Meta-analysis is defined as "a quantitative method of combining the results of independent studies (usually drawn from the published literature) and synthesizing summaries and conclusions which may be used to evaluate therapeutic effectiveness, plan new studies, etc., with application chiefly in the areas of research and medicine."   Standards for the reporting of meta-analyses exist. [1]

Studies on the validity of meta-analyses conflict on the concordance of meta-analysis and underlying research. [2], [3], [4]

Disease relevance of Meta-Analysis

• Meta-analyses of therapies for postmenopausal osteoporosis. II. Meta-analysis of alendronate for the treatment of postmenopausal women [5].
• CONCLUSIONS: Our meta-analysis indicates that reduction in LDL-C associated with statin drug treatment decreases the risk of coronary heart disease and all-cause mortality [6].
• DATA SOURCES--MEDLINE search for meta-analysis of 27 studies relating homocysteine to arteriosclerotic vascular disease and 11 studies of folic acid effects on tHcy levels [7].
• We describe the unanticipated problems we encountered in collecting data for a meta-analysis comparing a new antifungal agent, fluconazole, with amphotericin B in patients with cancer complicated by neutropenia [8].
• Dexamethasone as adjunctive therapy in bacterial meningitis. A meta-analysis of randomized clinical trials since 1988 [9].

Psychiatry related information on Meta-Analysis

• DATA EXTRACTION: We reviewed studies for methods, sources of bias, and outcomes and performed a meta-analysis of the 10 studies of postmenopausal estrogen use and risk of dementia using standard meta-analytic methods [10].
• The effectiveness of the nicotine patch for smoking cessation. A meta-analysis [11].
• Benzodiazepines and zolpidem for chronic insomnia: a meta-analysis of treatment efficacy [12].
• Efficacy and tolerability of serotonin transport inhibitors in obsessive-compulsive disorder. A meta-analysis [13].
• Population-based and family-based studies on the serotonin transporter gene polymorphisms and bipolar disorder: a systematic review and meta-analysis [14].

High impact information on Meta-Analysis

• In this meta-analysis we found that the consumption of soy protein rather than animal protein significantly decreased serum concentrations of total cholesterol, LDL cholesterol, and triglycerides without significantly affecting serum HDL cholesterol concentrations [15].
• NHS opens meta-analysis centre [16].
• Meta-analyses of therapies for postmenopausal osteoporosis. III. Meta-analysis of risedronate for the treatment of postmenopausal osteoporosis [17].
• Meta-analyses of therapies for postmenopausal osteoporosis. IV. Meta-analysis of raloxifene for the prevention and treatment of postmenopausal osteoporosis [18].
• Efficacy of cholinesterase inhibitors in the treatment of neuropsychiatric symptoms and functional impairment in Alzheimer disease: a meta-analysis [19].

Chemical compound and disease context of Meta-Analysis

• Cholinesterase inhibition for Alzheimer disease: a meta-analysis of the tacrine trials. Dementia Trialists' Collaboration [20].
• Oral triptans (serotonin 5-HT(1B/1D) agonists) in acute migraine treatment: a meta-analysis of 53 trials [21].
• Parenteral nutrition with branched-chain amino acids in hepatic encephalopathy. A meta-analysis [22].
• METHODS: The meta-analysis of quality-adjusted survival was based on data from 3920 patients aged 50 years or older with node-positive breast cancer randomly assigned in nine trials that compared combination chemotherapy plus tamoxifen with tamoxifen alone [23].
• Mesalamine in the maintenance treatment of Crohn's disease: a meta-analysis adjusted for confounding variables [24].

Biological context of Meta-Analysis

• Effects of sodium restriction on blood pressure, renin, aldosterone, catecholamines, cholesterols, and triglyceride: a meta-analysis [25].
• BACKGROUND: A recent meta-analysis of 23 studies supported the empirically derived hypothesis that women who lack one of the four common minisatellite alleles at the HRAS1 locus are at increased risk of breast cancer [26].
• A meta-analysis showed significant associations between COL1A1 "s" alleles and bone mineral density (BMD), body mass index (BMI), and osteoporotic fractures [27].
• For a summary estimation of the risk of the (+/+) genotype for CAD, we performed a meta-analysis on 8 different case-control studies on thermolabile MTHFR in CAD [28].
• Thus, we performed a meta-analysis using data from four genome scans conducted in African American families to identify chromosomal regions showing evidence of linkage for total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL) and high density lipoprotein cholesterol (HDL) [29].

Anatomical context of Meta-Analysis

• CONCLUSIONS: Meta-analysis of the trials of nifedipine therapy in patients with pulmonary hypertension demonstrated a decrease in pulmonary artery pressure that was associated with an amelioration of clinical symptoms [30].
• In this study we describe the localization of the cytoarchitectonic subdivisions of the human parietal operculum in stereotaxic space and relate these anatomically defined cortical areas to the location of the functionally defined secondary somatosensory cortex (SII cortex) using a meta-analysis of functional imaging results [31].
• Missense mutations in the pancreatic islet beta cell inwardly rectifying K+ channel gene (KIR6.2/BIR): a meta-analysis suggests a role in the polygenic basis of Type II diabetes mellitus in Caucasians [32].
• A meta-analysis of 12 angiographic studies showed that treatment to reduce low density lipoprotein (LDL) cholesterol levels decreases angiographic progression of coronary artery disease (CAD) by one-third, and increases the chance of lesion regression two-fold [33].
• Suppressive therapy with levothyroxine for solitary thyroid nodules: a double-blind controlled clinical study and cumulative meta-analyses [34].

Associations of Meta-Analysis with chemical compounds

• In the meta-analyses, summary risk estimates were not significantly elevated in women who ever used estrogen [35].
• Elective cyclosporine withdrawal after renal transplantation. A meta-analysis [36].
• In the meta-analyses, fluconazole and amphotericin B (mostly given orally) had similar effects (13 trials), whereas nystatin was no better than placebo (3 trials) [8].
• Meta-analysis of prevention of nonvertebral fractures by alendronate [37].
• In 3 large trials that comprised 43% of the patients identified for the meta-analysis, results for amphotericin B were combined with results for nystatin in a "polyene" group [8].

Gene context of Meta-Analysis

• CONCLUSION: TOP2A amplification-and possibly deletion-seems to be predictive markers for the effect of adjuvant epirubicin containing therapy in primary breast cancer, but a final conclusion has to await a confirmative study or a meta-analysis [38].
• Identification of GATA3 as a breast cancer prognostic marker by global gene expression meta-analysis [39].
• Lack of association of the HLA-DRB1 shared epitope with rheumatoid nodules: an individual patient data meta-analysis of 3,272 Caucasian patients with rheumatoid arthritis [40].
• A meta-analysis of the association between DRD4 polymorphism and novelty seeking [41].
• The results of our meta-analysis do not support an association between the COMT Val allele and schizophrenia case status, and do not support recent claims that this association may be moderated by ancestry [42].

Analytical, diagnostic and therapeutic context of Meta-Analysis

• OBJECTIVE: To evaluate benefit of glucosamine and chondroitin preparations for OA symptoms using meta-analysis combined with systematic quality assessment of clinical trials of these preparations in knee and/or hip OA [43].
• A meta-analysis recently performed by our group confirmed that in these patients hepatic arterial infusion of 5-fluoro-2'-deoxyuridine, compared with intravenous chemotherapy with fluoropyrimidines or supportive care (including symptom palliation when necessary), improved tumor response [44].
• Epoetin treatment of anemia associated with cancer therapy: a systematic review and meta-analysis of controlled clinical trials [45].
• METHODS: We carried out a meta-analysis of randomised controlled trials of respiratory rehabilitation in patients with COPD that assessed functional or maximal exercise capacity, HRQL, or both [46].
• Meta-analysis was used to study patients' preference in 37 crossover trials that compared indomethacin with newer non-steroidal, antiinflammatory drugs (NSAIDs) [47].

References