Abstract
OBJECTIVE: We assessed the impact of differing laboratory reporting scenarios on the completeness of estimates of people living with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) (PLWHA) in the U.S., which are used to guide allocation of federal Ryan White funds. METHODS: We conducted a four-year simulation study using clinical and laboratory data on 1,337 HIV-positive women, including 477 (36%) who did not have AIDS at baseline. We estimated the completeness of HIV (non-AIDS) case ascertainment for three laboratory reporting scenarios: CD4 < 200 cells/microL and detectable viral load (Scenario A); CD4 < 500 cells/microL and no viral load reporting (Scenario B); and CD4 < 500 cells/microL and detectable viral load (Scenario C). RESULTS: Each scenario resulted in an increasing proportion of HIV (non-AIDS) cases being ascertained over time, with Scenario C yielding the highest by Year 4 (Year 1: 69.0%, Year 4: 88.1%), followed by Scenario A (Year 1: 63.3%, Year 4: 84.5%), and Scenario B (Year 1: 43.0%, Year 4: 67.7%). Overall completeness of PLWHA ascertainment after four years was highest for Scenario C (95.8%), followed by Scenario A (94.5%), and Scenario B (88.5%). CONCLUSIONS: Differences in laboratory reporting regulations lead to substantial variations in the completeness of PLWHA estimates, and may penalize jurisdictions that are most successful at treating HIV/AIDS patients or those with weak or incomplete HIV/AIDS surveillance systems.