SEARCH · PubMed Health

Results for “Data Aggregation”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources

PubMed1992

Self-aggregation of squid cranial cartilage proteoglycans.

Squid cranial cartilage has been found to contain three different proteoglycan populations, two of which form aggregates (Vynios, D.H. and Tsiganos, C. P., Biochim. Biophys. Acta 1033: 139-147, 1990). The aggregation involves interaction of their protein cores as assessed by electron microscopy and biochemical data. Aggregating oligopeptides were isolated after mild trypsin digestion which inhibited self-aggregation of proteoglycans. The aggregation does not involve interaction of the side chains of polar amino acids and evidence is provided that it is mediated through hydrophobic interaction. It is enhanced upon concentration or incubation of the samples at 37 degrees C.

Animals↗

PubMed1997

Use of sumatriptan in Denmark in 1994-5: an epidemiological analysis of nationwide prescription data.

AIMS: We describe the use of medication with symptomatic relief of migraine as specific indication by analysing prescription data from the entire Danish population in 1994 and 1995. METHODS: The data for sumatriptan were analysed at the level of the individual user. We used aggregated data for ergotamine drugs. RESULTS: Sumatriptan constituted 46% of the total amount of defined daily doses (DDD) sold and 94% of the total pharmacy retail price expenses in the drug-group studied. In total, 43389 users of sumatriptan were identified who presented 340148 prescriptions, corresponding to 2.2 million DDD of sumatriptan. The quarterly consumption increased by 50% during the study period. Tablets accounted for 92% of consumption. The 1 year period prevalence of use of sumatriptan among persons 16 years and older was 7.8 per 1000 in 1995 with a female to male prevalence ratio of 3.8:1. Use was most common in the age interval 35-54 years. Regional differences in use, which were not large, were positively correlated to the degree of urbanization. The incidence of use of sumatriptan was estimated at 3.6 per 1000 person-years. The intensity of use of sumatriptan varied greatly with 1.1% of patients (n = 507) using 60 DDD or more within 30 days at some time during the observation period. Long-term high use of tablets was common in this group. CONCLUSIONS: We conclude that sumatriptan had a considerable impact on the treatment of migraine with prescription drugs in Denmark. The underlying reasons for high use of the drug in a smaller fraction of the patients deserve further study.

Adolescent↗

PubMed2001

Structuring prescribing data into traffic-light categories; a tool for evaluating treatment quality in primary care.

BACKGROUND: Prescribing feedback based on aggregated data alone does not give the information needed to improve treatment quality. OBJECTIVES: Our aim was to develop a new method, or tool, of presenting prescribing feedback which, combined with guideline recommendations, makes it possible for doctors to judge their own prescribing as good or bad. METHODS: Asthma was chosen as a disease model, as treatment recommendations are readily available published as national and international guidelines. Four mean daily dosage intervals of inhaled short-acting beta-agonists and four mean daily dosage intervals of inhaled steroids were combined into a 4 x 4 matrix. This matrix of 16 combined dosage boxes was presented to 68 Norwegian GPs participating in peer review groups. As a first step, the GPs in the groups reached consensus on what they considered to be appropriate and inappropriate combined dosage intervals of these drugs based on national guideline recommendations and their joint clinical experience. Accordingly, traffic-light colours, green and red, were assigned to the combined dosage boxes in the matrix. Treatments in boxes difficult to judge were coloured yellow. During a 1-year period prior to the consensus meetings, the dispensed inhaled short-acting beta-agonists and inhaled steroids of each of the doctors' patients were recorded at the local pharmacies. As a second step in developing the new method, the number of patients treated within each of the coloured boxes was presented to the GPs in the peer review groups. These combined presentations provided an overview to the whole group, and individually to each GP, of how many patients were actually given appropriate or inappropriate treatment according to their own agreed upon standard. RESULTS: The GPs categorized 34% of 1122 evaluated patients receiving inhaled short-acting beta-agonists or inhaled steroids as treated inappropriately during the 1-year registration period. Appropriate treatment was given to 47% of the patients, and in 19% of the cases the treatment was difficult to evaluate. CONCLUSIONS: A method has been developed enabling GPs to categorize prescribing information into good (green), bad (red) and difficult to judge (yellow) treatment qualities, based on guideline recommendations and clinical experience. The actual prescribing data for each GP were labelled according to the same colour scheme, thus revealing to each GP his or her own actual prescribing compared with their own treatment standard, yielding information and motivation for quality improvement efforts.

Adolescent↗

PubMed1995

Systematic reviews of randomized controlled trials: the need for complete data.

If the relative effectiveness of different treatments that might be used in clinical practice is to be evaluated reliably, it is very important that the evaluation is carried out in an appropriate manner. This is especially true where the differences between treatments are expected to be moderate, and so easily obscured by the play of chance or systematic bias. Although such differences are often of considerable clinical importance, they can be difficult to assess and require a large amount of randomized evidence. This evidence can be obtained through prospective randomized controlled trials, meta-analysis of results from past randomized trials, or ideally a combination of the two, with prospective trials contributing to future meta-analyses. Whichever technique is adopted, all possible biases must be minimized through the collection of as much randomized evidence as possible. In meta-analyses, this is best achieved by ensuring that all relevant trials, and all randomized participants in these trials, are included in the analysis. The gold standard for this might be a meta-analysis of individual patient data, in which details for each participant in every trial are collected and analysed centrally. This approach requires considerable time and effort. However, it will add to the analyses that can be performed and will remove many of the problems associated with a reliance on published data alone and some of the problems that can arise from the use of aggregate data. This paper sets out some of the reasons for this and some of the techniques used for individual patient data-based meta-analysis.

Bias↗

PubMed2001

Time on task effects on safety.

Reviewing the literature on time on task effects on safety shows contradictory evidence, especially with regard to 12 h shifts. It is argued that this might depend on methodological problems associated with the analysis of accident data, e.g. selectivity of samples, validity of data bases and study designs, especially for analyses at the company level. Analyses of aggregated data seem to indicate an exponential increase of accident risk with time on task beyond the normal working day. This is supported by some recent studies based on data from the Federal Republic of Germany.

Accidents, Occupational↗

PubMed2003

Land capability and topographic data as a surrogate for the mapping and classification of wetlands: a case example from the Daly basin, Northern Territory, Australia.

The Daly River (catchment 53,000 km2) has the largest flow of all rivers in the Northern Territory and, due to the vast underground aquifers supplying the river, reliable flows of water and areas of high potential soils, is the centre of a region where water resource and agricultural development is being given serious consideration. As part of a larger assessment of environmental flow requirements, an inventory and risk assessment of water dependent ecosystems (wetlands) was undertaken for the Daly basin, a limestone dominated region, 19,382 km2 in size, located in the centre of the catchment. The assessment utilized geographic information system technology to collate, interrogate and analyse soil and topographic data that had been collected previously for the purpose of land capability analysis. The aggregated data were used as a surrogate for mapping the distribution of wetlands in the Daly basin. The land units mapped were composed of individual areas within which the soil, vegetation and landform exhibited a uniform pattern on aerial photographs. The wetland features mapped were classified using landform and hydroperiod as a basis and, to assist in the classification process, a ground-truthing exercise and a basin-wide low-level aerial survey were conducted.

Ecosystem↗

PubMed1984

Methods and issues in the projection of population health status.

The discussion of strategies for forecasting health status changes in human populations often becomes immersed in efforts to utilize simple projection strategies that will produce crude projections. The motivation behind this effort is that simple projection strategies have limited data requirements and the crude projection strategies will be, in some ill-defined sense, robust (i.e., insensitive to assumptions). Actually there is a wide range of projection tools available. It seems appropriate to appraise the nature and attributes of each when considering the uses to which the projections will be put. For example, simple models are not necessarily more robust than more sophisticated procedures, especially for longer term temporal projections. Clearly we have many examples in developed countries where the use of simple actuarial or demographic projections has underestimated the true cost of a health programme by factors of 200-300%. The reason why the failures of such simple projection efforts become so rapidly manifest is that the programmes, once implemented, are expanded to meet the population's needs. In projecting only health services or utilization one has nearly a self-fulfilling prophecy--that resource constraints or the actual organization of the programme will directly determine the course of the level and mixture of health services consumption. Therefore failure to base the projections on a detailed model of underlying population needs leads in such cases to grossly inaccurate results. Clearly, projecting a population's health needs requires even more data than projecting health service requirements. Such information constraints require the use of a model to organize data from multiple objective and subjective sources, and to reflect the best scientific understanding of the processes involved. This article briefly discussed the application of 2 such models. One was designed for the analysis of discrete state health changes using population and vital statistics data, the other described both discrete and continuous changes using data from longitudinally followed community populations. One is designed to work only with detailed aggregate data with heavy inputs from scientific experts; the other deals with relatively information-rich measurements. Both can be modified on the basis of expert judgement to deal with simulations of a multiplicity of possible interventions. Both appropriately calculate the relative costs and benefits of select health initiatives.(ABSTRACT TRUNCATED AT 400 WORDS)

Actuarial Analysis↗

PubMedDate not supplied

Sequential analysis of erythrocyte aggregation in health and diseases.

Aggregation of erythrocytes requires prolonged interaction of cellular and plasma constituents similar to in vivo conditions. To achieve this and then to analyse this process in various clinical and laboratory conditions, a PC-AT based system is developed. The erythrocyte suspension at 5% hematocrit in plasma is placed in a glass chamber, and the changes in laser transmitted intensity due to movement of the aggregates and erythrocytes in the path of the beam are sequentially recorded. From these data, aggregate size index, aggregate sedimentation time index, time required for completion of process and total number of fluctuations are calculated. From these, two additional parameters - effective number of cells and effective sedimentation duration - are calculated. The results show that in leprosy the aggregation of erythrocytes is reduced. In in vitro studies due to the cholesterol-enrichment of the erythrocyte membrane and treatment with pentoxifylline the aggregation of cells is increased whereas in disprin treated cells this is reduced compared to that of normal erythrocytes.

Erythrocyte Aggregation↗

PubMed2003

The relationship of average volume of alcohol consumption and patterns of drinking to burden of disease: an overview.

AIMS: As part of a larger study to estimate the global burden of disease attributable to alcohol: to quantify the relationships between average volume of alcohol consumption, patterns of drinking and disease and injury outcomes, and to combine exposure and risk estimates to determine regional and global alcohol-attributable fractions (AAFs) for major disease and injury categories. DESIGN, METHODS, SETTING: Systematic literature reviews were used to select diseases related to alcohol consumption. Meta-analyses of the relationship between alcohol consumption and disease and multi-level analyses of aggregate data to fill alcohol-disease relationships not currently covered by individual-level data were used to determine the risk relationships between alcohol and disease. AAFs were estimated as a function of prevalence of exposure and relative risk, or from combining the aggregate multi-level analyses with prevalence data. FINDINGS: Average volume of alcohol consumption was found to increase risk for the following major chronic diseases: mouth and oropharyngeal cancer; oesophageal cancer; liver cancer; breast cancer; unipolar major depression; epilepsy; alcohol use disorders; hypertensive disease; hemorrhagic stroke; and cirrhosis of the liver. Coronary heart disease (CHD), unintentional and intentional injuries were found to depend on patterns of drinking in addition to average volume of alcohol consumption. Most effects of alcohol on disease were detrimental, but for certain patterns of drinking, a beneficial influence on CHD, stroke and diabetes mellitus was observed. CONCLUSIONS: Alcohol is related to many major disease outcomes, mainly in a detrimental fashion. While average volume of consumption was related to all disease and injury categories under consideration, pattern of drinking was found to be an additional influencing factor for CHD and injury. The influence of patterns of drinking may be underestimated because pattern measures have not been included in many epidemiologic studies. Generalizability of the results is limited by methodological problems of the underlying studies used in the present analyses. Future studies need to address these methodological issues in order to obtain more accurate risk estimates.

Acute Disease↗

PubMed2003

Effects of statins on nonlipid serum markers associated with cardiovascular disease: a systematic review.

BACKGROUND: Statins reduce cardiovascular events to a greater extent than can be explained by their effect on lipids. Several studies have attempted to elucidate mechanisms by which statins reduce cardiovascular risk. PURPOSE: To summarize the effects of statins on nonlipid serum markers and to correlate statins' effect on serum markers with lipid levels and cardiovascular outcomes. DATA SOURCES: MEDLINE (1980 to 2003) search limited to English-language articles. STUDY SELECTION: Studies reporting original data in at least 10 participants on the effect of statins on outcomes of interest, excluding studies of cerivastatin, drug combinations, and patients with organ transplants. DATA EXTRACTION: Study design, sample size, treatment, and outcome data extracted on the basis of preestablished criteria. When appropriate, meta-analysis was performed by using a random-effects model. DATA SYNTHESIS: All statins are effective at lowering C-reactive protein levels, and the effect is not dose-dependent. Studies do not demonstrate a correlation between statins' effects on C-reactive protein levels and on lipids or cardiovascular outcomes. Statins do not affect fibrinogen levels, and limited data suggest little effect on lipid oxidation, tissue plasminogen activator, or plasminogen activator inhibitor. Platelet aggregation data are inconclusive. CONCLUSIONS: Among nonlipid serum markers examined, only C-reactive protein levels are statistically significantly affected by statins. These findings suggest that statin-mediated anti-inflammatory effects may contribute to the ability of statins to reduce risk for cardiovascular disease. Overall, however, available data are insufficient to support recommendations for using nonlipid serum markers in decisions regarding statin therapy for individual patients.

Biomarkers↗

PubMed1999

Alcohol consumption and divorce rates in the United States.

OBJECTIVE: The objective of the present study is to analyze time series data on alcohol consumption and divorce rates and assess the directionality of this relationship using alternative aggregate measures of alcohol consumption rates. METHOD: Granger's causality test and Box-Jenkins time series analysis are used to examine aggregate data on divorce rates and two indicators of alcohol consumption: a per capita consumption measure based on sales and shipments, and an expenditure-based measure for U.S. data from 1934 to 1987. RESULTS: A consumption increase of 1 liter of alcohol per capita brings about an increase in the divorce rate of about 20%. This finding contrasts with results, using expenditures as the aggregate alcohol measure, that show that an increase of 1/1,000 in the divorce rate leads to a 10% increase in alcohol expenditures. (These latter findings confirm earlier published results.) CONCLUSIONS: The results from the present study provide support both for the effects of heavy drinking on divorce rates and the effects of divorce rates on expenditures for alcoholic beverages. While both aggregate measures of alcohol consumption are highly correlated, they may tap different aspects of consumption. The relationship between marital instability and alcohol consumption is far from a simple one, and more complete conceptual models need to be developed. Aggregate-level findings indicate that it is reasonable to assume that a bidirectional influence exists between divorce rates and alcohol consumption.

Alcohol Drinking↗

PubMed2006

Evaluating the performance of species richness estimators: sensitivity to sample grain size.

1. Fifteen species richness estimators (three asymptotic based on species accumulation curves, 11 nonparametric, and one based in the species-area relationship) were compared by examining their performance in estimating the total species richness of epigean arthropods in the Azorean Laurisilva forests. Data obtained with standardized sampling of 78 transects in natural forest remnants of five islands were aggregated in seven different grains (i.e. ways of defining a single sample): islands, natural areas, transects, pairs of traps, traps, database records and individuals to assess the effect of using different sampling units on species richness estimations. 2. Estimated species richness scores depended both on the estimator considered and on the grain size used to aggregate data. However, several estimators (ACE, Chao 1, Jackknifel and 2 and Bootstrap) were precise in spite of grain variations. Weibull and several recent estimators [proposed by Rosenzweig et al. (Conservation Biology, 2003, 17, 864-874), and Ugland et al. (Journal of Animal Ecology, 2003, 72, 888-897)] performed poorly. 3. Estimations developed using the smaller grain sizes (pair of traps, traps, records and individuals) presented similar scores in a number of estimators (the above-mentioned plus ICE, Chao2, Michaelis-Menten, Negative Exponential and Clench). The estimations from those four sample sizes were also highly correlated. 4. Contrary to other studies, we conclude that most species richness estimators may be useful in biodiversity studies. Owing to their inherent formulas, several nonparametric and asymptotic estimators present insensitivity to differences in the way the samples are aggregated. Thus, they could be used to compare species richness scores obtained from different sampling strategies. Our results also point out that species richness estimations coming from small grain sizes can be directly compared and other estimators could give more precise results in those cases. We propose a decision framework based on our results and on the literature to assess which estimator should be used to compare species richness scores of different sites, depending on the grain size of the original data, and of the kind of data available (species occurrence or abundance data).

Animals↗

PubMedDate not supplied

Strategies for analysing ecological health data: models of the biological risk of individuals.

Frequently, the analysis of environmental health hazards using ecological data does not involve explicit recognition of the difficulties in translating health effects expressed in the aggregate to the health risks of individuals. We discuss these difficulties and suggest the need for the appropriate conceptualization of risk mechanisms at the individual level and of the population processes that determine the form in which these risk mechanisms are expressed in aggregate data. To illustrate the implications of these concepts we develop a biologically motivated model of lung cancer risk and apply it to both national and county data. In addition, to measure the total health effects of the long term elevation or depression of lung cancer incidence rates, we calculate prevalence distributions from the time series analysis of incidence patterns in county data.

Adult↗

PubMedDate not supplied

Language validation of the air transport minimum data set: time-related terms.

INTRODUCTION: Transport times, such as time of call, are an essential part of the patient record. The purpose of this study was to validate a previously proposed minimum data set of time-related terms. METHODS: A stratified sample of 508 nurses, physicians, paramedics, pilots, and communication specialists was selected to participate in the validation survey. Subjects indicated their agreement/disagreement with the proposed terms and their definitions on a scale of 1 (low) to 3 (high). In addition, subjects indicated whether they currently collect the data elements or could do so easily. Finally, subjects said whether they were willing to release aggregate data for benchmarking purposes. RESULTS: One-hundred-eighteen subjects (23.2%) responded to the survey with usable data. Agreement to include the terms (level 3) ranged from 71.2% to 95.8%. Agreement with the proposed definition ranged from 72.9% to 95.8%. Seventy-eight of the respondents were willing to release all the data elements. CONCLUSION: Fourteen of the 19 terms are recommended for inclusion in a minimum data set for rotor-wing transport. Most persons expressed willingness to release data for benchmarking efforts.

Air Ambulances↗

PubMed2002

Error reduction and performance improvement in the emergency department through formal teamwork training: evaluation results of the MedTeams project.

OBJECTIVE: To evaluate the effectiveness of training and institutionalizing teamwork behaviors, drawn from aviation crew resource management (CRM) programs, on emergency department (ED) staff organized into caregiver teams. STUDY SETTING: Nine teaching and community hospital EDs. STUDY DESIGN: A prospective multicenter evaluation using a quasi-experimental, untreated control group design with one pretest and two posttests of the Emergency Team Coordination Course (ETCC). The experimental group, comprised of 684 physicians, nurses, and technicians, received the ETCC and implemented formal teamwork structures and processes. Assessments occurred prior to training, and at intervals of four and eight months after training. Three outcome constructs were evaluated: team behavior, ED performance, and attitudes and opinions. Trained observers rated ED staff team behaviors and made observations of clinical errors, a measure of ED performance. Staff and patients in the EDs completed surveys measuring attitudes and opinions. DATA COLLECTION: Hospital EDs were the units of analysis for the seven outcome measures. Prior to aggregating data at the hospital level, scale properties of surveys and event-related observations were evaluated at the respondent or case level. PRINCIPAL FINDINGS: A statistically significant improvement in quality of team behaviors was shown between the experimental and control groups following training (p = .012). Subjective workload was not affected by the intervention (p = .668). The clinical error rate significantly decreased from 30.9 percent to 4.4 percent in the experimental group (p = .039). In the experimental group, the ED staffs' attitudes toward teamwork increased (p = .047) and staff assessments of institutional support showed a significant increase (p = .040). CONCLUSION: Our findings point to the effectiveness of formal teamwork training for improving team behaviors, reducing errors, and improving staff attitudes among the ETCC-trained hospitals.

Attitude of Health Personnel↗

PubMed2004

Higher incidence of SIDS at weekends, especially in younger infants.

BACKGROUND: An increased incidence of sudden infant death syndrome (SIDS) at weekends has been previously noted, although it has not been found in all studies. Where a weekend effect has been found it is most prominent on Sundays. AIM: To identify the magnitude of this effect in British data before and after the fall in prevalence associated with the "back to sleep" campaign. METHODS: Aggregated data from England Wales, Scotland, and Northern Ireland for the years 1986-98 during which there were 12,762 deaths from SIDS were examined. RESULTS: Comparing the periods before (1986-90) and after (1993-98) the fall in incidence associated with the "back to sleep" campaign, the percentage of infants dying at the weekend in the later period (32.24%) was slightly greater than for the earlier period (31.30%), although this difference was not statistically significant. In both periods the observed weekend incidences were significantly higher than the expected weekend percentage of 28.6%. Although the proportion of infants aged < or =4 months and > or =5 months at death did not change between the two periods, the weekend effect was more marked in the younger infants, particularly in the 1993-98 period. There was no consistent Saturday effect. In 1993-98 deaths appeared to be more evenly distributed throughout the week for infants > or =5 months. CONCLUSION: The excess of SIDS at weekends still appears to be present despite the overall fall in prevalence associated with the "back to sleep" campaign. Increased risks at weekends might have implications for support to high risk families.

Age Factors↗

PubMed2005

Indirect comparisons of competing interventions.

OBJECTIVES: To survey the frequency of use of indirect comparisons in systematic reviews and evaluate the methods used in their analysis and interpretation. Also to identify alternative statistical approaches for the analysis of indirect comparisons, to assess the properties of different statistical methods used for performing indirect comparisons and to compare direct and indirect estimates of the same effects within reviews. DATA SOURCES: Electronic databases. REVIEW METHODS: The Database of Abstracts of Reviews of Effects (DARE) was searched for systematic reviews involving meta-analysis of randomised controlled trials (RCTs) that reported both direct and indirect comparisons, or indirect comparisons alone. A systematic review of MEDLINE and other databases was carried out to identify published methods for analysing indirect comparisons. Study designs were created using data from the International Stroke Trial. Random samples of patients receiving aspirin, heparin or placebo in 16 centres were used to create meta-analyses, with half of the trials comparing aspirin and placebo and half heparin and placebo. Methods for indirect comparisons were used to estimate the contrast between aspirin and heparin. The whole process was repeated 1000 times and the results were compared with direct comparisons and also theoretical results. Further detailed case studies comparing the results from both direct and indirect comparisons of the same effects were undertaken. RESULTS: Of the reviews identified through DARE, 31/327 (9.5%) included indirect comparisons. A further five reviews including indirect comparisons were identified through electronic searching. Few reviews carried out a formal analysis and some based analysis on the naive addition of data from the treatment arms of interest. Few methodological papers were identified. Some valid approaches for aggregate data that could be applied using standard software were found: the adjusted indirect comparison, meta-regression and, for binary data only, multiple logistic regression (fixed effect models only). Simulation studies showed that the naive method is liable to bias and also produces over-precise answers. Several methods provide correct answers if strong but unverifiable assumptions are fulfilled. Four times as many similarly sized trials are needed for the indirect approach to have the same power as directly randomised comparisons. Detailed case studies comparing direct and indirect comparisons of the same effect show considerable statistical discrepancies, but the direction of such discrepancy is unpredictable. CONCLUSIONS: Direct evidence from good-quality RCTs should be used wherever possible. Without this evidence, it may be necessary to look for indirect comparisons from RCTs. However, the results may be susceptible to bias. When making indirect comparisons within a systematic review, an adjusted indirect comparison method should ideally be used employing the random effects model. If both direct and indirect comparisons are possible within a review, it is recommended that these be done separately before considering whether to pool data. There is a need to evaluate methods for the analysis of indirect comparisons for continuous data and for empirical research into how different methods of indirect comparison perform in cases where there is a large treatment effect. Further study is needed into when it is appropriate to look at indirect comparisons and when to combine both direct and indirect comparisons. Research into how evidence from indirect comparisons compares to that from non-randomised studies may also be warranted. Investigations using individual patient data from a meta-analysis of several RCTs using different protocols and an evaluation of the impact of choosing different binary effect measures for the inverse variance method would also be useful.

Bias↗

PubMed2005

Dialysis session length ("t") as a determinant of the adequacy of dialysis.

Several studies have shown an association between the hemodialysis session length (the t of Kt or Kt/V) and favorable outcomes for patients on maintenance hemodialysis. In a single randomized controlled trial that systematically varied hemodialysis session length, shorter session length was associated with an increased risk for morbidity and mortality, independent of the time-averaged concentration of urea. Observational studies of dialysis session length have yielded conflicting results, although virtually all studies have confounded hemodialysis session length with hemodialysis efficiency or dose. Limited observational data from nocturnal hemodialysis programs more strongly suggest an independent beneficial effect of longer session length. In aggregate, data on the effects of hemodialysis session length are inconclusive. Future studies should evaluate hemodialysis session length independent of efficiency, and should consider the evaluation of dose by using other clearance parameters and the adequacy of ultrafiltration in addition to solute kinetics.

Chemical Phenomena↗