Moore R D, Keruly J C, Chaisson R E
Johns Hopkins University School of Medicine, Baltimore, Md, USA.
Arch Intern Med. 1996 May 27;156(10):1073-7.
Zidovudine therapy improves survival in advanced human immunodeficiency virus (HIV) infection and delays progression from earlier stages to advanced stage of HIV disease. The duration of the benefit of zidovudine therapy, however, may be limited.
To quantitate the duration of the survival benefit of zidovudine therapy in a heterogeneous patient population receiving care for HIV infection in an urban clinic.
We analyzed data from 393 HIV-infected patients with CD4+ cell counts of 0.5 x 10(9)/L (500 cells/microliter.) or less who first presented for care at The Johns Hopkins HIV Clinic, Baltimore, Md, from July 1989 through December 1993. Follow-up extended to a maximum of 3 years (median, 2 years). Survival probabilities in patients who received and who did not receive zidovudine therapy were analyzed by Kaplan-Meier methods and by multivariate Cox proportional hazards regression analysis adjusting for both time-dependent and fixed prognostic covariates.
Adjusting for baseline differences in CD4+ cell count, clinical stage of HIV disease, and prophylaxis for Pneumocystis carinii pneumonia, Cox regression analysis showed a significant effect of zidovudine compared with no treatment on the risk of dying during the first year of therapy (relative hazard for death, 0.32; 95% confidence interval [CI], 0.18 to 0.59). However, analysis of the time-dependent effect of zidovudine therapy showed that there was a diminishing relative hazard between treatment and no treatment of 0.75 (95% CI, 0.45 to 1.26) at 1 to 2 years of therapy and a relative hazard of 1.61 beyond 2 years (95% CI, 0.70 to 3.71).
The survival advantage of zidovudine therapy is time dependent, lasting between 1 and 2 years in patients with CD4+ cell counts of 0.5 x 10(9)/L or less. Alternative antiretroviral treatment may be indicated at that time.
齐多夫定疗法可提高晚期人类免疫缺陷病毒（HIV）感染者的生存率，并延缓HIV疾病从早期阶段进展至晚期。然而，齐多夫定疗法的获益持续时间可能有限。
在一家城市诊所接受HIV感染治疗的异质性患者群体中，定量评估齐多夫定疗法的生存获益持续时间。
我们分析了1989年7月至1993年12月期间首次在马里兰州巴尔的摩市约翰霍普金斯HIV诊所就诊的393例CD4+细胞计数为0.5×10⁹/L（500个细胞/微升）或更低的HIV感染患者的数据。随访最长达3年（中位数为2年）。采用Kaplan-Meier方法以及多变量Cox比例风险回归分析对接受和未接受齐多夫定治疗的患者的生存概率进行分析，并对随时间变化和固定的预后协变量进行调整。
在对CD4+细胞计数、HIV疾病临床分期以及卡氏肺孢子虫肺炎预防措施的基线差异进行调整后，Cox回归分析显示，与未治疗相比，齐多夫定在治疗的第一年对死亡风险有显著影响（死亡相对风险为0.32；95%置信区间[CI]为0.18至0.59）。然而，对齐多夫定疗法的时间依赖性效应分析显示，在治疗1至2年时，治疗组与未治疗组之间的相对风险逐渐降低至0.75（95%CI为0.45至1.26），而在2年之后相对风险为1.61（95%CI为0.70至3.71）。
齐多夫定疗法的生存优势具有时间依赖性，对于CD4+细胞计数为0.5×10⁹/L或更低的患者，该优势持续1至2年。届时可能需要采用其他抗逆转录病毒治疗方法。
