c ount. Kaplan-Meier analysis of time to AIDS and to infectious disease deaths by Viral load (<500, 500-9999, 10 000-29 999, greater than or e qual to 30 000 copies/mL) at 3 levels of CD4(+) cell count (<0.20, 0.2 0-0.49, and greater than or equal to 0.50X10(9)/L [<200, 200-499, and greater than or equal to 500/uL]) was reduced to a 5-stage classificat ion scheme using a backward stepwise regression procedure. The 5-year cumulative probabilities for AIDS and infectious disease deaths ranged from 0% and 0%, respectively, for group I (viral load, <500 copies/mL ; CD4(+) cell count, 0.50X10(9)/L) to 81.2% and 76.1% respectively, fo r group V (viral load, greater than or equal to 10000 copies/mL; CD4() cell count, 0.20X10(9)/L). Conclusions.-In this study, plasma HIV-1 viral load independently and in combination with CD4(+) cell count mea surements provided powerful prognostic information for progression to AIDS and death caused by infectious disease in a population of predomi nantly African American IDUs. Combining categories of both markers pro vided a simple method for prognostically staging HIV disease.