Profiling advanced disease in an Asian clinical human immunodeficiency virus cohort: comparison of two definitions for acquired immunodeficiency syndrome.

OBJECTIVE To compare advanced human immunodeficiency virus disease defined immunologically and clinically by evaluating the characteristics of human immunodeficiency virus patients in Hong Kong. DESIGN Retrospective observational study. SETTING A human immunodeficiency virus cohort database established at a university and the major human immunodeficiency virus specialist services in Hong Kong. PATIENTS Patients diagnosed with acquired immunodeficiency syndrome at the study centres between 1985 and 2006 were included. MAIN OUTCOME MEASURES Comparison of advanced human immunodeficiency virus disease defined (a) clinically as World Health Organization stage IV, and (b) immunologically as a CD4 count lower than 350/microL. RESULTS Between 1985 and 2006, a total of 1317 patients, a majority of whom Chinese, were evaluated. Of these, 914 (69%) and 335 (25%) fulfilled the criteria for immunologically and clinically defined advanced disease, respectively. The mean age of the study population was 38 years and male-to-female ratio 4:1. There were two peaks in the frequency distribution of CD4 counts, one at a low count of less than 100/microL and the other between 200 and 400/microL. All except four with clinically defined advanced disease had CD4 counts lower than 350/microL on presentation. Of those with immunologically defined advanced disease, men having sex with men accounted for a lower proportion in the clinically advanced category, and Pneumocystis pneumonia was the commonest advanced disease at presentation. CONCLUSIONS Both clinical and immunological definitions provide a consistent means for assessing advanced disease, the implications of which are different. Such profiling has been made possible through the operation of a standardised cohort database, which is useful in (1) enhancing human immunodeficiency virus epidemiology studies, and (2) evaluating the performance of public health services.