HIV-1 disease progression and AIDS-defining disorders in rural Uganda

Summary

Background

The majority of people infected with HIV-1 live in Africa, yet little is known about the natural history of the disease in that continent. We studied survival times, disease progression, and AIDS-defining disorders, according to the proposed WHO staging system, in a population-based, rural cohort in Uganda.

Methods

In 1990 we recruited a random sample of people already infected with HIV-1 (as prevalent cases) detected during the initial survey round of a general-population study to form a natural-history cohort. Individuals from the general-population cohort who seroconverted between 1990 and 1995 (incident cases) were also invited to enrol. Participants were seen routinely every 3 months and when they were iII.

Findings

By the end of 1995, 93 prevalent cases and 86 incident cases had been enrolled. Four patients in the prevalent group were in stage 4 (AIDS) at the initial visit. During the next 5 years, 37 prevalent cases progressed to AIDS. Seven incident cases progressed to AIDS and the cumulative progression to AIDS at 1, 3, and 5 years after seroconversion was 2%, 6%, and 22%, respectively. The cumulative probability of AIDS at 4 years from entering stages 1, 2, and 3 was 11%, 33%, and 58%, respectively. There were 47 deaths among prevalent cases and seven among incident cases during follow-up. The cumulative mortality 4 years after patients entered stages 1, 2, 3, and 4 was 9%, 33%, 56%, and 86%, respectively. The median survival after the onset of AIDS was 9·3 months.

Interpretation

Our results are important for the setting of priorities and rationalisation of treatment availability in countries with poor resources. We found that progression rates to AIDS are similar to those in developed countries for homosexual cohorts and greater than for cohorts infected by other modes of transmission. However, we have found that the rates of all-cause mortality are much higher and the progression times to death are shorter than in developed countries.

Introduction

WHO estimates that of the 16 million people infected with HIV-1 worldwide, more than 10 million live in sub-Saharan Africa.¹ Although progression rates of HIV-1 disease for Africans in Europe2, 3 and differences in progression of HIV-1 disease and AIDS-defining disorders between ethnic groups in the USA⁴ have been reported, few studies have addressed clinical manifestations and disease progression in Africa. AIDS cases were first reported in Uganda in 1985.⁵ By the end of 1995, more than 48 000 cases of AIDS had been reported.⁶ More than 1 million of a total population of 18 million are estimated to be infected with HIV-1.⁷ The management of patients with disease related to HIV-1 is difficult when yearly governmental health spending is only $3 per person. Hospital facilities are overwhelmed by the number of AIDS cases, budgets are strained, and drugs are often in short supply.⁸ The management of many young terminally ill patients puts health workers under a great deal of stress.

We report on the progression of HIV-1 disease and AIDS-defining disorders according to the proposed 1990 WHO staging system.⁹ Classification of stages is based on clinical criteria (including a performance scale) in four prognostic categories for adults who are confirmed as positive for HIV-1 antibodies. The staging is hierarchical; once a disorder classified in a higher stage develops, the individual remains in the higher stage irrespective of whether the disorder resolves. We chose this system because it should allow comparison of the natural history of HIV-1 infection, including survival times, in different communities and cohorts, since each stage represents the progression of immune deterioration and, therefore, prognostic significance. Stage 4 and AIDS are used synonymously in this paper.

We report on the natural history of HIV-1 infection and survival up to Dec 31, 1995, in a continuing, population-based, rural-cohort study in Uganda.