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PubMed2005

Primary operative versus nonoperative therapy for pediatric empyema: a meta-analysis.

OBJECTIVE: The optimal treatment of children with empyema remains controversial. The purpose of this review was to compare reported results of nonoperative and primary operative therapy for the treatment of pediatric empyema. METHODS: A systematic comprehensive review of the scientific literature was conducted with the PubMed (National Library of Medicine) database for the period from 1981 to 2004. This reproducible search identified all publications dealing with treatment of empyema in the pediatric population (<18 years of age). A meta-analysis was performed with studies with adequate data summaries for > or =1 of the outcomes of interest for both treatment groups. RESULTS: Sixty-seven studies were reviewed. Data were aggregated from reports of children initially treated nonoperatively (3418 cases from 54 studies) and of children treated with a primary operative approach (363 cases from 25 studies). The populations were similar in age. Patients who underwent primary operative therapy had a lower aggregate in-hospital mortality rate (0% vs 3.3%), reintervention rate (2.5% vs 23.5%), length of stay (10.8 vs 20.0 days), duration of tube thoracostomy (4.4 vs 10.6 days), and duration of antibiotic therapy (12.8 vs 21.3 days), compared with patients who underwent nonoperative therapy. In 8 studies for which meta-analysis was possible, patients who received primary operative therapy were found to have a pooled relative risk of failure of 0.09, compared with those who did not. Meta-analysis could not be performed for any of the other outcome measures investigated in this review. Similar complication rates were observed for the 2 groups (5% vs 5.6%). CONCLUSIONS: These aggregate results suggest that primary operative therapy is associated with a lower in-hospital mortality rate, reintervention rate, length of stay, time with tube thoracostomy, and time of antibiotic therapy, compared with nonoperative treatment. The meta-analysis demonstrates a significantly reduced relative risk of failure among patients treated operatively.

Adolescent↗

PubMed2004

Diabetes mellitus as a risk factor for primary open-angle glaucoma: a meta-analysis.

AIM: The association of diabetes mellitus with primary open-angle glaucoma has been controversial. The study aimed to examine the strength of this association through a detailed meta-analysis of studies published in peer-reviewed journals. METHODS: A comprehensive search for articles published through 2002 was performed and data were abstracted. Prior to meta-analysis, all studies were evaluated for publication bias and heterogeneity. Pooled odds ratio (OR) was calculated using the random and the fixed-effects model. RESULTS: Twelve studies published between 1987 and 2001 were included (five case-control studies and seven cross-sectional studies). Significant heterogeneity among the studies was detected (P = 0.023). No evidence of publication bias was found (P = 0.37). The association of diabetes mellitus with primary open-angle glaucoma was statistically significant assuming either a random effects [OR = 1.50, 95% confidence interval (CI) 1.16, 1.93], or a fixed-effects model (OR = 1.27, 95% CI 1.10, 1.45). CONCLUSIONS: Our meta-analysis results suggest that diabetic patients are at significantly increased risk of developing primary open-angle glaucoma. Clinicians should be aware of this possibility.

Diabetes Complications↗

PubMed1998

The incidence of dementia: a meta-analysis.

OBJECTIVE: To carry out a meta-analysis of the age-specific incidence of all dementias, including AD and vascular dementia. BACKGROUND: Several meta-analyses have been carried out on dementia prevalence, but none on its incidence. METHODS: We used loess-curve fitting to analyze data from 23 published studies reporting age-specific incidence data. RESULTS: The incidence of both dementia and AD rose exponentially up to the age of 90 years, with no sign of leveling off. The incidence rates for vascular dementia varied greatly from study to study, but the trend was also for an exponential rise with age. There was no sex difference in dementia incidence (p = 0.21), but women tended to have a higher incidence of AD in very old age, and men tended to have a higher incidence of vascular dementia at younger ages. East Asian countries had a lower incidence of dementia than Europe (p = 0.0004), and also tended to have a lower incidence of AD. CONCLUSIONS: The incidence of dementia rises exponentially to the age of 90 years. Any sex differences are small, and incidence is lower in East Asia than in Europe.

Age Factors↗

PubMed1999

Blood lead levels among children of lead-exposed workers: A meta-analysis.

BACKGROUND: To further assess the utility of targeted blood lead screening for children from households with members having occupational lead exposures, we conducted a meta-analysis of all available reports of take-home lead exposures. Our objective was to estimate the blood lead levels among U.S. children (ages 1-5) from households with lead-exposed workers. METHODS: Reports considered for inclusion were cited in Medline, Toxline, Excerpta Medica, and Bio-Med plus all unpublished reports available at the National Institute for Occupational Safety and Health through 1994. The a priori criteria for inclusion of U.S. reports required their having data on: (1) venous blood lead levels for children, (2) children's ages, (3) data for at least five children, (4) workers' occupations, (5) workers' blood lead levels, and (6) data collection methods. RESULTS: Based on a meta-analysis of 10 reports from 1987 through 1994, the children (n=139) of lead-exposed workers (n=222) had a geometric mean blood lead level of 9.3 microg/dL compared to a U.S. population geometric mean of 3.6 microg/dL (P=0.0006). Also in this group, 52% of the children had blood lead levels (BLLs) >/= 10 microg/dL compared to 8.9% in the U.S. (P=.0010), and 21% of the children had BLLs >/= 20 microg/dL compared to 1.1% in the U.S. (P=. 0258). CONCLUSIONS: We estimate, based on 1981-83 survey data, that there are about 48,000 families with children under six living with household members occupationally exposed to lead. If the findings from this meta-analysis (admittedly limited by small numbers) are generalizable, about half of the young children in these families may have BLLs >/= 10 microg/dL. Data were too sparse to determine if children of workers with elevated blood leads were at greater risk than children whose parents were only known to be lead exposed. Our findings support the position that children of lead-exposed workers should be targeted for blood lead screening. Am. J. Ind. Med. 36:475-481, 1999. Published 1999 Wiley-Liss, Inc.

Child, Preschool↗

PubMed2003

Effect-size indices for dichotomized outcomes in meta-analysis.

It is very common to find meta-analyses in which some of the studies compare 2 groups on continuous dependent variables and others compare groups on dichotomized variables. Integrating all of them in a meta-analysis requires an effect-size index in the same metric that can be applied to both types of outcomes. In this article, the performance in terms of bias and sampling variance of 7 different effect-size indices for estimating the population standardized mean difference from a 2 x 2 table is examined by Monte Carlo simulation, assuming normal and nonnormal distributions. The results show good performance for 2 indices, one based on the probit transformation and the other based on the logistic distribution.

Analysis of Variance↗

PubMed1991

Meta-analysis: the fashion of summing-up evidence. Part I. Rationale and conduct.

Meta-analysis is the process of formally combining the quantitative results of separate studies in order to increase the statistical precession of estimated effects. It has become fashionable when individual studies fail to yield conclusive results. A recent update of a meta-analysis (overview) for treatments of patients with early breast cancer motivated this commentary to discuss the rationale, principles of conduct, statistical methods, and graphical display for summing up results. In part II we will approach the issue of interpretation and use of overview data.

Bayes Theorem↗

PubMed2026

Maternal anemia and the risk of preterm birth: a meta-analysis.

BACKGROUND: Globally, preterm birth continues to be a primary contributor to neonatal complications and fatalities. Anemia among the most common nutritional disorders in pregnancy has been proposed as a potential contributor to early delivery. Although extensively studied, the available evidence does not yet provide a clear consensus. This study aimed to conduct a meta-analysis to quantitatively assess the relationship between maternal anemia and the risk of preterm birth. METHODS: This meta-analysis was conducted and reported in accordance with the PRISMA guidelines and the MOOSE checklist. A systematic and exhaustive search was performed across multiple electronic databases PubMed, Scopus, Web of Science, Embase, and the Cochrane Library to identify relevant studies published from inception to 1 January 2025. Effect sizes were combined using a random-effects meta-analysis. RESULTS: A total of 45 articles, reporting 60 independent study populations comprising 2,119,392 pregnant individuals were included. Considerable heterogeneity was found across the included studies (I2 = 95.54%, p < 0.001), which justified the application of a random-effects model for pooling effect sizes. Maternal anemia was significantly associated with an increased risk of preterm birth (pooled odds ratio[OR] = 1.28, 95% confidence interval [CI]: 1.20-1.36, p < 0.001). Despite substantial heterogeneity, sensitivity analyses confirmed the robustness of this association. The relationship was strongest in studies conducted in Asia (OR = 1.30, 95% CI: 1.22-1.40; p < 0.001) and the Europe (OR = 1.24, 95% CI: 1.08-1.41; p = 0.001) and reached statistical significance when anemia was assessed during the first trimester (OR = 1.12, 95% CI: 1.03-1.51; p = 0.007) and the third trimester (OR = 1.65, 95% CI: 1.42-1.91; p < 0.001), while no significant associations were found in the second trimesters (OR = 1.10, 95% CI: 0.99-1.22; p = 0.05). Funnel plot asymmetry and a significant Egger's test (p = 0.001) indicated potential publication bias, although Begg's test was not significant (p = 0.425). CONCLUSIONS: The current evidence suggests that maternal anemia, particularly in the third trimester, is significantly associated with an increased risk of preterm birth. These findings emphasize the clinical imperative for comprehensive and timely anemia screening during the third trimester. Integrating targeted interventions such as iron and micronutrient supplementation, is essential to mitigate the risk of preterm delivery and improve neonatal outcomes.

Humans↗

PubMed1989

Meta-analysis of the relationship between asymptomatic bacteriuria and preterm delivery/low birth weight.

The relationship between asymptomatic bacteriuria and prematurity/low birth weight (LBW) is still a controversial issue, despite many studies. Meta-analysis, a research tool designed to analyze and combine the results of previous studies, may resolve this discrepancy among contradictory results of clinical trials. The purpose of this study was to examine the relationship between asymptomatic bacteriuria and preterm delivery/LBW using meta-analysis. Reports from the literature were classified according to study design into cohort or randomized-treatment control trials. Meta-analysis of cohort studies showed that untreated asymptomatic bacteriuria during pregnancy significantly increased rates of LBW and preterm delivery. Nonbacteriuric patients had only about two-thirds the risk (typical relative risk = 0.65; 95% confidence interval 0.57, 0.74) of LBW and half the risk (typical relative risk = 0.50; 95% confidence interval 0.36, 0.70) of preterm delivery of those with untreated asymptomatic bacteriuria. These reduced risks correspond to a 3.4 (confidence interval 1.8, 5.0) percentage-point difference in LBW and a 3.8 (1.1, 6.4) percentage-point difference in preterm delivery. The analysis of randomized clinical trials showed that antibiotic treatment significantly reduced the risk of LBW (typical relative risk = 0.56; 95% confidence interval 0.43, 0.73), with a substantial reduction of 6.4 (confidence interval 3.3, 9.5) percentage points in the rate of LBW. We conclude that clinical and epidemiologic evidence indicates a strong association between untreated asymptomatic bacteriuria and LBW/preterm delivery and that antibiotic treatment is effective in reducing the occurrence of LBW.

Anti-Bacterial Agents↗

PubMedDate not supplied

Use of meta-analysis to combine candidate gene association studies: application to study the relationship between the ESR PvuII polymorphism and sow litter size.

This article investigates the application of meta-analysis on livestock candidate gene effects. The PvuII polymorphism of the ESR gene is used as an example. The association among ESR PvuII alleles with the number of piglets born alive and total born in the first (NBA1, TNB1) and later parities (NBA, TNB) is reviewed by conducting a meta-analysis of 15 published studies including 9329 sows. Under a fixed effects model, litter size values were significantly lower in the "AA" genotype groups when compared with "AB" and "BB" homozygotes. Under the random effects model, the results were similar although differences between "AA" and "AB" genotype groups were not clearly significant for NBA and TNB. Nevertheless, the most noticeable result was the high and significant heterogeneity estimated among studies. This heterogeneity could be assigned to error sampling, genotype by environment interaction, linkage or epistasis, as referred to in the literature, but also to the hypothesis of population admixture/stratification. It is concluded that meta-analysis can be considered as a helpful analytical tool to synthesise and discuss livestock candidate gene effects. The main difficulty found was the insufficient information on the standard errors of the estimated genotype effects in several publications. Consequently, the convenience of publishing the standard errors or the concrete P-values instead of the test significance level should be recommended to guarantee the quality of candidate gene effect meta-analyses.

Animals↗

PubMed2001

Guar gum for body weight reduction: meta-analysis of randomized trials.

PURPOSE: To determine the efficacy of the dietary fiber guar gum as a therapeutic option for reducing body weight by conducting a meta-analysis of randomized controlled trials. METHODS: Literature searches were performed on the electronic databases Medline, Embase, Biosis, Amed, and the Cochrane Library. Manufacturers of commercial guar gum preparations and experts on the subject were contacted to provide any published or unpublished trials. For inclusion, trials had to state that they were randomized, double blinded, and placebo controlled, used guar gum monopreparations, and reported body weight as an endpoint. No language restrictions were imposed. Two reviewers independently extracted data in a standardized manner according to predefined criteria and evaluated methodological quality using the scoring system developed by Jadad. Discrepancies were settled through discussion. RESULTS: Thirty-four trials were identified and 20 could be included. Eleven trials provided data that were suitable for statistical pooling. The meta-analysis indicated a nonsignificant difference in patients receiving guar gum compared with patients receiving placebo (weighted mean difference -0.04 kg; 95% confidence interval (CI): -2.2 to 2.1). Analysis of six trials with similar methodologic features corroborates these findings (weighted mean difference -0.3 kg; 95% CI: -4.0 to 3.5). Adverse events most frequently reported were abdominal pain, flatulence, diarrhea, and cramps. Overall, 11 patients (3%) dropped out owing to adverse events. CONCLUSIONS: This meta-analysis suggests that guar gum is not efficacious for reducing body weight. Considering the adverse events associated with its use, the risks of taking guar gum outweigh its benefits for this indication. Therefore, guar gum cannot be recommended as a treatment for lowering body weight.

Double-Blind Method↗

PubMed2005

Meta-analysis of soy food and risk of prostate cancer in men.

There has been considerable interest in recent years in the role of soy in cancer etiology. The purpose of this meta-analysis was to evaluate epidemiologic studies available to date that related soy consumption to the risk of prostate cancer in men. We conducted a thorough Medline search for English-language publications, supplemented with hand-searching of articles' bibliographies and nonindexed medical and professional journals, on epidemiologic studies of soy and prostate cancer. We identified 2 cohort and 6 case-control studies that met the following criteria for meta-analysis: a study must have assessed soy as a food and provided a risk estimate (relative risk or odds ratio) and its 95% confidence interval. Data from the same study population appearing in different journals were only used once with the most recent publication chosen for the analysis. Studies on fermented soy food were not included. We conducted the meta-analysis using a random-effects model. An analysis of these studies yielded an overall risk estimate of 0.70 (95% CI = 0.59-0.83; p < 0.001). No publication bias was detected. In summary, results of the analysis showed that consumption of soy food was associated with a lower risk of prostate cancer in men.

Cohort Studies↗

PubMed2005

Role of multivitamins and mineral supplements in preventing infections in elderly people: systematic review and meta-analysis of randomised controlled trials.

OBJECTIVE: To evaluate the effectiveness of multivitamins and mineral supplements in reducing infections in an elderly population. DESIGN: Systematic review and meta-analysis of randomised controlled trials. DATA SOURCES: Medline and other databases. Reference lists of identified articles were inspected for further relevant articles. SELECTION OF STUDIES: Trials were included if they evaluated the effect of multivitamins and mineral supplements on infections in an elderly population. REVIEW METHODS: Studies were assessed for the methodological quality by using the Jadad instrument. If the data required for the analyses were not available from the published articles we requested them from the original study authors. Meta-analysis was undertaken on three outcomes: the mean difference in number of days spent with infection, the odds ratio of at least one infection in the study period, and the incidence rate ratio for the difference in infection rates. Data on adverse events were also extracted. RESULTS: Eight trials met our inclusion criteria. Owing to inconsistency in the outcomes reported, only a proportion of the trials could be included in each meta-analysis. Multivitamins and mineral supplements were found to reduce the mean annual number of days spent with infection (three studies) by 17.5 (95% confidence interval 11 to 24, P < 0.001). The odds ratio for at least one infection in the study period (three studies) was 1.10 (0.81 to 1.50, P = 0.53). The infection rate ratio (four studies) was 0.89 (0.78 to 1.03, P = 0.11). Reporting of adverse events was poor. CONCLUSION: The evidence for routine use of multivitamin and mineral supplements to reduce infections in elderly people is weak and conflicting. Study results are heterogeneous, and this is partially confounded by outcome measure.

Aged↗

PubMedDate not supplied

Meta-analysis of the differences in the time to onset of action between rocuronium and vecuronium.

1. The aim of the present study was to conduct a meta-analysis of the magnitude of differences in the onset of action (T(max)) between rocuronium and vecuronium. 2. A search was made in PubMed, EMBASE Drugs and Pharmacology, Cochrane Controlled Trials Register and Cochrane Database on Systematic Reviews. Studies comparing the T(max) at the adductor policies between rocuronium and vecuronium administered as an intravenous bolus were included in the study. Twenty-nine effect sizes obtained from 21 studies were included. 3. The result of the meta-analysis of differences was -57.9 s (95% confidence interval -71.4 to -44.3 s), favouring rocuronium over vecuronium. The smallest difference in T(max) between these neuromuscular-blocking agents was observed in children (-19.1 s). The difference in T(max) between rocuronium and vecuronium in female patients was -38.7 s. The difference in T(max) between rocuronium and vecuronium measured by electromyography was approximately 50% shorter than that determined by acceleromyography or mechanomyography. In a subanalysis between rocuronium 600 mg/kg versus vecuronium 100 mg/kg, the difference in T(max) between them was very similar to that obtained in the general meta-analysis. 4. According to subanalyses of patient age and sex, drug dose and neuromuscular monitoring systems, the T(max) of rocuronium was approximately 20-70 s faster than that of vecuronium.

Adult↗

PubMed2006

Esomeprazole versus other proton pump inhibitors in erosive esophagitis: a meta-analysis of randomized clinical trials.

BACKGROUND & AIMS: There are limited data comparing the effectiveness of available proton pump inhibitors (PPIs) in erosive esophagitis (EE). We performed a meta-analysis to calculate the pooled effect of esomeprazole on healing rates, symptom relief, and adverse events versus competing PPIs in EE. METHODS: We performed a structured electronic search of MEDLINE and EMBASE and reviewed published abstracts to identify English-language, randomized clinical trials from 1995-2005, comparing rates of endoscopic healing, symptom relief, and adverse events with esomeprazole versus alternative PPIs in the treatment of gastroesophageal reflux disease (GERD)/EE. We then performed meta-analysis to compare the relative risk (RR) of EE healing, symptom relief, and adverse events between study arms and calculated the absolute risk reduction and number needed to treat (NNT) for each outcome. RESULTS: Meta-analysis was performed on 10 studies (n=15,316). At 8 weeks, there was a 5% (RR, 1.05; 95% confidence interval, 1.02-1.08) relative increase in the probability of healing of EE with esomeprazole, yielding an absolute risk reduction of 4% and NNT of 25. The calculated NNTs by Los Angeles grade of EE (grades A-D) were 50, 33, 14, and 8, respectively. Last, esomeprazole conferred an 8% (RR, 1.08; 95% confidence interval, 1.05-1.11) relative increase in the probability of GERD symptom relief at 4 weeks. CONCLUSIONS: As compared with other PPIs, esomeprazole confers a statistically significant improvement, yet, clinically, only a modest overall benefit in 8-week healing and symptom relief in all-comers with EE. The clinical benefit of esomeprazole appears negligible in less severe erosive disease but might be important in more severe disease.

Enzyme Inhibitors↗

PubMed2000

The effects of psychological therapies under clinically representative conditions: a meta-analysis.

Recently, concern has arisen that meta-analyses overestimate the effects of psychological therapies and that those therapies may not work under clinically representative conditions. This meta-analysis of 90 studies found that therapies are effective over a range of clinical representativeness. The projected effects of an ideal study of clinically representative therapy are similar to effect sizes in past meta-analyses. Effects increase with larger dose and when outcome measures are specific to treatment. Some clinically representative studies used self-selected treatment clients who were more distressed than available controls, and these quasi-experiments underestimated therapy effects. This study illustrates the joint use of fixed and random effects models, use of pretest effect sizes to study selection bias in quasi-experiments, and use of regression analysis to project results to an ideal study in the spirit of response surface modeling.

Humans↗

PubMed2025

Parent-Mediated Interventions for ASD Under 3 Years: A Systematic Review, Meta Analysis, and Moderator Analyses.

This study aimed to assess the effectiveness of PMIs for ASD under 3 years, and explore potential moderators influencing the effectiveness through moderator analyses. The study searched five English databases for randomized controlled trials (RCTs). The meta-analysis was conducted using a random-effects model to calculate Hedges's g. Subgroup analyses and meta regression assessed the effects of potential moderators on PMIs effectiveness, with evidence quality evaluated using GRADE. A total of 31 RCTs were included in the systematic review, with 26 included in the meta-analysis. The results showed a small overall beneficial effect of PMIs on ASD under 3 years (g = 0.20). Small to trivial positive effects were found in several subdomains, including adaptive skills (g = 0.29), parent responsiveness (g = 0.23), parent-child interaction (g = 0.35), social communication (g = 0.18), and symptoms (g =  - 0.22). However, PMIs did not show statistically significant effects on children's cognitive competence, language, or motor skills domains. Subgroup analysis and meta-regression explored potential moderators, but none significantly influenced the effectiveness of PMIs. The GRADE assessment showed that the certainty of the evidence ranged from moderate to low. This study confirmed that PMIs demonstrate positive effects on children under 3 years old with ASD, and showed beneficial outcomes in most subdomains. However, the evidence was of moderate to low certainty, so these findings should be interpreted with caution. In the future, broader databases and more large-scale, multicenter, high-quality clinical studies are needed to confirm these effects.

Humans↗

PubMed1999

Meta-analysis of randomized controlled trials comparing laparoscopic and open appendectomy.

We performed a meta-analysis to determine whether laparoscopic or open appendectomy gives better outcomes for patients with suspected acute appendicitis. Studies were selected from the MEDLINE database, personal files, and meeting abstracts. Eleven of 21 randomized controlled trials were included in the meta-analysis. Pooled effect size estimates were calculated using a random effects model. Laparoscopic appendectomy reduced time to full functioning by 5.48 days (95% confidence interval [CI] 3.70 to 7.26; p < 0.001), improved postoperative pain at 24 hours measured by a visual analog scale from 0 to 10 by 1.19 points (95% CI -2.14 to -0.24 points; p=0.014), and decreased the absolute risk for wound infection by 3.2% (95% CI -5.6% to -0. 8%; p=0.009). Operating time was increased by 17.12 min (95% CI 14.19 to 20.03; p < 0.0001). There was no difference between the two surgeries for length of hospital stay, readmission rate, and intra-abdominal abscess formation. Laparoscopic appendectomy improves patient outcomes.

Appendectomy↗

PubMed2004

[The role of meta-analysis in assessing the treatment of advanced non-small cell lung cancer].

Meta-analysis is a statistical method allowing an evaluation of the direction and quantitative importance of a treatment effect observed in randomized trials which have tested the treatment but have not provided a definitive conclusion. In the present review, we discuss the methodology and the contribution of meta-analyses to the treatment of advanced-stage or metastatic non-small-cell lung cancer. In this area of cancerology, meta-analyses have provided determining information demonstrating the impact of chemotherapy on patient survival. They have also helped define a two-drug regimen based on cisplatin as the gold standard treatment for patients with a satisfactory general status. Recently, the meta-analysis method was used to measure the influence of gemcitabin in combination with platinium salts and demonstrated a small but significant benefit in survival, confirming that gemcitabin remains the gold standard treatment in combination with cisplatin.

Antineoplastic Combined Chemotherapy Protocols↗