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Results for “Meta- analysis”

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PubMed1997

Meta-analysis of the effect of systemic metronidazole as an adjunct to scaling and root planing for adult periodontitis.

The purpose of this meta-analysis was to provide a quantitative overview of clinical trials assessing the use of systemic metronidazole (S-MET) as an adjunct to scaling and root planning (S&RP) in the treatment of adult periodontitis. Eight clinical trials were chosen based upon a priori selection criteria, and two outcomes, "reduction in probing pocket depth" (PD) and "gain in clinical attachment level" (CAL), were analyzed. Results for each outcome were stratified by initial PD 1-3 mm, 4-6 mm, or > or = 7 mm and length of follow-up 4-6 wk, 9-13 wk, or 14-26 wk. S-MET in conjunction with S&RP was superior to S&RP alone in reducing PD where initial PD was 4-6 mm and follow-up was 9-13 wk (0.43 mm; 99% CI 0.12, 0.73). No significant advantage was observed for S-MET for reducing PD where initial PD was less than 4 mm or follow-up was longer than 13 wk. S-MET in conjunction with S&RP was superior to S&RP alone in reducing CAL where initial PD was 4-6 mm and follow-up was 4-6 wk (0.29; 99% CI 0.01, 0.58) and where follow-up was 9-13 wk (weighted mean difference 0.32; 99% CI 0.03, 0.61). Significant heterogeneity of effect was not seen for PD or Cal at any level of initial PD or length of follow-up. No significant dose-response relationship was observed. This meta-analysis was limited due to diversity of data presentation and the small number of trials in each stratum. These results suggest that S-MET in conjunction with S&RP may offer a benefit over S&RP alone in the treatment of adult periodontitis patients in managing pockets of 4 mm or greater, but the additional benefit was not evident if initial PD was less than 4 mm or follow-up was beyond 13 wk.

Adult↗

PubMed2002

Dopamine system genes and attention deficit hyperactivity disorder: a meta-analysis.

The dopamine system may play a major role in the development of attention deficit hyperactivity disorder (ADHD). We applied a random-effects model meta-analysis to family-based studies of association between ADHD and the dopamine system genes DRD4, DRD5 and DAT1. A statistical test of heterogeneity was conducted for each group of studies. The meta-analysis of DRD4 included data from 13 studies, with a total of 571 informative meioses. The pooled odds ratio estimate was 1.41 (95% CI 1.20-1.64, =1.57 x 10 ), demonstrating positive association. For DRD5, data from five studies, with a total of 340 informative meioses, were combined yielding a pooled odds ratio of 1.57 (95% CI 1.25-1.96, =8.28 x 10 ). Eleven studies examining DAT1, with a total of 824 informative meioses, yielded a non-significant pooled odds ratio estimate of 1.27 (95% CI 0.99-1.63, 0.06). There was no support of heterogeneity between the studies. Overall, the meta-analyses support the involvement of the dopamine system genes in ADHD liability variation and suggest the need for studies examining interactions between these genes.

Attention Deficit Disorder with Hyperactivity↗

PubMed2026

Comparing the efficacy and safety of unilateral versus bilateral spinal anesthesia: a meta-analysis and systematic review.

BACKGROUND: Unilateral spinal anesthesia has gained increasing attention in recent years. Emerging evidence suggests that it provides comparable analgesia to conventional bilateral spinal anesthesia while reducing adverse effects, and its efficacy and safety compared to bilateral spinal anesthesia remains controversial. OBJECTIVE: This systematic review and meta-analysis aims to evaluate and compare the efficacy and safety of unilateral versus bilateral spinal anesthesia. DESIGN: Systematic reviews and meta-analysis of randomized controlled trials (RCTs). DATA SOURCES: A systematic search was conducted across PubMed, EMBASE, and Cochrane Library from inception to December 10, 2024. ELIGIBILITY CRITERIA: Included studies were randomized controlled trials involving adult patients (≥18 years) undergoing surgery under spinal anesthesia, comparing unilateral versus bilateral spinal anesthesia for efficacy and adverse effects. Studies that focused exclusively on either unilateral or bilateral spinal anesthesia were excluded. The comparator group used the same local anesthetic as the experimental group, with no restrictions on adjuncts (e.g. fentanyl, morphine). RESULTS: Nineteen randomized controlled trials including 1191 patients met the inclusion criteria. Compared with bilateral spinal anesthesia, unilateral spinal anesthesia has a longer onset of sensory blockade (MD = 2.58, 95% CI: 0.93 to 4.22, p = 0.002), a shorter duration of sensory blockade (MD = -27.83, 95% CI: -39.25 to -16.42, p < 0.00001). In addition, unilateral spinal anesthesia significantly reduced the incidence of hypotension (RR = 0.40, 95% CI: 0.31 to 0.52, p < 0.0001), nausea and vomiting (RR = 0.20, 95% CI: 0.07 to 0.56, p = 0.002), and post-dural puncture headache (RR = 0.44, 95% CI: 0.23 to 0.81, p = 0.009). No statistically significant differences were observed in bradycardia and urinary retention. Collectively, these findings support unilateral spinal anesthesia as a strategy that may enhance perioperative safety while maintaining adequate anesthetic efficacy in appropriately selected patients. CONCLUSIONS: Unilateral spinal anesthesia may offer a favorable balance between anesthetic efficacy and safety compared with bilateral spinal anesthesia, although its clinical utility may depend on surgical duration and patient characteristics.

Humans↗

PubMed2006

Diabetes mellitus and risk of bladder cancer: a meta-analysis.

AIMS/HYPOTHESIS: Epidemiological evidence indicates that individuals with diabetes mellitus have an increased risk of several cancers. We performed a systematic review with meta-analysis to evaluate the association between diabetes and risk of bladder cancer. METHODS: Pertinent studies were identified by searching MEDLINE (from January 1966 to July 2006) and by reviewing the reference lists of retrieved articles. We included case-control and cohort studies reporting relative risk (RR) estimates with 95% CIs (or data to calculate them) of bladder cancer associated with diabetes. Studies of type 1 diabetes were not included. Summary RRs were calculated using a random-effects model. RESULTS: A total of 16 studies (seven case-control studies, three cohort studies and six cohort studies of diabetic patients) fulfilled the inclusion criteria. Analysis of all studies showed that diabetes was associated with an increased risk of bladder cancer, compared with no diabetes (RR = 1.24, 95% CI 1.08-1.42). There was strong evidence of heterogeneity among these studies (p < 0.0001). Stratification by study design found that diabetes was associated with an increased risk of bladder cancer in case-control studies (RR = 1.37, 95% CI 1.04-1.80, p (heterogeneity) = 0.005) and cohort studies (RR = 1.43, 95% CI 1.18-1.74, p (heterogeneity) = 0.17), but not in cohort studies of diabetic patients (RR = 1.01, 95% CI 0.91-1.12, p (heterogeneity) = 0.35). CONCLUSIONS/INTERPRETATION: Findings from this meta-analysis suggest that individuals with diabetes may have a modestly increased risk of bladder cancer.

Case-Control Studies↗

PubMed2025

A systematic review and meta-analysis on antibiotic resistance genes in Ghana.

BACKGROUND: Addressing antimicrobial resistance (AMR) poses a complex challenge, primarily because of the limited understanding of bacterial antibiotic resistance genes (ARGs) and the spread of these genes across different domains. To bridge this knowledge gap in Ghana, we undertook a comprehensive systematic review and meta-analysis to quantify and estimate the prevalence of circulating ARGs in bacteria isolated from human, animal, and environmental sources. METHODS: A thorough literature search was conducted across three major databases-Web of Science, PubMed, and Scopus-to retrieve all relevant articles related to ARGs in Ghana from the inception of the databases to February 25, 2024. A risk-of-bias evaluation was performed using the Newcastle-Ottawa Scale (NOS), and the data analysis involved descriptive statistics and proportional meta-analysis. RESULTS: Of the 371 articles initially obtained, 38 met the inclusion criteria. These studies adequately covered Ghana geographically. The most prevalent ESBL gene identified was blaCTX-M, with a prevalence of 31.6% (95% CI: 17.6-45.7), followed by blaTEM (19.5% [95% CI: 9.7-29.3]), and blaSHV (3.5% [95% CI: 0.3-6.6]). The pooled prevalence of carbapenemase genes ranged from 17.2% (95% CI: 6.9-27.6) for blaNDM to 10.3% (95% CI: 1.9-18.7) for blaOXA. Additionally, other ARGs, including sul1, qnrS, gyrA, erm(B), and mecA, were detected, with prevalence ranging from 3.9% (95% CI: 0.0-8.5) to 16.4% (95% CI: 3.1-29.8). Several ARGs were shared across human, animal, and environmental sources. CONCLUSION: This review revealed that bacteria obtained from human, animal, and environmental samples in Ghana shared genes associated with AMR. This finding provides evidence on the interconnection of AMR across these three domains. Horizontal gene transfer, which enables the dissemination of ARGs between genetically diverse bacteria, can occur, necessitating a multidisciplinary approach to addressing antimicrobial resistance in Ghana.

Ghana↗

PubMed1991

Prophylaxis of stress ulcer bleeding. A meta-analysis.

Recent studies have reported upper gastrointestinal tract bleeding in 5-25% of intensive care unit (ICU) patients with severe stress despite the use of antacids and/or H2-antagonists. To evaluate the efficacy of this regimen, a meta-analysis of all prospective studies on the prevention of stress bleeding, available from the international literature, was conducted. Only macroscopically visible bleeds were considered. Because alkalinization of the gastric juice has been incriminated in facilitating gastric and pulmonary colonization, agents with little or no influence on the gastric pH have been increasingly investigated in stress bleeding prophylaxis. The meta-analysis was therefore extended to determine the efficacy of two newer substances, pirenzepine and sucralfate, in preventing macroscopically visible stress bleeding, as well as their influence on pulmonary infections and mortality. Antacids and H2-antagonists proved to be significantly superior to untreated controls, with the tendency in favor of antacids administered in short intervals as compared to H2-antagonists. Pirenzepine and sucralfate were significantly superior to H2-antagonists, and sucralfate was as effective as an adequate antacid regimen. Patient groups treated with antacids or H2-antagonists showed a significantly higher risk for the development of nosocomial pneumonia. The most significant differences was found in long-term ventilated patients compared with patients treated with sucralfate. In the same patient group, antacids and H2-antagonists also showed a significantly higher mortality rate than sucralfate.

Critical Care↗

PubMed1999

Valid inference in random effects meta-analysis.

The standard approach to inference for random effects meta-analysis relies on approximating the null distribution of a test statistic by a standard normal distribution. This approximation is asymptotic on k, the number of studies, and can be substantially in error in medical meta-analyses, which often have only a few studies. This paper proposes permutation and ad hoc methods for testing with the random effects model. Under the group permutation method, we randomly switch the treatment and control group labels in each trial. This idea is similar to using a permutation distribution for a community intervention trial where communities are randomized in pairs. The permutation method theoretically controls the type I error rate for typical meta-analyses scenarios. We also suggest two ad hoc procedures. Our first suggestion is to use a t-reference distribution with k-1 degrees of freedom rather than a standard normal distribution for the usual random effects test statistic. We also investigate the use of a simple t-statistic on the reported treatment effects.

Anticholesteremic Agents↗

PubMed2000

Comparison of long versus short duration of anticoagulant therapy after a first episode of venous thromboembolism: a meta-analysis of randomized, controlled trials.

OBJECTIVE: To assess the length of oral anticoagulant therapy (short versus long duration) after a first episode of venous thromboembolism (VTE). DESIGN: Meta-analysis of randomized controlled trials, comparing two durations of anticoagulation, identified in 1999 by a computerized search of the Cochrane Controlled Trial Register, Medline and Embase, completed by an extensive review of the references of pertinent articles. SETTING AND SUBJECTS: The meta-analysis was performed on literature data. Seven published controlled trials were included. Relative risks with 95% confidence intervals were computed using the relative risk logarithm method. Statistical significance was set up at 0.01 for the test of association. MAIN OUTCOME MEASURES: Outcomes are major haemorrhage and recurrence after a 12-month follow-up. RESULTS: For the recurrence end-point (sample size of 2304 patients), a duration treatment of 12-24 weeks seems preferable to a 3-6 week regimen, with a relative risk (RR) of 0.60 (95% CI: 0.45-0.79, P < 0.001). For the major haemorrhage end-point (1823 patients), the RR is not significantly different from 1 (RR = 1.43, 95% CI: 0.51-4.01, P = 0. 5). The results were similar for the subgroup 'permanent risk factors' or 'idiopathic VTE' (RR for recurrence = 0.48, 95% CI: 0. 34-0.68, P < 0.001). The tendency was similar, although not reaching statistical significance, for the 'temporary risk factors' subgroup (RR for recurrence = 0.34, 95% CI: 0.13-0.93, P = 0.035). CONCLUSIONS: After a first episode of VTE, a long-term treatment regimen allows a significant reduction in the incidence of recurrences without increasing the incidence of bleeding events.

Acute Disease↗

PubMed2006

Internet-based cognitive behaviour therapy for symptoms of depression and anxiety: a meta-analysis.

BACKGROUND: We studied to what extent internet-based cognitive behaviour therapy (CBT) programs for symptoms of depression and anxiety are effective. METHOD: A meta-analysis of 12 randomized controlled trials. RESULTS: The effects of internet-based CBT were compared to control conditions in 13 contrast groups with a total number of 2334 participants. A meta-analysis on treatment contrasts resulted in a moderate to large mean effect size [fixed effects analysis (FEA) d=0.40, mixed effects analysis (MEA) d=0.60] and significant heterogeneity. Therefore, two sets of post hoc subgroup analyses were carried out. Analyses on the type of symptoms revealed that interventions for symptoms of depression had a small mean effect size (FEA d=0.27, MEA d=0.32) and significant heterogeneity. Further analyses showed that one study could be regarded as an outlier. Analyses without this study showed a small mean effect size and moderate, non-significant heterogeneity. Interventions for anxiety had a large mean effect size (FEA and MEA d=0.96) and very low heterogeneity. When examining the second set of subgroups, based on therapist assistance, no significant heterogeneity was found. Interventions with therapist support (n=5) had a large mean effect size, while interventions without therapist support (n=6) had a small mean effect size (FEA d=0.24, MEA d=0.26). CONCLUSIONS: In general, effect sizes of internet-based interventions for symptoms of anxiety were larger than effect sizes for depressive symptoms; however, this might be explained by differences in the amount of therapist support.

Anxiety Disorders↗

PubMed2006

Efficacy of the ketogenic diet as a treatment option for epilepsy: meta-analysis.

The evidence base for the efficacy of the ketogenic diet was assessed among pediatric epileptic patients by application of a rigorous statistical meta-analysis. Nineteen studies from 392 abstracts met the inclusion criteria. The sample size was 1084 patients (mean age at initiation 5.78 +/- 3.43 years). The pooled odds ratio, using a random effects model, of treatment success (> 50% seizure reduction) among patients staying on the diet relative to those discontinuing the diet was 2.25 (95% confidence interval = 1.69-2.98). The reasons for diet discontinuation included < 50% seizure reduction (47.0%), diet restrictiveness (16.4%), and incurrent illness or diet side effects (13.2%). The results indicate that children with generalized seizures and patients who respond with > 50% seizure reduction within 3 months tend to remain on the diet longer. Although no class I or II studies have been published regarding the efficacy of the ketogenic diet, this meta-analysis shows that current observational studies reporting on the therapeutic effect of the ketogenic diet contain valuable statistical data. Future observational studies should aim for long-term follow-up, patient dropout analysis, and improved seizure type characterization.

Adolescent↗

PubMed2000

Follicle-stimulating hormone or human menopausal gonadotropin for ovarian stimulation in in vitro fertilization cycles: a meta-analysis.

OBJECTIVE: To reanalyze the results of using FSH alone and hMG during IVF treatment, taking into account the different protocols of administration of superactive GnRH agonist analogs. DESIGN: Meta-analysis. SETTING: The London Women's Clinic. PATIENT(S): Women undergoing IVF treatment. INTERVENTION(S): A meta-analysis of published randomized controlled trials from 1985 to 1999 of the use of FSH versus hMG for ovarian stimulation during IVF treatment. The common Peto odds ratio was calculated with use of a fixed effect model. The overall log odds ratio was estimated after demonstrating the consistency or homogeneity of the study results. MAIN OUTCOME MEASURE(S): Clinical pregnancy rate per cycle of IVF. RESULT(S): The results suggested that in the "long and short GnRH agonists protocol" of IVF, FSH, and hMG were equally effective in achieving ovarian stimulation, and there were no differences in the clinical pregnancy rates per cycle of IVF. However, in protocols where no pituitary desensitization was used, FSH alone was more efficacious. CONCLUSION(S): The optimum choice of gonadotropin preparation for ovarian stimulation during IVF treatment is influenced by the regimen of pituitary desensitization used. The optimum gonadotropin to be used when GnRH antagonists are used has yet to be determined.

Clinical Protocols↗

PubMedDate not supplied

Paternal smoking during pregnancy and the risk of childhood brain tumors: results of a meta-analysis.

OBJECTIVE: Prior epidemiological studies suggest a possible association between paternal smoking during pregnancy and risk of childhood brain tumors (CBT). A meta-analysis was performed statistically pooling all available observational studies on this topic in order to evaluate this suspected association. METHODS: Using previously described methods, a protocol was developed for a meta-analysis examining the association between paternal smoking during pregnancy and subsequent development of primary brain tumors in their offspring. Literature search techniques study inclusion criteria and statistical procedures were prospectively defined. Data from epidemiological studies were pooled using a general variance based meta-analytic method employing confidence intervals previously described by Greenland. The outcome of interest was a summary relative risk (RRs) reflecting the risk of childhood brain tumor development associated with father's smoking during the index pregnancy. Sensitivity analyses were performed when necessary to explain any observed statistical heterogeneity and/or to evaluate the impact of demographic or study characteristics on the summary estimate of effect. RESULTS: Seven observational studies meeting protocol specified inclusion criteria were obtained via a comprehensive literature search. These studies enrolled a total of 3,600 patients. Analysis for homogeneity demonstrated that the data were homogeneous (P = 0.52) and could be statistically combined. Pooling all seven reports yielded a RRs of 1.29 (1.07-1.53), a statistically significant result suggesting a 29% increased risk of brain tumor development associated with paternal smoking during pregnancy. An analysis of father's smoking impact on CBT risk based on "ever" versus "never" smoking history gave a RRs of 1.14 (0.98-1.34), a marginally non-statistically significant result. CONCLUSION: The available epidemiological data suggest an association between paternal smoking during pregnancy and pediatric brain tumor development. Although this association is biologically plausible, limitations in study designs limit definitive conclusions based on available data.

Adolescent↗

PubMed2005

Human leukocyte antigen class II DQB10301, DRB11101 alleles and spontaneous clearance of hepatitis C virus infection: a meta-analysis.

AIM: To assess the associations of human leukocyte antigen (HLA) class II DQB1*0301 and/or DRB1*1101 allele with spontaneous hepatitis C virus (HCV) clearance by meta-analysis of individual dataset from all studies published till date. METHODS: To clarify the impact of HLA class II polymorphisms on viral clearance, we performed a meta-analysis of the published data from 11 studies comparing the frequencies of DQB1*0301 and DRB1*1101 alleles in individuals with spontaneous resolution to those with persistent infection. As we identified the heterogeneity between studies, summary statistical data were calculated based on a random-effect model. RESULTS: Meta-analyses yielded summary estimates-odds ratio (OR) of 2.36 [95%CI (1.62, 3.43), P<0.00001] and 2.02 [95%CI (1.56, 2.62), P<0.00001] for the effects of DQB1*0301 and DRB1*1101 alleles on spontaneous clearance of HCV, respectively. CONCLUSION: These results support the hypothesis that specific HLA class II alleles might influence the susceptibility or resistance to persistent HCV infection. Both DQB1*0301 and DRB1*1101 are protective alleles and present HCV epitopes more effectively to CD4(+)T lymphocytes than others, and subjects with these two alleles are at a lower risk of developing chronic HCV infection. Large, multi-ethnic confirmatory and well-designed studies are needed to determine the host genetic determinants of HCV infection.

Alleles↗

PubMed1991

Relationship between gestational cocaine use and pregnancy outcome: a meta-analysis.

Despite a growing number of studies that have investigated the reproductive effects of maternal cocaine use, a homogeneous pattern of fetal effects has not been established and there is little consensus on the adverse effects of the drug. We used meta-analysis to evaluate the reproductive risks of cocaine. We reviewed the 45 scientific papers published in the English language dealing with effects of cocaine used during pregnancy on pregnancy outcome in humans, and identified 20 papers eligible for meta-analysis (cocaine use in pregnancy, pregnancy/fetal outcome studies, human studies, original work, cohort or case control studies, control group present, English language). Our analysis revealed that very few adverse reproductive effects could be shown to be significantly associated with cocaine use by polydrug users when compared to control groups of polydrug users not using cocaine [genitourinary malformations; odds ratio of 6.08 (95% CI 1.18-31.3); gestation age: Cohen's d 0.37 (CI 0.2-0.55)]. When the control groups consisted of no drug users, the polydrug users abusing cocaine had a higher risk for spontaneous abortions [odds ration 10.50 (CI 11.74-64.1)]. Similarly, comparison of users of cocaine alone or no drug users revealed a higher risk for in utero death, in addition to genitourinary tract malformations. Analysis of continuous variables (head circumference, gestational age, birth weight and length) revealed that the effect size was dependent upon the nature of the comparison. Comparison of cocaine users to no drug users consistently yielded a medium effect size (Cohen's d) between 0.50 and 0.58, while comparison of polydrug/cocaine users to polydrug/no cocaine users provided effect sizes small to non existent (0.06-0.37). These discrepancies suggest that a variety of adverse reproductive effects commonly quoted to be associated with maternal use of cocaine may be caused by confounding factors clustering in cocaine users.

Abortion, Spontaneous↗

PubMed1991

A meta-analysis of cancer incidence in United States and Canadian native populations.

A meta-analytic approach was used to summarize studies of cancer incidence among Native populations in the United States and Canada. Native males and females were found to have a significantly lower incidence of cancer for all sites combined. Among Native males, kidney cancer was found to exhibit significantly elevated incidence, while significantly lower incidence was found for cancers of the colon, lung, and prostate, and for lymphomas and leukaemias. Native females were found to have significantly elevated incidence for cancers of the gallbladder, cervix, and kidney, while significantly decreased incidence was found for cancers of the colon, breast and uterus, and for lymphomas. The use of meta-analysis to integrate the findings from these studies allowed the identification of subtle differences in cancer incidence. Although these findings are not definitive, they overcome the limited numbers of site-specific cancers reported in many previous studies and are suggestive of general patterns of cancer incidence among Native populations. In addition, these results may be useful in indicating directions for future research involving specific cancer sites with elevated incidence.

Canada↗

PubMed2004

Efficacy of exclusively oral antibiotic therapy in patients hospitalized with nonsevere community-acquired pneumonia: a retrospective study and meta-analysis.

PURPOSE: To assess the efficacy of oral antibiotics in patients hospitalized with community-acquired pneumonia and to identify factors precluding oral therapy. METHODS: In a meta-analysis, we compared inpatient oral and parenteral therapy in community-acquired pneumonia. Studies were reviewed independently and rated by two reviewers, and results were summarized. We also performed a retrospective cohort study of hospitalized patients with community-acquired pneumonia and compared outcomes in patients treated with oral versus parenteral therapy. RESULTS: For the meta-analysis, we identified seven studies involving 1366 patients. Study exclusions included severe pneumonia or impaired oral absorption. There was no significant difference in the relative risk of mortality at the end of treatment or at follow-up. Mean length of hospital stay was shorter (6.1 days vs. 7.8 days) in patients taking oral antibiotics than in those taking the parental form. In the retrospective cohort, 18% (124/698) of patients received oral-only therapy; these patients were younger (median age, 75 vs. 78 years, P = 0.01) and had lower mean pneumonia severity index scores (101 vs. 119, P <0.0001) than those who received parenteral therapy. In multivariable models, oral-only patients had a median length of stay that was 1.3 days shorter (95% CI: 0.4% to 2.2% days; P = 0.008) and a median antibiotic cost that was 56 dollars lower (95% CI: 53 dollars to 58 dollars; P <0.0001) than that of patients in the parenteral group, but mortality was similar. CONCLUSION: Although prospective data are limited, oral antibiotics in certain hospitalized patients with community-acquired pneumonia are effective. More data are needed to identify appropriate candidates for exclusively oral antibiotic therapy.

Administration, Oral↗

PubMed2003

Meta-analysis in evidence-based orthodontics.

OBJECTIVE: In the last 10 years, health sciences literature has seen a significant increase in papers that report findings of meta-analyses. Meta-analysis overcomes the weakness of conventional narrative literature review. Moreover, it has established itself as a significant tool in clinical research and evidence-based medicine. But despite its station in the field, it is not without controversy. The aim of this paper is to present the main controversies that surround meta-analyses and to discuss the most important issues of conduct and reporting of results derived from these studies. RESULTS: Controversial issues include the ability of the investigators to combine studies that differ in important aspects; such as study populations, experimental designs and quality controls, and the like. It has been argued that selection bias could exist. Thus, it is common for the results of metaanalyses to be contradictory. As any other statistical procedure or analytical approach, meta-analyses too can be misused or abused. Misleading results could be avoided if certain basic principles are followed in the conduct of a meta-analysis. In particular, attention should be given to: (a) the methods of literature search for the studies to be included in the analysis, (b) the measures taken to reduce or eliminate bias, (c) the inclusion and exclusion criteria of the individual studies from the analysis, (d) how the data will be extracted from the literature, and (e) how the data will be analyzed statistically. CONCLUSION: Reports of meta-analytical studies carried out with the above parameters in mind yield a more objective appraisal of the evidence, and a more precise estimate of the treatment effect.

Dental Research↗

PubMed2004

Intravenous amiodarone for conversion of atrial fibrillation: misled by meta-analysis?

Therapeutic goals for atrial fibrillation (AF) include ventricular rate control, stroke prevention, conversion to normal sinus rhythm, and maintenance of normal sinus rhythm. The optimal strategy of rate versus rhythm control for acute management of patients with AF is a continuing debate. However, selected patients may require acute treatment with antiarrhythmic agents for conversion of symptomatic AF episodes to normal sinus rhythm. Recently published randomized controlled trials, qualitative systematic reviews, meta-analyses, and evidence-based international consensus guidelines have addressed the controversy regarding acute conversion of AF using antiarrhythmic therapy. Although meta-analyses often provide the highest level of evidence, the validity and application of their results are based on the quality of their methodology and accuracy of reporting. Authors of the most recent meta-analysis of amiodarone for conversion of AF state that the drug is effective and relatively rapid acting in converting AF to normal sinus rhythm in a wide range of patients, and they recommend it as a first-line drug. We feel that these conclusions are overstated and potentially misleading due to methodologic limitations of the analysis. The results of this meta-analysis and others concerning acute conversion of AF should be viewed as hypothesis generating and not the definitive answer to this question. Ultimately, well-designed, adequately powered, randomized placebo- or rate-controlled trials are needed in specific patient populations with AF to determine the absolute benefit of intravenous amiodarone for conversion of AF to normal sinus rhythm. Until more data are available, intravenous amiodarone cannot be promoted as a first-line agent for this purpose.

Administration, Oral↗