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PubMed2006

Recent changes in the spatial pattern of prostate cancer in the U.S.

INTRODUCTION: Spatial-temporal trends in prostate cancer mortality are of interest because of the introduction and increasing use of the prostate-specific antigen (PSA) screening test after 1986. This article describes spatial-temporal changes in U.S. prostate cancer mortality from 1968 to 1998. METHODS: Prostate cancer mortality data were obtained from Compressed Mortality Files available from the National Center for Health Statistics. To minimize potential problems such as small numbers or missing data, the analysis was limited to white males aged 25 and over, and located in 2970 counties with complete data. Statistical analyses included the global distance between observed and expected multinomial probabilities, Hoover's Index of Concentration, and a retrospective test for change in spatial patterns. RESULTS: Fairly steady declines were observed in prostate cancer mortality from 1968 until 1993, with an increasing tendency toward spatial uniformity. Spatial concentration increased from 1994 to 1998, and by 1998 the level of spatial concentration had returned to levels that prevailed during the early to mid-1980s. Comparing 1991-1998 to 1968-1990, the observed number of prostate deaths increased the most rapidly with respect to the expected number in western Appalachia and the south central U.S. Recent relative declines in mortality were observed in southern California and parts of Florida. CONCLUSIONS: The observed results are generally consistent with prior evaluations of prostate cancer spatial-temporal patterns. However, the current study identified a heretofore unnoticed recent pattern of change in western Appalachia and the south central U.S. Recent declines in Florida and southern California may have contributed to recent increases in spatial concentration of prostate cancer mortality, and may possibly be associated with realized benefits from screening programs.

Aged↗
PubMed2006

Donepezil in patients with severe Alzheimer's disease: double-blind, parallel-group, placebo-controlled study.

BACKGROUND: The cholinesterase inhibitor donepezil is used to treat mild-to-moderate Alzheimer's disease. Its efficacy in severe dementia has not been assessed and is controversial. Our aim was to ascertain the effectiveness of donepezil in patients with severe Alzheimer's disease, by focusing primarily on cognition and activities of daily living. METHODS: We did a 6-month, double-blind, parallel-group, placebo-controlled study in 248 patients with severe Alzheimer's disease (mini mental state examination score 1-10) who were living in assisted care nursing homes ran by trained staff in Sweden. We assigned patients oral donepezil (5 mg per day for 30 days then up to 10 mg per day thereafter, n=128) or matched placebo (n=120). Our primary endpoints were change from baseline to month 6 in the severe impairment battery (SIB) and modified Alzheimer's Disease Cooperative Study activities of daily living inventory for severe Alzheimer's disease (ADCS-ADL-severe). We analysed outcomes for patients with data at baseline and at one or more other timepoints (modified intent-to-treat population) with last observation carried forward used to replace missing data. FINDINGS: 95 patients assigned donepezil and 99 patients assigned placebo completed the study. Patients treated with donepezil improved more in SIB scores and declined less in ADCS-ADL-severe scores at 6 months after initiation of treatment compared with baseline than did controls (least squares [LS] mean difference, 5.7, 95% CI 1.5-9.8; p=0.008, and 1.7, 0.2-3.2; p=0.03, respectively). The incidence of adverse events was comparable between groups (donepezil 82% [n=105] vs placebo 76% [n=91]), with most being transient and mild or moderate in severity. More patients discontinued treatment because of adverse events in the donepezil group (n=20) than in the placebo group (n=8). INTERPRETATION: Donepezil improves cognition and preserves function in individuals with severe Alzheimer's disease who live in nursing homes.

Activities of Daily Living↗
PubMed1995

Exploratory research synthesis--methodological considerations for addressing limitations in data quality.

Exploratory meta-analysis or research synthesis has been advocated as a way of developing important hypotheses for further study. An exploratory research synthesis was conducted on the carotid endarterectomy (CE) literature to illustrate this method. The CE scientific literature is similar to that of many other new medical interventions because it contains numerous limitations to data quality. Exploratory research synthesis of such literature necessitates a number of methodological and statistical considerations to address these limitations, including the problems of missing data, appropriate unit of analysis, nonnormal distribution of outcomes, and lack of controlled studies. Strengths and limitations of the exploratory research synthesis approach are discussed within the context of public policy decisions for assessing medical technologies.

Data Collection↗
PubMed2004

Design and analysis of group-randomized trials: a review of recent methodological developments.

We review recent developments in the design and analysis of group-randomized trials (GRTs). Regarding design, we summarize developments in estimates of intraclass correlation, power analysis, matched designs, designs involving one group per condition, and designs in which individuals are randomized to receive treatments in groups. Regarding analysis, we summarize developments in marginal and conditional models, the sandwich estimator, model-based estimators, binary data, survival analysis, randomization tests, survey methods, latent variable methods and nonlinear mixed models, time series methods, global tests for multiple endpoints, mediation effects, missing data, trial reporting, and software. We encourage investigators who conduct GRTs to become familiar with these developments and to collaborate with methodologists who can strengthen the design and analysis of their trials.

Cluster Analysis↗
PubMed2003

Estimating haplotype frequencies and standard errors for multiple single nucleotide polymorphisms.

Estimating haplotype frequencies becomes increasingly important in the mapping of complex disease genes, as millions of single nucleotide polymorphisms (SNPs) are being identified and genotyped. When genotypes at multiple SNP loci are gathered from unrelated individuals, haplotype frequencies can be accurately estimated using expectation-maximization (EM) algorithms (Excoffier and Slatkin, 1995; Hawley and Kidd, 1995; Long et al., 1995), with standard errors estimated using bootstraps. However, because the number of possible haplotypes increases exponentially with the number of SNPs, handling data with a large number of SNPs poses a computational challenge for the EM methods and for other haplotype inference methods. To solve this problem, Niu and colleagues, in their Bayesian haplotype inference paper (Niu et al., 2002), introduced a computational algorithm called progressive ligation (PL). But their Bayesian method has a limitation on the number of subjects (no more than 100 subjects in the current implementation of the method). In this paper, we propose a new method in which we use the same likelihood formulation as in Excoffier and Slatkin's EM algorithm and apply the estimating equation idea and the PL computational algorithm with some modifications. Our proposed method can handle data sets with large number of SNPs as well as large numbers of subjects. Simultaneously, our method estimates standard errors efficiently, using the sandwich-estimate from the estimating equation, rather than the bootstrap method. Additionally, our method admits missing data and produces valid estimates of parameters and their standard errors under the assumption that the missing genotypes are missing at random in the sense defined by Rubin (1976).

Algorithms↗
PubMed2000

Thrombolysis for acute ischaemic stroke.

BACKGROUND: The majority of strokes are due to blockage of an artery in the brain by a blood clot. Clot dissolving (or thrombolytic) drugs may reduce brain damage from the stroke, but may also cause serious bleeding in the brain. Thrombolytic therapy has now been evaluated in several randomised trials in acute ischaemic stroke. OBJECTIVES: The objective of this review was to assess the safety and efficacy of thrombolytic agents in patients with acute ischaemic stroke. SEARCH STRATEGY: Cochrane Stroke Review Group search strategy plus ongoing contact with researchers and pharmaceutical companies. Last search conducted March 1999. SELECTION CRITERIA: Randomised trials of any thrombolytic agent compared with control in patients with definite ischaemic stroke. DATA COLLECTION AND ANALYSIS: One reviewer applied the inclusion criteria and extracted the data. Trial quality was assessed. The extracted data were verified by the principal investigators of all major trials. MAIN RESULTS: Seventeen trials including 5216 patients were included. Fifteen trials were double-blind. The trials tested urokinase, streptokinase, recombinant tissue plasminogen activator or recombinant pro-urokinase. Two trials used intra-arterial administration but the rest used the intravenous route. About 50% of the data come from trials testing intravenous tissue Plasminogen Activator. Thrombolytic therapy significantly increased the odds of death within the first ten days (odds ratio [OR] 1.85, 95% confidence interval [CI] 1.48 to 2.32). The main cause of the increase in deaths was fatal intracranial haemorrhage following thrombolysis (OR 4.15, 95% CI 2.96 to 5.84). Symptomatic intracranial haemorrhage is also increased following thrombolysis (OR 3.53, 95% CI 2.79 to 4.45). Thrombolytic therapy also increased the odds of death at the end of follow-up (OR 1.31, 95% CI 1.13 to 1. 52). Despite this, thrombolytic therapy, administered up to six hours after ischaemic stroke, significantly reduced the proportion of patients who were dead or dependent (modified Rankin 3 to 6) at the end of follow-up (OR 0.83, 95% CI 0.73 to 0.94). For patients treated within three hours of stroke, thrombolytic therapy appeared more effective in reducing death or dependency (OR 0.58, 95% CI 0.46 to 0.74) with less adverse effect on death (OR 1.11, 95% CI 0.84 to 1.47). There was heterogeneity between the trials that could have been due to : thrombolytic drug used, variation in the concomitant use of aspirin and heparin, severity of the stroke, and time to treatment. Trials testing intravenous recombinant tissue Plasminogen Activator suggest that it may be associated with slightly less hazard and more benefit when given up to six hours after stroke - death within the first ten days OR 1.24, 95% CI 0.85 to 1.81, death at the end of follow-up OR 1.16, 95% CI 0.94 to 1.44, dead or dependent at the end of follow-up OR 0.79, 95% CI 0.68 to 0.92. One trial that tested thrombolysis plus aspirin showed an increase in deaths of patients given both drugs in combination compared with thrombolysis alone. REVIEWER'S CONCLUSIONS: Thrombolytic therapy increases deaths within the first seven to ten days, and deaths at final follow-up. Thrombolytic therapy also significantly increases symptomatic and fatal intracranial haemorrhage. These risks are offset by a reduction in disability in survivors, so that there is, overall, a significant net reduction in the proportion of patients dead or dependent in activities of daily living. The data from trials using intravenous recombinant tissue Plasminogen Activator, from which there is the most evidence on thrombolytic therapy so far, suggest that it may be associated with less hazard and more benefit. There was heterogeneity between the trials and the optimum criteria to identify the patients most likely to benefit and least likely to be harmed, the agent, dose, and route of administration, are not clear. (ABSTRACT TRUNCATED)

Brain Ischemia↗
PubMed1992

A new computer program for detailed off-line analysis of swimming navigation in the Morris water maze.

The program TRACK-ANALYZER runs on AT-compatible microcomputers and performs off-line analysis of data recorded from Morris water-maze experiments by means of a video tracking system or digitizing tablet. Raw data must be available on disk as ASCII-files listing position coordinates sampled at a constant frequency. Automatic recognition and correction of artifacts and missing data is a key feature of the program, as well as the option to combine commands to user-defined macros. TRACK-ANALYZER offers maximal flexibility regarding experimental schedule, maze geometry and recording parameters and may also be used to analyze open-field activity. In addition to calculating basic parameters of the swim path, such as path length and time, the program counts crossings and hits of goal platform and four virtual reference annuli, calculates search times in five different maze fields, determines directionality, tortuosity and turning preferences of swimming behavior and allows the viewing of any number of trials simultaneously on screen. ASCII-formated data output may easily be exported to commercial statistics and graphics software.

Animals↗
PubMed2004

Presentation of medical guidelines on a computer.

Free-text forms of medical guidelines that are used in medical care are often cumbersome and difficult to memorize. Therefore a system that is able to present guidelines in a user-friendly manner has been designed. Guidelines are at first formalized by means of the popular GLIF3 model. Subsequently, the GLIF3 model is coded in XML. The system uses patient data and an XML-coded GLIF3 model graph evaluating the conditions of decision steps. If some conditions cannot be evaluated, (due to the unavailability of required data items), the system stops and highlights a branch from the root of the decision tree to the final step. Then, the user can input missing data into the system so that the system can continue to provide visualization. Thus, the presentation of guidelines is data-driven, making its use easier. The visualization system and the Electronic Health Record can be integrated in a system that can, during examination of a patient, suggest subsequent medical actions according to medical guidelines. Such a system has been designed and is now under development.

Decision Support Systems, Clinical↗
PubMed2000

Early versus delayed initiation of progressive enteral feedings for parenterally fed low birth weight or preterm infants.

BACKGROUND: Enteral feedings in very-low-birth-weight or sick preterm infants are often delayed for several days or weeks after birth even though delayed enteral feeding could diminish the functional adaptation of the gastrointestinal tract and result in feeding intolerance later. Early initiation of feedings, if well-tolerated, may promote growth and shorten the duration of parenteral nutrition and hospital stay without increasing the risk for necrotizing enterocolitis (NEC). OBJECTIVES: For parenterally fed low-birth-weight infants, to assess the effects of early enteral feedings initiated shortly after birth compared to delayed enteral feedings (with similar schedules for advancing feedings in each group). SEARCH STRATEGY: Searches were performed of the Oxford Database of Perinatal Trials, the Cochrane Neonatal Review Group registry, MEDLINE, abstracts and conference proceedings, references from relevant publications in the English language, and studies identified by personal communication. SELECTION CRITERIA: Only randomized or quasi-randomized clinical trials were considered. Trials were included if 1) they enrolled low birth weight or preterm infants who were all given parenteral nutrition; 2) the infants were randomly assigned to either early enteral feedings (mean or median age <=4 days) or late enteral feedings (>4 days) of formula or breast milk; 3) except when feeding intolerance developed, the feedings were progressively advanced starting within 72 hours after initiating feedings; and 4) the goals for total nutrient intake were similar for both groups. (We did not require the duration or total intake of parenteral nutrients to be similar for both groups because these variables may be affected by the age at which feedings are initiated.) DATA COLLECTION AND ANALYSIS: The two reviewers reached consensus for inclusion of trials. Data regarding clinical outcomes were extracted and evaluated by two reviewers (JET and KAK) independently. Authors were contacted as needed and feasible to clarify or provide missing data. The specific data that were needed were requested in writing and by telephone. MAIN RESULTS: Only two small studies were identified (one with 60 patients and one with 12 patients). Five randomized trials were excluded because parenteral nutrition was not provided or because the groups were assigned to receive different parenteral intakes as well as different enteral intakes. An additional unpublished small trial was excluded because both groups were fed "late" according to our categorization. Because there were no clinical outcomes which were reported in both of the included studies, no meta analysis of the results was performed. Based on the results of the individual studies, early feedings had no significant effect on weight gain, necrotizing enterocolitis, mortality, or age at discharge, although important effects cannot be excluded with the small number of patients studied. Some benefits of early feedings were noted in the larger trial (Davey) -- fewer days on parenteral nutrition, fewer infants who were treated with gastric suction and interruption of feedings, fewer infants with sepsis evaluations, and fewer infants with percutaneous central venous catheters. REVIEWER'S CONCLUSIONS: The benefits and hazards of early and delayed feedings have received very little study in clinical trials, and the effects on major clinical outcomes, including necrotizing enterocolitis and death, remain uncertain. With the availability of parenteral nutrition in contemporary neonatal units, it is unclear whether high-risk infants should receive early or delayed feedings.

Enteral Nutrition↗
PubMed2006

Inhaled corticosteroids versus sodium cromoglycate in children and adults with asthma.

BACKGROUND: Inhaled corticosteroids (ICS) and sodium cromoglycate (SCG) have become established as effective controller medications for children and adults with asthma, but their relative efficacy is not clear. OBJECTIVES: To compare the relative effectiveness and adverse effects of ICS and SCG among children and adults with chronic asthma. SEARCH STRATEGY: Systematic search of the Cochrane Airways Group's special register of controlled trials (to Feb. 2004), hand searches of the reference lists of included trials and relevant review papers, and written requests for identification of additional trials from pharmaceutical manufacturers. SELECTION CRITERIA: Randomized controlled trials comparing the effect of ICS with SCG in children and adults with chronic asthma. DATA COLLECTION AND ANALYSIS: All studies were assessed independently for eligibility by three review authors. Disagreements were settled by consensus. Trial authors were contacted to supply missing data or to verify methods. Eligible studies were abstracted and fixed- and random-effects models were implemented to pool studies. Separate analyses were conducted for paediatric and adult studies. Subgroup analyses and meta-regression models were fit to explore heterogeneity of lung function outcomes by type of RCT, category of ICS or SCG dosage, asthma severity of participants, and study quality on outcomes. MAIN RESULTS: Of 67 identified studies, 17 trials involving 1279 children and eight trials involving 321 adults with asthma were eligible. Thirteen (76%) of the paediatric studies and six (75%) of the adult studies were judged to be high quality. Among children, ICS were associated with a higher final mean forced expiratory volume in 1 second [FEV1] (weighted mean difference [WMD] 0.07 litres, 95% confidence interval [CI] 0.02 to 0.11) and higher mean final peak expiratory flow rate [PEF] (WMD 17.3 litres/minute, 95% CI 11.3 to 23.3) than SCG. In addition, ICS were associated with fewer exacerbations (WMD -1.18 exacerbations per year, 95% CI -2.15 to - 0.21), lower asthma symptom scores, and less rescue bronchodilator use than SCG. There were no group differences in the proportion of children with adverse effects. Among adults, ICS were similarly associated with a higher mean final FEV1 (WMD 0.21 litres, 95% CI 0.13 to 0.28) and a higher final endpoint PEF (WMD 28.2 litres/minute, 95% CI 18.7 to 37.6) than SCG. ICS were also associated with fewer exacerbations (WMD -3.30 exacerbations per year, 95% CI -5.62 to -0.98), lower asthma symptom scores among cross-over trials but not parallel trials, and less rescue bronchodilator use than SCG. There were no differences in the proportion of adults with adverse effects. In subgroup analyses involving lung function measures, paediatric and adult studies judged to be of high quality had results consistent with the overall results. Lung function measures in children were higher in studies with medium BDP-equivalent steroid dosages than low BDP-equivalent dosages, while adult studies could not be compared by steroid dosage since they all incorporated similar dosages. There were no significant differences in lung function by the asthma severity of participants for adult or child studies. AUTHORS' CONCLUSIONS: ICS were superior to SCG on measures of lung function and asthma control for both adults and children with chronic asthma. There were few studies reporting on quality of life and health care utilization, which limited our ability to adequately evaluate the relative effects of these medications on a broader range of outcomes. Although there were no differences in adverse effects between ICS and SCG, most trials were short and may not have been of sufficient duration to identify long-term effects. Our results support recent consensus statements in the U.S. and elsewhere that favour the use of ICS over SCG for control of persistent asthma.

Administration, Inhalation↗
PubMed1996

Analysis of space radiation data of semiconductor memories.

This article presents an analysis of radiation effects for several select device types and technologies aboard the Combined Release and Radiation Effects Satellite (CRRES) satellite. These space-flight measurements covered a period of about 14 months of mission lifetime. Single Event Upset (SEU) data of the investigated devices from the Microelectronics Package (MEP) were processed and analyzed. Valid upset measurements were determined by correcting for invalid readings, hard failures, missing data tapes (thus voids in data), and periods over which devices were disabled from interrogation. The basic resolution time of the measurement system was confirmed to be 2 s. Lessons learned, important findings, and recommendations are presented.

Computers↗
PubMed1995

Adequacy of hospital discharge data for determining trauma morbidity patterns.

To determine the adequacy of hospital discharge data for describing the nature and severity of multiple trauma, injury data coded from full hospital records were compared with injury data coded from discharge summaries for 83 plane crash survivors admitted to 14 different hospitals. Full hospital records indicated that 33% sustained intracranial, 39% thoracic, and 27% abdominal/pelvic injuries. Thirty-five percent had spinal fractures, 40% upper limb fractures, and 70% lower limb fractures. Discharge summary data missed 52% of the intracranial injuries, 28% of the thoracic injuries, and 30% of the spinal fractures, yet only missed 5% of the lower limb and 15% of the skull, pelvic, and upper limb fractures. These differences point to concerns regarding the use of discharge data for determining the nature, severity, and sequelae of injuries. The observed underreporting of neurological injury suggests a need to re-evaluate discharge data systems for measuring brain and spinal cord injury patterns, particularly given the increasing reliance on these systems for health policy and programmatic decision making.

Hospital Records↗
PubMed2004

Monitoring stage-specific trends in melanoma incidence across Europe reveals the need for more complete information on diagnostic characteristics.

Cutaneous malignant melanoma has been characterized by rapid and steady increases in incidence and mortality in white populations. Some reports mentioned declining trends in the mean thickness of these tumours, but other studies suggested a stable incidence of thick melanomas. The aim of this study was to describe the stage distribution of melanomas across Europe, with particular reference to temporal trends. Twenty-three cancer registries provided data sets containing information on stage and histology, 21 of which were used for a general description and nine for trends analyses. Despite a preponderance of missing data, interesting patterns emerged: a less favourable stage distribution in populations with relatively low incidence, but high case-fatality rates, and a favourable trend in stage and histology distribution over time, including a shift from later to earlier stages in recent years. Early detection campaigns raising awareness for thin lesions can potentially improve melanoma survival rates. Monitoring of stage-specific trends in melanoma incidence can assess the impact of such interventions. This paper demonstrates the potential utility of high-quality, timely cancer registry data in pursuing such public health objectives and addresses the need for more complete information on diagnostic features of melanoma patients. This will allow more informative evaluations of preventive strategies.

Adult↗
PubMed2006

Customised birthweight: coefficients for an Australian population and validation of the model.

BACKGROUND: Published birthweight references in Australia do not fully take into account constitutional factors that influence birthweight and therefore may not provide an accurate reference to identify the infant with abnormal growth. Furthermore, studies in other regions that have derived adjusted (customised) birthweight references have applied untested assumptions in the statistical modelling. AIMS: To validate the customised birthweight model and to produce a reference set of coefficients for estimating a customised birthweight that may be useful for maternity care in Australia and for future research. METHODS: De-identified data were extracted from the clinical database for all births at the Mater Mother's Hospital, Brisbane, Australia, between January 1997 and June 2005. Births with missing data for the variables under study were excluded. In addition the following were excluded: multiple pregnancies, births less than 37 completed week's gestation, stillbirths, and major congenital abnormalities. Multivariate analysis was undertaken. A double cross-validation procedure was used to validate the model. RESULTS: The study of 42,206 births demonstrated that, for statistical purposes, birthweight is normally distributed. Coefficients for the derivation of customised birthweight in an Australian population were developed and the statistical model is demonstrably robust. CONCLUSIONS: This study provides empirical data as to the robustness of the model to determine customised birthweight. Further research is required to define where normal physiology ends and pathology begins, and which segments of the population should be included in the construction of a customised birthweight standard.

Australia↗
PubMed2004

Applications of Bayesian statistical methods in microarray data analysis.

Microarray technology allows one to measure gene expression levels simultaneously on the whole-genome scale. The rapid progress generates both a great wealth of information and challenges in making inferences from such massive data sets. Bayesian statistical modeling offers an alternative approach to frequentist methodologies, and has several features that make these methods advantageous for the analysis of microarray data. These include the incorporation of prior information, flexible exploration of arbitrarily complex hypotheses, easy inclusion of nuisance parameters, and relatively well developed methods to handle missing data. Recent developments in Bayesian methodology generated a variety of techniques for the identification of differentially expressed genes, finding genes with similar expression profiles, and uncovering underlying gene regulatory networks. Bayesian methods will undoubtedly become more common in the future because of their great utility in microarray analysis.

Bayes Theorem↗
PubMed1985

The nominative technique: a new method of estimating heroin prevalence.

Over the years, nominative estimates of heroin prevalence have been consistently higher than self-reports of heroin use. During this time, nominative data have generally followed mainstream patterns of drug use: nominative estimates for young adults and for males are higher than nominative estimates for older persons, youth, and females; moreover, the recent downward trends in drug use have been replicated by the nominative heroin data. Thus, the overall picture presented by the nominative data--similar patterns but higher levels of prevalence--seems to support the validity of the new approach. Nevertheless, considerable caution should be exercised in interpreting nominative data. This is chiefly because a substantial minority of nominators cannot report the number of other close friends of the heroin user who also "know." While missing data has been handled by a conservative imputation rule, the fact that so many persons are unable to provide an answer to this key question casts doubt on the accuracy of the answers that were given. In fact, the nominative approach might tend to produce over-estimates, because of the potential for undercounts of the numbers of others who "know." Additional tests of validity should be performed, such as application of the nominative approach to nonsensitive behaviors or minimally sensitive behaviors, such as marijuana use or perhaps cocaine use. Certainly, the overall validity of the nominative heroin data would be supported if in future surveys new nominative heroin estimates for relatively unstigmatized forms of drug use proved to be similar to self-reported levels of use, thus pointing to the unique difference in estimates that might be observed for heroin. Finally, in interpreting the heroin estimates presented here, it should be remembered that both the nominative and self-report estimates refer to heroin use in the household population of the United States. Thus, many heroin addicts and other users who reside in various unconventional living arrangements would not be included in the counts presented here. Among the excluded groups are transients residing in rooming houses or "crashing" in the home of one "friend" after another or who are incarcerated in jails or confined to residential drug treatment centers. This is a caution for interpreting the estimates presented in this paper, not a criticism of the nominative technique itself.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed2000

Minimal enteral nutrition for promoting feeding tolerance and preventing morbidity in parenterally fed infants.

BACKGROUND: Because of concern that feedings may increase the risk of necrotizing enterocolitis, some high-risk infants have received prolonged periods of parenteral nutrition without enteral feedings. Providing minimal enteral feedings during this period of parenteral nutrition was developed as a strategy to enhance feeding tolerance and decrease time to reach full feedings. OBJECTIVES: For high-risk neonates receiving parenteral feedings, to assess the effect of minimal enteral nutrition (MEN) compared to no enteral nutrient intake on measures of feeding tolerance and neonatal outcome. SEARCH STRATEGY: Searches were performed of the Oxford Database of Perinatal Trials, MEDLINE, abstracts and conference proceedings, references from relevant publications in the English language, and studies identified by personal communication. SELECTION CRITERIA: Only randomized or quasi-randomized clinical trials were considered. Trials were included if they enrolled high-risk infants randomly assigned to receive minimal enteral feedings (defined as dilute or full strength feedings providing <= 25 kcal/kg/d for >= 5d) or no enteral nutrient intake (no feedings or water only). DATA COLLECTION AND ANALYSIS: The two reviewers reached consensus for inclusion of trials. Data regarding clinical outcomes were extracted and evaluated by the two reviewers independently of each other. Authors were contacted as needed and feasible to clarify or provide missing data. The specific data that were needed were requested in writing. MAIN RESULTS: Among infants given minimal enteral nutrition (MEN), there was an overall reduction in days to full enteral feeding, total days that feedings were held, and total hospital stay. There was no discernible effect on necrotizing enterocolitis. REVIEWER'S CONCLUSIONS: The evidence of benefit from MEN in these analyses is not convincing for a variety of reasons--the inherent difficulty of assessing enteral feedings in high-risk infants, the small size and methodologic limitations of the studies to date, unexplained heterogeneity with respect to some of the apparent benefits, the potential for bias to affect the findings in unblinded studies, and the unexcluded possibility that MEN might increase necrotizing enterocolitis. For these reasons, it is unclear whether MEN should be used in lieu of an equal period of time without enteral feedings.

Enteral Nutrition↗
PubMed2005

Trophic feedings for parenterally fed infants.

BACKGROUND: Because of concern that feedings may increase the risk of necrotizing enterocolitis, some high-risk infants have received prolonged periods of parenteral nutrition without enteral feedings. Providing trophic feedings (small volume feedings given at the same rate for at least 5 days) during this period of parenteral nutrition was developed as a strategy to enhance feeding tolerance and decrease time to reach full feedings. Whether trophic feedings result in better outcomes than initially withholding feedings or providing progressively increasing feedings can be established only in proper clinical trials. OBJECTIVES: 1. For high-risk neonates receiving parenteral feedings, to assess the effect of trophic feeding compared to no enteral nutrient intake on measures of feeding tolerance and neonatal outcome.2. For high-risk neonates receiving parenteral feedings to assess the effect of trophic feedings compared to a specific initial feeding regimen involving a greater enteral nutrient intake on measures of feeding tolerance and neonatal outcome. SEARCH STRATEGY: Searches were performed of MEDLINE (1966 - June 2004), CINAHL (1982 - June 2004), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2004), abstracts and conference proceedings, references from relevant publications in the English language, and studies identified by personal communication. SELECTION CRITERIA: Only randomized or quasi-randomized clinical trials were considered. Trials were included if they enrolled high-risk infants randomly assigned to receive trophic feedings (defined as dilute or full strength feedings providing < = 25 kcal/kg/d for > = 5d) compared to either 1) no enteral nutrient intake (no feedings or water only) or 2) a specific feeding regimen involving a greater enteral intake of formula or human milk than with trophic feedings. DATA COLLECTION AND ANALYSIS: The two reviewers reached consensus for inclusion of trials. Data regarding clinical outcomes were extracted and evaluated by the two reviewers independently of each other. Authors were contacted as needed and feasible to clarify or provide missing data. The specific data that were needed were requested in writing. MAIN RESULTS: 1. Trophic feedings vs. no feedings (10 trials): Among infants given trophic feedings, there was an overall reduction in days to full feeding (weighted mean difference [WMD] = -2.6 [95% confidence limits = -4.1, -1.0]), total days that feedings were held (WMD = -3.1 [-4.6, -1.6]), and total hospital stay (WMD = -11.4 [-17.2, -5.7] compared to infants given no enteral nutrient intake. Tests for heterogeneity were significant in analyses of days to full enteral feedings, days to regain birth weight, days of phototherapy, and hospital stay. There was no significant difference in necrotizing enterocolitis, although the findings do not exclude an important effect (relative risk = 1.16 [0.75, 1.79]; risk difference = 0.02 [-0.03, 0.06].2. Trophic feedings vs. advancing feedings (one trial): Infants given trophic feedings required more days to reach full enteral feeding (13.4 [8.2, 18.6]) and tended to have a longer hospital stay (11.0 [-1.4, 23.4]) than did infants given advancing feedings. With only eight total cases of necrotizing enterocolitis, trophic feedings were associated with a marginally significant reduction in necrotizing enterocolitis (relative risk =0.14 [0.02, 1.07]; risk difference = -0.09 [-0.16, -0.01]. AUTHORS' CONCLUSIONS: In both comparisons, the group with the greater enteral intake (trophic feedings in the first comparison and advancing feedings in the second comparison) required significantly less time to reach full feedings and had a significant or near significant reduction in hospital stay. In both comparisons, the group with the greater intake also had a higher incidence of necrotizing enterocolitis although the difference was not statistically significant. The concern is greatest for the advancing feeding regimen. Even when trophic feedings were compared to no feedings, the relative risk for necrotizing enterocolitis was 1.16 (0.75 - 1.79), a finding consistent with a 16% increase in necrotizing enterocolitis and a number needed to harm of 50. A true increase of this magnitude might outweigh any short- or long-term benefits of trophic feedings. Moreover, the 95% confidence interval does not exclude the possibility that trophic feedings increase necrotizing enterocolitis by as much as 79% with a number needed to harm of 17. Whether no feedings, trophic feedings, or advancing feedings should initially be used is difficult to discern for a variety of reasons--the inherent difficulty of assessing enteral feedings in high-risk infants, the limited sample size and methodologic limitations of most studies to date, unexplained heterogeneity with respect to a number of outcomes, the potential for bias to affect the findings in unblinded studies, and the large number of infants who must be studied to assess the effect on necrotizing enterocolitis. One or more large, well designed, multi-center trials are needed to compare these approaches to early feeding with respect to important clinical outcomes. A conclusive evaluation would assess effects on not only the survival rate without necrotizing enterocolitis prior to discharge from the neonatal unit but also on the survival rate without severe gastrointestinal or neurodevelopmental disability at >= 18 months age.

Enteral Nutrition↗