Background: Natural history studies of untreated HIV infection are useful for clinicians, public health experts and policymakers to improve and monitor care, plan services and control, and to model the epidemic. Several natural history studies on homosexual men and intravenous drug users have been published from developed countries. A few studies have emerged on heterosexual populations from Africa. With an emerging epidemic, a similar study was required in India. This study was designed to determine the progression of HIV disease in a prevalent cohort of adult HIV-seropositive patients.
Methods: A prevalent cohort of 1009 patients comprising 488 asymptomatic HIV-seropositive persons, 259 with AIDS-related complex (ARC), and 262 with acquired immunodeficiency syndrome (AIDS) were recruited for the study at Sir J.J. Hospital, Mumbai. A case-control study was conducted to determine the correlation of clinical features and other factors with disease progression. Disease progression was determined from the asymptomatic stage to that of ARC and AIDS using time series analysis. The incubation period from HIV to AIDS was also determined, using Weibull curves.
Results: The median incubation periods for progression were: HIV to AIDS-7.9 years and ARC to AIDS--1.9 years. The median survival after developing AIDS was 19.2 months. A comparison of progressors and non-progressors revealed that disease progression correlated with clinical features such as chronic fever (OR 5.6), persistent generalized lymphadenopathy (OR 4.7), persistent cough for >1 month (OR 3.5), chronic diarrhoea (OR 3.3), oral candidiasis (OR 3.2), >10% loss of body weight within 1 month (OR 2.9), incident tuberculosis (OR 2.8) and herpes zoster (OR 2.5). The annual incidence of active clinical tuberculosis was 86/1503 person-years (5.7/ 100 person-years), the median time to occurrence of active tuberculosis was 21.6 months and the annual incidence of mortality was 96/2009 person-years (4.8/100 person-years, 95% CI 3.4, 6.2).
Conclusion: Progression to AIDS and death was faster among the heterosexual cohort in Mumbai than that reported for homosexual men and haemophiliacs in the USA and Europe. Strategies need to be developed to prevent the occurrence of tuberculosis among HIV-infected patients because that would help to reduce the morbidity and mortality. This is the first large study from the Indian subcontinent of a longitudinal follow up of HIV-infected persons. The findings will be useful for advocacy and assessing the impact of antiretroviral therapy (ART) in India.