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PubMed2001

Bayesian methods in meta-analysis and evidence synthesis.

This paper reviews the use of Bayesian methods in meta-analysis. Whilst there has been an explosion in the use of meta-analysis over the last few years, driven mainly by the move towards evidence-based healthcare, so too Bayesian methods are being used increasingly within medical statistics. Whilst in many meta-analysis settings the Bayesian models used mirror those previously adopted in a frequentist formulation, there are a number of specific advantages conferred by the Bayesian approach. These include: full allowance for all parameter uncertainty in the model, the ability to include other pertinent information that would otherwise be excluded, and the ability to extend the models to accommodate more complex, but frequently occurring, scenarios. The Bayesian methods discussed are illustrated by means of a meta-analysis examining the evidence relating to electronic fetal heart rate monitoring and perinatal mortality in which evidence is available from a variety of sources.

Bayes Theorem↗

PubMed2006

Re-examining the efficacy of beta-blockers for the treatment of hypertension: a meta-analysis.

BACKGROUND: In a recently published meta-analysis, investigators asserted that beta-blockers should not be used to treat hypertension. Because the pathophysiology of hypertension differs in older and younger patients, we designed this meta-analysis to clarify the efficacy of beta-blockers in different age groups. The primary outcome was a composite of stroke, myocardial infarction and death. METHODS: We identified randomized controlled trials that evaluated the efficacy of beta-blockers as first-line therapy for hypertension in preventing major cardiovascular outcomes. Both authors independently evaluated the eligibility of all trials. Trials enrolling older (mean age at baseline > or = 60 years) patients were separated from those enrolling younger (mean age < 60 years) patients. Data were pooled using a random effects model. RESULTS: Our analysis incorporated data from 145 811 participants in 21 hypertension trials. In placebo-controlled trials, beta-blockers reduced major cardiovascular outcomes in younger patients (risk ratio [RR] 0.86, 95% confidence interval [CI] 0.74-0.99, based on 794 events in 19 414 patients) but not in older patients (RR 0.89, 95% CI 0.75-1.05, based on 1115 events in 8019 patients). In active comparator trials, beta-blockers demonstrated similar efficacy to other antihypertensive agents in younger patients (1515 events in 30 412 patients, RR 0.97, 95% CI 0.88-1.07) but not in older patients (7405 events in 79 775 patients, RR 1.06, 95% CI 1.01-1.10), with the excess risk being particularly marked for strokes (RR 1.18, 95% CI 1.07-1.30). INTERPRETATION: beta-blockers should not be considered first-line therapy for older hypertensive patients without another indication for these agents; however, in younger patients beta-blockers are associated with a significant reduction in cardiovascular morbidity and mortality.

Adrenergic beta-Antagonists↗

PubMed1989

Meta-analysis in medical research: strong encouragement for higher quality in individual research efforts.

In this article, we counter some criticism regarding the desirability of performing meta-analysis in clinical research. These criticisms, we argue, are based mainly on current difficulties in deriving firm conclusions based on meta-analysis, resulting from poor methodology and reporting of primary studies. This is not a fault of meta-analysis. In fact, with a better understanding of meta-analysis in the context of the full scientific research process, meta-analysis is seen as a key element for improving individual research efforts and their reporting in the literature. This in turn will further enhance the role of meta-analysis in helping clinicians and policy makers answer clinical questions.

Humans↗

PubMed2004

The effectiveness of workplace smoking cessation programmes: a meta-analysis of recent studies.

OBJECTIVE: Using meta-analytic procedures, we compare the effectiveness of recent controlled trials of worksite smoking cessation during the 1990s with a previous meta-analysis of programmes conducted in the 1980s. DATA SOURCES: ABI/Inform, BRS, CHID, Dissertation Abstracts International, ERIC, Medline, Occupational Health and Safety Database, PsycInfo, Smoking and Health Database, SSCI, and Sociological Abstracts. STUDY SELECTION: Controlled smoking cessation interventions at the workplace with at least six months follow up published from 1989 to 2001 and reporting quit rates (QRs). DATA EXTRACTION: Two reviewers independently scanned titles/abstracts of relevant reports, and we reached consensus regarding inclusion/exclusion of the full text reports by negotiation. A third reviewer resolved disagreements. Two reviewers extracted data according to a coding manual. Consensus was again reached through negotiation and the use of a third reviewer. DATA SYNTHESIS: 19 journal articles were found reporting studies conforming to the study's inclusion criteria. Interventions included self help manuals, physician advice, health education, cessation groups, incentives, and competitions. A total of 4960 control subjects were compared with 4618 intervention subjects. The adjusted random effects odds ratio was 2.03 (95% confidence interval 1.42 to 2.90) at six months follow up, 1.56 (95% CI 1.17 to 2.07) at 12 months, and 1.33 (95% CI 0.95 to 1.87) at more than 12 months follow up. Funnel plots were consistent with strong publication bias at the first two follow ups but not the third. In Fisher et al's 1990 study, the corresponding ORs were 1.18, 1.66, and 1.18. CONCLUSIONS: Smoking cessation interventions at the worksite showed initial effectiveness, but the effect seemed to decrease over time and was not present beyond 12 months. Compared to the Fisher (1990) analysis, the effectiveness was higher for the six month follow up. Disappointingly, we found methodological inadequacies and insufficient reporting of key variables that were similar to those found in the earlier meta-analysis. This prevented us from determining much about the most effective components of interventions. It is advisable for researchers conducting studies in the future to report data on attrition and retention rates of participants who quit, because these variables can affect QRs.

Adult↗

PubMed2000

[A simple biostatistical method for meta analysis of the data on 2 x 2 table].

Meta-analysis is a method in common use for data analysis in evidence-based medicine. In this paper, based on the Mantel-Haenszel and Peto methods used for Meta-analysis of the data on 2 x 2 table, we put forward a simple calculating method for clinicians. It is useful for Meta-analysis and can be easily applied to analysis of the data from multi-studies in evidence-based medicine.

Biometry↗

PubMed1998

Cytomegalovirus prophylaxis with antiviral agents in solid organ transplantation: a meta-analysis.

BACKGROUND: The aim of this meta-analysis was to assess the efficacy of antiviral agents to prevent, in solid organ transplant recipients, cytomegalovirus infection and symptomatic disease and to decrease the incidence of acute rejection, graft loss, and death. METHODS: Of the studies identified, 13 met the following inclusion criteria: prospective randomized study, in adults or pediatric recipients of a solid organ transplant, where one group in the study received a prophylactic treatment with acyclovir and/or ganciclovir begun before the cytomegalovirus infection and a control group was not treated or receive placebo. RESULTS: Prophylactic treatment was found to be associated with a significant decrease of cytomegalovirus disease compared with placebo or no treatment, using the logarithm of relative risk method (relative risk=0.50; 95% confidence interval, 0.40-0.62; P-value for chi-square association <0.001). Prophylactic treatment decreased also the rate of cytomegalovirus infection (relative risk=0.74; 95% confidence interval, 0.62-0.88; P<0.001). Our analysis failed to show a significant decrease of graft loss, acute rejection, and death in the prophylactic treatment group. Subgroup analysis based on the type of antiviral agent (acyclovir or ganciclovir) and on the type of organ (kidney or liver) gave comparable results. CONCLUSION: The use of antiviral agents for the prevention of cytomegalovirus disease and cytomegalovirus infection in solid organ transplantation is supported by this meta-analysis.

Acyclovir↗

PubMed2026

Comparing the Efficacy of Mechanochemical Ablation Versus Radiofrequency Ablation for Treating Great Saphenous Vein Incompetence: A Meta-Analysis.

BACKGROUND: The objective of this meta-analysis was to compare the efficacy of mechanochemical ablation (MOCA) and radiofrequency ablation (RFA) in the treatment of great saphenous vein (GSV) incompetence. METHODS: Online databases including PubMed, Cochrane Library, Embase, and Web of Science were searched to collect randomized controlled trials (RCTs) and cohort studies comparing MOCA and RFA in the treatment of varicose veins in lower extremities from database inception to October 2025. Primary outcome was anatomic success. Secondary outcomes were visual analog scale (VAS), Aberdeen Varicose Vein Questionnaire score (AVVQ), and complications. Two reviewers independently screened the retrieved literature, extracted data, and assessed the risk of bias in the included studies. Subsequent analysis was performed using RevMan 5.3. RESULTS: A total of four RCTs, one cohort study and retrospective cross-sectional study involving 737 patients (380 MOCA patients and 357 RFA patients) were included. The meta-analysis results showed that the RFA group was significantly better than the MOCA group in short term and long term of anatomical success rate [(odds ratio [OR] = 0.38; 95% confidence interval [CI] (0.20, 0.71), P = 0.003), (OR = 0.17, 95% CI (0.06, 0.45), P = 0.0003)], but patients in the MOCA group had significantly lower perioperative period pain (mean difference [MD] = -4.48, 95% CI (-7.58, -1.37), P = 0.005] and required fewer days to return to normal activities (MD = -0.76, 95% CI, (-0.95, -0.57), P < 0.001). No significant differences were observed between the two groups in minor and major complications [(OR = 0.93, 95% CI (0.66, 1.33), P = 0.70), (OR = 1.30, 95% CI (0.32, 5.28), P = 0.72)] or quality of life scores (MD = -0.45, 95% CI (-2.53 to 1.63), P = 0.67). CONCLUSION: MOCA of GSV incompetence is an effective and safe method. Compared with RFA, it has lower postoperative pain score and faster recovery time. However, the anatomical success rates were significantly lower with MOCA than with RFA. Therefore, long-term follow-up to evaluate the impact on clinical results is required.

Humans↗

PubMed2006

A Bayesian meta-analysis of prophylactic granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor in children with cancer.

The purpose of this analysis was to examine the efficacy of prophylactic hematopoietic colony-stimulating factors (CSFs) in pediatric cancer and to describe how a Bayesian meta-analysis can be conducted and then modified to incorporate information not readily included in a frequentist meta-analysis. Three Bayesian models were developed. The simplest model used the same data as a published frequentist meta-analysis. The second model included data that could not easily be incorporated into the frequentist meta-analysis, including data from different courses of chemotherapy and continuous outcomes that did not report variance estimates. The third model examined the effect of CSF type (granulocyte CSF vs. granulocyte-macrophage CSF). Compared with the frequentist model, the Bayesian model with the most data suggested a greater benefit of CSFs, with a 3.2-day reduction in duration of parenteral antibiotics (95% credible interval: -7.1, 0.7) in the expanded Bayesian model compared with a 0.8-day (95% confidence interval: -2.3, 0.7) reduction in the frequentist model. Bayesian meta-analysis also suggested that, compared with granulocyte-macrophage CSF, granulocyte CSF was associated with a 4.8-day decrease in the duration of parenteral antibiotics. Bayesian meta-analysis can readily include information not easily incorporated in a frequentist meta-analysis. Some treatment effect estimates were larger by a clinically important amount when additional data contributed to the pooled estimate.

Bayes Theorem↗

PubMed1999

Discontinuation rates of Helicobacter pylori treatment regimens: a meta-analysis.

We conducted a meta-analysis to determine what factors in treatment regimens for Helicobacter pylori are associated with increased discontinuation rates. Studies were selected from the 1990-1996 MEDLINE data base, and references in published articles and reviews were obtained. Each article was uniformally abstracted for factors that could potentially affect dropout rates. Drug regimens with high numbers of doses per day had highest dropout rates (p=0.0001). The total dropout rate was lowest for regimens containing a proton pump inhibitor (OR = 0.75, CI 0.57, 0.98). The rate was high in regimens containing a bismuth compound due to side effects (OR = 2.79, CI 1.78, 4.36). The main finding was that drug regimens for eradication of H. pylori that have a high number of doses per day result in higher discontinuation rates than regimens with fewer doses per day.

Antacids↗

PubMed2006

Reference values for the five-repetition sit-to-stand test: a descriptive meta-analysis of data from elders.

This meta-analysis was conducted to generate normative values for the 5-repetition sit-to-stand (STS) test suitable for application to individuals at least 60 years of age. A thorough review of the literature yielded 13 papers (14 studies) relevant to this purpose. After the exclusion of potentially unrepresentative data, meta-analysis of these 13 papers indicated that judgments about normal performance should be based on age. Analysis demonstrated that individuals with times for 5 repetitions of this test exceeding the following can be considered to have worse than average performance: 11.4 sec (60 to 69 years), 12.6 sec. (70 to 79 years), and 14.8 sec. (80 to 89 years).

Aged↗

PubMed2003

Reinterpretations across studies: an approach to meta-analysis.

The authors undertook a qualitative meta-analysis of their own studies to examine the context of health care and health care relationships. They "translated" selected concepts and metaphors from each study through those of the other studies, yielding new interpretations. In this article, they present their methods, discuss possible applications of this approach, and examine some issues that remain unresolved in the area of qualitative meta-analysis. They offer this approach, which produced broader perspectives than the individual studies afforded, as a promising way of synthesizing qualitative findings, providing a foundation for praxis, and influencing practice toward health and social justice.

Anthropology, Cultural↗

PubMed1994

Gender differences in personality: a meta-analysis.

Four meta-analyses were conducted to examine gender differences in personality in the literature (1958-1992) and in normative data for well-known personality inventories (1940-1992). Males were found to be more assertive and had slightly higher self-esteem than females. Females were higher than males in extraversion, anxiety, trust, and, especially, tender-mindedness (e.g., nurturance). There were no noteworthy sex differences in social anxiety, impulsiveness, activity, ideas (e.g., reflectiveness), locus of control, and orderliness. Gender differences in personality traits were generally constant across ages, years of data collection, educational levels, and nations.

Adolescent↗

PubMed2005

Sexual versus nonsexual workplace aggression and victims' overall job satisfaction: a meta-analysis.

A meta-analytic approach was used to examine whether sexual and nonsexual forms of nonviolent workplace aggression (both verbal and nonverbal) share equivalent or differential relationships with victims' overall job satisfaction. When the meta-analytic comparison was restricted to all-female samples to hold victims' gender constant, nonsexual aggression was found to share a significantly stronger negative relationship with victims' overall job satisfaction than was sexual aggression. In addition, nonsexual aggression was found to share a stronger negative link with women's level of job satisfaction than with men's.

Aggression↗

PubMed1994

Breast cancer risk and duration of estrogen use: the role of study design in meta-analysis.

Recent meta-analyses of studies of the risk of breast cancer associated with hormone replacement therapy agree that little risk is associated with ever-use or short-term use of estrogen replacement. These analyses disagree, however, about the effect of long-duration estrogen use. To understand differences in the findings among the meta-analyses of the effect of long-term use, we investigated the source of heterogeneity among the included studies. We analyzed subgroups by source of controls (community vs hospital), study design (case-control vs follow-up), and types of estrogen. We also examined the effect of modeling assumptions: that before women began estrogen use, those who chose to use estrogen replacement (1) were, or (2) were not, at substantially different risk from those who chose not to use estrogen. We found a small increase in risk in all subgroups of studies except those that used hospital controls. From a homogeneous group of case-control studies using community controls that analyzed the effect of conjugated equine estrogens, we estimated that the risk of breast cancer after 10 years of estrogen use increased by at least 15% and up to 29%.

Breast Neoplasms↗

PubMed2005

Physical activity and multiple sclerosis: a meta-analysis.

Using meta-analytic procedures, this study involved a quantitative synthesis of the difference in physical activity among individuals with multiple sclerosis (MS) compared with nondiseased and diseased populations and then examined factors (i.e., moderators) that explain variation in the overall difference in physical activity. We searched MEDLINE, PsycINFO and Current Contents Plus using the key words physical activity, exercise and physical fitness in conjunction with multiple sclerosis; conducted a manual search of bibliographies of the retrieved papers; and contacted study authors about additional studies. Overall, 53 effects were retrieved from 13 studies with 2360 MS participants and yielded a weighted mean effect size (ES) of -0.60 (95% CI = -0.44, -0.77). The weighted mean ES was heterogenous, Q = 1164.11, df = 52, P < 0.0001. There were larger effects with objective versus self-report measures of physical activity, nondiseased versus diseased populations and primary progressive versus relapsing remitting MS. The cumulative evidence suggests that individuals with MS are less physically active than nondiseased, but not diseased, populations.

Female↗

PubMed2001

Cyclosporine in severe psoriasis. Results of a meta-analysis in 579 patients.

OBJECTIVE: A meta-analysis of 3 major German studies conducted between 1989 and 1994 with cyclosporine in severe psoriasis was performed to allow an integrated evaluation of the efficacy and tolerability of cyclosporine in this indication. DESIGN AND SETTING: All 3 studies were prospective, randomized, parallel group studies. The studies were conducted in 61 dermatologic centers in Germany. PATIENTS AND INTERVENTIONS: The studies involved 597 patients with severe plaque type psoriasis. Treatment consisted of cyclosporine (at a dosage of 1.25, 2.5 or 5 mg/kg/day), etretinate (at a mean daily dose of 0.53 mg/kg/day) or placebo in a total of 756 treatment cycles with a maximum duration of 12 weeks. MAIN OUTCOME MEASURES: The main outcome measures were the psoriasis area and severity index (PASI) and serum creatinine level. RESULTS: The meta-analysis revealed that cyclosporine given in a dosage of 2.5 and 5 mg/kg/day was significantly superior to etretinate. In addition cyclosporine 1.25 mg/kg/day proved to be significantly more effective than placebo. An increase in serum creatinine level that required intervention occurred in 3.4% of cyclosporine treatment cycles. CONCLUSION: Cyclosporine is highly effective and well tolerated in the short term treatment of severe psoriasis.

Adolescent↗

PubMed2006

HMG versus rFSH for ovulation induction in developing countries: a cost-effectiveness analysis based on the results of a recent meta-analysis.

Both cost and effectiveness should be considered conjointly to aid judgments about drug choice. Therefore, based on the results of a recent published meta-analysis, a Markov model was developed to conduct a cost-effectiveness analysis for estimation of the cost of an ongoing pregnancy in IVF/intracytoplasmic sperm injection (ICSI) cycles. In addition, Monte Carlo micro-simulation was used to examine the potential impact of assumptions and other uncertainties represented in the model. The results of the study reveal that the estimated average cost of an ongoing pregnancy is 13,946 Egyptian pounds (EGP), and 18,721 EGP for a human menopausal gonadotrophin (HMG) and rFSH cycle respectively. On performing a sensitivity analysis on cycle costs, it was demonstrated that the rFSH price should be 0.61 EGP/IU to be as cost-effective as HMG at the price of 0.64 EGP/IU (i.e. around 60% reduction in its current price). The difference in cost between HMG and rFSH in over 100,000 cycles would result in an additional 4565 ongoing pregnancies if HMG was used. Therefore, HMG was clearly more cost-effective than rFSH. The decision to adopt a more expensive, cost-ineffective treatment could result in a lower number of cycles of IVF/ICSI treatment undertaken, especially in the case of most developing countries.

Cost-Benefit Analysis↗

PubMed2003

Ultrasound-guided embryo transfer: a meta-analysis of randomized controlled trials.

OBJECTIVE: To conduct a meta-analysis of randomized controlled studies to evaluate abdominal ultrasound-guided embryo transfer compared to the clinical touch method. DESIGN: Meta-analysis. SETTING: Four studies performed in academic research centers in Barcelona, Vizcaya, Hong Kong, and Madrid. PATIENT(S): A total of 2,051 patients: 1,024 received ultrasound-guided embryo transfers and 1,027 received clinical touch method transfers. INTERVENTION(S): Fourteen studies were retrieved from the literature, but only four of them fitted our selection criteria. The meta-analysis was conducted using the RevMan software with the Peto-modified Mantel-Haenszel method and the fixed effect model. MAIN OUTCOME MEASURE(S): The primary outcome measures were the clinical pregnancy and ongoing pregnancy rates. The secondary outcome measures were the incidences of ectopic pregnancies, miscarriage rate, multiple pregnancies, and difficult transfers. RESULT(S): Compared to the clinical touch method, abdominal ultrasound-guided transfer significantly increased the clinical pregnancy rate and the ongoing pregnancy rate. There was no effect on the incidence of ectopic pregnancy, multiple pregnancy, or miscarriage rate. CONCLSUION(S): Ultrasound-guided embryo transfer increases the clinical pregnancy and ongoing pregnancy rates significantly compared to the clinical touch method.

Abortion, Spontaneous↗