Yu L M, Easterbrook P J, Marshall T
HIV Epidemiology Unit, Chelsea and Westminster Hospital, London, UK.
Int J Epidemiol. 1997 Dec;26(6):1367-72. doi: 10.1093/ije/26.6.1367.
To describe the relationship between absolute CD4 count and CD4%, and the influence on this of gender, risk group, age, a diagnosis of AIDS, use of zidovudine (ZDV) therapy and PCP prophylaxis.
9203 paired serial measurements of CD4 count and CD4% on 1017 initially AIDS-free and ZDV-naive HIV positive patients from a London-based cohort were available for analysis. Multi-level regression procedures were used on log-transformed data to relate values of CD4 count to a given level of CD4%. We estimated the effect of selected covariates on this relationship from the exponent of the covariate coefficient.
A strong linear relationship was found between log CD4 and log CD4%, CD4 = e 1.78(CD4%)1.26 or 5.93 (CD4%)1.26 (excluding covariates). Based on this model, a CD4% of 5%, 15%, and 30% corresponded to an estimated CD4 count (95% confidence interval [CI]) of 45 cells/mm3 (17-117 cells/mm3), 182 cells/mm3 (64-499 cells/mm3) and 438 cells/mm3 (132-1395 cells/mm3), respectively. However, after adjustment for selected covariates, the predicted CD4 count for a given CD4% was found to be lower among heterosexuals and injecting drug users as compared with homosexual men by 30% and 17% respectively; following an AIDS diagnosis by 21%; and after initiation of ZDV therapy and PCP prophylaxis by 19% and 10%, respectively.
This analysis should be useful to clinicians and researchers in relating values of CD4 count to CD4%, although we have demonstrated that this is not a simple relationship. The wide CI observed in the estimated CD4 count particularly at high CD4% values, and the adjustments necessary according to risk group, following an AIDS diagnosis and use of ZDV and PCP therapy limit its application in the clinical setting.
描述绝对CD4细胞计数与CD4%之间的关系，以及性别、风险组、年龄、艾滋病诊断、齐多夫定（ZDV）治疗的使用和肺孢子菌肺炎（PCP）预防对其的影响。
从伦敦的一个队列中选取了1017名最初无艾滋病且未接受过ZDV治疗的HIV阳性患者，对其进行了9203次CD4细胞计数和CD4%的配对系列测量，用于分析。对对数转换后的数据使用多水平回归程序，将CD4细胞计数的值与给定水平的CD4%相关联。我们从协变量系数的指数估计选定协变量对这种关系的影响。
在对数CD4与对数CD4%之间发现了很强的线性关系，CD4 = e 1.78(CD4%)1.26 或 5.93 (CD4%)1.26（不包括协变量）。基于该模型，CD4%为5%、15%和30%时，估计的CD4细胞计数（95%置信区间[CI]）分别为45个细胞/mm³（17 - 117个细胞/mm³）、182个细胞/mm³（64 - 499个细胞/mm³）和438个细胞/mm³（132 - 1395个细胞/mm³）。然而，在对选定协变量进行调整后，发现对于给定的CD4%，异性恋者和注射吸毒者的预测CD4细胞计数分别比同性恋男性低30%和17%；在诊断为艾滋病后低21%；在开始ZDV治疗和PCP预防后分别低19%和10%。
尽管我们已证明这不是一种简单的关系，但该分析对临床医生和研究人员将CD4细胞计数的值与CD4%相关联应是有用的。在估计的CD4细胞计数中观察到的宽置信区间，特别是在高CD4%值时，以及根据风险组、艾滋病诊断以及ZDV和PCP治疗的使用进行必要调整，限制了其在临床环境中的应用。
