用三种基数估计方法对广东省某市吸毒人群规模的估计研究

目的采用三种基数估计方法对广东省某地吸毒人群的规模进行估计，力图找到一种经济、方便、快捷和相对准确的基数估计方法。方法采用简易乘数法、捕获-再捕获法、公安人员定性估计的方法对该地的吸毒人群规模进行估计。结果公安人员定性估计该地吸毒人群数量为15900人，简易乘数法估计该地吸毒人群数量为15745～19614人。捕获．再捕获法估计该地吸毒人群数量为36210～41902人。三种不同方法估计数的中位数为18540人。结论该地吸毒人群规模估计数为18540人。简易乘数法是一种经济、简便、可行的基数估计方法，且能获得一个较为准确的估计数。     

深圳市2010年男男性行为人群基数估计调查

目的估计深圳市男男性行为人群(MSM)的规模,为调整防治策略和公共卫生资源的投放提供依据。方法使用捕获-再捕获方法对深圳市20个MSM场所进行调查,估计MSM人群的数量。结果两次调查共捕获MSM 2 982人,第一次1 577人,第二次1 405人,共标记312人,估计活跃在MSM场所的约有6 468~7 706人。对1 577知情者、MSM人群及场所业主进行定性访谈,估算深圳市约有MSM人群10万~20万人。结论深圳市MSM人群占男性人口的比例与全国的水平相近。社会歧视减少,使MSM人群更容易被接触。     

基于捕获—再捕获法线上估计福州市高校学生MSM人群规模

目的 摸清福州市高校学生男男性行为者（MSM）人群规模以及特征,为开展针对性艾滋病宣传和干预提供依据。方法 利用捕获—再捕获法在线上分别通过网络简单随机抽样和滚雪球抽样进行问卷调查并估算被调查人群规模。结果 通过估算得出福州市高校学生MSM人群约8 506(4 865～12 146)人,约占在校男学生的4.33%(2.48%～6.18%);第一次捕获与第二次捕获MSM学生在学历、性取向、性行为角色、找性伴方式、近6个月性伴人数方面差异均有统计学意义（P<0.05）。结论 福州市高校学生MSM人群规模较大,需加强该人群的艾滋病防治工作。     

利用多种方法联合估计哈尔滨市MSM的规模

目的估计哈尔滨市男男性行为人群(MSM)的规模,为制定和实施有针对性的艾滋病高危人群干预策略提供科学依据。方法利用捕获再捕获法、除数法和乘数法,对哈尔滨市MSM的规模进行估计。结果捕获再捕获法估计哈尔滨市MSM规模为9197人(8520~9874人),MSM在18~77岁男性人口中比例为0.28%;除数法估计哈尔滨市浴池类MSM规模为4311人,酒吧类人群规模为3689人,所有活动场所内MSM规模为7381人;乘数法估计哈尔滨市MSM规模为14 812人。结论同时使用捕获再捕获法、除数法和乘数法进行人群规模估计,可以整合资源、节约时间,各种方法的结果可以相互验证,可信度高。     

用捕获-再捕获法对泗洪县疟疾流行现状评估

目的掌握江苏省泗洪县的疟疾发病情况,评估疟疾在该区域的流行现状。方法采用捕获-再捕获统计学方法(CRM),估计该县的疟疾发病数和发病率。结果调查3个乡9个行政村,1248户,访问居民4986人,查出2002年疟疾56例(疫情报告65例),用CRM处理后,估计病例为121例,推算总体理论值是全县疫情的1.86倍。结论泗洪县血检资料与乡(镇)血检登记资料明显不符,说明该县对发热病人的常规血检工作存在较大隐患。个别乡发病率仍在0.2%以上,疟疾在该县的流行现状不容乐观。     

应用乘数法估计深圳市性工作者和吸毒人群规模

目的 调查估计深圳市性工作者和吸毒人群规模，分析影响评估结果的因素，为制定有针对性的艾滋病(AIDs)防治策略提供科学依据。方法 在6个区中，分别应用乘数法对各区的性工作者和吸毒人群规模进行调查估计，将吸毒人群规模估计数与专家估计数和普查人数进行比较。结果 深圳市约有63706名性工作者和21741名吸毒者，两类高危人群中，特区内分别占28．8％和52．5％。应用专家估计法和普查法获得的吸毒人群规模分别为20950名和17581名，与乘数法评估结果比较，分别相差3．6％和19．1％。结论 乘数法是AIDS流行相关高危人群规模估计的一种较实用的方法，具有方法简便、结果可靠、费用较低、省时省力等优点。但应注意调查时问、指定机构在辖区的代表性、目标人群的识别及调查员培训和调查方法的标准化等因素，以减少评估结果的偏差。     

珠海市不同活动场所MSM规模估计的研究

目的了解珠海市实体活动场所和虚拟活动场所男男性行为者(MSM)的人群规模,为制定艾滋病干预措施提供依据。方法利用单样本人群规模估计法(LMS法)和捕获-再捕获法估计珠海市实体场所和虚拟场所的MSM人群规模。结果利用LMS法估计珠海市实体场所MSM的人群规模为5 767人(3 718~8 053人),虚拟场所为18 734人(16 925~20 541人),校正结果为14 753人(13 328~16 176人)。利用捕获-再捕获法估计MSM的人群规模为17 089人(10 742~23 436人)。结论珠海市MSM规模较大,虚拟场所的MSM人数远高于实体场所。应重视在互联网等虚拟场所实施有针对性的艾滋病防制策略。     

捕获-再捕获法分析云南澜沧县疟疾漏报程度

目的了解澜沧县的疟疾发病实情和漏报程度。方法采用回顾性调查方法,统计2002年疟疾疫情报告、血检情况、疟疾治疗及村民疟史等。用捕获-再捕获方法估计疟疾实际发病和漏报率。结果澜沧县疟疾发病率为0·297‰,22个乡均有病例分布,被调查3个乡的疟疾发病率分别为0·62‰、0·42‰和0·08‰,被调查的21个自然村在2002年共报告9例疟疾,采用发热患者血检、医生疟疾治疗处方、疟史3种再捕获方法核实疫情,估算澜沧县的疟疾漏报率分别是35·71%、0·00%和95·89%。结论澜沧县的疟疾漏报现象比较普遍。     

用捕获-再捕获方法调查龙陵县疟疾漏报情况的调查

目的 分析疟疾漏报现状，掌握云南省龙陵县疟疾发病实际情况。方法 采取分层随机不等比例抽样法，抽取镇安、木城、腊勐3个乡9个行政村，逐户调查村民疟史情况。采用捕获-再捕获方法（CMR）估计疟疾实际发病数和漏报率。结果 镇安、木城和腊勐3乡2002年疟疾疫情报告发病人数74例；随访2880人，有疟史27例，疫情上报8例。估计全县疟疾发病数为177例，疫情漏报率为95．48％。结论龙陵县疟疾疫情漏报严重。     

普查法与乘数法估计暗娼人群基数方法学的试点研究

目的 通过普查法与乘数法的现场应用，探索不同地区暗娼人群规模估计的有效方法，为疫情估计及预防控制策略制定提供科学依据。方法 普查法是存短时间内对城区所有可能存在暗娼的场所的暗娼人数进行清点计数；乘数法是3个月内到指定性病门诊就诊的暗娼人数，乘以暗娼人群中在3个月内到指定门诊就诊的比例的倒数，得到暗娼人数。结果 兴义市暗娼人数普查法结果为1521人，乘数法结果为2542人。结论 普查法结果直接，原理简单，省时省力，对经费的要求小，适合在小城市或县城开展，但容易造成遗漏。乘数法需要开展流行病学调查，花费较多人力物力，但可利用现有的监测及流行病学调查资源，适合在大中型城市开展，且估计结果相对准确。     

Assessment of Leishmaniasis notification system in Santiago del Estero, Argentina, 1990-1993

Using a capture-recapture method, this study evaluates the completeness of the cutaneous leishmaniasis (CL) surveillance system in four districts of Santiago del Estero province, Argentina, for the period 1990-1993. Four reporting sources were evaluated: medical records kept by health facilities, interviews conducted during a case-control study, and the national and provincial levels of the leishmaniasis surveillance system (LSS). Using the capture-recapture method it was estimated that 210 cases (95% confidence interval [CI]: 202-218) of CL occurred in the four districts during the study period. Completeness of reporting to the leishmaniasis surveillance system at the national level was estimated to be 44.8% (95% CI: 43.2-46.4). The study results indicate that there is substantial underreporting within the LSS, although it did show the appropriate secular trends. The reasons for under-reporting and methods for addressing this problem are discussed.     

Estimation of non-fatal road traffic injuries in Thai Nguyen, Vietnam using capture-recapture method

Road traffic injuries (RTIs) are increasing in developing countries where accurate routine data are usually not available. Although a capture-recapture technique has increasingly been employed in studies of human populations to provide reliable estimates of the magnitude of problems, it has rarely been used in road traffic injury research. We applied two sample capture-recapture methods using hospital and traffic police records to estimate non-fatal road traffic injuries in Thai Nguyen City during the years 2000-2004. We generated a conservative adjusted estimate of non-fatal RTIs using data from the two sources matched by name, surname, sex of victims and at least one of the other matching variables, of age, address of victim and date of injuries. We then compared the estimated rates with those reported based on police and hospital data. The results show that during years 2000-2004, the police reported 1,373 non-fatal RTIs, while hospital records revealed 6,069 non-fatal RTIs. Most reported victims on both hospital and police reports were males (67.3 % and 74.4%, respectively). More than half the victims on both hospital and police reports were drivers (77.5% and 66.1%, respectively) or pedestrians (10.6% and 7.1%, respectively). Youth and young adults (ages 15-34) constituted the majority of the victims on the hospital and police reports (52.8% and 63.7%, respectively). The capture-recapture analysis estimated that 11,140 (95% CI: 10,626-11,654) subjects were involved in RTIs during the study period. In comparison to the estimated figure, official sources accounted for only 21.9 to 60.1% of total non-fatal RTIs. Estimated rates of non-fatal RTIs were 105.5 injuries/10,000 population per year and 393 injuries/10,000 vehicles. Given the fact that under reporting of RTIs has been a major limitation of routine official data sets in developing countries, we suggested the capture-recapture method be used as a tool to provide affordable and reliable estimates of RTIs in resource-poor countries.     

Capture-recapture estimates of drug misuse in urban and non-urban settings in the north east of Scotland

Aims. To estimate the prevalence of opiate or benzodiazepine misuse in the Grampian Health Board area, Scotland and illustrate the use of the capture-recapture method in both rural and urban settings. Design. Capture-recapture analyses on six distinct sources of data with unequal coverage of the geographical area. Setting. Grampian Health Board area, including the City of Aberdeen. Participants. Data were collated from the Police, Social Work Departments, GPs contributing to the Scottish Drug Misuse Database, statutory drug agencies, a voluntary sector drug agency and a needle/syringe exchange. Measurements. In total 1770 individuals were identified as misusing opiates or benzodiazepines and residing in the Grampian Health Board area; 1129 individuals were resident in the City of Aberdeen. Findings. The total number of opiate or benzodiazepine misusers in the City of Aberdeen was estimated to be 2519 (95% CI 2048-3200). This figure corresponds to 2.0% (1.6-2.5%) of the population aged 15-54 years. In a town to the north of Aberdeenshire where high levels of heroin use had previously been reported in the media, 2.5% of the population aged 15-54 (1.8-3.8%) were estimated to be misusing opiates or benzodiazepines. Conclusions. Although there may be difficulties in applying capture-recapture methods in all settings, the methodology can give valuable information on the extent of drug misuse in both urban and non-urban areas. This information is particularly important to assess the spread of drug misuse from cities to rural areas.     

Potential unmet need for gout diagnosis and treatment: capture-recapture analysis of a national administrative dataset

Objective: To estimate the degree of undercount of people diagnosed with gout in administrative datasets using capture-recapture methods. Methods: Hospitalization and drug dispensing claims (allopurinol or colchicine) data for all Aotearoa New Zealand were used to estimate the prevalence of gout in 2009 (n = 4 295 296). As a comparison, we calculated gout prevalence using a large primary care dataset using general practitioner diagnosis and prescribing records (n = 555 313). For each of these datasets, we estimated the undercount through capture-recapture analysis using a Poisson regression model. A two-list model was used, which included covariates such as age, gender, ethnic groups and New Zealand deprivation quintiles. Results: The crude prevalence of diagnosed gout in the Aotearoa New Zealand population aged ≥20 years was 3.75%. The covariate-adjusted capture-recapture estimate of those not recorded but likely to have gout was 0.92%, giving an overall estimated prevalence of 4.67% (95% CI 4.49, 4.90%) for the population aged ≥20 years. This amounts to 80% of people with gout being identified by the algorithm for the Aotearoa New Zealand data-that is being recorded in either lists of dispensing of allopurinol or colchicine or hospital discharge. After capture-recapture, gout prevalence for all males aged ≥20 years was 7.3% and in older (≥65 years) Māori and Pacific men was >30%. Conclusion: Capture-recapture analysis of administrative datasets provides a readily available method for estimating an aspect of unmet need in the population-in this instance potentially 20% of those with gout not being identified and treated specifically for this condition.     

Capturing crack cocaine use: estimating the prevalence of crack cocaine use in London using capture-recapture with covariates

AIM: To estimate the prevalence of crack cocaine use in 12 London Boroughs (and London as a whole). SETTING: Twelve London Boroughs, 2000-01. METHODS: (1) Covariate capture-recapture techniques applied to three data sources of subjects reporting crack cocaine use: specialist drug treatment (2905), arrest referral (1188) and accident and emergency and community survey (531); and (2) ratio-estimation multiplier, using an estimate of number of injecting drug users and proportion that use crack cocaine. FINDINGS: After matching, 4117 individuals aged 15-44 were identified. The best-fitting model estimated 16 855 unobserved crack cocaine users, giving an overall estimate of approximately 21 000 [95% confidence interval (CI) 13 000-43,000] and a prevalence of 1.5% (95% CI 1.0-3.2%). Prevalence of crack cocaine use was 2.4% (95% CI 1.5-5.0%) among men and 0.7% (95% CI 0.5-1.0%) among women, and similar by age groups 15-29 and 30-44 years. Overall, approximately 11 900 (57%) of the estimated number of crack cocaine users were also opiate users. In London as a whole there may be 46,000 (1.3%) crack cocaine users aged 15-44 years, with 28 000 (1.9%) in inner London-four times higher than estimates from population surveys. Some corroboration was provided by the ratio-estimation method, which estimated 23 000 users in the 12 Boroughs. CONCLUSIONS: Capture-recapture can be applied to crack cocaine and obtain better estimates than population surveys. The size of the crack cocaine-using population in London is large, although currently the majority are also opiate users. Given that half of current users are under 30 the problems associated with crack cocaine use are likely to increase in the future.     

Yearly number of patients diagnosed with primary HIV-1 infection in France estimated by a capture-recapture approach

We used a two-source capture-recapture method to estimate the number of patients diagnosed at the time of primary HIV infection in France between 1999 and 2002. The sources were the French PRIMO cohort and the French Hospital Database on HIV. The estimated number of patients was 325 per year, which represents only 5% (approximately 6000 cases) of all new cases diagnosed each year and only 8% of all new infections (approximately 4000 cases).     

Hospitalizations for suspected dengue in Puerto Rico, 1991-1995: estimation by capture-recapture methods. The Puerto Rico Association of Epidemiologists.

Capture-recapture estimations compare the results of 2 or more independent surveillance systems for the same event, and by measuring the degree of overlap between them, provide an estimate of the total number of events, and therefore the completeness of ascertainment in each system. The Puerto Rico Department of Health and the Dengue Branch of the Centers for Disease Control and Prevention (CDC) monitor dengue activity in Puerto Rico through 2 distinct surveillance systems: diagnostic specimens from patients with suspected dengue and infection control nurses' reports on patients hospitalized for suspected dengue. The patient listings from these systems were used in a 2-sample, capture-recapture calculation to estimate the total number of persons with suspected dengue hospitalized from 1991 to 1995. The laboratory positivity rate for suspected dengue cases who submitted appropriately timed serum samples in those years ranged from 72.1% to 81.2%. The laboratory-based (diagnostic sample) surveillance system (routinely used to monitor hospitalizations for suspected dengue) detected an average of 1,197 hospitalized cases during non-epidemic years, and 4,329 cases during the epidemic year of 1994. The detection rate of this system averaged 42% of the numbers derived by the capture-recapture method. In non-epidemic years, an estimated average of 2,791 patients (range = 1,553-3,481) was estimated to have been hospitalized with a clinical diagnosis of dengue, compared with 9,479 during 1994. These results demonstrate the under-detection inherent in passive surveillance systems for hospitalized cases of suspected dengue, and illustrate the value of capture-recapture techniques to better estimate the true incidence of hospitalizations for this disease.     

Estimating the prevalence of problem drug use in inner London: a discussion of three capture-recapture studies

Aims. To provide an evidence base of estimates of the prevalence of problem drug use in inner London. Design. Re-analysis of three capture-recapture studies using subjects aged 15-49 years, that aim to estimate the hidden population from analysing the overlaps between three data sources. Setting. Newham (1995) Camden and Islington (C&I) (1993/4) and Lambeth, Southwark and Lewisham (LSL) (1992). Participants. Each study collected data from three sources of problem drug users including: the Regional Drug Misuse Database, specialist drug agencies, HIV tests, social services, police arrests and court records. In LSL opiate users were analysed separately. The studies identified 1832 individuals in LSL, 543 in Newham, and 1321 in C&I. Measurements. Poisson models were fitted to the data testing different interactions between the data sources representing potential dependencies. The simplest model was selected on the basis of its AIC score and log-likelihood ratio tests. Findings. The number of hidden problem drug users were estimated to be 12 500 (95% CI 9600-16100) in LSL with 4400 (3200-6100) opiate users; 7000 (5000-10000) in C&I and 3800 (2000-7200) in Newham. The prevalence of problem drug use in those aged 15-49 was estimated to be 3.1% (2.5-3.9%) in LSL with 1.3% (1.0-1.6%) opiate users; and 3.6% (2.7-4.9%) and 3.3% (1.9-5.7%) in C&I and Newham, respectively. Conclusions. Despite the inherent problems with capture-recapture methods, our three studies establish an evidence base for estimates of problem drug use in London. It is important that a larger study is carried out in London.