Meta-Analysis
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Meta-analyses, which present the best source of information on the effectiveness of interventions, are influenced by several biases. One category relates to the convenience of selective inclusion of those primary studies, which are more easily available than others. This availability bias includes bias from excluding the grey literature, bias from excluding non-English literature, and bias from excluding older studies. Existing studies are not conclusive about the impacts of this bias; in addition, none of them focus on road safety meta-analyses. To fill this gap, the present paper consisted of two studies: (1) exploring the presence of availability bias in road safety meta-analyses, and (2) demonstrating the impact of availability bias in several example meta-analyses. Based on an analysis of 80 existing meta-analyses, the first study concluded that compared to the medicine meta-analyses, the road safety meta-analyses use a longer time range, are more often restricted in terms of language, and less often involve the grey literature. The second study utilized selected unrestricted data samples to demonstrate the impact of availability bias in seven meta-analyses. The differences in intervention effectiveness in terms of crash frequency changes between unrestricted and restricted scenarios were identified. This shows that the search restrictions clearly lead to availability bias, which influences the differences in meta-analysis results.
- Klíčová slova
- Availability bias, Meta-analysis, Road safety, Systematic review,
- MeSH
- bezpečnost * MeSH
- dopravní nehody * statistika a číselné údaje prevence a kontrola MeSH
- lidé MeSH
- metaanalýza jako téma * MeSH
- systematický přehled jako téma * MeSH
- zkreslení výsledků (epidemiologie) MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Recently, concerns regarding the safety of red yeast rice (RYR) have been raised after the publication of some case reports claiming toxicity. Since the previous meta-analyses on the effects of RYR were mainly focused on its efficacy to improve lipid profile and other cardiovascular parameters, we carried out a meta-analysis on safety data derived from the available randomized controlled clinical trials (RCTs). Primary outcomes were musculoskeletal disorders (MuD). Secondary outcomes were non-musculoskeletal adverse events (Non-MuD) and serious adverse events (SAE). Subgroups analyses were carried out considering the intervention (RYR alone or in association with other nutraceutical compounds), monacolin K administered daily dose (≤3, 3.1-5 or >5 mg/day), follow-up (>12 or ≤12 weeks), with statin therapy or statin-intolerance and type of control treatment (placebo or statin treatment). Data were pooled from 53 RCTs comprising 112 treatment arms, which included 8535 subjects, with 4437 in the RYR arm and 4303 in the control one. Monacolin K administration was not associated with increased risk of MuD (odds ratio (OR) = 0.94, 95% confidence interval (CI) 0.53,1.65). Moreover, we showed reduced risk of Non-MuD (OR = 0.59, 95%CI 0.50, 0.69) and SAE (OR = 0.54, 95%CI 0.46, 0.64) vs. control. Subgroups analyses confirmed the high tolerability profile of RYR. Furthermore, increasing daily doses of monacolin K were negatively associated with increasing risk of Non-MuD (slope: -0.10; 95%CI: -0.17, -0.03; two-tailed p < 0.01). Based on our data, RYR use as lipid-lowering dietary supplement seems to be overall tolerable and safe in a large kind of moderately hypercolesterolaemic subjects.
- Klíčová slova
- Musculoskeletal disorders, Non-musculoskeletal adverse events, Red yeast rice, Safety, Serious adverse events,
- MeSH
- biologické přípravky škodlivé účinky MeSH
- lidé MeSH
- muskuloskeletální nemoci MeSH
- potravní doplňky škodlivé účinky MeSH
- randomizované kontrolované studie jako téma MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- systematický přehled MeSH
- Názvy látek
- biologické přípravky MeSH
- red yeast rice MeSH Prohlížeč
Vaccination as an important tool in the fight against infections has been suggested as a possible trigger of autoimmunity over the last decades. To confirm or refute this assumption, a Meta-analysis of Autoimmune Disorders Association With Immunization (MADAWI) was conducted. Included in the meta-analysis were a total of 144 studies published in 1968-2019 that were available in six databases and identified by an extensive literature search conducted on 30 November 2019. The risk of bias classification of the studies was performed using the Newcastle-Ottawa Quality Assessment Scale. The strength of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation. While our primary analysis was conducted in terms of measures of association employed in studies with a low risk of bias, the robustness of the MADAWI outcome was tested using measures independent of each study risk of bias. Additionally, subgroup analyses were performed to determine the stability of the outcome. The pooled association of 0.99 (95% confidence interval, 0.97-1.02), based on a total of 364 published estimates, confirmed an equivalent occurrence of autoimmune disorders in vaccinated and unvaccinated persons. The same level of association reported by studies independently of the risk of bias was supported by a sufficient number of studies, and no serious limitation, inconsistency, indirectness, imprecision, and publication bias. A sensitivity analysis did not reveal any discrepancy in the primary result. Current common vaccination is not the cause of any of the examined autoimmune disorders in the medium and long terms.
- Klíčová slova
- immunization, meta-analysis, vaccine safety, vaccine-associated autoimmune disease,
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
BACKGROUND AND OBJECTIVE: The availability of immune checkpoint inhibitors (ICIs) has expanded perioperative treatment options for urothelial carcinoma. Our aim was to evaluate the effect of neoadjuvant ICI-based regimens on oncological outcomes for patients with muscle-invasive bladder cancer (MIBC). METHODS: We systematically searched MEDLINE, Embase, Web of Science, and ClinicalTrials.gov in September 2024 for studies on neoadjuvant therapies for MIBC. A proportion meta-analysis and network meta-analysis (NMA) using random-effect models were conducted to evaluate pooled pathological complete response (pCR) rates and to compare overall survival (OS) and adverse events. The review is registered on PROSPERO (CRD42024587964). KEY FINDINGS AND LIMITATIONS: We included 12 randomized controlled trials (RCTs; 5004 patients) and 35 non-RCTs (2964 patients). ICI-chemotherapy combination therapy was associated with a significantly higher pCR rate versus chemotherapy alone (40.6% vs 17.9%; p < 0.01). In the two phase 3 RCTs included (1556 patients) there was no significant difference in OS between dose-dense methotrexate + vinblastine + Adriamycin + cisplatin (ddMVAC) and durvalumab + gemcitabine + cisplatin (GC; hazard ratio 1.06, 95% confidence interval [CI] 0.72-1.55; p = 0.8). ddMVAC significantly increased the risk of grade ≥3 anemia (risk ratio [RR] 2.81, 95% CI 1.62-4.88) and asthenia (RR 3.46, 95% CI 1.68-7.14) in comparison to GC, while durvalumab + GC did not. Limitations include data heterogeneity across studies and the limited number of studies included in the NMA. CONCLUSIONS AND CLINICAL IMPLICATIONS: ICI addition to chemotherapy in the neoadjuvant MIBC setting significantly increased pCR rates in comparison to chemotherapy alone. However, there was no difference in OS between durvalumab + GC and ddMVAC. Further studies are needed to clarify the OS benefit of ICI-based combination therapy in comparison to the current standard chemotherapy regimen.
OBJECTIVE: A considerable number of clients report adverse or unwanted effects of psychological treatments. This study aimed to synthesize the findings of qualitative studies focused on what clients perceive as negative experiences in psychotherapy. METHOD: A database search was conducted to find primary studies, and a qualitative meta-analysis was used to aggregate the findings on the kinds of negative experiences psychotherapy clients reported. RESULTS: A total of 936 statements were extracted from 51 primary studies and categorized into 21 meta-categories, some of which were further divided into subcategories. These meta-categories covered clients' experiences, which fell into four broad clusters: therapists' misbehaviour, hindering aspects of the relationship, poor treatment fit, and negative impacts of treatment. CONCLUSION: Clients' negative experiences of psychotherapy are a vast and heterogeneous area, the breadth of which is not captured by any single study. By synthesizing the findings of many primary studies, this meta-analysis represents the most comprehensive summary of these experiences to date.
- Klíčová slova
- clients’ perspective, meta-synthesis, negative experience, psychotherapy, qualitative meta-analysis,
- MeSH
- kvalitativní výzkum MeSH
- lidé MeSH
- psychoterapie * MeSH
- vztahy mezi zdravotnickým pracovníkem a pacientem * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
The sciatic nerve has varying anatomy with respect to the piriformis muscle. Understanding this variant anatomy is vital to avoiding iatrogenic nerve injuries. A comprehensive electronic database search was performed to identify articles reporting the prevalence of anatomical variations or morphometric data of the sciatic nerve. The data found was extracted and pooled into a meta-analysis. A total of 45 studies (n = 7068 lower limbs) were included in the meta-analysis on the sciatic nerve variations with respect to the piriformis muscle. The normal Type A variation, where the sciatic nerve exits the pelvis as a single entity below the piriformis muscle, was most common with a pooled prevalence of 85.2% (95%CI: 78.4-87.0). This was followed by Type B with a pooled prevalence of 9.8% (95%CI: 6.5-13.2), where the sciatic nerve bifurcated in the pelvis with the exiting common peroneal nerve piercing, and the tibial nerve coursing below the piriformis muscle. In morphometric analysis, we found that the pooled mean width of the sciatic nerve at the lower margin of the piriformis muscle was 15.55 mm. The pooled mean distance of sciatic nerve bifurcation from the popliteal fossa was 65.43 mm. The sciatic nerve deviates from its normal course of pelvic exit in almost 15% of cases. As such we recommend that a thorough assessment of sciatic nerve variants needs to be considered when performing procedures in the pelvic and gluteal regions in order to reduce the risk of iatrogenic injury. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1820-1827, 2016.
- Klíčová slova
- anatomy, meta-analysis, piriformis muscle, sciatic nerve, variations,
- MeSH
- anatomická variace MeSH
- lidé MeSH
- nervus ischiadicus anatomie a histologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- práce podpořená grantem MeSH
BACKGROUND: BRCA1 codes for a tumor suppressor protein involved in DNA repair. Based on the role of single nucleotide polymorphisms (SNPs) in the modification of gene expression and function and the existence of certain SNPs within 3-untranslated region of BRCA1 with the ability to change binding sites for mirRNAs, several association studies have been designed to explore the significance of SNPs within BRCA1 gene in conferring breast cancer (BC) risk. This study aims to assess the relationship between BRCA1 SNPs and BC using meta-analysis. AIM: To conduct a meta-analysis for retrieving case-control studies on the associations between the rs11655505, rs1799966, rs3737559, rs1799950, rs799917 and rs16941 BRCA1 polymorphisms and BC. The pooled odds ratios and its 95% confidence intervals were measured using fixed and random model to define the association between these polymorphisms and BC risk. CONCLUSION: No significant association was found for any of these polymorphisms and BC risk in the allelic, homozygote, dominant or recessive models. Overall, our study implies that the mentioned polymorphisms are not associated with BC risk. However, our study did not exclude the possible contribution of other SNPs within this gene in BC nor substantial contribution of multiple variants within this gene in conferring BC risk. Key words: BRCA1 - breast cancer - meta-analysis.
- Klíčová slova
- BRCA1 - breast cancer - meta-analysis,
- MeSH
- genetická predispozice k nemoci * MeSH
- jednonukleotidový polymorfismus MeSH
- lidé MeSH
- nádory prsu genetika MeSH
- protein BRCA1 genetika MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- systematický přehled MeSH
- Názvy látek
- BRCA1 protein, human MeSH Prohlížeč
- protein BRCA1 MeSH
Evidence from preclinical studies suggests a preventive effect of proton pump inhibitors (PPIs) in preeclampsia. Recently, several epidemiological studies have described a conflicting association between the use of PPIs during pregnancy and preeclampsia risk. This study aimed to evaluate the association between PPI use and the risk of preeclampsia. We searched databases, including MEDLINE, Embase, Scopus, Web of Science Core Collection, Emcare, CINAHL, and the relevant grey literature from inception until 13 September 2021. Studies reporting the preeclampsia risk with the use of PPIs were eligible for inclusion. Literature screening, data extraction, and the risk of bias assessment were performed independently by two investigators. Random-effect meta-analysis was performed to generate relative risks (RR) and 95% confidence intervals (CI). The risk of preeclampsia and preterm preeclampsia among women receiving PPIs during pregnancy were the primary outcomes of interest. This meta-analysis comprised three studies involving 4,877,565 pregnant women, of whom 119,017 were PPI users. The included studies were judged to have a low risk of bias. The risk of preeclampsia among pregnant women who received PPIs anytime during pregnancy was significantly increased (RR 1.27 (95% CI: 1.23-1.31)), although the increase was trivial in absolute terms (2 per 1000). The subgroup analysis revealed that the risk was increased in each of the three trimesters. The risk of preterm preeclampsia among pregnant women receiving PPIs anytime during pregnancy was not significantly increased (RR 1.04 (95% CI: 0.70-1.55)). The certainty evaluated by GRADE in these estimates was low. PPI use may be associated with a trivial increase in the risk of preeclampsia in pregnant women. There is no evidence supporting that PPI use decreases the risk of preeclampsia or preterm preeclampsia.
- Klíčová slova
- PPIs, hypertension, meta-analysis, preeclampsia, pregnancy, proton pump inhibitors,
- Publikační typ
- časopisecké články MeSH
To reduce the psycho-social burden increasing attention has focused on brain abnormalities in the most prevalent and highly co-occurring neuropsychiatric disorders, such as mood and anxiety. However, high inter-study variability in these patients results in inconsistent and contradictory alterations in the fast temporal dynamics of large-scale networks as measured by EEG microstates. Thus, in this meta-analysis, we aim to investigate the consistency of these changes to better understand possible common neuro-dynamical mechanisms of these disorders.In the systematic search, twelve studies investigating EEG microstate changes in participants with mood and anxiety disorders and individuals with subclinical depression were included in this meta-analysis, adding up to 787 participants.The results suggest that EEG microstates consistently discriminate mood and anxiety impairments from the general population in patients and subclinical states. Specifically, we found a small significant effect size for B microstates in patients compared to healthy controls, with larger effect sizes for increased B presence in unmedicated patients with comorbidity. In a subgroup meta-analysis of ten mood disorder studies, microstate D showed a significant effect size for decreased presence. When investigating only the two anxiety disorder studies, we found a significantly small effect size for the increased microstate A and a medium effect size for decreased microstate E (one study). However, more studies are needed to elucidate whether these findings are diagnostic-specific markers.Results are discussed in relation to the functional meaning of microstates and possible contribution to an explanatory mechanism of overlapping symptomatology of mood and anxiety disorders.
- Klíčová slova
- Anxiety, Bipolar Disorder, Depression, Meta-Analysis, Microstates, PTSD, Panic Disorder,
- MeSH
- elektroencefalografie * metody MeSH
- lidé MeSH
- mozek * patofyziologie MeSH
- poruchy nálady * patofyziologie MeSH
- úzkostné poruchy * patofyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
Systematic reviews are widely used in medicine as a method of decision making based on evidences. The systematic review is a method of locating and evaluation of a synthesising evidence. Meta-analysis refers to quantitative synthesis of the results of clinical trials or other primary studies. Simple introductory account about meta-analysis is given. We describe two examples of meta-analysis application and strengths and weaknesses of this research method.
