在愛滋病毒感染匿名篩檢服務中利用三種不同方式 估算愛滋病毒感染發生率

Abstract

背景：雖然我國靜脈藥癮愛滋病毒感染疫情在推動減害計畫後已獲得有效控制，但經由性行為感染的新通報感染者，特別是男男性行為者（含雙性間性行為者），仍持續增加。我們有必要釐清新個案的增加是因為政府擴大愛滋病毒篩檢，或因為愛滋病毒感染發生率在高危險族群中確有上升。 目的：我們利用前來台大醫院接受自願匿名諮詢篩檢者的檢驗結果及背景資料，以三種不同方法估算愛滋病毒感染新個案或近期感染發生率變化趨勢，並比較不同危險族群發生率是否有統計顯著差異。 方法：自2006年4月至2010年12月止，共有10,198人次使用衛生署疾病管制局補助之台大醫院匿名篩檢服務。篩檢方法係採用顆粒凝集反應 （Particle Agglutination, SFD HIV 1/2 PA, Bio-Rad FUJIREBIO, Japan) 偵測愛滋病毒抗體；若為陽性則進一步以西方墨點法確認愛滋病毒感染。我們收集受檢者在篩檢時填寫之自填式問卷資料，包含基本人口學及行為變項，並以下列三種方式計算愛滋病毒感染發生率：一、以自行回顧前次篩檢時間（SR）估算新個案發生率。二、以獨特的識別碼（UTC）估算新個案發生率。三、以血清檢測方式（BED）估算近期愛滋病毒感染發生率（153天內）。年度趨勢分析分別以Poisson regression及weighted linear regression分析。而發生率比（rate ratio）或風險比（odds ratio）則以Poisson regression或配合病例研究對照設計以conditional logistic regression分析。 結果：在10,198人次篩檢中，有360位受檢者證實感染愛滋病毒（3.5%）。以三種方法計算的平均愛滋病毒感染發生率分別為每一百人年5.24、5.76及3.83例。以BED法配合病例研究對照設計估算近期愛滋病毒感染發生率比顯示男男性行為者相較於異性間性行為者，風險比顯著較高（odds ratio, 9.31; 95% CI, 4.77-18.20）。以下5個行為變項不論在所有受檢者中或男男性行為者中均為近期愛滋病毒感染或新個案發生之危險因子：性伴侶確認為愛滋病毒感染陽性者、保險套使用比率未達100%、曾使用違禁藥品者、基礎血清梅毒篩檢大於或等於4倍者及有肛交性行為者（BED and SR：所有p<0.05）。在男男性行為者中，自2006至2010年，以自行回顧前次篩檢時間（SR）估算新個案發生率有顯著逐年上升趨勢（p=0.0025; Poisson regression）；而以血清檢測方式（BED）並考慮重複篩檢間距（0.5年）估算近期愛滋病毒感染發生率則呈現持平趨勢，逐年變化未達統計顯著（p=0.6388, weighted linear regression）。 結論：在使用匿名篩檢服務者中，不論是愛滋病毒新個案發生率或近期感染發生率，均無下降趨勢。男男性行為者近期愛滋病毒感染的風險確實高於異性間性行為者，尤其是曾使用違禁藥物或有其他高危險行為者。

Introduction: The annual case number of persons who are newly diagnosed with human immunodeficiency virus (HIV) infection continues to increase in Taiwan after successful control of HIV outbreak among injecting drug users. Whether the increasing case number is related to increased awareness and HIV testing activities or increasing incidence in high-risk populations, such as men who have sex with men (MSM), remains to be investigated. Objectives: In this study, we aimed to compare three methods to estimate the incidence rates of HIV infection among persons seeking voluntary, anonymous counseling and testing services (VCT) at a university hospital and the difference incidence rates among risk populations. Methods: Between 1 April 2006 and 30 September, 2010, 10198 persons sought VCT services for HIV testing at the National Taiwan University Hospital, which was sponsored by the Taiwan Centers for Disease Control (CDC).Anti-HIV antibody was tested using particle agglutination (SFD HIV 1/2 PA, Bio-Rad FUJIREBIO, Japan) and HIV infection was confirmed using Western blot. Demographics and behavioral data were obtained at the time of counseling. Three methods were used to estimate HIV incidence: first, based on self-reported dates of prior tests (SR); second, based on linking prior records with an unique testing code (UTC); and third, based on the BED IgG-Capture Enzyme Immunoassay (BED assay) for recent HIV infection (within 153 days). Trends in HIV incidence were analyzed by Poisson regression and weighted linear regression. The incidence rate ratios or odds ratios between risk populations were analyzed by Poisson regression and conditional logistic regression in the case-control study. Results: During the study period, 360 individuals (3.5%) were test positive for HIV infection (3.5%). Comparable overall seroconversion rate was found by the three methods, 5.24, 5.76, and 3.83 per 100 person-years [PY], respectively. The incidence rate of recent HIV infections in MSM was significantly higher than that in heterosexuals in the case-control study (odds ratio, 9.31; 95% CI, 4.77-18.20). Five behaviors/characteristics: “ever use illicit drug”, “ the baseline RPR≧4”, “condom use in anal sex <100%” , “confirmed sexual partner to be HIV-positive”, or “having anal sex” were risk factors for both recent HIV infection and new HIV cases among either all clients or MSM (SR and BED, all p values <0.05). There was a trend of increase in new HIV cases incidence in MSM from 2006 to 2010 by the SR method (p=0.0025, Poisson regression), but the trend in the incidence rate of recent HIV infection in MSM was not significant during the study period by the BED assay (p=0.6388, weighted linear regression). Conclusions: From 2006 to 2010, the incidence rates of HIV infections among clients of this VCT program did not decrease. MSM had a significantly higher incidence rate of recent HIV infections than heterosexuals, especially those with illicit drug use or other high risk behaviors.