SEARCH · PubMed Health

Results for “systematics”

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 379 records · Page 21Linked to original sources

PubMed2004

Systematic reviews of health care interventions: an essential component of health sciences graduate programs.

Systematic reviews are an objective, rigorous assessment of both published and unpublished research that enable the reviewer to make recommendations to clinicians, policy-makers, consumers, and researchers. The steps in a systematic review include: (a) developing a research question, (b) developing relevance and validity tools, (c) conducting a thorough literature search of published and unpublished studies, (d) using relevance and validity tools to assess the studies, (e) completing data extraction for each study, (f) synthesizing the findings and, (g) writing the report. The purpose of this paper is to demonstrate the value of providing health science graduate students with the opportunity to learn about the conduct of a systematic review. An example of a thesis utilizing the method of a systematic review is presented.

Curriculum↗

PubMed2005

A randomised controlled trial and cost-effectiveness study of systematic screening (targeted and total population screening) versus routine practice for the detection of atrial fibrillation in people aged 65 and over. The SAFE study.

OBJECTIVES: To determine the most cost-effective method of screening for atrial fibrillation (AF) in the population aged 65 years and over, as well as its prevalence and incidence in this age group. Also to evaluate the relative cost-effectiveness of different methods of recording and interpreting the electrocardiogram (ECG) within a screening programme. DESIGN: Multicentred randomised controlled trial. Purposefully selected general practices were randomly allocated to 25 intervention practices and 25 control practices. SETTING: Fifty primary care centres across the West Midlands, UK. PARTICIPANTS: Patients aged 65 years and over. INTERVENTIONS: GPs and practice nurses in the intervention practices received education on the importance of AF detection and ECG interpretation. Patients in the intervention practices were randomly allocated to systematic (n = 5000) or opportunistic screening (n = 5000). Prospective identification of pre-existing risk factors for AF within the screened population enabled comparison between targeted screening of people at higher risk of AF and total population screening. MAIN OUTCOME MEASURES: AF detection rates in systematically screened and opportunistically screened populations in the intervention practices were compared with AF detection rate in 5000 patients in the control practices. The screening period was 12 months. RESULTS: Baseline prevalence of AF was 7.2%, with a higher prevalence in males (7.8%) and patients aged 75 years and over (10.3%). The control population demonstrated higher baseline prevalence (7.9%) than either the systematic (6.9%) or opportunistic (6.9%) intervention population. In the control population 47 new cases were detected (incidence 1.04% per year). In the opportunistic arm 243 patients without a baseline diagnosis of AF were found to have an irregular pulse, with 177 having an ECG, yielding 31 new cases (incidence 0.69% per year). A further 44 cases were detected outside the screening programme (overall incidence 1.64% per year). In the systematic arm 2357 patients had an ECG yielding 52 new cases (incidence 1.1% per year). Of these, 31 were detected by targeted screening and a further 21 by total population screening. A further 22 cases were detected outside the screening programme (overall incidence 1.62% per year). In terms of ECG interpretation, computerised decision support software (CDSS) gave a sensitivity of 87.3%, a specificity of 99.1% and a positive predictive value (PPV) of 89.5% compared with the gold standard (cardiologist reporting). GPs and practice nurses performed less well. The only difference in performance between intervention populations and controls was that practice nurses from the control arm performed less well than with intervention practice nurses on interpretation of limb-lead (PPV 38.8% versus 20.8%) and single-lead (PPV 37.7% versus 24.0%) ECGs. The within-trial economic evaluation results showed the lowest incremental cost to be for the opportunistic arm, with an incremental cost-effectiveness ratio of 337 pounds Sterling for each additional case detected compared to the control arm. Opportunistic screening dominated both more intensive screening strategies. Model-based analyses showed small differences in cost and quality-adjusted life-years for different methods and intensities of screening, but annual opportunistic screening resulted in the lowest number of ischaemic strokes and greatest proportion of cases of AF diagnosed. Probabilistic sensitivity results indicated that there was a probability of approximately 60% that screening from the age of 65 years was cost-effective in both men and women. CONCLUSIONS: The results of the study indicated that in terms of a screening programme for atrial fibrillation in patients 65 and over, the only strategy that improved on routine practice was opportunistic screening, model-based analyses indicated that there was a probability of approximately 60% of annual opportunistic screening being cost effective. It is suggested that the following topics are worthy of further investigation: the effect of the implementation of a screening programme for AF on the uptake and maintenance of anticoagulation in patients aged 65 years and over; an evaluation of the role of CDSS in the diagnosis of cardiac arrythmias; the best method for routinely detecting paroxysmal AF; ways of improving healthcare professionals' performance in ECG interpretation; development of a robust economic model to incorporate data on new therapeutic agents for use as thromboprophylactic agents for patients with AF, and an evaluation of the relative risk of stroke for patients with incident as opposed to prevalent AF.

Aged↗

PubMed1996

Crossroads, milestones and landmarks in insect development and evolution: implications for systematics.

Our understanding of insect development and evolution has increased greatly due to recent advances in the comparative developmental approach. Modern developmental biology techniques such as in situ hybridization and molecular analysis of developmentally important genes and gene families have greatly facilitated these advances. The role of the comparative developmental approach in insect systematics is explored in this paper and we suggest two important applications of the approach to insect systematics--character dissection and morphological landmarking. Existing morphological characters can be dissected into their genetic and molecular components in some cases and this will lead to more and richer character information in systematic studies. Character landmarking will he essential to systematic studies for clarifying structures such as shapes or convergences, which are previously hard to analyze anatomical regions. Both approaches will aid greatly in expanding our understanding of homology in particular, and insect development in general.

Animals↗

PubMed1997

Systematic reviews: synthesis of best evidence for clinical decisions.

Systematic reviews can help practitioners keep abreast of the medical literature by summarizing large bodies of evidence and helping to explain differences among studies on the same question. A systematic review involves the application of scientific strategies, in ways that limit bias, to the assembly, critical appraisal, and synthesis of all relevant studies that address a specific clinical question. A meta-analysis is a type of systematic review that uses statistical methods to combine and summarize the results of several primary studies. Because the review process itself (like any other type of research) is subject to bias, a useful review requires clear reporting of information obtained using rigorous methods. Used increasingly to inform medical decision making, plan future research agendas, and establish clinical policy, systematic reviews may strengthen the link between best research evidence and optimal health care.

Decision Making↗

PubMed2005

Challenges in systematic reviews that assess treatment harms.

An evidence synthesis of a medical intervention should assess the balance of benefits and harms. Investigators performing systematic reviews of harms face challenges in finding data, rating the quality of harms reporting, and synthesizing and displaying data from different sources. Systematic reviews of harms often rely primarily on published clinical trials. Identifying important harms of treatment and quantifying the risk associated with them, however, often require a broader range of data sources, including unpublished trials, observational studies, and unpublished information on published trials submitted to the U.S. Food and Drug Administration. Each source of data has some potential for yielding important information. Criteria for judging the quality of harms assessment and reporting are still in their early stages of development. Investigators conducting systematic reviews of harms should consider empirically validating the criteria they use to judge the validity of studies reporting harms. Synthesizing harms data from different sources requires careful consideration of internal validity, applicability, and sources of heterogeneity. This article highlights examples of approaches to methodologic issues associated with performing systematic reviews of harms from 96 Evidence-based Practice Center evidence reports.

Evidence-Based Medicine↗

PubMed2006

Evaluation of the quality of prognosis studies in systematic reviews.

BACKGROUND: To provide valid assessments of answers to prognostic questions, systematic reviews must appraise the quality of the available evidence. However, no standard quality assessment method is currently available. PURPOSE: To appraise how authors assess the quality of individual studies in systematic reviews about prognosis and to propose recommendations for these quality assessments. DATA SOURCES: English-language publications listed in MEDLINE from 1966 to October 2005 and review of cited references. STUDY SELECTION: 163 systematic reviews about prognosis that included assessments of the quality of studies. DATA EXTRACTION: A total of 882 distinct quality items were extracted from the assessments that were reported in the various reviews. Using an iterative process, 2 independent reviewers grouped the items into 25 domains. The authors then specifically identified domains necessary to assess potential biases of studies and evaluated how often those domains had been addressed in each review. DATA SYNTHESIS: Fourteen of the domains addressed 6 sources of bias related to study participation, study attrition, measurement of prognostic factors, measurement of and controlling for confounding variables, measurement of outcomes, and analysis approaches. Reviews assessed a median of 2 of the 6 potential biases; only 2 (1%) included criteria aimed at appraising all potential sources of bias. Few reviews adequately assessed the impact of confounding (12%), although more than half (59%) appraised the methods used to measure the prognostic factors of interest. LIMITATIONS: Reviews may have been missed by the search or misclassified because of incomplete reporting. Validity and reliability testing of the authors' recommendations are required. CONCLUSIONS: Quality appraisal, a necessary step in systematic reviews, is incomplete in most reviews of prognosis studies. Adequate quality assessment should include judgments about 6 areas of potential study biases. Authors should incorporate these quality assessments into their synthesis of evidence about prognosis.

Bias↗

PubMed2000

[How to produce systematic reviews of excellent quality and to define evidence-based nephrology].

Since recent years, a number of systematic reviews have been published in the renal field. These publications will be used to develop the concept of evidence based nephrology. The design and quality of renal systematic reviews relies on technical skills and efficient trials search. The reasons for discrepancies that are sometimes reported between systematic reviews and controlled clinical trials are now better understood and may be partly explained by inadequate trial recovery and publication biases. The applicability of evidence findings is not always an easy task on patients level. The example of the low protein diet in chronic renal failure highlights such caveats. However, producing high level systematic reviews in the renal field may be of great help to clarify the use of controversial treatments and to design new studies in the renal field.

Evidence-Based Medicine↗

PubMed2000

Can simulators evaluate systematic differences between oscillometric non-invasive blood-pressure monitors?

BACKGROUND: Oscillometric non-invasive blood-pressure (NIBP) monitors estimate the arterial pressure using model-specific signal processing and algorithms. Hence each model's accuracy must be clinically evaluated. Simulators may assist the evaluation, but their ability to do so has not been verified. OBJECTIVE: To investigate whether simulators can detect systematic differences between NIBP monitors. METHODS: We tested whether a simulator can distinguish between the two different algorithms available in a particular monitor, detect calibration errors and detect systematic differences between monitors that are observed clinically. RESULTS: Simulator evaluation correctly detected 1.8 and 4.2 mmHg systolic and diastolic differences between the two Nellcor N-3100 algorithms (with specified 2 and 5 mmHg differences) but found no difference between their mean arterial pressures (as expected from the specification). Simulator evaluations detected calibration adjustments at 80/50, 120/80 and 200/150 mmHg. Simulator and clinical comparisons of two devices of the same type recording slightly different blood pressures were in close agreement, but simulator and clinical comparisons of three different models (Propaq, Critikon DINAMAP and Datex Cardiocap) were not consistently in agreement. The simulators generated oscillometric pulse shapes different from physiological recordings. CONCLUSION: The results suggest that, although simulators can reveal systematic differences between devices of the same model, they cannot be used to detect systematic differences between different NIBP models. This could be at least partly because the oscillometric pulses generated by the simulators are dissimilar to physiologically recorded pulses.

Algorithms↗

PubMed2000

Clarifying the abstracts of systematic literature reviews.

BACKGROUND: There is a small body of research on improving the clarity of abstracts in general that is relevant to improving the clarity of abstracts of systematic reviews. OBJECTIVES: To summarize this earlier research and indicate its implications for writing the abstracts of systematic reviews. METHOD: Literature review with commentary on three main features affecting the clarity of abstracts: their language, structure, and typographical presentation. CONCLUSIONS: The abstracts of systematic reviews should be easier to read than the abstracts of medical research articles, as they are targeted at a wider audience. The aims, methods, results, and conclusions of systematic reviews need to be presented in a consistent way to help search and retrieval. The typographic detailing of the abstracts (type-sizes, spacing, and weights) should be planned to help, rather than confuse, the reader.

Abstracting and Indexing↗

PubMed2001

[Systematic conservative surgery for kidney cancer smaller than 4 cm: multicenter study].

OBJECTIVE: To evaluate tumour control and morbidity of systematic conservative surgery for patients with a renal cancer < or = 4 cm. MATERIALS AND METHODS: A retrospective multicentre study was performed in 73 patients undergoing systematic conservative surgery for renal cancer < or = 4 cm. The mean age of the patients was 55.8 years (range: 19-82). The mean diameter of the tumour was 2.8 cm +/- 0.9. Tumour stage was pT1 in 97% of cases and pT3a in 3% of cases. The mean follow-up was 46.2 months (range: 12-138). RESULTS: The postoperative morbidity was 11%, including urinary fistulas in 5 cases and haemorrhage in 3 cases. No patient has developed local recurrence. One patient died from metastases. The 5-year recurrence-free survival was 97.4%. CONCLUSION: Systematic partial nephrectomy has a low morbidity in patients with a renal cancer less than 4 cm. It ensures satisfactory medium-term tumour control. However, only long-term follow-up can establish the place of systematic partial nephrectomy in the treatment of renal cancer.

Adult↗

PubMedDate not supplied

[Systematics on the threshold of the XXI century. Traditional principles and fundamentals from today's point of view].

Systematics as regarded is a purely theoretical domain of biology, and its product, system, as a specific biological theory, or a topologo-genetic model of the biota. Linnaeus was the first to introduce the idea of system and the systematic approach into the natural history. The advent of evolutionism brought new meaning to the old term "affinity", so Linnaeus' slogan of natural system got new life, and Linnaeus taxonomy assimilated the evolutionary ideology quite naturally and much easier than many other departments of biology. The difference between natural and artificial systems is remaining, and it is in their goals, as formulated by Linnaeus: heuristic of the former and cataloguing of the latter. Linnaeus' clairvoyance discovered the existence of an infrageneric level of genetic integration provable by naturalists' experience. He chose for it the designation of "species" and laid it down as primary, basic unit of his system. This is plainly evident from his own writings; the story about Linnaean species being products of a logical division of genera is a pure fiction. Modern populational model of species, by 3 important criteria, appears to be more akin to the Linneaean one than to the ideas of Lamarckism and early Darwinism. Systematic approach focuses rather on the interrelations among elements and their relative position, then on the properties and qualities of separately treated individual elements. In the development of systematics the aspect of "nexification" (study of connections) has been continuously gaining attention especially regarding the nomenclature where connotation has been totally forced out by denotation.

Biological Evolution↗

PubMed1998

Incorporating systematic reviews into nursing education.

Systematic reviews of research are important to the quality of nursing care. A number of sources of systematic reviews of nursing research are available. Nursing education programs should introduce students to these as crucial resources for utilizing research in practice. This article describes sources of systematic reviews and proposes teaching strategies for incorporating the use of systematic reviews into undergraduate and graduate programs. Nurse educators are invited to contribute to this ongoing column their accounts of successful teaching strategies.

Journal Article↗

PubMed2003

SysBank: a knowledge base for systematic reviews of randomized clinical trials.

The Systematic Review Bank (SysBank) is a structured knowledge base that captures information about the design, execution, and results of systematic reviews of randomized controlled trials (RCTs). The SysBank data model has been adapted from RCT Bank, a knowledge base of randomized trials, and refined using three published systematic reviews. SysBank links directly to the RCT Bank entries of studies included in the systematic review. SysBank builds upon RCT Bank to support computer-assisted evidence-based medicine.

Artificial Intelligence↗

PubMedDate not supplied

Systematic reviews and meta-analyses: an illustrated, step-by-step guide.

Systematic reviews and meta-analyses synthesize data from existing primary research, and well-conducted reviews offer clinicians a practical solution to the problem of staying current in their fields of interest. A whole generation of secondary journals, pre-appraised evidence libraries and periodically updated electronic texts are now available to clinicians. However, not all systematic reviews are of high quality, and it is important to be able to critically assess their validity and applicability. This article is an illustrated guide for conducting systematic reviews. A clear understanding of the process will provide clinicians with the tools to judiciously appraise reviews and interpret them. We hope that it will enable clinicians to conduct systematic reviews, generate high-quality evidence, and contribute to the evidence-based medicine movement.

Bibliometrics↗

PubMed2006

[Centralisation of pancreatic resection: a systematic review and evaluation in the Netherlands].

OBJECTIVE: To analyse the volume-outcome effect of pancreatic surgery by means of a systematic review, and to determine the effect of the ongoing plea for centralisation of pylorus-preserving pancreaticoduodenectomy in the Netherlands. DESIGN: Systematic review and retrospective evaluation. METHOD: A systematic search for studies comparing hospital mortality rates after pancreatic resection in high- and low-volume hospitals was conducted. The studies were independently assessed regarding design, inclusion criteria, threshold value for high and low volume and primary hospital mortality outcome. Data were obtained from the Dutch nation-wide registry on the mortality outcome of pancreaticoduodenectomy in 1994-2003. Hospitals were divided into 4 categories based on the number of pancreaticoduodenectomies performed. The effect of the ongoing plea for centralisation was analysed. RESULTS: Twelve observational studies comprising a total of 19,688 patients were included. Because the studies were too heterogeneous to allow a meta-analysis, a qualitative analysis was performed. The relative risk of dying in a high-volume hospital compared with a low-volume hospital was between 0.07 and 0.76 and was inversely proportional to the arbitrarily defined volume cut-off values. Various analyses conducted over a to-year period in the Netherlands reported mortality rates of 14-17% in hospitals that performed fewer than 5 pancreaticoduodenectomies per year, compared with rates of 0.0-3.50 degrees h in hospitals that performed more than 24 pancreaticoduodenectomies per year. The percentage of patients undergoing surgery in hospitals with a volume less than ro pancreaticoduodenectomies per year was 57% in 2000-2003 (454/792), compared with 65% (280/428) in 1994-1995. CONCLUSION: This systematic review provided evidence of an inverse relationship between hospital volume and mortality after pancreaticoduodenectomy and confirmed the value of centralisation of this procedure in high-volume hospitals. The 10-year-long plea of the Dutch surgical community for quality assessment and, if necessary, centralisation has not resulted in a reduction in mortality rates after pancreatic resection or a change in referral patterns in The Netherlands.

English Abstract↗

PubMed2002

Medial branch neurotomy in management of chronic spinal pain: systematic review of the evidence.

Zygapophysial or facet joints have been implicated as cause of low back, mid back, upper back and neck pain with referred pain. Cervical, thoracic and lumbar facet joints are innervated by the medial branches of the dorsal rami. Zygapophysial (facet) joints have been implicated as the source of chronic pain in 15% to 45% of the patients with chronic low back pain, 54% to 60% of the patients with chronic neck pain and 48% of the patients with thoracic pain. A systematic review of the evidence of effectiveness of radiofrequency denervation in the management of chronic spinal pain was undertaken. This review included randomized clinical trials, as well as non-randomized or observational studies in the analysis. Literature search included MEDLINE, EMBASE, systematic reviews, narrative reviews, cross-references to the reviews and various published trials; and peer reviewed abstracts from scientific meetings during the past two years. An algorithmic approach was followed in study evaluation with a description of inclusion and exclusion criteria. A set of high-performing scales or checklists pertaining to randomized clinical trials and observational trials derived from the Agency for Healthcare Research and Quality (AHRQ) was utilized; Systems to Rate the Strength of Scientific Evidence. Qualitative analysis was conducted, using five levels of evidence for effectiveness of medial branch neurotomy. Our search strategy identified over 1,000 citations as the result of electronic and manual screening. A total of 7 randomized trials of radiofrequency neurotomy for spinal pain were identified. However, only 4 related to medial branch neurotomy. Two of the four met the inclusion criteria. Among the multiple observational studies considered for inclusion, 4 prospective evaluations were included in the systematic review. In addition, 3 retrospective evaluations were also included. Two randomized trials comprised of 27 patients receiving active treatment. The first study consisted of cervical facet joint pain and the second consisted of lumbar facet joint pain. Both studies showed positive results. Similar to randomized trials, prospective, as well as retrospective evaluations showed positive evidence, both in short-term and long-term. The results of this systematic review of 2 well-designed randomized trials, 4 prospective well-designed trials without randomization and 3 retrospective evaluations provided strong evidence that radiofrequency denervation offers short-term relief and moderate evidence of long-term pain relief of facet joint origin.

Journal Article↗

PubMed1988

Reducing nocturnal awakening and crying episodes in infants and young children: a comparison between scheduled awakenings and systematic ignoring.

Infants and toddlers (N = 33) exhibiting spontaneous awakening and crying episodes during the night were randomly assigned to one of three groups: scheduled awakenings, systematic ignoring or control. Scheduled awakenings consisted of a parent arousing and feeding or consoling the child 15 to 60 minutes before typical spontaneous awakenings. Once spontaneous awakenings were precluded, scheduled awakenings by parents were gradually eliminated. Systematic ignoring consisted of allowing the child to "cry it out" without parental attention except to ensure physical well-being of their child. Children in the scheduled awakening group and the systematic ignoring group awoke and cried less frequently than children in the control group during 8 weeks of treatment and during two follow-up checks, 3 and 6 weeks after treatment. Systematic ignoring was found to be more effective than the scheduled awakenings condition during 1 week of treatment; otherwise effects of the two conditions were similar. Implications of the use of these treatment procedures are discussed.

Child, Preschool↗

PubMed1984

Effects of extended systematic lymphadenectomy for adenocarcinoma of the rectum--significant improvement of survival rate and decrease of local recurrence.

The effects of extended systematic lymphadenectomy were evaluated by the rate of survival of the patients and incidence of local failure in 643 patients with single primary adenocarcinoma of the rectum, who were operated on at the National Cancer Center Hospital from 1962 to 1981. Our extended systematic lymphadenectomy consists of high ligation of the inferior mesenteric vessels and meticulous dissection of the abdominopelvic lymphatic system. Potentially curative resection was performed on 495 patients (77%) with seven operative deaths (1.4%). Extended systematic lymphadenectomy was carried out on 74 of 168 patients with Dukes B cancer and 89 of 213 patients with Dukes C cancer. Five-year survival rates for patients with or without systematic extended lymphadenectomy were 83.2% vs 63.7% (P less than 0.05) in Dukes B and 52.5% vs 30.8% (P less than 0.05) in Dukes C classes. The cumulative incidence of local failure at 5 years was decreased from 26.1% to 8.4% (P less than 0.01) and from 44.3% to 24.5% (P less than 0.01) by extended lymphadenectomy in Dukes B and C classes, respectively. Prolongation of operation time (plus 60 min), slight increase in blood loss (plus 150 ml) and no increase in operative mortality (1/161, 0.6%), were observed in the case of extended lymphadenectomy.

Adenocarcinoma↗