The effectiveness of regionalization of perinatal care services - a systematic review

BackgroundSeveral reports recommend the implementation of perinatal regionalization for improvements in maternal and neonatal outcomes, while research evidence on the effectiveness of perinatal regionalization has been limited. The interventional studies have been assessed for robust evidence on the effectiveness of perinatal regionalization on improving maternal and neonatal health outcomes.MethodsBibliographic databases of Medline, EMbase, EconLit, HMIC have been searched using sensitive search terms for interventional studies that reported important patient or process outcomes. At least two authors assessed eligibility for inclusion and the risk of biases and extracted data from the included studies. As meta-analysis was not possible, a narrative analysis as well as a 'vote-counting' analysis has been conducted for important outcomes.ResultsAfter initial screenings 53 full text papers were retrieved. Eight studies were included in the review from the USA, Canada and France. Studies varied in their designs, and in the specifications of the intervention and setting. Only three interrupted time series studies had a low risk of bias, of which only one study reported significant reductions in neonatal and infant mortality. Studies of higher risk of bias were more likely to report improvements in outcomes.ConclusionsImplementing perinatal regionalization programs is correlated with improvements in perinatal outcomes, but it is not possible to establish a causal link. Despite several high profile policy statements, evidence of effect is weak. It is necessary to assess the effectiveness of perinatal regionalization using robust research designs in a more diverse range of countries.     

Meta-analysis of quasi-experimental research: are systematic narrative reviews indicated?

Context  Meta-analyses are commonly performed on quasi-experimental studies in medical education and other applied field settings, with little or no apparent concern for biases and confounds present in the studies synthesised. The implicit assumption is that the biases and confounds are randomly distributed across the studies and are averaged or cancelled out by the synthesis.
Objectives  We set out to consider the possibility that the results and conclusions of meta-analyses in medical education are subject to biases and confounds and to illustrate this possibility with a re-examination of the studies synthesised in an important, recently published meta-analysis of problem-based learning.
Methods  We carefully re-examined the studies in the meta-analysis. Our aims were to identify obvious biases and confounds that provided plausible alternative explanations of each study's results and to determine whether these threats to validity were considered and convincingly ruled out as plausible rival hypotheses.
Results  Ten of the 11 studies in the meta-analysis used quasi-experimental designs; all 10 were subject to constant biases and confounds that favoured the intervention condition. Threats to validity were not ruled out in the individual studies, nor in the meta-analysis itself.
Conclusions  Our re-examination of the results and conclusions of the meta-analysis illustrates our concerns about the validity of meta-analyses based primarily on quasi-experimental studies. Our tentative conclusion is that the field of medical education might be better served in most instances by systematic narrative reviews that describe and critically evaluate individual studies and their results in light of threats to their validity.     

Interrater reliability of grading strength of evidence varies with the complexity of the evidence in systematic reviews

ObjectivesTo examine consistency (interrater reliability) of applying guidance for grading strength of evidence in systematic reviews for the Agency for Healthcare Research and Quality Evidence-based Practice Center program.Study Design and SettingUsing data from two systematic reviews, authors tested the main components of the approach: (1) scoring evidence on the four required domains (risk of bias, consistency, directness, and precision) separately for randomized controlled trials (RCTs) and observational studies and (2) developing an overall strength of evidence grade, given the scores for each of these domains.ResultsConclusions about overall strength of evidence reached by experienced systematic reviewers based on the same evidence can differ greatly, especially for complex bodies of evidence. Current instructions may be sufficient for straightforward quantitative evaluations that use meta-analysis for summarizing RCT findings. In contrast, agreement suffered when evaluations did not lend themselves to meta-analysis and reviewers needed to rely on their own qualitative judgment. Three areas raised particular concern: (1) evidence from a combination of RCTs and observational studies, (2) outcomes with differing measurement, and (3) evidence that appeared to show no differences in outcomes.ConclusionInterrater reliability was highly variable for scoring strength of evidence domains and combining scores to reach overall strength of evidence grades. Future research can help in establishing improved methods for evaluating these complex bodies of evidence.     

Review and Meta-analysis of Emerging Risk Factors for Agricultural Injury

Agricultural injury is a significant public health problem globally. Extensive research has addressed this problem, and a growing number of risk factors have been reported. The authors evaluated the evidence for frequently reported risk factors earlier. The objective in the current study was to identify emerging risk factors for agricultural injury and calculate pooled estimates for factors that were assessed in two or more studies. A total of 441 (PubMed) and 285 (Google Scholar) studies were identified focusing on occupational injuries in agriculture. From these, 39 studies reported point estimates of risk factors for injury; 38 of them passed the Newcastle-Ottawa criteria for quality and were selected for the systematic review and meta-analysis. Several risk factors were significantly associated with injury in the meta-analysis. These included older age (vs. younger), education up to high school or higher (vs. lower), non-Caucasian race (vs. Caucasian), Finnish language (vs. Swedish), residence on-farm (vs. off-farm), sleeping less than 7–7.5 hours (vs. more), high perceived injury risk (vs. low), challenging social conditions (vs. normal), greater farm sales, size, income, and number of employees on the farm (vs. smaller), animal production (vs. other production), unsafe practices conducted (vs. not), computer use (vs. not), dermal exposure to pesticides and/or chemicals (vs. not), high cooperation between farms (vs. not), and machinery condition fair/poor (vs. excellent/good). Eighteen of the 25 risk factors were significant in the meta-analysis. The identified risk factors should be considered when designing interventions and selecting populations at high risk of injury.     

Potato Consumption and Risk of Site-Specific Cancers in Adults: A Systematic Review and Dose-Response Meta-Analysis of Observational Studies

The etiology of cancer type may vary significantly due to anatomy, embryology, and physiology of the cancer site. Although the association between potato consumption and colorectal cancer (CRC) was summarized in a 2018 meta-analysis of 5 cohort studies, to the best of our knowledge, no meta-analysis has evaluated potato consumption in relation to multiple cancer sites in adults. Medline/PubMed, ISI Web of Knowledge, Scopus, and the Cochrane Database of Systematic Reviews were searched for relevant publications through August 2020. We selected cohort or case-control studies conducted in adults that reported risk estimates (relative risk [RRs], HRs, and ORs) of potato intake for any cancer type. Random effects meta-analyses compared high and low intake categories. Twenty prospective cohort studies (total n = 785,348) including 19,882 incident cases, and 36 case-control studies (21,822 cases; 66,502 controls) were included. Among cohort studies, we did not find an association between high versus low intake of total potato (white and yellow) consumption and overall cancers: 1.04 (95% CI: 0.96, 1.11; tau² = 0.005, n = 18). We found no relation between total potato consumption (high compared with low intake) and risk of CRC, pancreatic cancer, colon, gastric, breast, prostate, kidney, lung, or bladder cancer in cohort or case-control studies. We did not find an association between high versus low consumption of potato preparations (boiled/fried/mashed/roasted/baked) and risk of gastrointestinal-, sex-hormone-, or urinary-related cancers in cohort or case-control studies. Certainty of the evidence was low for total cancer, CRC, colon, rectal, renal, pancreatic, breast, prostate, and lung cancer and very low for gastric and bladder cancer. In conclusion, potato intake or potato preparations were not associated with multiple cancer sites when comparing high and low intake categories. This finding was consistent with the findings from the 2018 meta-analysis regarding potato intake and risk of CRC.     

A Bayesian approach for correcting exposure misclassification in meta-analysis

In observational studies, misclassification of exposure is ubiquitous and can substantially bias the estimated association between an outcome and an exposure. Although misclassification in a single observational study has been well studied, few papers have considered it in a meta-analysis. Meta-analyses of observational studies provide important evidence for health policy decisions, especially when large randomized controlled trials are unethical or unavailable. It is imperative to account properly for misclassification in a meta-analysis to obtain valid point and interval estimates. In this paper, we propose a novel Bayesian approach to filling this methodological gap. We simultaneously synthesize two (or more) meta-analyses, with one on the association between a misclassified exposure and an outcome (main studies), and the other on the association between the misclassified exposure and the true exposure (validation studies). We extend the current scope for using external validation data by relaxing the “transportability” assumption by means of random effects models. Our model accounts for heterogeneity between studies and can be extended to allow different studies to have different exposure measurements. The proposed model is evaluated through simulations and illustrated using real data from a meta-analysis of the effect of cigarette smoking on diabetic peripheral neuropathy.     

Ethnic minorities and weight control research priorities: where are we now and where do we need to be?

Within the overall obesity epidemic, the burden of obesity and related health problems is particularly high among African Americans, Hispanic/Latino Americans, American Indians, and Pacific Islanders—both children and adults. The often asked question of what types of obesity interventions work in these populations reflects uncertainty about how applicable standard interventions are to diverse socio-cultural groups and socio-environmental contexts. A meta-analysis in this issue of Preventive Medicine (Seo and Sa, 2008. A meta-analysis of psycho-behavioral obesity interventions among US multiethnic and minority adults) includes selected multi-ethnic and minority-focused studies that in total had 40% minority participants. Although the authors' conclusions were congruent with current general guidance for weight loss programs, insights about how to intervene with minority populations were limited by the small amount and nature of the available evidence. Ethnic minorities in the aggregate are now a third of the U.S. population. We should be purposeful in identifying research needs and quality standards for conducting and reporting studies with these populations and in motivating related research. Improving the relevance to and quality of evidence on obesity prevention and treatment for a more diverse set of populations will also improve the weight control literature as a whole.     

Conceptos básicos del metaanálisis en red

Systematic reviews and meta-analyses have long been fundamental tools for evidence-based clinical practice. Initially, meta-analyses were proposed as a technique that could improve the accuracy and the statistical power of previous research from individual studies with small sample size. However, one of its main limitations has been the fact of being able to compare no more than two treatments in an analysis, even when the clinical research question necessitates that we compare multiple interventions. Network meta-analysis (NMA) uses novel statistical methods that incorporate information from both direct and indirect treatment comparisons in a network of studies examining the effects of various competing treatments, estimating comparisons between many treatments in a single analysis. Despite its potential limitations, NMA applications in clinical epidemiology can be of great value in situations where there are several treatments that have been compared against a common comparator. Also, NMA can be relevant to a research or clinical question when many treatments must be considered or when there is a mix of both direct and indirect information in the body of evidence.     

The Economic Value of Enteral Medical Nutrition in the Management of Disease-Related Malnutrition: A Systematic Review

Economic evaluations for medical nutrition, such as oral nutritional supplements (ONS), are relatively uncommon compared with other health technologies, and represent an area that has not been reviewed so far. In this systematic review, economic evaluations of enteral medical nutrition in the management of disease-related malnutrition (DRM) were reviewed and qualified to estimate the economic value. Initially, 481 studies were found, of which 37 full-text articles were assessed for eligibility and were rated on their quality using the Quality of Health Economic Studies (QHES) instrument. The final review focused on the high QHES quality economic evaluation studies. As both the studied medical nutrition intervention and the form of the economic evaluation varied, a quantitative synthesis (meta-analysis) was not attempted but a critical analysis and comparison of the individual study results were performed. ONS was the most studied intervention, covering several patient populations and different health care settings. Outcomes included cost savings (n = 3), no significant extra costs per unit of clinical and/or functional improvement (n = 1), or significantly higher costs per unit of clinical and/or functional improvement but still cost-effective for the used threshold (n = 4). This review shows that the use of enteral medical nutrition in the management of DRM can be efficient from a health economic perspective.     

Efficacy and Acceptability of Pharmacological Treatments for Depressive Disorders in Primary Care: Systematic Review and Network Meta-Analysis

PURPOSEThe purpose of this study was to investigate whether antidepressants are more effective than placebo in the primary care setting, and whether there are differences between substance classes regarding efficacy and acceptability.METHODSWe conducted literature searches in MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and PsycINFO up to December 2013. Randomized trials in depressed adults treated by primary care physicians were included in the review. We performed both conventional pairwise meta-analysis and network meta-analysis combining direct and indirect evidence. Main outcome measures were response and study discontinuation due to adverse effects.RESULTSA total of 66 studies with 15,161 patients met the inclusion criteria. In network meta-analysis, tricyclic and tetracyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), a serotonin-noradrenaline reuptake inhibitor (SNRI; venlafaxine), a low-dose serotonin antagonist and reuptake inhibitor (SARI; trazodone) and hypericum extracts were found to be significantly superior to placebo, with estimated odds ratios between 1.69 and 2.03. There were no statistically significant differences between these drug classes. Reversible inhibitors of monoaminoxidase A (rMAO-As) and hypericum extracts were associated with significantly fewer dropouts because of adverse effects compared with TCAs, SSRIs, the SNRI, a noradrenaline reuptake inhibitor (NRI), and noradrenergic and specific serotonergic antidepressant agents (NaSSAs).CONCLUSIONSCompared with other drugs, TCAs and SSRIs have the most solid evidence base for being effective in the primary care setting, but the effect size compared with placebo is relatively small. Further agents (hypericum, rMAO-As, SNRI, NRI, NaSSAs, SARI) showed some positive results, but limitations of the currently available evidence makes a clear recommendation on their place in clinical practice difficult.