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At least 1,423 records · Page 79Linked to original sources
PubMed2006

Coexistent chronic conditions and asthma quality of life: a population-based study.

OBJECTIVE: Reports of the prevalence and impact of comorbid conditions among people with asthma have been limited to certain population groups or convenience samples. Our aim was to examine the prevalence of major comorbidity in asthma and associations with quality of life and functional status in the general population. STUDY DESIGN/SETTING: The WANTS Health and Well-being Survey is a cross-sectional representative population household telephone interview survey in three Australian states. PARTICIPANTS: Representative sample of noninstitutionalized adults in three Australian states. MEASUREMENT AND RESULTS: From the available sample of 10,080 patients, 7,619 interviews were completed (participation rate, 74.8%), with 834 people reporting current doctor-diagnosed asthma (11.2%). People with asthma were more likely to report one of the selected comorbid conditions: diabetes, arthritis, heart disease, stroke, cancer, osteoporosis (adjusted odds ratio, 1.9; 95% confidence interval, 1.5 to 2.2). Among people with asthma, there were statistically and clinically significant decreases in usual activity levels and in Short Form-12 physical component summary scores when another chronic condition was also present. For those with any of the chronic conditions, the additional presence of asthma was associated with significant further impairment in quality of life in those aged > 35 years but not in younger adults. CONCLUSION: The significant reduction in quality of life associated with comorbidity in asthma has implications for disease management and organization of care, as well as for the design and external validity of single-disease clinical trials.

Activities of Daily Living↗
PubMed2006

Early goal-directed therapy in severe sepsis and septic shock revisited: concepts, controversies, and contemporary findings.

Studies of acute myocardial infarction, trauma, and stroke have been translated into improved outcomes by earlier diagnosis and application of therapy at the most proximal stage of hospital presentation. Most therapies for these diseases are instituted prior to admission to an ICU; this approach to the sepsis patient has been lacking. In response, a trial comparing early goal-directed therapy (EGDT) vs standard care was performed using specific criteria for the early identification of high-risk sepsis patients, verified definitions, and a consensus-derived protocol to reverse the hemodynamic perturbations of hypovolemia, vasoregulation, myocardial suppression, and increased metabolic demands. Five years after the EGDT publication, there has been much discussion generated with regard to the concepts of EGDT, as well as debate fueled regarding diagnostic and therapeutic interventions. However, during this time period further investigations by the primary investigators and others have brought additional contemporary findings. EGDT modulates some of the components of inflammation, as reflected by improved organ function. The end points used in the EGDT protocol, the outcome results, and the cost-effectiveness have subsequently been externally validated, revealing similar or even better findings than those from the original trial. Although EGDT is faced with challenges, a coordinated approach to sepsis management is necessary to duplicate the progress in outcomes seen in patients with conditions such as acute myocardial infarction, stroke, and trauma.

Algorithms↗
PubMed2005

truPK -- human pharmacokinetic models for quantitative ADME prediction.

The use of in silico prediction of absorption, distribution, metabolism and excretion (ADME) properties is gaining acceptance as a useful assessment tool for early identification of likely drug candidate failures. However, it has been difficult to locate reliable models for the prediction of human pharmacokinetics (PK) in silico Currently available methods for estimating ADME and toxicity properties, such as in vitro and animal models, are not very predictive of what is observed in the clinic. Existing in silico ADME prediction tools concentrate on physicochemical properties, such as solubility, log P, rule-of-five compliance, Caco-2 permeability, blood-brain barrier and so on, or only classify drug-like candidates as 'poor', 'medium' or 'good' for a PK parameter, without ascribing values. Although physiology-based pharmacokinetic -models can predict ADME properties, they rely on using various measured properties as input for better accuracy. Strand Genomics has developed a tool, truPK, that predicts the properties of a molecule (bioavailability, protein binding, volume of distribution, elimination half-life and absorption rate) that affect its dose and dose frequency in humans. truPK's five models built using sophisticated machine methods have predicted with > 75% accuracies in external validation sets.

Animals↗
PubMed2000

A framework for epistemological analysis in empirical (laboratory and field) studies.

In their search for generalizable behavioral patterns and design principles, cognitive field researchers should reflect on the epistemological limitations of empirical studies. In this paper we describe a framework for epistemological analysis that can help serve this purpose and discuss its application to two prototypical cases of cognitive engineering research: laboratory experiments and field studies. The framework examines two, often implicit, processes in empirical research: the abstraction from empirical data and the substantiation of theoretical constructs and principles. By explicitly considering these two processes in several systematic steps, we can gain appreciation for the epistemological contribution of empirical studies to cognitive engineering research. The framework and its application also provide guidance to such important issues as generalizability of results and external validity. Possible applications of this research include providing guidance to researchers and practitioners in evaluating design principles or conducting field studies.

Cognitive Science↗
PubMed2004

Randomized controlled versus naturalistic studies: a new research agenda.

The present article addresses the question of what kind of evidence is required to demonstrate that a method of psychotherapy works. Referring to recent conceptualizations of the logical structure of scientific theories, that is, the structuralistic view of theories, the author shows that randomized controlled studies (RCTs) and naturalistic studies (effectiveness studies) refer to different domains of intended applications (laboratory vs. field). This view has several important implications: (1) RCTs and naturalistic studies do not differ concerning their internal and external validity; (2) naturalistic studies do not necessarily provide lower-level evidence than RCTs; (3) evidence from RCTs cannot be transferred to psychotherapeutic practice in the field; (4) naturalistic studies are required to demonstrate that a form of therapy works in the field; (5) The proposed catalogues for levels of evidence focus on RCTs; thus, they cannot be applied to the question if a therapy works in the field; (6) It is necessary to define separate criteria for levels of evidence of naturalistic studies; and (7) a new research agenda for naturalistic studies can be derived, which is analogous to that of efficacy studies. In this article, a proposal is made to define levels of evidence of naturalistic studies. A gold standard for naturalistic studies is proposed.

Humans↗
PubMed1993

Drinking in various settings as it relates to demographic variables and level of consumption: findings from a national survey in Canada.

Based on a large-scale 1989 national survey in Canada, the extent of drinking in different social settings is estimated. Home consumption accounts for the greatest share of total drinking. while drinking in licensed establishments accounts for approximately one-fourth of consumption. This estimate is externally validated against scales data. The set of questions on drinking venues produces estimates of individual's alcohol consumption which have higher coverage rates than the more commonly used quantity-frequency or recent occasion approaches. The distribution of total drinking in different settings is strongly related to demographic variables and individual level of consumption. In particular, drinking in bars and taverns is related to higher levels of drinking and self-reported drinking problems. The proportion of drinking in different venues is not strongly related to drinking problems, once demographic variables and individual consumption patterns are taken into account. This does not mean that drinking venue is not a significant factor in the development of problems--it may be via its impact on consumption level and heavy drinking occasions that drinking venue relates to drinking problems.

Adolescent↗
PubMed1997

Physiological alcohol dependence as a "specifier" of risk for medical problems and relapse liability in DSM-IV.

OBJECTIVE: This study tested the ability of DSM-IV physiological alcohol dependence to predict multiple indices of medical problems and relapse behavior. It also tested the ability of three additional variables--DSM-IV nonphysiological dependence, an alternative dichotomous criterion for coding physiological dependence and a dimensional measure of physiological dependence--to predict medical problems and relapse behavior in alcoholism. METHOD: A heterogeneous group of 365 patients was recruited from eight addictions treatment programs in the northeastern United States. A multidimensional assessment battery able to diagnose the presence of physiological dependence according to each of three systems--the criteria of DSM-IV, alternative dichotomous criteria and a dimensional scale-- was administered about 2 weeks after admission, and 241 subjects were reinterviewed 6 months later. The three systems were compared for their ability to predict a variety of external measures of medical complications and relapse liability. RESULTS: Physiological alcohol dependence as diagnosed by DSM-IV bore no relationship to either risk for medical problems or relapse behavior. Further analyses showed that this failure was due to operational problems of physiological dependence in DSM-IV, rather than to a lack of conceptual merit for physiological dependence per se as a course specifier. Use of alternative criteria for coding physiological dependence which are difficult and less internally consistent, and use of a dimensional measure, found improved relationships with the external validators. CONCLUSIONS: Contrary to early reports, physiological dependence can serve as a course specifier for alcohol problems, but must be more sensitively scaled than it was in DSM-IV. Tests of alternative options suggest that a multistage criterion to replace DSM-IV's dichotomous criterion is the best remedy.

Adolescent↗
PubMed2002

Clinical discriminators between acute brain hemorrhage and infarction: a practical score for early patient identification.

New treatments for acute stroke require a rapid triage system, which minimizes treatment delays and maximizes selection of eligible patients. Our aim was to create a score for assessing the probability of brain hemorrhage among patients with acute stroke based upon clinical information. Of 1805 patients in the Stroke Data Bank, 1273 had infarction (INF) and 237 had parenchymatous hemorrhage (HEM) verified by CT. INF and HEM discriminators were determined by logistic regression and used to create a score. ROC curve was used to choose the cut-point for predicting HEM (score </= 2), with sensitivity of 76% and specificity of 83%. External validation was done using the NOMASS cohort. Although the use of a practical score by emergency personnel cannot replace the gold-standard brain image differentiation of HEM from INF for thrombolytic therapy, this score can help to select patients for stroke trials and pre-hospital treatments, alert CT scan technicians, and warn stroke teams of incoming patients to reduce treatment delays.

Acute Disease↗
PubMed1991

[Methodological considerations in the interpretation of serologic screening for hepatitis B virus among blood donors].

Between October 1988 and February 1989, 1,033 voluntary first-time blood donors were screened for hepatitis B infection in five blood banks in Goiâna, Central Brazil. The survey was part of a major study designed to estimate seroprevalence of HBsAg and anti-HBs and to discuss methodological issues related to prevalence estimation based on data from blood banks. Donors were interviewed and blood samples were collected and tested for HBsAg and anti-HBs by ELISA tests. Prevalences of 1.9% and 10.9% were obtained for HBsAg and anti-HBs, respectively, and no statistical difference was found between the sexes. Prevalence of anti-HBs increased with age (X2 for trend = 7.9 p = 0.004). The positive predictive value and sensitivity of history of jaundice or hepatitis reported in the interview in detecting seropositives were 13.6% and 2.2%, respectively. The methodological issues, including internal and external validity of HBV prevalence estimated among blood donors are discussed. The potential usefulness of blood banks as a source of morbidity information for surveillance for Hepatitis B virus infection is stressed.

Adolescent↗
PubMedDate not supplied

Systematic reviews on leptospirosis.

OBJECTIVES: To find the existing clinical evidence on interventions for leptospirosis. The objective is to evaluate the effectiveness and safety of any intervention on leptospirosis through systematic reviews of randomized controlled trials (RCTs). DATA SOURCE: The sources of studies used (where there were no limitations concerning language, date, or other restrictions) were: EMBASE, LILACS, MEDLINE, the Cochrane Controlled Clinical Trials Database, and the Cochrane Hepato-Biliary Group Randomized Trials register. SELECTION OF STUDIES TYPE OF STUDY: All systematic reviews of randomized controlled trials. PARTICIPANTS: patients with clinical and/or laboratorial diagnosis of leptospirosis, and subjects potencially exposed to leptospirosis as defined by the authors INTERVENTIONS: any intervention for leptospirosis (as antibiotics or vaccines for prevention or treatment). DATA COLLECTION: The assessment will be independently made by the reviewers and cross-checked. The external validity was assessed by analysis of: studies, interventions, and outcomes. DATA SYNTHESIS: Located 163 studies using the search strategy described above, at the electronic databases above. Only 2 hits were selected, which are protocols of systematic reviews of Cochrane Collaboration, and not full reviews. One of the protocols evaluates antibiotics for treatment, and the other evaluates antibiotics for prevention of leptospirosis. CONCLUSIONS: There were not complete systematic reviews on interventions for leptospirosis. Any interventions for leptospirosis, such as prevention and treatment remains unclear for guidelines and practice.

Databases, Bibliographic↗
PubMed2003

[Respiratory illnesses in children younger than 5 years of age in southern Brazil: the influence of the home environment].

OBJECTIVE: To determine the prevalence of acute lower respiratory tract infections and the risk factors associated with living conditions among children up to 5 years of age in the city of Rio Grande, in the state of Rio Grande do Sul, Brazil. METHODS: A population-based cross-sectional study was carried out with 775 children. A standardized questionnaire was administered to the mother or other caregiver at the child's home in order to collect information on housing conditions, socioeconomic status, and smoking in the home. Additional variables examined included nutritional status, duration of breast-feeding, prenatal care, and utilization of health care services. Environmental variables were analyzed individually and were also grouped together in an "environmental score" that encompassed 10 variables: type of house construction, type of floor, home heating system, type of stove, dog in the child's room, dog in the house, cat in the child's room, cat in the house, number of people per room, and maternal smoking. The grouped environmental score ranged from 0 (best) to 10 (worst). The analysis included two stages: a bivariate stage, in which the prevalence ratio was calculated for each risk factor, and a multivariate stage, with logistic regression. RESULTS: The overall prevalence of acute lower respiratory tract infections was 23.9%. The main risk factors identified were: environmental score >/= 3 points, maternal schooling < 5 years, monthly family income < US$ 200, four or more people sharing the child's bedroom, and maternal smoking. Maternal age > or = 30 years was found to protect against the development of respiratory illness. CONCLUSIONS: Specific programs need to be implemented to control acute respiratory illnesses in the population studied. In future studies with this population, the environmental score that we developed could be used in place of the complete set of environmental variables that we tested. This environmental score should be applied in other contexts so as to determine its external validity.

Adolescent↗
PubMed2005

HIV infection in mobile populations: the case of Mexican migrants to the United States.

OBJECTIVE: Previous studies have indicated varying rates of HIV infection among labor migrants to the United States of America. Most of these studies have been conducted with convenience samples of farmworkers, thus presenting limited external validity. This study sought to estimate the prevalence of HIV infection and risk factors among Mexican migrants traveling through the border region of Tijuana, Baja California, Mexico, and San Diego, California, United States. This region handles 37% of the migrant flow between Mexico and the United States and represents the natural port of entry for Mexican migrants to California. METHODS: From April to December 2002 a probability survey was conducted at key migrant crossing points in Tijuana. Mexican migrants, including ones with a history of illegal migration to the United States, completed an interview on HIV risk factors (n = 1 429) and an oral HIV antibody test (n = 1,041). RESULTS: Despite reporting risk factors for HIV infection, none of the migrants tested positive for HIV. CONCLUSIONS: Our findings contrast with previous estimates of HIV among labor migrants in the United States that were based on nonprobability samples. Our findings also underline the need for early HIV prevention interventions targeting this population of Mexican migrants.

Adult↗
PubMed2002

Stapled versus handsewn methods for colorectal anastomosis surgery: a systematic review of randomized controlled trials.

CONTEXT: The interest in the results from comparisons between handsewing and stapling in colorectal anastomoses has been reflected in the progressive increase in the number of clinical trials. These studies, however, do not permit conclusions to be drawn, given the lack of statistical power of the samples analyzed. OBJECTIVE: To compare stapling and handsewing in colorectal anastomosis, testing the hypothesis that in colorectal anastomosis the technique of stapling is superior to that of handsewing. DESIGN: A systematic review of randomized controlled trials. SURVEY STRATEGY: Systematic revision of the literature and meta-analysis were used, without restrictions on language, dates or other considerations. The sources of information used were Embase, Lilacs, Medline, Cochrane Controlled Clinical Trials Database, and letters to authors and industrial producers of staples and thread. SELECTION CRITERIA: Studies were included in accordance with randomization criteria. The external validity of the studies was investigated via the characteristics of the participants, the interventions and the variables analyzed. An independent selection of clinical studies focusing on analysis of adult patients attended to on an elective basis was made by two reviewers. DATA COLLECTION AND ANALYSIS: The methodological quality of the studies was assessed by the same reviewers. In addition to the randomization criteria, the masking, treatment intention, losses and exclusions were also analyzed. The meta-analysis was performed using risk difference and weighted average difference, with their respective 95% confidence intervals. The variables studied were mortality, clinical and radiological anastomotic dehiscence, anastomotic stricture, hemorrhage, reoperation, wound infection, time taken to perform the anastomosis and hospital stay. RESULTS: Nine clinical trials were selected. After verifying that it was possible to perform one of the two techniques being compared, 1,233 patients were included, of whom 622 underwent stapling and 611 the handsewing technique. No statistical difference was found between the variables, except for stenosis, which was more frequent in stapling (p < 0.05), and the time taken to perform the anastomosis, which was greater in handsewing (p < 0.05). CONCLUSION: The evidence found was insufficient to demonstrate superiority of the stapling method over handsewing, independent of the level of colorectal anastomosis.

Anastomosis, Surgical↗
PubMed2003

Asperger syndrome: an update.

This article provides an overview of the history and clinical features of Asperger syndrome, and considers guidelines for clinical assessment and treatment. A review of issues related to external validity is provided, which points out the limitations of current research, and lists several potentially beneficial areas of investigation into the nosologic status of the condition. It concludes with a discussion of the unequivocal need of individuals with severe social disabilities for comprehensive and adequate educational services and other treatments irrespective of the fact that the validity and the utility of this specific diagnostic concept is far from resolved.

Asperger Syndrome↗
PubMed2005

Consumer preferences for food product quality attributes from Swedish agriculture.

This paper employs a choice experiment to obtain consumer preferences and willingness to pay for food product quality attributes currently not available in Sweden. Data were obtained from a large mail survey and estimated with a random parameter logit model. We found evidence for intraproduct differences in consumer preferences for identical attributes, as well as interproduct discrepancies in ranking of attributes. Furthermore, we found evidence of a market failure relating to the potential use of genetically modified animal fodder. Finally, we found support for the idea that a cheap-talk script can alleviate problems of external validity of choice experiments. Our results are useful in forming product differentiation strategies within the food industry, as well as for the formation of food policy.

Agriculture↗
PubMed2005

Commitment to Health Scale.

The Commitment to Health Scale (CHS) was developed to predict likelihood of clients being able to permanently adopt new health-promoting behaviors. Commitment is based on the association between starting new health behaviors and long-term performance of those behaviors. The CHS evolved from an examination of Prochaska and DiClemente's Stages of Change Algorithm, Decisional Balance Scale, and Strong and Weak Principle (Velicer, Rossi, Prochaska, & DiClemente, 1996). Scale items were assessed by classical and Rasch measurement methods. The research was performed in three separate studies at various locations in the United States and included approximately 1100 subjects. A new unidimensional variable was identified called Commitment to Health. Internal consistency reliability of the scale was .94 (Cronbach's alpha). External validity and reliability were assessed based on expected and observed ordering and between known groups. Scale scores predicted self-reported health behaviors and body mass index.

Adolescent↗
PubMed1973

Methodological and assessment considerations in evaluating reinforcement programs in applied settings.

The extensive use of reinforcement programs in applied settings has led to experimentation that often fails to consider potential problems in design. The logic of the within-subject design is reviewed and specific designs employed in reinforcement programs are discussed. For each design (ABAB, or multiple-baseline design across behaviors, individuals, or situations), effects are discussed that make that design less powerful with respect to demonstrating the effect of the experimental variable. Problems in interpreting results of experiments in this area of inquiry are evaluated from the standpoint of internal and external validity. The issue of control groups is presented with considerations as to situations that require their use. Finally, the assessment strategy for evaluating operant programs is discussed and recommendations are made for measurement of behaviors in addition to the target response.

Journal Article↗
PubMed1993

Treatment integrity in applied behavior analysis with children.

Functional analysis of behavior depends upon accurate measurement of both independent and dependent variables. Quantifiable and controllable operations that demonstrate these functional relationships are necessary for a science of human behavior. Failure to implement independent variables with integrity threatens the internal and external validity of experiments. A review of all applied behavior analysis studies with children as subjects that have been published in the Journal of Applied Behavior Analysis between 1980 and 1990 found that approximately 16% of these studies measured the accuracy of independent variable implementation. Two thirds of these studies did not operationally define the components of the independent variable. Specific recommendations for improving the accuracy of independent variable implementation and for defining independent variables are discussed.

Adolescent↗