PRE-AIDS MORTALITY IN THE EDINBURGH-CITY-HOSPITAL HIV COHORT

In this paper, we look at the incidence and predictive factors of pre- AIDS mortality among HIV-infected individuals, and injecting drug user s (IDUs) in particular, and compare IDUs with non-IDUs. 627 patients ( 73 per cent IDUs) of the Edinburgh City Hospital HIV Cohort were enrol led pre-AIDS and followed up until September 1994. Analyses were perfo rmed using cumulative hazard and cumulative incidence estimators for a competing risks model, the Cox proportional hazards model and the non -parametric hazard estimator of Fusaro et al, (1993). The effects of a ge and CD4 T-lymphocyte cell count, progressively depleted during HIV progression, were investigated, 60 deaths occurred in AIDS-free patien ts during follow-up; 25 were drug-related deaths in IDUs. Pre-AIDS mor tality was higher among IDUs than non-IDUs (p=0.07). The cumulative in cidences of pre-AIDS death after five years from enrolment were 11 per cent in IDUs and 6 per cent in non-IDUs; the cumulative AIDS incidenc es were, respectively, 19 per cent and 32 per cent. After eight years, cumulative pre-AIDS death incidence was 15 per cent among IDUs; cumul ative AIDS incidence among IDUs was 35 per cent. Both groups had simil ar risks of medically-related (non-AIDS) MRNA - death, Age and CD4 cou nt were both individually predictive of MRNA death (relative risks (RR s): 2.1 per decade of life, p < 0.01; and 1.9 for each 100 cells per 1 00 mu l lost, p < 0.0001), although when used together age was less si gnificant (RR 1.6, p=0.07), Neither was statistically significant for drug-related mortality, although hazard may be lower in older individu als and may increase with falling CD4 count. The drug-related mortalit y was 1.1 per cent:2.3 per cent in the first two years after enrolment , and 0.4 per cent thereafter. We conclude that older HIV-infected ind ividuals are at greater risk of medically-related death before AIDS. T his risk increases as CD4 count declines. Drug-related hazard may be g reater in younger individuals and may increase as CD4 counts fall, but neither effect was formally significant. (C) 1997 by John Wiley & Son s, Ltd.