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Blood pressure as a surrogate end point for hypertension.

OBJECTIVE: To review relevant literature and provide opinions regarding the use of blood pressure as a surrogate measure to predict cardiovascular risk. DATA SOURCES: Primary and review articles were identified by MEDLINE search (1990-January 2001) and through secondary sources. STUDY SELECTION AND DATA EXTRACTION: Studies and review articles that related to the interpretation of blood pressure as a surrogate measure were reviewed. Information that was relevant to this topic was included. DATA SYNTHESIS: The measurement of blood pressure is subject to numerous sources of error and bias. Patients who perform home blood pressure testing and self-report these values frequently leave out high values and add ghost values into logbooks. Additionally, analysis of recent data suggests that at any given level of blood pressure that is achieved, cardiovascular risk reduction may not be the same with different therapeutic agents. It is also now recommended that systolic blood pressure be used in preference to diastolic blood pressure to determine risk and to assess management strategies. Although 24-hour blood pressure measurements may be the best predictors of cardiovascular risk, this has not been demonstrated in a long-term morbidity trial. CONCLUSIONS: Blood pressure is a relatively poor surrogate measure. Unfortunately, no alternatives are available at this time. Therefore, every attempt must be made to accurately determine blood pressure and to assess risk and benefit from specific antihypertensive agents. Systolic blood pressure should be the predominant blood pressure measure used to evaluate patients, especially middle-aged and elderly individuals.

Antihypertensive Agents↗

Basic characteristics of radiology practices: results from the American College of Radiology's 1999 survey.

OBJECTIVE: The basic characteristics of radiology practices in the United States are described. We defined radiology practices as diagnostic-radiology-only practices, either solo or multiradiologist practices. Findings were compared with those from other data sources. MATERIALS AND METHODS: In May 1999, the American College of Radiology surveyed 970 practices by mail using a 65-item questionnaire. A final response rate of 66% was achieved. Weighting was used to make responses representative of all radiology practices in the United States. RESULTS: Approximately 4400 radiology practices existed in the country; 39% were located in nonmetropolitan or rural areas. The greatest percentage of practices (85%) was private nonacademic radiology practices. The greatest percentage of practices (43%) served only hospitals. However, solo practices were particularly likely (p < or = 0.01) to serve only nonhospital sites. Of all multiradiologist practices, 87% were completely owned by their members, but approximately two thirds of academic multiradiologist practices had outside owners. Seventy percent of multiradiologist practices interpreted images from outside clinics or groups; these averaged 3.2 outside clinics or groups for which they interpreted images. CONCLUSION: The basic characteristics of radiology practices in 1999 are described. Good agreement was seen with findings obtained from other data sources.

Data Collection↗

Olmesartan medoxomil: the seventh angiotensin receptor antagonist.

OBJECTIVE: To review the pharmacology, pharmacokinetics, efficacy, and adverse effects of olmesartan medoxomil, an angiotensin II receptor antagonist for the treatment of hypertension. DATA SOURCES: Information was obtained from MEDLINE searches (1996-April 2002) of English-language medical literature. Search terms included CS-866, olmesartan, olmesartan medoxomil, RNH-6270 (active metabolite of olmesartan), Benicar, angiotensin receptors, and antihypertensive agents. In addition, references from relevant articles were reviewed for additional citations. The authors independently reviewed literature identified in the searches. Studies evaluating olmesartan (i.e., abstracts, clinical trials, data on file with manufacturer) were considered for inclusion. STUDY SELECTION: All articles identified from data sources with pertinent information regarding olmesartan medoxomil were evaluated, and all information deemed relevant was included in this review. DATA SYNTHESIS: Olmesartan medoxomil is a competitively priced addition to the class of angiotensin II receptor antagonists. Monotherapy with olmesartan medoxomil in once-daily doses of 20-40 mg has produced significant reductions in systolic and diastolic blood pressure in hypertensive patients. Adverse effects have been minimal with olmesartan medoxomil, with dizziness being the only adverse effect occurring more often than with placebo in clinical trials. Additionally, animal studies indicate that olmesartan medoxomil may prove to be useful treatment for diabetic nephropathy, as well as atherosclerosis. CONCLUSIONS: Olmesartan medoxomil has a favorable safety and efficacy profile, with blood pressure-lowering effects comparable to those of other angiotensin receptor blockers (i.e., losartan, valsartan, irbesartan). At this time, formulary decisions will be driven primarily by economic issues. Theoretical benefits of olmesartan medoxomil in reducing atherogenesis and lowering angiotensin II concentrations better than the alternative agents will be determined only with more extensive research.

Angiotensin II↗

Adverse events in acute care: an integrative literature review.

An integrative literature review was conducted to investigate studies on adverse events reported in medical, health services, and nursing literature. The review was guided by the method proposed by Jackson (1980) and Ganong (1987). Three questions shaped the review: (a) What terms are used to denote adverse events? (b) What purposes drive adverse events research? and (c) What data sources are used to study adverse events? Adverse events was the dominant term, the study of adverse events as an outcome variable was the prevailing research purpose, and monitoring or screening the patient clinical record and self-reported incidents by health care professionals were the main data sources. Future research is recommended to conceptualize and study adverse events.

Acute Disease↗

Room for improvement? A survey of the methods used in systematic reviews of adverse effects.

BACKGROUND: Although the methods for conducting systematic reviews of efficacy are well established, there is much less guidance on how systematic reviews of adverse effects should be performed. METHODS: In order to determine where methodological research is most needed to improve systematic reviews of adverse effects of health care interventions, we conducted a descriptive analysis of systematic reviews published between 1994 and 2005. We searched the Database of Abstracts of Reviews of Effects (DARE) and The Cochrane Database of Systematic Reviews (CDSR) to identify systematic reviews in which the primary outcome was an adverse effect or effects. We then extracted data on many of the elements of the systematic review process including: types of interventions studied, adverse effects of interest, resources searched, search strategies, data sources included in reviews, quality assessment of primary data, nature of the data analysis, and source of funding. RESULTS: 256 reviews were included in our analysis, of which the majority evaluated drug interventions and pre-specified the adverse effect or effects of interest. A median of 3 resources were searched for each review and very few reviews (13/256) provided sufficient information to reproduce their search strategies. Although more than three quarters (185/243) of the reviews sought to include data from sources other than randomised controlled trials, fewer than half (106/256) assessed the quality of the studies that were included. Data were pooled quantitatively in most of the reviews (165/256) but heterogeneity was not always considered. Less than half (123/256) of the reviews reported on the source of funding. CONCLUSION: There is an obvious need to improve the methodology and reporting of systematic reviews of adverse effects. The methodology around identification and quality assessment of primary data is the main concern.

Data Interpretation, Statistical↗

Comparison of mortality between private for-profit and private not-for-profit hemodialysis centers: a systematic review and meta-analysis.

CONTEXT: Private for-profit and private not-for-profit dialysis facilities provide the majority of hemodialysis care in the United States. There has been extensive debate about whether the profit status of these facilities influences patient mortality. OBJECTIVE: To determine whether a difference in adjusted mortality rates exists between hemodialysis patients receiving care in private for-profit vs private not-for-profit dialysis centers. DATA SOURCES: We searched 11 bibliographic databases, reviewed our own files, and contacted experts in June 2001-January 2002. In June 2002, we also searched PubMed using the "related articles" feature, SciSearch, and the reference lists of all studies that fulfilled our eligibility criteria. STUDY SELECTION: We included published and unpublished observational studies that directly compared the mortality rates of hemodialysis patients in private for-profit and private not-for-profit dialysis centers and provided adjusted mortality rates. We masked the study results prior to determining study eligibility, and teams of 2 reviewers independently evaluated the eligibility of all studies. Eight observational studies that included more than 500 000 patient-years of data fulfilled our eligibility criteria. DATA EXTRACTION: Teams of 2 reviewers independently abstracted data on study characteristics, sampling method, data sources, and factors controlled for in the analyses. Reviewers resolved disagreements by consensus. DATA SYNTHESIS: The studies reported data from January 1, 1973, through December 31, 1997, and included a median of 1342 facilities per study. Six of the 8 studies showed a statistically significant increase in adjusted mortality in for-profit facilities, 1 showed a nonsignificant trend toward increased mortality in for-profit facilities, and 1 showed a nonsignificant trend toward decreased mortality in for-profit facilities. The pooled estimate, using a random-effects model, demonstrated that private for-profit dialysis centers were associated with an increased risk of death (relative risk, 1.08; 95% confidence interval, 1.04-1.13; P<.001). This relative risk suggests that there are annually 2500 (with a plausible range of 1200-4000) excessive premature deaths in US for-profit dialysis centers. CONCLUSIONS: Hemodialysis care in private not-for-profit centers is associated with a lower risk of mortality compared with care in private for-profit centers.

Health Services Research↗

A comparison of dietary reference values for energy of different countries.

Dietary reference values for food energy for population groups are set at the level of average energy requirement without a safety margin to avoid any risk of inadequate energy intake. Average energy requirements and hence reference values for energy can be determined from either energy intake data or energy expenditure. In this article, the present reference values for energy of 12 countries, the FAO/WHO/UNU and the Scientific Committee on Food (SCF/EC) are compared regarding the level of their standards and underlying concepts. Methods for estimating energy requirements of different population groups and data sources for reference values for energy are summarized. Furthermore, reference values for energy for males and females of all ages are presented in separate graphs. The comparison of national standards illustrates that the level of reference values for energy for individual countries is dependent on variables such as methodology, data sources, allowances for physical activity, reference body weight, and age range. Standards for adolescents and elderly persons reveal that differences in reference values are most apparent in population groups for which only limited data on energy requirements are available. Although it is not possible to evaluate the adequacy of reference values for energy by comparing data of different countries, many differences in the level of reference values can be explained on the basis of underlying concepts.

Adolescent↗

Methodology of studies evaluating death certificate accuracy were flawed.

BACKGROUND AND OBJECTIVE: Statistics on causes of death are important for epidemiologic research. Studies that evaluate the source data often give conflicting results, which raise questions about comparability and validity of methods. METHODS: For 44 recent evaluation studies we examined the methods employed and assessed the reproducibility. RESULTS: Thirty studies stated who reviewed the source data. Six studies reported reliability tests. Twelve studies included all causes of death, but none specified criteria for identifying the underlying cause when several, etiologically independent conditions were present. We assessed these as not reproducible. Of 32 studies that focussed on a specific condition, 21 provided diagnostic criteria such that the verification of the focal diagnosis is reproducible. Of 16 that discussed the difference between dying "with" and "from" a condition, eight described how competing causes had been handled. For these eight, the selection of a principal cause is reproducible, but in three the selection strategy conflicts with the international instructions issued by the World Health Organization. CONCLUSION: Methods and criteria are often insufficiently described. When described, they sometimes disagree with the international standard. Explicit descriptions of methods and criteria would contribute to methodologic improvement and would allow readers to assess the generalizability of the conclusions.

Cause of Death↗

DIAN: a novel algorithm for genome ontological classification.

Faced with the determination of many completely sequenced genomes, computational biology is now faced with the challenge of interpreting the significance of these data sets. A multiplicity of data-related problems impedes this goal: Biological annotations associated with raw data are often not normalized, and the data themselves are often poorly interrelated and their interpretation unclear. All of these problems make interpretation of genomic databases increasingly difficult. With the current explosion of sequences now available from the human genome as well as from model organisms, the importance of sorting this vast amount of conceptually unstructured source data into a limited universe of genes, proteins, functions, structures, and pathways has become a bottleneck for the field. To address this problem, we have developed a method of interrelating data sources by applying a novel method of associating biological objects to ontologies. We have developed an intelligent knowledge-based algorithm, to support biological knowledge mapping, and, in particular, to facilitate the interpretation of genomic data. In this respect, the method makes it possible to inventory genomes by collapsing multiple types of annotations and normalizing them to various ontologies. By relying on a conceptual view of the genome, researchers can now easily navigate the human genome in a biologically intuitive, scientifically accurate manner.

Algorithms↗

A comparative study of two nutrient data bases.

Reported dietary intake records of 18 infants, 22 young children, and 20 women were analyzed using the nutrient data base systems of the Second National Health and Nutrition Examination Survey (NHANES II) and the Nutrient Dietary Data Analysis (NDDA) System. Significant differences between the nutrient data bases were found in the calculations of potassium and niacin for infants and of energy and nine nutrients for women and children. The energy and nutrient composition of many commonly consumed food items in the two nutrient data base systems was different, even though the systems shared common data sources. Differences in the nutrient data bases were primarily due to the timing of data base updates, as well as to the differential use of industry, private, and government food analysis sources, procedural differences in data base updating, and random data entry error. Resolution of differences among nutrient data base systems may depend upon comprehensive reviews of all data base systems or the establishment of a national nutrient data base to serve as a standard for the professional.

Child, Preschool↗

The effectiveness of cost-effectiveness analysis in containing costs.

OBJECTIVE: Although cost-effectiveness analyses (CEAs) have been advocated as a tool to critically appraise the value of health expenditures, it has been widely hoped that they might also help contain health care costs. To determine how often they discourage additional expenditures, we reviewed the conclusions of recently published CEAs. DATA SOURCES: A search of the Abridged Index Medicus (a subset of MEDLINE designed to afford rapid access to the literature of "immediate interest" to the practicing physician) between 1990 and 1996. STUDY SELECTION: We only included articles that reported an explicit cost-effectiveness (CE) ratio (a cost for some given health effect) in the abstract. DATA ABSTRACTION: From each abstract, we collected the value for the incremental CE ratio and the measure of health effect (life-years, quality-adjusted life-years [QALYs], other). We then categorized the authors' conclusion into one of three categories: supports strategy requiring additional expenditure, no firm conclusion, and supports low-cost alternative. Finally, we obtained the article and collected information on funding source. DATA SYNTHESIS: Among the 109 eligible articles, the authors' conclusion supported strategies requiring additional expenditure in 58 (53%) and supported the low-cost alternative in 28 (26%). We then focused on the 65 articles reporting either life-years or QALYs. Cost-effectiveness ratios ranged from $400 to $166,000 (per life-year or QALY) in the 39 articles (60%) in which authors supported additional expenditure, and ranged from $61,500 to $11,600,000 in the 13 articles (20%) in which authors supported the low-cost alternative. Despite identifying similar CE ratios, authors arrived at different conclusions in the overlapping range ($61,500 to $166,000). Of the 10 articles acknowledging industry funding, 9 supported a strategy requiring additional expenditure (p = .01 as compared with those without such funding). CONCLUSIONS: Authors of CEAs are more likely to support strategies requiring additional expenditure than the low-cost alternative. There is no obvious consensus about how small the CE ratio should be to warrant additional expenditure. Finally, concerns about funding source seem to be warranted.

Cost Control↗

Health and health care of rural populations in the UK: is it better or worse?

OBJECTIVE--To review available evidence on the problems facing rural health care in the UK. In particular, to determine whether the health of rural populations is worse than that of town dwellers and how the quality of health care is influenced by rurality. CRITERIA FOR INCLUSION AND EXCLUSION OF ARTICLES--A wide variety of publications and data sources were used. A number of computerised databases with different specialisations (for example medical, health care management) were used to identify relevant published articles. In addition, reports, reviews, and surveys produced by agencies for local circulation were identified by approaching academic, service, and voluntary bodies thought likely to have an interest in rural health. Although this "grey" literature is not subject to peer review, the relative lack of relevant UK publications made it a useful data source for illustrative purposes. Similarly, published articles based on rural health in other developed countries were used when UK data were lacking. CONCLUSIONS--Although the evidence concerning the health and health care of the UK rural populations is suggestive, it is very general and further research is needed. Levels of urban health seem to be generally worse than in rural areas, but contradictions do exist. The evidence on quality of care suggests that service accessibility is a central problem, and rural populations have poorer access than others. Within rural populations, such disadvantage is not uniformly experienced--it affects some groups more than others. In addition, the NHS does not seem to have a consistent policy about whether rurality should influence resource allocation, and how it should be incorporated.

Health Care Rationing↗

Management of influenza in patients with asthma or chronic obstructive pulmonary disease.

OBJECTIVE: To review the prevention and treatment of influenza in patients with asthma and/or chronic obstructive pulmonary disease (COPD). DATA SOURCES: Computer-assisted MEDLINE searches for article and manual searches of conference proceedings on influenza, influenza vaccination, rimantadine, amantadine, oseltamivir, zanamivir, asthma, and/or COPD. STUDY SELECTION: Published articles and pertinent conference abstracts in the areas mentioned in Data sources were selected. Articles included for review were studies conducted on humans. RESULTS: Annual vaccination against influenza is the currently accepted practice for influenza management in patients with asthma and/or COPD. However, despite the availability and use of vaccination, influenza continues to cause serious morbidity and increased mortality. The management of influenza in at-risk patients with the older antivirals such as amantadine or rimantadine has not been widely accepted because of the rapid emergence of resistant variants, their lack of effect against influenza B, and poor adverse event profile. A new class of influenza antivirals, the neuraminidase inhibitors, has recently become available for the management of influenza. The currently marketed neuraminidase inhibitors are zanamivir and oseltamivir. Clinical studies have shown that these neuraminidase inhibitors are effective for the treatment and chemoprophylaxis of influenza A and B. CONCLUSIONS: Vaccination against influenza remains the gold standard for the prevention of influenza in patients with asthma and/or COPD. The neuraminidase inhibitors zanamivir and oseltamivir are useful adjuncts to influenza vaccines for the management of influenza in these patients who are at high-risk of developing influenza related complications.

Antiviral Agents↗

Changes in prevalence of problem opiate use in Germany between 1990 and 2000.

OBJECTIVES: Estimates of opiate use are calculated for the years 1990/1991, 1995 and 2000 in order to explore the development of problem opiate use in Germany in the preceding decade. METHODS: The estimates stem from multiplier methods which extrapolate from a sample (benchmark) of known drug users to the total population by multiplying the benchmark by an appropriate factor that accounts for the unknown population. Data came from the German treatment monitoring system, police and mortality statistics. RESULTS: The population estimates for 2000 resulted in 166,300-197,500 problem opiate users based on treatment data, 153,000-190,000 heroin users from police data, and 126,900-169,200 (current) injectors from mortality data. Recalculated estimates for 1990/1991 and 1995 derived from the same data sources were found to be somewhat lower. DISCUSSION: The reported estimates between 1990 and 2000 point at a moderate increase of problem opiate users in the 1990s. The population estimates based on the multiplier method using three different data sources may be considered consistent for the highly overlapping target groups of (current) injectors, problem heroin and problem opiate users. Nevertheless, some of the applied multipliers are based on small-scale studies, raising the question of representativeness. National prevalence estimates may be improved by using other techniques such as multivariate indicator, capture-recapture, or dynamic models.

Germany↗

caCORE: a common infrastructure for cancer informatics.

MOTIVATION: Sites with substantive bioinformatics operations are challenged to build data processing and delivery infrastructure that provides reliable access and enables data integration. Locally generated data must be processed and stored such that relationships to external data sources can be presented. Consistency and comparability across data sets requires annotation with controlled vocabularies and, further, metadata standards for data representation. Programmatic access to the processed data should be supported to ensure the maximum possible value is extracted. Confronted with these challenges at the National Cancer Institute Center for Bioinformatics, we decided to develop a robust infrastructure for data management and integration that supports advanced biomedical applications. RESULTS: We have developed an interconnected set of software and services called caCORE. Enterprise Vocabulary Services (EVS) provide controlled vocabulary, dictionary and thesaurus services. The Cancer Data Standards Repository (caDSR) provides a metadata registry for common data elements. Cancer Bioinformatics Infrastructure Objects (caBIO) implements an object-oriented model of the biomedical domain and provides Java, Simple Object Access Protocol and HTTP-XML application programming interfaces. caCORE has been used to develop scientific applications that bring together data from distinct genomic and clinical science sources. AVAILABILITY: caCORE downloads and web interfaces can be accessed from links on the caCORE web site (http://ncicb.nci.nih.gov/core). caBIO software is distributed under an open source license that permits unrestricted academic and commercial use. Vocabulary and metadata content in the EVS and caDSR, respectively, is similarly unrestricted, and is available through web applications and FTP downloads. SUPPLEMENTARY INFORMATION: http://ncicb.nci.nih.gov/core/publications contains links to the caBIO 1.0 class diagram and the caCORE 1.0 Technical Guide, which provide detailed information on the present caCORE architecture, data sources and APIs. Updated information appears on a regular basis on the caCORE web site (http://ncicb.nci.nih.gov/core).

Animals↗

Measuring aspects of women's life and work for the study of variations in health.

BACKGROUND: Studies of occupation and health commonly examine only men. This paper draws on reviews of inequalities in health carried out by the Office for National Statistics in London which in recent years have focused more on women. METHODS: Many sources of official statistics such as censuses, surveys, vital registration and health service records are used to explore different ways of measuring and monitoring economic activity, education, socio-economic, and family status and their impact on fertility and health among women. RESULTS: Taking a life cycle approach we first look at fertility and family formation, the time around childbirth, age 15-49, and finally 50+. Some relevant health issues are used to illustrate how we use available data to describe and monitor inequalities in health. CONCLUSIONS: In Britain, there is a wealth of information and linked data sources which enable us to analyze patterns and trends in fertility, morbidity, and mortality. Nevertheless, none of the traditional data sources or methods of analysis are suitable for all purposes nor for keeping up with changes in society. Sources of official statistics and ways of linking and analyzing need then to be continuously developed.

Female↗

The clinical significance of axillary lymph node micrometastases in breast cancer.

OBJECTIVE: To evaluate the clinical significancer of axillary lymph-node micrometastases, in the era of sentinel lymph node (SLN) biopsy. DATA SOURCES: Searches of MEDLINE (1966-2003) and an extensive manual review of journals were performed using the key search terms breast cancer, axillary lymph-node micrometastases, micrometastatic disease, and SLN biopsy. STUDY SELECTION: All articles identified from the data sources were evaluated and all information deemed relevant was included for this review. CONCLUSIONS: Axillary lymph-node micrometastases can be detected by serial sectioning, immunohistochemistry, or reverse transcriptase-polymerase chain reaction (RT-PCR). The presence of axillary SLN micrometastases is generally associated with a worse prognosis and is an indication for axillary lymph node dissection (ALND) and adjuvant therapy. The clinical significance of micrometastases identified by RT-PCR remains unknown and further research with longer follow-up is needed to ascertain the clinical implications of a positive result.

Axilla↗

Reviewing the reviews: the example of chronic fatigue syndrome.

OBJECTIVE: To test the hypothesis that the selection of literature in review articles is unsystematic and is influenced by the authors' discipline and country of residence. DATA SOURCES: Reviews in English published between 1980 and March 1996 in MEDLINE, EMBASE (BIDS), PSYCHLIT, and Current Contents were searched. STUDY SELECTION: Reviews of chronic fatigue syndrome (CFS) were selected. Articles explicitly concerned with a specialty aspect of CFS and unattributed, unreferenced, or insufficiently referenced articles were discarded. DATA EXTRACTION: Record of data sources in each review was noted as was the departmental specialty of the first author and his or her country of residence. The references cited in each index paper were tabulated by assigning them to 6 specialty categories, by article title, and by assigning them to 8 categories, by country of journal publication. DATA SYNTHESIS: Of 89 reviews, 3 (3.4%) reported on literature search and described search method. Authors from laboratory-based disciplines preferentially cited laboratory references, while psychiatry-based disciplines preferentially cited psychiatric literature (P = .01). A total of 71.6% of references cited by US authors were from US journals, while 54.9% of references cited by United Kingdom authors were published in United Kingdom journals (P = .001). CONCLUSION: Citation of the literature is influenced by review authors' discipline and nationality.

Authorship↗