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Screenings for the genetic disorder alpha(1) antitrypsin deficiency (AAT Deficiency) have been one of two models: large screenings of general populations and small targeted detection programs in high-risk groups. The most appropriate screening and detection methodologies in terms of target populations, subject participation and yield of positive tests, however, have not been well defined. The major objective of this pilot study was to evaluate the effectiveness in terms of participation of two different AAT Deficiency detection programs using a self-administered fingerstick blood test. Individuals ages 30-60 under the care of a pulmonary physician and with a diagnosis of emphysema, COPD, chronic bronchitis, or bronchiectasis were the targeted population. Participants were offered AAT Deficiency testing in the pulmonary physician's office compared with testing offered through mail. Participation (i.e., frequency of subject participation in the detection program) of two different AAT Deficiency detection programs. Non-participation was due to fear of self-administered testing and research studies; women were more likely to participate than men. Eligible subjects were significantly more likely to participate when offered testing by their pulmonary physician in-office (83%) than mail-only (42%) (P < 0.02). Although self-administered genetic testing is available, highest participation in AAT Deficiency detection program was found when offered directly by the physician. This finding may have implications for screening and detection of other genetic diseases. Future studies need to evaluate the yield (i.e., frequency of positive tests) of these detection methodologies in highly targeted populations.
The target population is a key concept for the planning and evaluation of health services. However, in developing countries, health professionals in the field are often uneasy with the determination of the population denominator. In Zaire, where reliable demographic data are hardly available, we make use of two different methods aimed to the determination of the size of the target population: (1) an exhaustive population based survey performed by trained interviewers, and (2) a rapid census of the target population performed by community health workers. This paper presents both the results of a demographic survey organized in 1984, and two consecutive census performed by community health workers in 1986 an 1988, in the same area (Northern-Kivu, Zaire). Our results suggest that community health workers under close supervision are able to perform rapidly and at low cost a reliable collection of the demographic data needed for the implementation and monitoring of health programmes at the local level.
One difficulty in estimating the target population for public health programs is identifying a current and appropriate indicator of the low-income population. Using data from Mississippi and Maryland, we determined that educational attainment of women giving birth is a feasible substitute for census data in estimating the low-income maternity population, and that vital statistics data offer several advantages for estimating the maternity services target population over census data.
BACKGROUND: Since the identification of the cystic fibrosis (CF) gene, large-scale CF carrier screening has become possible. One possible target group is couples planning a pregnancy (preconceptional screening), providing a maximum number of reproductive options and a minimum of time constraints. OBJECTIVES: To identify obstacles in the implementation of a preconceptional CF carrier screening programme, to find out how potential providers and the target population think the screening should be implemented, and to determine whether potential providers think they are able to provide the screening programme. METHODS: A survey was conducted among 200 general practitioners (GPs), 134 Municipal Health Service (MHS) workers and 303 recently married couples. RESULTS: 52% (102/197) of the eligible GPs participated, 84% (113/134) of the MHS workers and 70% (380/544) of the individuals planning a pregnancy. In general, potential providers and the target population had a positive attitude towards CF screening. Preferred methods of informing the target population were: in leaflets, during a GP consultation for those people seeking advice before pregnancy, and sending a personal invitation to all people of reproductive age. Potential providers believed that they would be able to provide the screening programme. Important perceived obstacles were the absence of a preconceptional care setting, high workload, and lack of financial resources. CONCLUSION: Different intervention strategies will be necessary to overcome the obstacles in the implementation. The positive attitude towards CF carrier screening in combination with the willingness of the potential providers to participate in the screening programme will make it easier to overcome the obstacles.
In connection with developing a benefit-cost approach to evaluating proposed rehabilitation research or demonstration projects, the need to estimate the numerical size of the associated target population is explained and a process is described for making such estimates. The process consists of 7 steps: (1) delineating project objectives, (2) specifying target group(s) in operational terms, (3) determining whether satisfactory target population prevalence estimates are available, (4) in the absence of such estimates, identifying a critical parent population and establishing its prevalence, (5) identifying an accessible population, (6) enumerating the number and proportion of target group members in the accessible population, (7) calculating the estimated target population by multiplying data yielded in steps (4) and (6), adjusting for inferred biases and indicating uncertainties of estimation. Consideration is given to the kinds of data bases upon which this estimation process depends, to the feasibility of providing such estimates, and to their probable accuracy.
The performance of tests for the detection of antibodies to Aujeszky's disease virus glycoprotein E (gE) in a target population was evaluated by constructing and analysing receiver operating characteristic (ROC) curves. These curves assess the discriminating ability of a test over the entire range of test signals. The advantages of applying the analysis to a sample of the target population (all commercial pigs in the Netherlands), as compared to using a panel of test sera, are that the estimates of sensitivity and specificity, the comparisons between tests and the choices of the cut-off values are all relevant for the target population. The results of a gE-ELISA in colostrum (test A) and in a single droplet of whole blood (test B) were compared with the results obtained with the same ELISA in serum (gold standard). The area under the ROC curve, which is a quantitative measure of test performance, was significantly (P < 0.01) smaller with test A than test B or the gold standard, indicating that test B performed better than test A. No significant difference was observed between test B and the gold standard.
Nurses contribute to the social support field primarily through study of clinical and community populations. A review of the target populations identified in 63 empirical studies of social support conducted in the past decade revealed that nurses have, to date, studied populations central to their profession's activities and concerns. They have uniquely focused on surgical patients, the chronically ill, expectant couples and parents of infants, the bereaved, and lay caregivers. These target groups have suffered from maturational (transitional) and/or situational stressors. However, some at-risk groups have been overlooked; in particular, children, males only, native peoples, the poor, the unemployed, and the victims of child and elder abuse. Nurses practice in diverse institutional and community-based sites, and hence have direct contact with all these population groups. Once the features of a population that make it a fruitful focus of study by nurse investigators are identified, pertinent interventions can be tested.
A review of articles in Psychological Assessment reveals that many researchers develop instruments without the benefit of consultation with members of the target population. To the extent that researchers do consult the target population, most fail to bring consultation in early enough to inform the identification and specification of key constructs. Moreover, this consultation typically takes the form of one-to-one interviews. The authors' goal in this article was to elaborate on the importance of population consultation as part of content validation and to critically evaluate the potential of one method of consultation, focus groups, to inform multiple stages of instrument development. The authors suggest that this method holds promise for enhancing the content validity of instruments and, ultimately, the validity of research findings.
PURPOSE: A pilot study to assess how successful a newspaper advertisement and a radio interview about glaucoma are at reaching their target population. METHODS: The health intervention comprised two components: an interview on local radio and an advertisement in the local paper. Our target population were residents aged 45 years and above in either Southall (West London) or the Isle of Wight (IOW). A questionnaire was developed to be carried out pre- and post-intervention. The data from both locations pre and post were coded and cleaned. Tests of significance were carried out to assess statistical significance for differences in proportion, with tests for trend used where appropriate. All statistical analyses were carried out using Stata7. RESULTS: Overall, the proportion who had heard of glaucoma increased from 54% before the intervention to 60% after (chi(2) = 3.7, P = 0.055). The proportion who had heard of the disease increased by 13% (chi(2) = 8.76, P = 0.003) in Southall and by 8% (chi(2) = 5.02, P = 0.025) on the IOW. The proportion reporting seeing the advert increased significantly in both areas with greater effect in Southall. Those reporting hearing the radio interview only increased in Southall. On the IOW, females were more knowledgeable and responded more positively to the intervention. This differed in Southall where males tended to be the positive responders. Conclusion In both areas a significant effect on those having heard of glaucoma was found. This could be attributed to both the advert and interview in Southall but would appear to be attributable to the newspaper advertisement alone on the IOW.
Target populations for chemoprevention trials should include those at higher than average risk for the development of prostate cancer as defined by explicit epidemiologic and genetic criteria. Such populations include a "primary prevention" group without histologic or clinical evidence of cancer, and several clinical models of "secondary prevention," including those with clinically evident disease prior to definitive therapy and those at high risk of recurrence after therapy based on histological or biochemical status. Each risk group and clinical model has potential advantages and disadvantages, and the mechanisms that underlie disease development and progression in each group may be unique. These observations give rise to many potential clinical trials of specific agents. These trials should also include collection of data on potentially confounding influences on disease development and progression.
The study populations taking part in early clinical drug development of reproductive endocrine treatments are discussed. After having compared subjects in phase I studies with subsequent target populations, the question was posed as to whether the inclusion of the later target population could accelerate the developmental process. This applies only to certain specific clinical questions that are posed in phase I studies. From the authors' perspective, the key goal of rapid and well-structured early drug development is to be attained by using reliable surrogate markers that are able to reflect the clinical effects.
A review of tuberculosis surveillance data from a program of school-based tuberculin testing demonstrates the natural evolution of targeted populations. In the 7 years encompassed by this study, the prevalence of tuberculin reactivity ranged from 4.3% to 6.1% in the Amarillo public school populations which were tested. The initial screening was a sampling of all students in the school district. In subsequent years' screening, the targeted populations were increasingly refined to eliminate lower-risk populations. Children enrolled in "English as a Second Language" (ESL) classes were found to have an 8.5% tuberculosis infection rate. The purpose of this study was to alert nurses that culturally sensitive approaches are needed for successful future testing.
BACKGROUND: Many persons with HIV infection do not receive consistent ambulatory medical care and are excluded from studies of patients in medical care. However, these hard-to-reach groups are important to study because they may be in greatest need of services. OBJECTIVE: This study compared the sociodemographic, clinical, and health care utilization characteristics of a multisite sample of HIV-positive persons who were hard to reach with a nationally representative cohort of persons with HIV infection who were receiving care from known HIV providers in the United States and examined whether the independent correlates of low ambulatory utilization differed between the 2 samples. METHODS: We compared sociodemographic, clinical, and health care utilization characteristics in 2 samples of adults with HIV infection: 1286 persons from 16 sites across the United States interviewed in 2001-2002 for the Targeted HIV Outreach and Intervention Initiative (Outreach), a study of underserved persons targeted for supportive outreach services; and 2267 persons from the HIV Costs and Services Utilization Study (HCSUS), a probability sample of persons receiving care who were interviewed in 1998. We conducted logistic regression analyses to identify differences between the 2 samples in sociodemographic and clinical associations with ambulatory medical visits. RESULTS: Compared with the HCSUS sample, the Outreach sample had notably greater proportions of black respondents (59% vs. 32%, P = 0.0001), Hispanics (20% vs. 16%), Spanish-speakers (9% vs. 2%, P = 0.02), those with low socioeconomic status (annual income < Dollars 10,000 75% vs. 45%, P = 0.0001), the unemployed, and persons with homelessness, no insurance, and heroin or cocaine use (58% vs. 47%, P = 0.05). They also were more likely to have fewer than 2 ambulatory visits (26% vs. 16%, P = 0.0001), more likely to have emergency room visits or hospitalizations in the prior 6 months, and less likely to be on antiretroviral treatment (82% vs. 58%, P = 0.0001). Nearly all these differences persisted after stratifying for level of ambulatory utilization (fewer than 2 vs. 2 or more in the last 6 months). In multivariate analysis, several variables showed significantly different associations in the 2 samples (interacted) with low ambulatory care utilization. The variables with significant interactions (P values for interaction shown below) had very different adjusted odds ratios (and 95% confidence intervals) for low ambulatory care utilization: age greater than 50 (Outreach 0.55 [0.35-0.88], HCSUS 1.17 [0.65-2.11)], P = 0.05), Hispanic ethnicity (Outreach 0.81 [0.39-1.69], HCSUS 2.34 [1.56-3.52], P = 0.02), low income (Outreach 0.73 [0.56-0.96], HCSUS 1.35 [1.04-1.75], P = 0.002), and heavy alcohol use (Outreach 1.74 [1.23-2.45], HCSUS 1.00 [0.73-1.37], P = 0.02). Having CD4 count less than 50 was associated with elevated odds of low ambulatory medical visits in the Outreach sample (1.53 [1.00-2.36], P = 0.05). CONCLUSIONS: Compared with HCSUS, the Outreach sample had far greater proportions of traditionally vulnerable groups, and were less likely to be in care if they had low CD4 counts. Furthermore, heavy alcohol use was only associated with low ambulatory utilization in Outreach. Generalizing from in care populations may not be warranted, while addressing heavy alcohol use may be effective at improving utilization of care for hard-to-reach HIV-positive populations.
Many HIV prevention funding agencies require the use of evidence-based behavioral interventions (EBIs) previously shown to be effective through rigorous outcome evaluation. Often, the implementing agency's setting or target population is different than those in the original implementation and evaluation. The Centers for Disease Control and Prevention Division of HIV/AIDS Prevention, in collaboration with internal and external partners, developed draft guidance to adapt an EBI to fit the cultural context, risk determinants, risk behaviors, and unique circumstances of the agency without competing with or contradicting the core elements and internal logic. The guidance described in this article provides a systematic approach to help agencies identify the most appropriate intervention for their target population and agency capacity, monitor the process, and evaluate the outcomes of the adapted intervention. This guidance, currently being piloted with five community-based organizations, will be revised and disseminated at the conclusion of project activities.
Scholars have devoted considerable attention to analyzing the social construction of AIDS. To explore the politics of AIDS policymaking, this research uses Schneider and Ingram's (1993) theory of the social construction of target populations to evaluate the U.S. Senate's response to AIDS between 1987 and 1992. Our study found that Schneider and Ingram's model provides important insights into how political processes affect AIDS policy design. While our data did not strictly conform to all of the model's theoretical expectations, the data provided evidence confirming its predictions about broad patterns in the allocation of both substantive and symbolic policy benefits and burdens to different target populations.
Our experience with studies investigating central nervous system active compounds in Alzheimer disease (AD) patients suggest that conducting a "bridging study," in which patients from the target population are included in Phase I, could expedite the drug development process in AD. With one acetylcholinesterase (AChE) inhibitor compound (velnacrine), we found that AD patients tolerated considerably lower dosages than young normals and healthy elderly subjects, whereas our findings were exactly the opposite with another AChE inhibitor (eptastigmine). In studies of a muscarinic agonist (CI-979), AD patients were able to tolerate dosages higher than those that were well tolerated in young normals. A possible explanation for differences in drug effect and tolerance in the target population may be the pathologic changes in both the brain and the peripheral nervous system that are associated with AD.
The efficacy of a drug is a quantitative concept rather than a qualitative one. This quantity is expressed by several efficacy indices. None of them meet all the requirements. However, that of absolute benefit is especially suitable for the patients because it tells them the exact gain they can expect from taking the treatment. The absolute benefit varies according to patients' profiles because it interacts with some components of these profiles. In theory, such interactions can be used to predict the size of the absolute benefit for each patient, as well to describe better than with the current tools the therapy target population. We explain why meta-analysis and effect models are means of improving the prediction of the size of the effect and the definition of the therapy target population.