Hendriks J C, Medley G F, van Griensven G J, Coutinho R A, Heisterkamp S H, van Druten H A
Department of Public Health, Municipal Health Service, Amsterdam, The Netherlands.
AIDS. 1993 Feb;7(2):231-9. doi: 10.1097/00002030-199302000-00012.
The treatment-free incubation period distribution was estimated from data obtained from a cohort of homo/bisexual men in Amsterdam.
Participants in a cohort study that started in Amsterdam at the end of 1984 were seen at 3- or 6-monthly intervals. The analysis excluded time since the start of zidovudine treatment (given to 27 individuals) and no cohort member received primary Pneumocystis carinii pneumonia prophylaxis (i.e., before AIDS diagnosis) before February 1990.
Both HIV-positive (n = 269) and HIV-seroconverted (n = 79) homosexual men were included in this study. Of these, 68 developed AIDS before February 1990. The unobserved dates of seroconversion were obtained by multiple imputation. The incubation period distribution was estimated from these data by direct Kaplan-Meier analysis and by using parametric Weibull and gamma distributions (including a parameter describing the probability of never progressing to AIDS). Our results are compared with published estimates of progression to AIDS from other homo/bisexual cohort studies.
Both the Weibull and the gamma distributions provide equally good empirical descriptions of the incubation period distribution for up to 7 years postseroconversion, but the estimated gamma distribution (median, 9.2; mean, 10.2; percentage AIDS at 7 years, 33%) should be preferred beyond that time, due to a slowing of the hazard rate. There is insufficient information to be able to estimate accurately the probability of never progressing to AIDS.
The time-dependent pattern of HIV incidence should be considered in the analysis of prevalent cohort studies. Our results are in agreement with other homo/bisexual cohort studies, and will be valuable for future comparison with and understanding of the epidemiological consequences of clinical treatment that delays the onset of AIDS.
根据从阿姆斯特丹一组同性恋/双性恋男性队列中获取的数据，估算未接受治疗的潜伏期分布情况。
1984年末在阿姆斯特丹启动的一项队列研究的参与者，每隔3或6个月接受一次检查。分析排除了齐多夫定治疗开始后的时间（27人接受了该治疗），且在1990年2月之前，没有队列成员接受过原发性卡氏肺孢子虫肺炎预防治疗（即在艾滋病诊断之前）。
本研究纳入了HIV阳性（n = 269）和HIV血清转化（n = 79）的同性恋男性。其中，68人在1990年2月之前患上了艾滋病。通过多重填补法获取未观察到的血清转化日期。通过直接的Kaplan-Meier分析以及使用参数化的威布尔分布和伽马分布（包括一个描述从未进展至艾滋病的概率的参数），从这些数据中估算潜伏期分布。我们的结果与其他同性恋/双性恋队列研究中已发表的艾滋病进展估计值进行了比较。
对于血清转化后长达7年的潜伏期分布，威布尔分布和伽马分布都能提供同样良好的经验描述，但由于风险率放缓，超过该时间后，应优先选择估计的伽马分布（中位数为9.2；均值为10.2；7年后艾滋病患者百分比为33%）。没有足够的信息能够准确估计从未进展至艾滋病的概率。
在分析现患队列研究时，应考虑HIV发病率随时间变化的模式。我们的结果与其他同性恋/双性恋队列研究一致，对于未来与延迟艾滋病发病的临床治疗的流行病学后果进行比较和理解将具有重要价值。
