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PubMed1994

Meta-analysis. A useful tool for the spine researcher.

Meta-analysis is a systematic and objective methodology for synthesizing research literature. The authors present the history and definition of meta-analysis, discuss the generic framework for design and implementation of a meta-analysis, and review the problems and pitfalls that can accompany meta-analyses. Their discussion draws on practical experience with several meta-analyses of the low back pain literature. Meta-analysis can be used to help answer the questions about various options for diagnosis and treatment of low back problems and also to point out gaps in our knowledge base that may have a high priority for research. Meta-analytic methods are an informative means of addressing health care controversies with major patient management and cost implications.

Humans↗

PubMed2000

Child sexual abuse prevention programs: a meta-analysis.

Conducted a meta-analytic evaluation of the effectiveness of school-based child abuse prevention programs. Literature searches identified 27 studies meeting inclusion criteria for use in this meta-analysis. The average effect size for all programs studied was 1.07, indicating that children who participated in prevention programs performed 1.07 SD higher than control group children on the outcome measures used in the studies. Analysis of moderator variables revealed significant effects for age, number of sessions, participant involvement, type of outcome measure, and use of behavioral skills training. Most important, programs presented over 4 or more sessions that allowed children to become physically involved produced the highest effect sizes. Although most often used only with younger children, findings suggest that active, long-term programs may be more effective for children of all ages.

Age Factors↗

PubMed1998

Aging and the Stroop effect: a meta-analysis.

In this meta-analysis, data from 20 studies comparing younger and older adults on the Stroop interference effect, contained in 15 articles, were analyzed. No significant difference was found in the Stroop interference effect, expressed as mean standardized difference, between the 2 age groups (for younger adults: d = 2.04; for older adults: d = 2.17). Moderator variables were present, but these did not produce age differences. Brinley analysis showed that a single regression line with a slowing factor of 1.9 described the data well (R2 = .83) and confirmed that no Age x Condition interaction was present in the data. Likewise, no Age x Condition interaction was found when the data were fitted to the information loss model; the age ratio of decay rates was estimated to be 1.4. Consequently, the apparent age-sensitivity of the Stroop interference effect appears to be merely an artifact of general slowing.

Adult↗

PubMed2002

When worlds collide. Social science, politics, and the Rind et al. (1998). Child sexual abuse meta-analysis.

A 1998 meta-analysis by B. Rind, P. Tromovitch, and R. Bauserman in Psychological Bulletin indicated that the relations between child sexual abuse and later psychopathology were weak in magnitude. Shortly thereafter, this article was condemned by media personality Dr. Laura Schlessinger and numerous conservative organizations and was denounced by the United States Congress. In addition, the American Psychological Association (APA) distanced itself from the authors' conclusions. This incident raises questions regarding (a) authors' responsibilities concerning the reporting of politically controversial findings, (b) academic and scientific freedom, (c) the role of the APA in disabusing the public and media of logical errors and fallacies, and (d) the substantial gap between popular and academic psychology and the responsibility of the APA to narrow that gap.

Child↗

PubMed1995

Comparison of carbamazepine and lithium in the prophylaxis of bipolar disorders. A meta-analysis.

BACKGROUND: This meta-analysis assessed the equipotency of carbamazepine and lithium prophylaxis in bipolar disorder. METHOD: We selected only randomised, double-blind, controlled studies comparing carbamazepine with lithium from a manual and computerised search, and subjected them to a quality inventory. Their statistical results were weighted by their quality score and combined. RESULTS: Four studies met our criteria, yielding, overall, P = 0.15. This result is not straightforward because the studies showed significant heterogeneity (P < 0.01). CONCLUSION: Differences in statistical power and sensitivity of outcome measure explain this heterogeneity and the conflicting results of the studies. Therefore, the prophylactic efficacy of carbamazepine remains questionable.

Bipolar Disorder↗

PubMed1997

Vaginal douching and adverse health effects: a meta-analysis.

OBJECTIVES: The meta-analysis described here reviewed the current literature on adverse health effects of vaginal douching. METHODS: Papers published in English from 1965 through 1995 were potentially eligible. RESULTS: One third of White women and two thirds of Black women of reproductive age reported douching regularly. Analyses indicated that vaginal douching increases the overall risk of pelvic inflammatory disease by 73% and the risk of ectopic pregnancy by 76%. Frequent douching was shown to be highly associated with pelvic inflammatory disease and modestly associated with cervical cancer. CONCLUSIONS: Current literature suggests that frequent douching increases the risk of pelvic inflammatory disease, ectopic pregnancy, and, possibly, cervical cancer.

Female↗

PubMed1997

Maternal cigarette smoking and oral clefts: a meta-analysis.

OBJECTIVE: A meta-analysis was performed to estimate the association between maternal cigarette smoking and the risk of having a child with a nonsyndromic oral cleft (NSOC). DESIGN: Studies published from 1966 through 1996 were retrieved using MEDLINE, Current Contents, bibliographies, and other sources. MEDLINE and Current Contents search terms included "oral clefts," "cigarette smoking," "birth defects," and "congenital malformations." Cohort and case-control studies that enrolled oral cleft patients [cleft lip with or without cleft palate (CL/P), cleft palate (CP), or both] and controls, and presented information on maternal cigarette exposure during pregnancy were included in the analysis. Descriptive and outcome data from each study were independently abstracted by two authors. RESULTS: The overall odds ratio of the 11 studies satisfying criteria was 1.29 [95% confidence interval (CI), 1.18 to 1.42] for CL/P and 1.32 (95% CI: 1.10 to 1.62) for CP, indicating a small increase risk of having a child with either a CL/P or a CP for mothers who smoke during the first trimester of the pregnancy. CONCLUSIONS: These analyses suggest a small but statistically significant association between maternal cigarette smoking during the first trimester of gestation and increased risk of having a child with a CL/P or CP.

Cleft Lip↗

PubMed1995

The effect of human chorionic gonadotropin (HCG) in the treatment of obesity by means of the Simeons therapy: a criteria-based meta-analysis.

1. A meta-analysis was conducted to assess if there is scientific ground for the use of human chorionic gonadotropin (HCG) as adjunctive therapy in the treatment of obesity. 2. Published papers relating to eight controlled and 16 uncontrolled trials that measured the effect of HCG in the treatment of obesity were traced by computer-aided search and citation tracking. 3. The trials were scored for the quality of the methods (based on four main categories: study population, interventions, measurement of effect, and data presentation and analysis) and the main conclusion of author(s) with regard to weight-loss, fat-redistribution, hunger, and feeling of well-being. 4. Methodological scores ranged from 16 to 73 points (maximum score 100), suggesting that most studies were of poor methodological quality. Of the 12 studies scoring 50 or more points, one reported that HCG was a useful adjunct. The studies scoring 50 or more points were all controlled. 5. We conclude that there is no scientific evidence that HCG is effective in the treatment of obesity; it does not bring about weight-loss of fat-redistribution, nor does it reduce hunger or induce a feeling of well-being.

Body Weight↗

PubMed2002

Negative life events and depression in elderly persons: a meta-analysis.

In a meta-analysis of 25 studies, the relationship of both specific types of negative life events and the total number of experienced events to depression in old age was studied. Almost all negative life events appeared to have a modest but significant relationship with depression. The total number of negative life events and the total number of daily hassles appeared to have the strongest relationship with depression (respectively, combined r =.15, n = 5,037, and combined r =.41, n = 461), whereas sudden unexpected events were the only cluster of negative life events that seemed not to be related to depression scores (combined r =.05, n = 857). These findings suggest that providers and developers of intervention and prevention programs for elderly people should pay attention to the occurrence of negative life events. Special attention should be given to elderly people who have experienced an accumulation of stressful events and daily hassles, because they seem to be a group at greater risk.

Adaptation, Psychological↗

PubMed1997

Propranolol and sclerotherapy in the prevention of gastrointestinal rebleeding in patients with cirrhosis: a meta-analysis.

BACKGROUND/AIMS: A meta-analysis of nine selected randomized trials was performed to compare the effects of propranolol and sclerotherapy in the prevention of rebleeding and on survival in patients with cirrhosis. METHODS: Five end points were assessed: rebleeding, esophageal rebleeding, death, death due to bleeding, and adverse events. Analyses were performed according to the intention-to-treat method. For each end point, heterogeneity and treatment efficacy were assessed by the Der Simonian and Peto methods. When a significant difference was observed, sensitivity analyses were performed by successive stratification according to treatment duration, type of publication, severity of cirrhosis, and methodological quality. RESULTS: The mean percentage of patients free of rebleeding, the mean survival rate and the mean percentage of patients free of death from bleeding were not significantly different between patients treated with propranolol and those treated by sclerotherapy. The mean percentage of patients free of variceal rebleeding was 39% in propranolol group and 55% in sclerotherapy group (mean difference: 17%, 95% confidence interval: 9-25%, p < 0.001). The mean percentage of patients free of adverse events was significantly higher in the propranolol group than in the sclerotherapy group (mean difference: 22%, 95% confidence interval: 6-38%, p < 0.007). CONCLUSION: In patients with cirrhosis and esophageal varices, endoscopic sclerotherapy is more effective than propranolol in preventing variceal rebleeding, but the incidence of adverse events is significantly higher with sclerotherapy. There was no difference in survival between the treatments. Propranolol should be considered as a first choice treatment for preventing rebleeding.

Adult↗

PubMed2003

Amiodarone versus placebo and class Ic drugs for cardioversion of recent-onset atrial fibrillation: a meta-analysis.

OBJECTIVES: This meta-analysis compared amiodarone with placebo and class Ic drugs for the cardioversion of recent-onset atrial fibrillation (AF), defined as lasting less than seven days. BACKGROUND: Despite the lack of trials that support its efficacy convincingly, amiodarone is widely used for conversion of recent-onset AF. METHODS: We searched Medline and EMBASE databases, as well as the Cochrane Controlled Trials Register for randomized trials on recent-onset AF comparing amiodarone to placebo or class Ic drugs. Data were combined according to a fixed effect model. The primary end point was the rate of conversion at 24 h. To study time-dependency of the drugs, efficacy at 1 to 2 h, 3 to 5 h, 6 to 8 h, and at 24 h was analyzed. RESULTS: We found six studies randomizing amiodarone versus placebo (595 patients) and seven studies versus class Ic drugs (579 patients). There was no significant difference between amiodarone and placebo at 1 to 2 h, but significant efficacy was found after 6 to 8 h (relative risk [RR] 1.23, p = 0.022) and at 24 h (RR 1.44, p < 0.001). Efficacy with amiodarone was inferior to class Ic drugs for up to 8 h (RR 0.67, p < 0.001) but no difference was seen at 24 h (RR 0.95, p = 0.50). There were no major adverse effects. CONCLUSIONS: Amiodarone is superior to placebo for cardioversion of AF, and even though the onset of conversion is delayed, its efficacy is similar at 24 h compared with class Ic drugs. These results favor amiodarone as a reasonable alternative for patients with recent AF in whom class Ic and other, more rapidly acting antiarrhythmic drugs cannot be used.

Adult↗

PubMed1994

Prenatal care and maternal health during adolescent pregnancy: a review and meta-analysis.

PURPOSE: A meta-analysis and review of pregnancy complications and behavioral risk factors associated with infant low birth weight and other poor outcomes which occur during adolescent pregnancy was undertaken using the published literature. METHODS: Studies were eligible for inclusion if they: 1) utilized a clearly defined sample of teenagers 2) provided numeric data on complications of interest or the proportions needed to compute this information 3) included a control or comparison group. RESULTS: Many behavioral risk factors (smoking, drinking and drug use) appeared to be less prevalent among teenage gravidas, particularly when the young women were ethnic minorities. An increased risk of preterm delivery was associated with young maternal age in both developed and developing countries. In the developed world, risk of cesarean delivery was reduced for teenagers and there was a secular decline in maternal anemia and pregnancy induced hypertension in comparison to the risk sustained by more mature women. Programs of comprehensive prenatal care appeared to have the potential to diminish risk of many complications. In the developing world, teenagers were at increased risk of maternal anemia, preterm birth and cesarean delivery. CONCLUSIONS: Although future research efforts will need to address the issues of bias inherent in much of the published research, the published literature suggests that prenatal care regimens which provide social and behavioral services along with medical care could improve both the health of the mother and the outcome of her pregnancy.

Adolescent↗

PubMed1998

A comparison of the efficacy and tolerability of adapalene 0.1% gel versus tretinoin 0.025% gel in patients with acne vulgaris: a meta-analysis of five randomized trials.

The purpose of this meta-analysis was to determine if adapalene 0.1% gel (Differin) provided superior efficacy and better tolerability than tretinoin 0.025% gel in the treatment of acne vulgaris. All comparative studies, both published and unpublished, from the United States and Europe, that fulfilled rigorous protocol criteria (multicentre, randomized, investigator-blind) were used. Five comparative studies met these criteria. In total, the meta-analysis evaluated 900 patients (450 treated with adapalene 0.1% gel, 450 treated with tretinoin 0.025% gel) with mild-to-moderate acne from the combined clinical trials. To avoid study bias, the meta-analysis used an intention-to-treat analysis. Statistical methodology for the meta-analysis included analysis of covariance, analysis of variance and Cochran-Mantel-Haenszel test. All statistical tests were two-sided, with the 0.05 probability level used to establish statistical significance, and 95% confidence intervals used to assess equivalence. Adapalene demonstrated equivalent efficacy to tretinoin in terms of reducing total lesion count. Adapalene demonstrated more rapid efficacy, as evidenced by a significant difference in the reduction of inflammatory and total lesions at week 1. Adapalene also demonstrated considerably greater local tolerability at all evaluation periods. The findings from this meta-analysis suggest that adapalene 0.1% gel constitutes a pharmacologic advance over such classic retinoids as tretinoin for the treatment of acne vulgaris.

Acne Vulgaris↗

PubMed1996

The use and misuse of meta-analysis.

OBJECTIVE: To demonstrate how the results of a meta-analysis can confuse rather than clarify therapeutic dilemmas if clinical heterogeneity among trials is ignored. Then to further discuss the qualities emergency physicians should expect from published meta-analyses if they are to affect clinical practice. SUBJECTS AND METHODS: The data and results were examined from 23 randomised controlled trials of selective decontamination of the digestive tract (SDD), which have been combined in a previous meta-analysis. These were reviewed to take account of clinical heterogeneity, particularly with regard to severity of patient illness. RESULTS: Severity of patient illness predicts degree of reduction in mortality with SDD in a regression analysis: log odds ratio (OR) of death with SDD = -0.0074 - (0.0035 x control group mortality rate), P = 0.017. This is also true when trials are stratified into more and less severely ill patients: pooled OR (a) for CMR > 41% = 0.69 (0.54 to 0.89), with (b) CMR < 3% = 1.02 (0.86 to 1.21). This difference was not suggested by the original meta-analysis result. CONCLUSIONS: Failure to take account of clinical heterogeneity between trials can mean a meta-analysis result ignores important differences in the effect of a treatment on different groups of patients. The discussion indicates how emergency physicians might guard against basing clinical practice on misleading meta-analysis results.

Anti-Bacterial Agents↗

PubMed2001

Is meta-analysis clinically useful for perianesthesia nurses?

Meta-analyses can provide clinicians with the evidence-based information necessary to effect change in patient care delivery. Meta-analysis, the application of statistical techniques to condense data from a group of individual studies, is the most sophisticated summary of research evidence. An example meta-analysis study of inadvertent surgical hypothermia is used in this article to describe how nurses can locate, evaluate, and apply synthesized research data for perianesthesia clinical practice. Without data to support decisions, nurses will increasingly be faced with decisions made by others based on cost-cutting measures alone. Although meta-analysis may resolve a controversy or solve a clinical problem, it will not provide simple statistical answers for complex problems or obviate the need for sound and compassionate clinical judgment.

Clinical Competence↗

PubMed1996

Meta-analysis of clinical trials: a consumer's guide.

Meta-analysis is a popular statistical tool allowing the synthesis of related research studies in a quantitative manner. Components of a good meta-analysis are first discussed, with a view toward critical reading of reports of meta-analyses. Examples include lipid-lowering drugs and coronary artery bypass graft surgery. A role for meta-analysis in the design and monitoring of clinical trials was examined at a workshop held at the National Institutes of Health and aspects of these uses of meta-analyses are considered. Basic analytical and graphical methods of meta-analysis are briefly reviewed. The goal is to encourage more thoughtful evaluation of the many meta-analyses that are published or are presented.

Clinical Trials as Topic↗

PubMedDate not supplied

Effects of acadesine on myocardial infarction, stroke, and death following surgery. A meta-analysis of the 5 international randomized trials. The Multicenter Study of Perioperative Ischemia (McSPI) Research Group.

OBJECTIVE: To determine the effects of a purine nucleoside, acadesine, on the incidence of fatal and nonfatal cardiovascular and cerebrovascular complications following coronary artery bypass graft (CABG) surgery. DATA SOURCES: Individual patient data from 5 randomized, placebo-controlled, double-blind clinical trials, including 81 international medical centers of the United States, Canada, and Europe. STUDY SELECTION: All patients from all clinical trials were included: a total of 4043 patients undergoing CABG surgery, evaluable for efficacy, and randomized to receive either placebo (n= 2031) or acadesine (0.1 mg x kg(-1) x min(-1); n=2012) by intravenous infusion for 7 continuous hours and via the cardioplegia solution. DATA EXTRACTION: Individual patient data were collected prospectively using standardized forms and methods and double-data entry. A general parametric approach and analysis-by-patient meta-analysis were used, including both fixed effects and random effects models. Inclusion and exclusion criteria, general methodology, and outcome assessment techniques were similar for all trials. DATA SYNTHESIS: Acadesine decreased the incidence of the primary outcome, perioperative myocardial infarction (MI) by 27% (odds ratio [OR], 0.69; 95% confidence interval [CI], 0.51-0.95; P=.02), decreased the incidence of cardiac death through postoperative day 4 by 50% (OR, 0.52; 95% Cl, 0.27-0.98; P=.04), and decreased the incidence of combined outcome (MI, stroke, or cardiac death) by 26% (OR, 0.73; 95% Cl, 0.57-0.93; P=.01). The random effects models for these outcomes also yielded significant results. The incidence of cerebrovascular accident was not significantly reduced by acadesine (OR, 0.69; 95% Cl, 0.44-1.08; P=.10). A secondary analysis of cardiac death following MI through postoperative day 4 demonstrated that acadesine decreased by 89% the number of deaths from 13.3% (13 deaths/98 MIs) in the placebo group to 1.4% (1 death/71 MIs) in acadesine-treated patients (P=.003). Acadesine also reduced the use of ventricular-assistance devices for severe postoperative heart failure by approximately one third (P=.05). Finally, regarding safety, the incidence of adverse events was similar in the acadesine vs placebo groups, with the exception of a transient increase in serum uric acid in the acadesine group. CONCLUSIONS: The results of this meta-analysis indicate that in patients undergoing CABG surgery, treatment with acadesine before and during surgery can reduce early cardiac death, MI, and combined adverse cardiovascular outcomes.

Aminoimidazole Carboxamide↗

PubMed1992

Meta-analysis and quality of evidence in the economic evaluation of drug trials.

Meta-analysis is an important part of assessing cost-effectiveness in that it may help determine which treatments are indeed effective and estimate the level of effectiveness of each. Meta-analysis uses the data from all the relevant trials and is a powerful tool for detecting effects too small to be picked up by individual trials. The assessment of quality of studies in a meta-analysis is critical, with priority needing to be given to high quality randomised studies. A written protocol, literature retrieval system, evaluation and selection criteria, choice of endpoints and ways to evaluate bias must all be pre-defined. Nevertheless, problems can arise when meta-analysis is used for cost-effectiveness analysis, due to variation in study medication protocols, duration of follow-up, and difficulties in interpreting patient subgroups and compliance. Despite being subject to the design flaws of both the trials analysed and the methods used in the analysis itself, meta-analysis provides a more objective and thorough means of evaluating effectiveness and hence the cost-effectiveness of treatments. Based on the meta-analysis evidence, we recommend that the current QALY league tables be split into an implementation table for clearly effective therapies, and a research priority table where the evidence of treatment effectiveness is less clear and more research is needed.

Clinical Protocols↗