An Ming-Wen, Frangakis Constantine E, Musick Beverly S, Yiannoutsos Constantin T
Department of Biostatistics, Johns Hopkins University, Baltimore, Maryland 21205, USA.
Biometrics. 2009 Mar;65(1):301-6. doi: 10.1111/j.1541-0420.2008.01043.x. Epub 2008 May 13.
In 2007, there were 33.2 million people around the world living with HIV/AIDS (UNAIDS/WHO, 2007). In May 2003, the U.S. President announced a global program, known as the President's Emergency Plan for AIDS Relief (PEPFAR), to address this epidemic. We seek to estimate patient mortality in PEPFAR in an effort to monitor and evaluate this program. This effort, however, is hampered by loss to follow-up that occurs at very high rates. As a consequence, standard survival data and analysis on observed nondropout data are generally biased, and provide no objective evidence to correct the potential bias. In this article, we apply double-sampling designs and methodology to PEPFAR data, and we obtain substantially different and more plausible estimates compared with standard methods (1-year mortality estimate of 9.6% compared to 1.7%). The results indicate that a double-sampling design is critical in providing objective evidence of possible nonignorable dropout and, thus, in obtaining accurate data in PEPFAR. Moreover, we show the need for appropriate analysis methods coupled with double-sampling designs.
2007年，全球有3320万人感染艾滋病毒/艾滋病（联合国艾滋病规划署/世界卫生组织，2007年）。2003年5月，美国总统宣布了一项全球计划，即总统艾滋病紧急救援计划（PEPFAR），以应对这一流行病。我们试图估算PEPFAR中的患者死亡率，以便对该计划进行监测和评估。然而，这一努力受到高失访率的阻碍。因此，标准生存数据以及对观察到的未退出数据的分析通常存在偏差，并且无法提供纠正潜在偏差的客观证据。在本文中，我们将双重抽样设计和方法应用于PEPFAR数据，与标准方法相比，我们获得了截然不同且更合理的估计值（1年死亡率估计值为9.6%，而标准方法为1.7%）。结果表明，双重抽样设计对于提供可能不可忽略的失访的客观证据至关重要，从而对于在PEPFAR中获得准确数据也至关重要。此外，我们表明需要结合双重抽样设计采用适当的分析方法。
