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Results for “Data Aggregation”

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PubMed2002

Monitoring antimicrobial use and resistance: comparison with a national benchmark on reducing vancomycin use and vancomycin-resistant enterococci.

To determine if local monitoring data on vancomycin use directed quality improvement and decreased vancomycin use or vancomycin-resistant enterococci (VRE), we analyzed data from 50 intensive-care units (ICUs) at 20 U.S. hospitals reporting data on antimicrobial-resistant organisms and antimicrobial agent use. We compared local data with national benchmark data (aggregated from all study hospitals). After data were adjusted for changes in prevalence of methicillin-resistant Staphylococcus aureus, changes in specific prescriber practice at ICUs were associated with significant decreases in vancomycin use (mean decrease -48 defined daily doses per 1,000 patient days, p<0.001). These ICUs also reported significant decreases in VRE prevalence compared with those not using unit-specific changes in practice (mean decrease of 7.5% compared with mean increase of 5.7%, p<0.001). In this study, practice changes focused towards specific ICUs were associated with decreases in ICU vancomycin use and VRE prevalence.

Anti-Bacterial Agents↗

PubMed2002

Estimation of an errors-in-variables regression model when the variances of the measurement errors vary between the observations.

It is common in the analysis of aggregate data in epidemiology that the variances of the aggregate observations are available. The analysis of such data leads to a measurement error situation, where the known variances of the measurement errors vary between the observations. Assuming multivariate normal distribution for the 'true' observations and normal distributions for the measurement errors, we derive a simple EM algorithm for obtaining maximum likelihood estimates of the parameters of the multivariate normal distributions. The results also facilitate the estimation of regression parameters between the variables as well as the 'true' values of the observations. The approach is applied to re-estimate recent results of the WHO MONICA Project on cardiovascular disease and its risk factors, where the original estimation of the regression coefficients did not adjust for the regression attenuation caused by the measurement errors.

Algorithms↗

PubMedDate not supplied

Fire fatalities among children: an analysis across Philadelphia's census tracts.

OBJECTIVE: This study investigates the possible causes of high levels of residential fire deaths to children younger than 15 years of age in Philadelphia from 1989 to 2000. METHODS: The authors analyzed 246 deaths from 146 residential fires by census tract in Philadelphia using both individual level data and aggregate level data drawn from the records of the Fire Marshall's Office. Death rates by age and sex were calculated using the 1990 Census. Data on fires from official records were combined with aggregate level data by census tract from the 1990 Census and analyzed using logistic regression. Newspaper articles on the fires analyzed were used to identify residences with possible fire code violations. The authors used data from the Philadelphia Bureau of Licenses and Inspections to provide evidence of code violations. RESULTS: The statistically significant variables that resulted from the logistic regression were census tracts in the highest quartile for low income households, census tracts in the highest quartile for single-parent households with children younger than age 18, census tracts in the highest quartile for houses built before 1939, and the number of children younger than 15 years of age in a census tract. CONCLUSION: Population characteristics by census tract are useful in identifying risk factors for residential fire deaths of children. Census tracts identified as at highest risk can provide fire prevention units with opportunities to take preventative measures such as the distribution of smoke detectors, and the education of residents about the dangers of careless smoking and planning for the rescue of children in the event of a fire.

Adolescent↗

PubMed2001

Development and utilization of paperless medical records: a unique approach.

The purpose of this article is to describe the development and utilization of a unique paperless medical record system in a large multispeciality group practice setting. The Scott and White integrated health care delivery system provides care over a 34-county area in Central Texas. Since 1988, clinicians at Scott and White have developed a text-based, content-searchable electronic medical record system known as EMRx. This system provides a single clinical data repository that allows patient care activities and aggregate data analyses to occur by using the same set of data on a daily basis. Use of this approach has led to the aggregation of over 9.8 million clinical documents since 1994. Over 1,845 health care providers used the system during May 2000 for direct patient care; 866,114 patient records have been accessed since January 1, 1999 to answer questions related to patient care, quality assurance, outcomes research, and accreditation.

Group Practice↗

PubMed2001

Physiologic tolerance to uncompensable heat: intermittent exercise, field vs laboratory.

PURPOSE: This study determined whether exercise (30 min)-rest (10 min) cycles alter physiologic tolerance to uncompensable heat stress (UCHS) when outdoors in the desert. In addition, the relationship between core temperature and exhaustion from heat strain previously established in laboratory studies was compared with field studies. METHODS: Twelve men completed four trials: moderate intensity continuous exercise (MC), moderate intensity exercise with intermittent rest (MI), hard intensity continuous exercise (HC), and hard intensity exercise with intermittent rest (HI). UCHS was achieved by wearing protective clothing and exercising (estimated at 420 W or 610 W) outdoors in desert heat. RESULTS: Heat Stress Index values were 200%, 181%, 417%, and 283% for MC, MI, HC, and HI, respectively. Exhaustion from heat strain occurred in 36 of 48 trials. Core temperatures at exhaustion averaged 38.6 +/- 0.5 degrees, 38.9 +/- 0.6 degrees, 38.9 +/- 0.7 degrees, and 39.0 +/- 0.7 degrees C for MC, MI, HC, and HI, respectively. Core temperature at exhaustion was not altered (P > 0.05) by exercise intensity or exercise-rest cycles and 50% of subjects incurred exhaustion at core temperature of 39.4 degrees C. These field data were compared with laboratory and field data collected over the past 35 years. Aggregate data for 747 laboratory and 131 field trials indicated that 50% of subjects incurred exhaustion at core temperatures of 38.6 degrees and 39.5 degrees C, respectively. When heat intolerant subjects (exhaustion < 38.3 degrees C core temperature) were removed from the analysis, subjects from laboratory studies (who underwent short-term acclimation) still demonstrated less (0.8 degrees C) physiological tolerance than those from field studies (who underwent long-term acclimatization). CONCLUSION: Exercise-rest cycles did not alter physiologic tolerance to UCHS. In addition, subjects from field studies demonstrate greater physiologic tolerance than subjects from laboratory studies.

Adaptation, Physiological↗

PubMed1996

Polyphasic taxonomy, a consensus approach to bacterial systematics.

Over the last 25 years, a much broader range of taxonomic studies of bacteria has gradually replaced the former reliance upon morphological, physiological, and biochemical characterization. This polyphasic taxonomy takes into account all available phenotypic and genotypic data and integrates them in a consensus type of classification, framed in a general phylogeny derived from 16S rRNA sequence analysis. In some cases, the consensus classification is a compromise containing a minimum of contradictions. It is thought that the more parameters that will become available in the future, the more polyphasic classification will gain stability. In this review, the practice of polyphasic taxonomy is discussed for four groups of bacteria chosen for their relevance, complexity, or both: the genera Xanthomonas and Campylobacter, the lactic acid bacteria, and the family Comamonadaceae. An evaluation of our present insights, the conclusions derived from it, and the perspectives of polyphasic taxonomy are discussed, emphasizing the keystone role of the species. Taxonomists did not succeed in standardizing species delimitation by using percent DNA hybridization values. Together with the absence of another "gold standard" for species definition, this has an enormous repercussion on bacterial taxonomy. This problem is faced in polyphasic taxonomy, which does not depend on a theory, a hypothesis, or a set of rules, presenting a pragmatic approach to a consensus type of taxonomy, integrating all available data maximally. In the future, polyphasic taxonomy will have to cope with (i) enormous amounts of data, (ii) large numbers of strains, and (iii) data fusion (data aggregation), which will demand efficient and centralized data storage. In the future, taxonomic studies will require collaborative efforts by specialized laboratories even more than now is the case. Whether these future developments will guarantee a more stable consensus classification remains an open question.

Amino Acid Sequence↗

PubMed1991

Physician customary charges and Medicare payment experience: study findings.

Customary charges have had significant impacts in determining reasonable prices under the historic Medicare physician payment system. This article contains new, comprehensive information on customary charges as well as data aggregated at the physician level. These baseline data have some important policy implications, such as the study findings, that indicate that the Medicare fee schedule is likely to have significant impacts on individual physician practices. The study is based on data for medical, surgical, and consultation services for nine States.

Fee Schedules↗

PubMed1990

Mutations causing hemophilia B: direct estimate of the underlying rates of spontaneous germ-line transitions, transversions, and deletions in a human gene.

Spontaneous mutation provides the substrate for evolution on one hand and for genetic susceptibility to disease on the other hand. X-linked diseases such as hemophilia B offer an opportunity to examine recent germ-line mutations in humans. By utilizing the direct sequencing method of genomic amplification with transcript sequencing, eight regions (2.46 kb) of likely functional significance in the factor IX gene have been sequenced in a total of 60 consecutive, unrelated hemophiliacs. The high frequency of patient ascertainment from three regions in the midwestern United States and Canada suggests that the sample is representative of hemophiliacs of northern European descent. Twenty-six of the delineated mutations are reported herein, and the group of 60 is analyzed as a whole. From the pattern of mutations causing disease and from a knowledge of evolutionarily conserved amino acids, it is possible to reconstruct the underlying pattern of mutation and to calculate the mutation rates per base pair per generation for transitions (27 x 10(-10)), transversions (4.1 x 10(-10), and deletions (0.9 x 10(-10)) for a total mutation rate of 32 x 10(-10). The proportion of transitions at non-CpG nucleotides is elevated sevenfold over that expected if one base substitution were as likely as another. At the dinucleotide CpG, transitions are elevated 24-fold relative to transitions at other sites. The pattern of spontaneous mutations in factor IX resembles that observed in Escherichia coli when the data are corrected for ascertainment bias. The aggregate data hint that most mutations may be due to endogenous processes. The following additional conclusions emerge from the data: (1) Although in recent decades reproductive fitness in individuals with mild and moderate hemophilia has been approximately normal, the large number of different mutations found strongly suggest that these levels of disease substantially compromised reproduction in previous centuries. (2) Mutations which putatively affect splicing account for at least 13% of independent mutations, indicating that the division of the gene into eight exons presents a significant genetic cost for the organism. In one individual a "silent" mutation at lysine 5 is likely to cause hemophilia by generating a perfect splice donor consensus sequence in exon b. (3) All the missense mutations occurred at evolutionarily conserved amino acids. As additional data are generated on the pattern of mutations caused by specific mutagens, it will be possible to utilize the pattern of spontaneous mutation to estimate the maximal contribution of that mutagen during the past century.

Amino Acid Sequence↗

PubMedDate not supplied

A clinical information system for ambulatory care.

This article describes a clinical information system developed for ambulatory care nurse practitioners. An overview of the clinical information system is presented, followed by a detailed description. The clinical information system uses the relational database structure proposed by Hettinger and Brazile (1992), and creates a longitudinal electronic health care record. The database design includes the Nursing Minimum Data Set and provides links to external aggregate data sets such as the U. S. Census data. Special features are discussed such as the ability to select from several problem classification schemes, including North American Nursing Diagnosis Association, Omaha, and International Classification of Diseases, 9th Revision; insert new menu selections whenever needed; create and track groups; and store detailed outcome data. A brief summary of implementation considerations is included.

Ambulatory Care Information Systems↗

PubMed2000

Individual patient data meta-analysis of randomized anti-epileptic drug monotherapy trials.

Meta-analysis may be based on either aggregate data or individual patient data (IPD). Three reasons why IPD are desirable for the meta-analysis of anti-epileptic drug (AED) monotherapy trials are: (1) to undertake a more complete analysis of time-to-event outcomes; (2) to investigate the interaction between AED and type of epilepsy; and (3) to undertake re-analysis of the trial to obtain results for all relevant outcomes. We demonstrate that IPD meta-analysis is possible in AED research. Problems arose from missing data at four levels: (1) unknown trials; (2) known trials but no IPD supplied; (3) known trials but missing outcome data for some individuals within trials; and (4) known trials but missing covariate data for some individuals within trials. Empirical evidence of the reliability of meta-analyses based on aggregate rather than individual patient data is still lacking. Examples of other benefits such projects may bring include improvements to the design of a new trial in the area, in terms of the sample size considerations, the definition of outcomes and data collection.

Anticonvulsants↗

PubMed2001

Processing and representation of meta-data for sleep apnea diagnosis with an artificial intelligence approach.

In this article, we revise and try to resolve some of the problems inherent in questionnaire screening of sleep apnea cases and apnea diagnosis based on attributes which are relevant and reliable. We present a way of learning information about the relevance of the data, comparing this with the definition of the information by the medical expert. We generate a predictive data model using a data aggregation operator which takes relevance and reliability information about the data into account to produce a diagnosis for each case. We also introduce a grade of membership for each question response which allows the patient to indicate a level of confidence or doubt in their own judgement. The method is tested with data collected from patients in a Sleep Clinic using questionnaires specially designed for the study. Other artificial intelligence predictive modeling algorithms are also tested on the same data and their predictive accuracy compared to that of the aggregation operator.

Adult↗

PubMed1991

Effect of food competition on aggregation: evidence for social recognition in the plains garter snake (Thamnophis radix).

Competition for food and aggregating behavior were examined in plains garter snakes (Thamnophis radix), in 11 groups of 1 noncompetitor and 2 competitors. Aggregation data were obtained in 48 daily scans. During food competition, success at obtaining food was asymmetrical across pairs. For aggregation, competitors were mostly associated with noncompetitors. After removal of noncompetitors, competitors were more likely to be solitary, but associations between competitors increased. After a 5-month separation, 5 of the original groups were reconstituted; aggregation patterns similar to the 1st experiment were observed. In a 3rd experiment, unfamiliar animals with and without competitive experience did not aggregate preferentially. Garter snakes discriminate on the basis of sex and species; in this study individual relationships (prior competition) affected aggregation, and the data suggest individual recognition both occurs and persists over time.

Agonistic Behavior↗

PubMed2006

Bridging biological scales by state-space analysis and modeling using molecular, tissue cytometric and physiological data.

Combining data streams across different levels of biological organization such as molecular, cellular, and physiological responses support to a system-wide view in biology. Recently, an unbiased analysis of tissues that provides data-rich descriptors of tissue architecture, cell types, and cell states has become available. As tissues are centrally located in the biological hierarchy, these advancements give rise to a new class of state variables that are critical to elucidate both underlying cellular, molecular and emergent physiological properties. Concepts to statistically identify, correlate, and model relationships across scales are introduced, which rely on a state-space matrix derived by multi-omics data aggregation.

Computational Biology↗

PubMed2003

The potential of electronic medical record systems to support quality improvement work and research in Norwegian general practice.

BACKGROUND: Electronic medical record (EMR) systems are used for many purposes including patient care, administration, research, quality improvement and reimbursement. This study aimed to test a data extraction tool (QTools) and to provide information to support the interpretation of EMR data. METHODS: Comparison of aggregated practice data for selected EMR fields and interviews with practice staff. Practices received summaries of their data and aggregated data for other practices. Summaries were discussed in interviews. RESULTS: Fourteen general practices in the Oslo area using the Winmed EMR participated. QTools ran successfully at all 14 practices. Nine practices agreed to interviews. Apart from age and sex, general patient information was poorly recorded. Face-to-face consultations account for 59% of contacts but differences in coding led to variations between practices. Psychiatric problems accounted for 13% of diagnoses, other diagnosis groups rarely accounted for more than 5%. Over 90% of diabetics and 75% of patients with heart disease were identified by diagnosis code alone. CONCLUSION: Some variation seen in EMR data is due to differences in the way staff use their EMR. These data can support quality improvement work but this requires an awareness of how the EMR is actually used by practice staff.

Chronic Disease↗

PubMed2002

Benchmarking process: select targets for change.

Previously uncollected data will be used to fuel ongoing improvement. Aggregate data will be shared with all 239 participating facilities. Member survey identifies most beneficial areas to target.

Benchmarking↗

PubMed2004

Smoking-adjusted incidence of lung cancer by occupation among Norwegian men.

OBJECTIVE: To use aggregated data on smoking habits and lung cancer incidence in occupations assumed to carry no lung cancer risk to control for confounding in other occupational groups. METHODS: Lung cancer incidence was observed from 1971 to 1991 for 53 occupational groups and a group of economically inactive men in a national cohort study. Data on occupation and smoking habits were collected from national surveys during 1965-1980. The relationship between smoking habits and lung cancer incidence was estimated on aggregated level using data from 12 occupational groups that were initially assumed not to be exposed to occupational lung carcinogens. The estimated relationship was used to control confounding from smoking in the other groups. The results were presented as smoking-adjusted incidence ratios. RESULTS: A significant excess risk was found for 26 groups. It was estimated that about 20% of all lung cancer among men could be related to occupation after adjusting for the effect of smoking. CONCLUSIONS: Our method provided a clearer picture of the occupational risk and could be useful in other situations where individual information on smoking habits is lacking.

Adult↗

PubMed2001

The Val-210-Ile pathogenic Creutzfeldt-Jakob disease mutation increases both the helical and aggregation propensities of a sequence corresponding to helix-3 of PrP(C).

A peptide corresponding to the third helical region within the PrP(C) protein, from residues 198 to 218 (helix-3), was synthesised with and without the familial 210-Val to Ile Creutzfeldt-Jakob disease mutation. The NMR structure of PrP(C) predicts no global variation in stability for this mutation, indicating that local sequence rather than global structural factors are involved in the pathological effects of this mutation. 1H NMR analysis of peptides with and without this mutation indicated that it had no significant effect on local helical structure. Temperature denaturation studies monitored by CD showed that the mutation increased the helical content within this region (helical propensity), but did not stabilise the helix toward denaturation (helical stability). Aggregation data indicated that, in addition to increasing helical propensity, this mutation increased the aggregation propensity of this sequence. CD and NMR data indicate that helical interactions, stabilised by the Val-210-Ile mutation, may precede the formation of beta-sheet aggregates in this peptide sequence. Therefore, this pathological mutation probably does not facilitate PrP(C) to PrP(Sc) conversion by directly destabilising the helical structure of PrP(C), but may preferentially stabilise PrP(Sc) by facilitating beta-sheet formation within this sequence region of PrP. In addition, helical interactions between helix-3 in two or more PrP(C) molecules may promote conversion to PrP(Sc).

Amino Acid Sequence↗

PubMed2004

Highly active antiretroviral therapy and sexual risk behavior: a meta-analytic review.

CONTEXT: Evidence suggests that since highly active antiretroviral therapy (HAART) became available, the prevalence of unprotected sex and the incidence of sexually transmitted infections (STIs) have increased. OBJECTIVE: To conduct 3 meta-analyses to determine whether (1) being treated with HAART, (2) having an undetectable viral load, or (3) holding specific beliefs about HAART and viral load are associated with increased likelihood of engaging in unprotected sex. DATA SOURCES: A comprehensive search included electronic bibliographic databases, including AIDSLINE, MEDLINE, PubMed, CINHAL, PsycInfo, ERIC, EMBASE, and Sociofile, from January 1996 to August 2003, conference proceedings, hand searches of journals, reference lists of articles, and contacts with researchers. STUDY SELECTION: Twenty-five English-language studies (some contributing >1 finding) met the selection criteria and examined the association of unprotected sexual intercourse or STIs with receiving HAART (21 findings), having an undetectable viral load (13 findings), or beliefs about HAART and viral load (18 findings). DATA EXTRACTION: Reports were screened and information from eligible studies was abstracted independently by pairs of reviewers using a standardized spreadsheet. DATA SYNTHESIS: Random-effects models were used to aggregate data. The prevalence of unprotected sex was not higher among persons with the human immunodeficiency virus (HIV) receiving HAART (prevalence range, 9%-56%; median, 33%) vs those not receiving HAART (range, 11%-77%; median, 44%; odds ratio [OR], 0.92; 95% confidence interval [CI], 0.65-1.31) or among HIV-positive persons with an undetectable viral load (range, 10%-68%; median, 39%) vs those with a detectable viral load (range, 14%-70%; median, 42%; OR, 0.99; 95% CI, 0.82-1.21). The prevalence of unprotected sex was elevated (OR, 1.82; 95% CI, 1.52-2.17) in HIV-positive, HIV-negative, and unknown serostatus persons who believed that receiving HAART or having an undetectable viral load protects against transmitting HIV or who had reduced concerns about engaging in unsafe sex given the availability of HAART (range, 17%-81% [median, 49%] vs 9%-68% [median, 38%] for counterparts). CONCLUSIONS: In the studies reviewed, HIV-positive patients receiving HAART did not exhibit increased sexual risk behavior, even when therapy achieved an undetectable viral load. However, people's beliefs about HAART and viral load may promote unprotected sex and may be amenable to change through prevention messages.

Antiretroviral Therapy, Highly Active↗