College of Public Health, University of Iowa, Iowa City, IA, USA.
VA Connecticut Health Care System, West Haven, CT, USA.
AIDS Behav. 2022 Feb;26(2):613-622. doi: 10.1007/s10461-021-03419-1. Epub 2021 Aug 6.
The CD4 depletion model estimates diagnosis delays by approximating infection date from CD4 T-cell count at diagnosis, and back-calculation can compute the proportion of undiagnosed PLWHA. The model assumes the immigration of PLWHA to the U.S. is negligible and counts as a transmission event, which may be impractical outside high prevalence states. Duration of U.S. residency among foreign-born PLWHA and diagnosis delays were compared. The impact on estimates of undiagnosed PLWHA was tested through simulation with different proportions of foreign-born people assumed to have acquired HIV abroad. In 67% of foreign-born people, the mean (SD) years of delay (9.9 (6.3)) exceeded the duration of U.S. residency (2.0 (1.9)). Additionally, inaccuracies in the estimates for proportions of undiagnosed PLWHA were pronounced when foreign-born people who acquired HIV abroad comprised 30% of diagnoses. The CD4 model inadvertently misclassified some diagnoses as in-state transmission events. Consequently, simulated results demonstrated inaccuracies and unstable calculations.
CD4 细胞耗竭模型通过在诊断时用 CD4 T 细胞计数来近似估计感染日期，然后回溯计算未确诊的 PLWHA 比例。该模型假设 PLWHA 移民到美国的人数可以忽略不计，并将其视为传播事件，这在高流行率州以外可能不切实际。比较了外国出生的 PLWHA 的美国居住时间和诊断延迟。通过模拟不同比例的假设在国外获得 HIV 的外国出生者，测试了对未确诊的 PLWHA 估计数的影响。在 67%的外国出生者中，平均（SD）延迟年数（9.9（6.3））超过了美国居住时间（2.0（1.9））。此外，当在国外获得 HIV 的外国出生者占诊断的 30%时，未确诊的 PLWHA 比例的估计值会出现明显的不准确。CD4 模型无意中将一些诊断错误地归类为州内传播事件。因此，模拟结果显示存在不准确和不稳定的计算。
