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PubMed2005

An estimator of the survival function based on the semi-Markov model under dependent censorship.

Lee and Wolfe (Biometrics vol. 54 pp. 1176-1178, 1998) proposed the two-stage sampling design for testing the assumption of independent censoring, which involves further follow-up of a subset of lost-to-follow-up censored subjects. They also proposed an adjusted estimator for the survivor function for a proportional hazards model under the dependent censoring model. In this paper, a new estimator for the survivor function is proposed for the semi-Markov model under the dependent censorship on the basis of the two-stage sampling data. The consistency and the asymptotic distribution of the proposed estimator are derived. The estimation procedure is illustrated with an example of lung cancer clinical trial and simulation results are reported of the mean squared errors of estimators under a proportional hazards and two different nonproportional hazards models.

Disease-Free Survival↗
PubMed1999

Facility characteristics associated with hospitalization of nursing home residents: results of a national study.

OBJECTIVES: To test the effect of facility characteristics on the probability of hospitalization of nursing home residents, controlling for resident characteristics and the competing risk of death. RESEARCH DESIGN: Study data were derived from the evaluation of the implementation of the Resident Assessment Instrument, the Minimum Data Set (MDS) in 1993. The data consisted of 2080 residents in 253 NHs as well as the annual On-Line Survey Certification of Automated Records (OSCAR). MEASURES: Multinomial logistic regression was used to determine the effects of selected resident and facility characteristics on hospitalization or death within 6 months of baseline, adjusting for the complex sampling design (using SUDAAN). RESULTS: By controlling for resident demographics, advance directives, diagnoses, selected clinical signs, and type of payer, we found that homes with special care units, more physicians (above the median 0.08 FTE physicians on staff or contract), and any physician extenders (nurse practitioners or physician assistants) were less likely to hospitalize their residents. Homes in which over 3.6% of the residents received respiratory treatment were more likely to hospitalize their residents. CONCLUSIONS: Findings suggest that Medicare HMOs should consider the capacity of nursing facilities, especially in terms of medical care capacity and clinical resources, to limit hospital admissions.

Advance Directives↗
PubMed1997

Rehabilitation in nursing homes: a cross-national comparison of recipients.

OBJECTIVE: to examine the prevalence of therapy use in nursing homes in selected countries and to describe the characteristics of nursing home residents who receive therapy. DESIGN and SAMPLING: the design of the study is cross-sectional, using Minimum Data Set (MDS) assessments of nursing home residents. The sample includes all nursing home residents in six US states (n = 273491), in Copenhagen, Denmark (n = 3451), Reyjkavik, Iceland (n = 1254), and selected locations in Italy (n = 1089) and Japan (n = 1255). METHOD: we determined who had received physical or occupational therapy treatments in the last 7 days. Demographic and clinical characteristics of recipients were compared relative to other nursing home residents within each country. RESULTS: in the five countries, the prevalence of receiving therapy was 31% (Iceland), 30% Japan), 23% (Denmark), 14% (Italy) and 11% (USA). Substantial proportions of the recipients were over the age of 85, were clinically stable and had been in the nursing home for longer than 90 days. Across all countries, residents with poorer activities of daily living (ADL) scores but good cognitive scores were more likely to receive therapy than other residents. Rehabilitation nursing, an adjunct to therapy, was concentrated on residents with poor ADL scores. CONCLUSIONS: substantial numbers of long-stay residents receive therapy in nursing homes, including those over the age of 85 years and those with cognitive impairment. Hence, future rehabilitation outcome studies can involve these previously understudied patient populations.

Activities of Daily Living↗
PubMed1995

PCR and non-isotopic labeling techniques for plant virus detection.

PCR technology permits the detection of viruses at levels several orders of magnitude lower than is possible by other methods. This high sensitivity facilitates detection of virus sequences during the early stages of infection of plants and in soil and vector samples. Early detection of beet necrotic yellow vein virus (BNYVV) in Beta vulgaris is an important part of the strategy for prevention of the spread of rhizomania, a commercially significant disease of sugar beet. A diagnostic test for BNYVV has been developed. This test involves amplification of the viral genome by PCR coupled with non-isotopic labeling and detection of specific sequences. The PCR amplification of BNYVV sequences has been optimized with respect to primer design, sample preparation and reaction conditions. Several non-isotopic labeling strategies for signal amplification have been compared. Hybridization with digoxigenin-labelled cDNA permits the most sensitive detection of PCR products and is the most appropriate method for routine diagnosis. These observations are discussed in the context of the application of PCR for detecting a wide range of viruses.

Base Sequence↗
PubMed1994

Design of the Project NetWork return-to-work experiment for persons with disabilities.

As the Nation's first rigorous large-scale evaluation of vocational rehabilitation (VR) assistance to persons with severe disabilities, the Project NetWork demonstration will provide a wide range of information to policy-makers, researchers, and other interest groups. The evaluation of Project NetWork addresses two key policy questions: Is it feasible to increase participation in VR services among Disability Insurance (DI) beneficiaries and Supplemental Security Income (SSI) applicants/recipients through a combination of intensive outreach, case management, and enhanced work incentives? Do the interventions tested produce net benefits from the perspective of participants, society, the DI Trust Fund, and the Federal Government, as a whole? The study utilizes a randomized field experiment design to evaluate the net impact of the demonstration on participant employment, earnings, receipt of transfer benefits, social and psychological well-being, and other variables of interest to policymakers. A combination of SSA administrative data, information from the demonstration's onsite management information system (MIS), and in-person interviews (containing a rich array of information on disability, health, and attitudes) supports the evaluation. This article summarizes three aspects of the evaluation: Its experimental and sample design; the methods and data to be used to analyze project benefits, costs, and participation; and the challenges faced during demonstration implementation. It also presents preliminary data on the characteristics of Project NetWork participants and eligibles.

Adult↗
PubMed1998

Hunger in children in the United States: potential behavioral and emotional correlates.

OBJECTIVE: Results from a recent series of surveys from 9 states and the District of Columbia by the Community Childhood Hunger Identification Project (CCHIP) provide an estimate that 4 million American children experience prolonged periodic food insufficiency and hunger each year, 8% of the children under the age of 12 in this country. The same studies show that an additional 10 million children are at risk for hunger. The current study examined the relationship between hunger as defined by the CCHIP measure (food insufficiency attributable to constrained resources) and variables reflecting the psychosocial functioning of low-income, school-aged children. METHODS: The study group included 328 parents and children from a CCHIP study of families with at least 1 child under the age of 12 years living in the city of Pittsburgh and the surrounding Allegheny County. A two-stage area probability sampling design with standard cluster techniques was used. All parents whose child was between the ages of 6 and 12 years at the time of interview were asked to complete a Pediatric Symptom Checklist, a brief parent-report questionnaire that assesses children's emotional and behavioral symptoms. Hunger status was defined by parent responses to the standard 8 food-insufficiency questions from the CCHIP survey that are used to classify households and children as "hungry," "at-risk for hunger," or "not hungry." RESULTS: In an area probability sample of low-income families, those defined as hungry on the CCHIP measure were significantly more likely to have clinical levels of psychosocial dysfunction on the Pediatric Symptom Checklist than children defined as at-risk for hunger or not hungry. Analysis of individual items and factor scores on the Pediatric Symptom Checklist showed that virtually all behavioral, emotional, and academic problems were more prevalent in hungry children, but that aggression and anxiety had the strongest degree of association with experiences of hunger. CONCLUSION: Children from families that report multiple experiences of food insufficiency and hunger are more likely to show behavioral, emotional, and academic problems on a standardized measure of psychosocial dysfunction than children from the same low-income communities whose families do not report experiences of hunger. Although causality cannot be determined from a cross-sectional design, the strength of these findings suggests the importance of greater awareness on the part of health care providers and public health officials of the role of food insufficiency and hunger in the lives of poor children.

Affective Symptoms↗
PubMed2006

Hardness evaluation of penile prostheses.

AIM: This work investigates the hardness and buckling force of penile prostheses to further understand the rigidity of penile prostheses before and after implantation. METHODS: Evaluated herein are four prosthetic samples (three inflatable, one semi-rigid), five real prostheses (one inflatable, four semi-rigid), and one prosthesis after implantation. The hardness is measured with a Shore Durimeter by pressing the tester's indentor to the surface of the specimen. A volunteer with inflatable prosthesis implantation is evaluated with respect to penile hardness versus various numbers of pumping. The buckling force of the prosthesis is also determined by a push-pull gauge and a specially designed sampling table. RESULTS: Results in this study demonstrate that although the inflatable prosthesis could only be pumped to a certain amount of hardness, hardness and buckling force correlate well with each other. After reaching the hardness limit, prostheses can even be pumped a further few times. However, continuous pumping only puts more tension on the prosthetic material without increasing hardness and could induce mechanical failure of the prosthesis. Results also indicate that the buckling force decreases with increasing length of the semirigid prostheses, and increases when the prosthesis has a larger diameter. CONCLUSION: This mechanical measurement of rigidity in penile prostheses could provide more information to clinicians about the penile prosthesis before surgical implantation, and to patients about prosthesis usage after implantation.

Hardness Tests↗
PubMed2005

Confidence interval construction for proportion difference in small-sample paired studies.

Paired dichotomous data may arise in clinical trials such as pre-/post-test comparison studies and equivalence trials. Reporting parameter estimates (e.g. odds ratio, rate difference and rate ratio) along with their associated confidence interval estimates becomes a necessity in many medical journals. Various asymptotic confidence interval estimators have long been developed for differences in correlated binary proportions. Nevertheless, the performance of these asymptotic methods may have poor coverage properties in small samples. In this article, we investigate several alternative confidence interval estimators for the difference between binomial proportions based on small-sample paired data. Specifically, we consider exact and approximate unconditional confidence intervals for rate difference via inverting a score test. The exact unconditional confidence interval guarantees the coverage probability, and it is recommended if strict control of coverage probability is required. However, the exact method tends to be overly conservative and computationally demanding. Our empirical results show that the approximate unconditional score confidence interval estimators based on inverting the score test demonstrate reasonably good coverage properties even in small-sample designs, and yet they are relatively easy to implement computationally. We illustrate the methods using real examples from a pain management study and a cancer study.

Biometry↗
PubMedDate not supplied

Paraprofessional support for pregnant & parenting women.

PURPOSE: To review evidence regarding the role of paraprofessional support in improving maternal and infant outcomes in pregnant and parenting women. Although support provided by significant others (social support), by professionals, and by paraprofessionals are frequently considered together in literature reviews, this is inappropriate because the components of the support in each case differ. DATA SOURCES: Data were limited to published studies. Searches of computerized databases (CINAHL, Medline, PsychLit, Social sciences abstracts, Social sciences citation, and Social work abstracts), hand searches of journals, and backward searches from reference lists of studies were conducted. Nursing, medicine, psychology, public health, sociology, and social work literatures were searched. STUDY SELECTION: The studies included had statistically significant outcomes of paraprofessional support to pregnant and parenting women. Studies were published in 1985 or later, were conducted in the United States or Canada, and included maternal and/or infant outcomes. DATA EXTRACTION: Data were extracted from each study concerning the theoretical framework, design, sample, measuring instruments, interventions, and outcomes. CONCLUSIONS: Programs providing paraprofessional support to childbearing women are clearly providing an important service, but empirical evidence is not adequate to determine which specific paraprofessional program works for a specific population of women to achieve the best long-term outcomes for both women and children. Although proponents of paraprofessional support programs for pregnant and parenting women have reported some successes, more data are needed. Researchers should continue to conduct well-designed and controlled studies to compare outcomes from the three types of support. Nurses in practice should build on services provided by paraprofessionals in order to meet women's need for support and to achieve desired outcomes.

Community Health Services↗
PubMed2005

The Canadian Community Health Survey: mental health and well-being.

As part of the Canadian Community Health Survey (CCHS) biennial strategy, the provincial survey component of the first CCHS cycle (Cycle 1.2) focused on different aspects of the mental health and well-being of Canadians living in private dwellings. Moreover, the survey collected data on prevalences of specific mental disorders and problems, use of mental health services, and economic and personal costs of having a mental illness. Data collection began in May 2002 and extended over 8 months. More than 85% of all interviews were conducted face-to-face and used a computer-assisted application. The survey obtained a national response rate of 77%. This paper describes several key aspects of the questionnaire content, the sample design, interviewer training, and data collection procedures. A brief overview of the CCHS regional component (Cycle 1.1) is also given.

Adolescent↗
PubMed2004

A USA national survey of program services provided by child advocacy centers.

OBJECTIVE: Child Advocacy Centers (CACs) are designed to improve the community collaborative response to child sexual abuse and the criminal justice processing of child sexual abuse cases. CACs, in existence for 16 years, now have standards for membership developed by the National Children's Alliance (NCA) that include nine core components. And yet no systematic examination of the CAC model exists. The purpose of this paper was to assess the variations within these core components as they exist in the field. METHOD: Using a stratified random sampling design, 117 CAC directors were interviewed using a semi-structured interview that was based on the NCA's standards for membership. The eight core components of the CAC model examined in this study include: a child-friendly facility, a multidisciplinary team, an investigative child interview, a medical examination of the child, provision of mental health services, victim advocacy, case review, and case tracking. RESULTS: Results reveal the CAC model has been widely adopted by both member and nonmember centers, although variations in implementation exist. CONCLUSIONS: Future developments in the CAC model must include evaluation of the model.

Administrative Personnel↗
PubMed2004

[Is the technique used to collect urine important in avoiding contamination of samples?].

OBJECTIVE: To appraise the efficacy of hygienic standards in preventing the contamination of urine samples. DESIGN: Randomised clinical trial. 515 women assigned at random: 279 to the Intervention group and 236 to Control. SETTING: Population registered with 4 doctors at 2 health centres. PARTICIPANTS: Women from 15 to 65 who attended the clinic for on-demand care. Criteria for exclusion from the trial were: permanent bladder catheter, anomalies in genito-urinary apparatus, antibiotic treatment in the 7 previous days and inability to understand instructions. INTERVENTION: Verbal instructions on hygienic standards for collecting the sample and explanatory leaflet, as against the customary guidelines. MAIN MEASUREMENTS: The main result was the combination of contamination levels and infection. Analysis by intention to treat. RESULTS: Irregularities in the urine culture in 113 (41%) patients from the Intervention group and in 133 (56%) from the Control group (P<.001), with RRR of 28% (95% CI, 14%-40%) and NNT of 6 (95% CI, 4-14). Taking only serious contamination or urinary infection, we had 14 in the Intervention group and 36 in the Control (P<.0001), with RRR of 67% (95% CI, 41%-82%) and NNT of 10 (95% CI, 6-20). CONCLUSIONS: Providing an explanatory leaflet and giving verbal instructions on hygienic standards for urine collection reduces contamination of the samples.

Adolescent↗
PubMed1991

An introduction to research: a primer for the nurse anesthetist.

The goals of this article are to provide an overview of the research process and highlight some of the most important aspects. In the process, the definition of research and some general terminology will be reviewed. Discussions of how to define a problem, reviewing the literature, types of study designs, sampling, types of measurement, reliability and validity, limitations and assumptions, data analysis, ethical concerns with human subjects, and time management are included, as are examples of published research.

Data Collection↗
PubMed1986

Problems in setting up an executing large-scale psychiatric epidemiological studies.

This paper focuses on problems that can be encountered in conceptualizing, executing and writing up large-scale psychiatric epidemiological studies. It makes no attempt to cover fundamental issues of design and analysis, rather it centers on problems associated with projects of considerable size. In the conceptual area, it discusses the prerequisites to be considered before deciding to launch such a study. It notes the administrative and scientific uses of epidemiological studies and considers the strengths and weaknesses of large-scale studies to address those concerns. Issues in carrying out such studies are discussed including decisions about study design, sampling method and instrumentation. All are dependent on the central purpose of the study but trade-offs between feasibility and scientific rigor are always present. Data collection and analysis problems highlighted in large-scale studies are examined. They include the difficulty, in the former, of adequately motivating and supervising field personnel and, in the latter, of dealing with problems that accompany missing data and complicated sampling strategies. Potential problems in data access and use and writing up the results are seen as arising from the presence of a large investigative team with diverse interests. Lastly, the comparative worth of these studies is considered.

Data Collection↗
PubMed2004

The DSM-IV rates of child and adolescent disorders in Puerto Rico: prevalence, correlates, service use, and the effects of impairment.

BACKGROUND: Few prevalence studies in which DSM-IV criteria were used in children in representative community samples have been reported. We present prevalence data for the child and adolescent population of Puerto Rico and examine the relation of DSM-IV diagnoses to global impairment, demographic correlates, and service use in an island-wide representative sample. METHODS: We sampled 1886 child-caretaker dyads in Puerto Rico by using a multistage sampling design. Children were aged 4 to 17 years. Response rate was 90.1%. Face-to-face interviews of children and their primary caretakers were performed by trained laypersons who administered the Diagnostic Interview Schedule for Children, version IV (DISC-IV) in Spanish. Global impairment was measured by using the Children's Global Assessment Scale scored by the interviewer of the parent. Reports of service use were obtained by using the Service Assessment for Children and Adolescents. RESULTS: Although 19.8% of the sample met DSM-IV criteria without considering impairment, 16.4% of the population had 1 or more of the DSM-IV disorders when a measure of impairment specific to each diagnosis was considered. The overall prevalence was further reduced to 6.9% when a measure of global impairment was added to that definition. The most prevalent disorders were attention-deficit/hyperactivity disorder (8.0%) and oppositional defiant disorder (5.5%). Children in urban settings had higher rates than those in rural regions. Older age was related to higher rates of major depression and social phobia, and younger age was related to higher rates of attention-deficit/hyperactivity disorder. Both overall rates and rates of specific DSM-IV/DISC-IV disorders were related to service use. Children with impairment without diagnosis were more likely to use school services, whereas children with impairment with diagnosis were more likely to use the specialty mental health sector. Of those with both a diagnosis and global impairment, only half received services from any source. CONCLUSIONS: Because we used the DISC-IV to apply DSM-IV criteria, the study yielded prevalence rates that are generally comparable with those found in previous surveys. The inclusion of diagnosis-specific impairment criteria reduced rates slightly. When global impairment criteria were imposed, the rates were reduced by approximately half.

Adolescent↗
PubMed2006

Modeling species-habitat relationships with spatially autocorrelated observation data.

Spatial autocorrelation in wildlife observation data arises when extrinsic environmental processes and patterns that influence the spatial distribution of wildlife are themselves spatially structured, or when species are subject to intrinsic population processes, causing contagion or dispersion effects. Territoriality, Allee effects, dispersal limitations, and social clustering are examples of intrinsic processes. Both forms of autocorrelation can violate the assumptions of generalized linear regression models, resulting in biased estimation of model coefficients and diminished predictive performance. Such consequences may be avoided for extrinsic autocorrelation when autocorrelated environmental variables are available for use as model covariates, whereas intrinsic spatial autocorrelation requires an alternative modeling approach. The autologistic model provides an approach suited to the binary observations often obtained in wildlife surveys, but its performance has not been tested across widely varying sampling intensities or strengths of intrinsic spatial structure. Here we use simulated data to test the autologistic model under a range of sampling conditions. The autologistic model obtains better fits and substantially better predictive performance than the standard logistic regression model over the full range of sampling designs and intensities tested. We provide a simple Bayesian implementation of the autologistic model, which until now has not been achieved with standard statistical software alone. A step-by-step procedure is given for characterizing and modeling spatial autocorrelation in binary observation data, along with computer code for fitting autologistic models in WinBUGS, a freeware Bayesian analysis package. This approach avoids normal approximations to the pseudo-likelihood, in contrast to previous Bayesian applications of the autologistic model. We provide a sample application of the autologistic model, fitted to survey data for a gliding marsupial in southeastern Australia.

Bayes Theorem↗
PubMed1999

Psychosocial correlates of cancer relapse and survival: a literature review.

This article reviews literature on the psychosocial correlates of cancer relapse and survival from 1979 through 1995. The factors studied were structured according to a theoretical model of coping with cancer. Reviewed studies have shown that factors most frequently evaluated were depression, anxiety, hopelessness/helplessness, hostility, marital status and social involvement. Mainly inconsistent results were found. The strongest evidence for a relationship between psychosocial variables and prognosis was found for social involvement/social support; in 7 of 15 studies a positive relationship was demonstrated, while no negative associations were found. Coping styles e.g., fighting spirit and stoic acceptance, and severe/stressful life events were found to have no conclusive influence on the length of survival. Important determinants of the coping model, such as uncertainty and information given by the specialist were not studied as possible predictors of survival and/or relapse free period. Among the factors that showed no correlation at all was multidimensional health locus of control. For the inconsistent findings, a considerable number of methodologic shortcomings with respect to study design, sample size, measure and statistical analysis are enumerated.

Adaptation, Psychological↗
PubMed1989

Meta-analysis of home-care effects on mortality and nursing-home placement.

This meta-analysis was designed to illustrate how the relatively new discipline of meta-analysis could be employed in health-services research. In pursuit of this goal, the results of 13 studies on the effect of home care on mortality and nursing-home placements were examined. The analysis demonstrated a small, beneficial effect of home care on mortality, which fell short of statistical significance. Study-to-study variation in the odds ratio was found that was not strongly associated with differences in the study samples, designs, or interventions as categorized here. The analysis produced stronger evidence of a reduction in nursing-home placements. In this case, differences in study design explained much of the heterogeneity in results, with the randomized controlled trials showing considerably weaker effects. The analysis also provides insight into the benefits and limitations of alternative meta-analytic methods. The "odd man out" method recently described by Walker et al. detected statistically significant heterogeneity of effects across studies for nursing-home placement, but not for mortality. Loglinear modeling made it easier to detect and explore study-to-study variation in home-care effects.

Confidence Intervals↗