Sawanpanyalert P, Supawitkul S, Yanai H, Saksoong P, Piyaworawong S
Department of Medical Services, Ministry of Public Health, Nonthaburi, Thailand.
J Epidemiol. 1999 Apr;9(2):114-20. doi: 10.2188/jea.9.114.
To determine trends and associated risk factors of HIV incidence (1989-1997) in a drug abuse treatment clinic in northern Thailand where HIV is epidemic.
Retrospective cohort study.
Nine-years (1989-1997) of data (excluding names) from the logbook of drug abusers seeking treatments in Mae Chan Hospital in Chiangrai Thailand, were transcribed and double-entered into separate computer files which were later validated against each other. For each patient, the dates of the first HIV negative, the last HIV negative, and the first HIV positive were determined. A retrospective cohort of drug users who were initially HIV-negative and treated for more than once was constructed. HIV seroconversion was assumed to follow a uniform distribution between the last negative and the first positive HIV tests. The incidence rates and their 95% confidence intervals (CI) were calculated.
Of the 378 repeat patients, 16 (4.2%) HIV seroconverted. This is equivalent to 5.11 per 100 person-years of observation (PYO) (95% CI = 3.13-8.35). The incidence remained relatively stable over the study period while the prevalence was on the decline. The younger, Thai lowlanders, drug injectors had higher incidence rates than the older, ethnic minorities and drug smokers, respectively.
Prevalence can give illusional results. It is necessary to know baseline HIV incidence to monitor and evaluate an HIV intervention program.
确定泰国北部一家药物滥用治疗诊所（该地区为艾滋病流行区）1989年至1997年期间艾滋病病毒感染率的趋势及相关危险因素。
回顾性队列研究。
转录泰国清莱府湄占医院药物滥用者治疗登记本中9年（1989年至1997年）的数据（不包括姓名），并将其双录入到不同的计算机文件中，随后相互验证。确定每位患者首次艾滋病病毒检测阴性、最后一次艾滋病病毒检测阴性以及首次艾滋病病毒检测阳性的日期。构建一个最初艾滋病病毒检测阴性且接受过多次治疗的药物使用者回顾性队列。假定艾滋病病毒血清转化在最后一次阴性检测和首次阳性检测之间呈均匀分布。计算发病率及其95%置信区间（CI）。
在378名复诊患者中，16人（4.2%）发生了艾滋病病毒血清转化。这相当于每100人年观察期（PYO）有5.11例（95%CI = 3.13 - 8.35）。在研究期间发病率保持相对稳定，而患病率呈下降趋势。年轻人、泰国低地人、注射吸毒者的发病率分别高于年长者、少数民族和吸烟吸毒者。
患病率可能产生误导性结果。了解艾滋病病毒感染率基线对于监测和评估艾滋病病毒干预项目很有必要。
