Objective: To identify a definition of presentation after clinical or immunological disease progression that will reliably identify an individual at high risk of mortality over the first 3 months after HIV diagnosis and that can be adopted as a basis for comparing over time and regions.
Design: An observational cohort study.
Methods: Individuals seen for the first time at a UK Collaborative HIV Cohort study clinic from 1996 to 2006 were identified. Two immunological (CD4 cell count < 200 cells/microl and CD4 cell count <50 cells/microl) and two clinical (AIDS and severe/moderate AIDS) criteria for presentation with advanced HIV disease were compared, as well as combinations of them. The predictive ability of each diagnosis for identifying individuals who died in the first 3 months after HIV diagnosis was assessed.
Results: Fifteen thousand seven hundred and seventy-four patients were included, of whom 1495 (9.5%), 4231 (26.8%), 1523 (9.7%) and 379 (2.4%) had a CD4 cell count below 50 cells/microl, CD4 cell count below 200 cells/microl, AIDS or severe/moderate AIDS at diagnosis; CD4 cell counts were unavailable for 2264 (14.4%) patients. Two hundred and six (1.3%) patients died within the first 3 months. Sensitivities of the individual criteria ranged from 18.0% (severe/moderate AIDS) to 50.5% (CD4 cell count < 200 cells/microl) with specificities ranging from 73.5% (CD4 < 200 cells/microl) to 97.8% (severe/moderate AIDS). Combinations of clinical and immunological criteria increased the sensitivity but decreased the specificity.
Conclusion: We propose that presentation with 'advanced HIV disease' is presentation with a CD4 cell count below 200 cells/microl or AIDS, whereas 'late' presentation is defined as presentation when the CD4 cell count is below that when treatment should be initiated (currently CD4 cell count < 350 cells/microl or AIDS).