392,304 papers found

INTRODUCTION: Perforated peptic ulcers are a life-threatening complication associated with high morbidity and mortality. Several treatment approaches are available. The aim of this network meta-analysis (NMA) is to compare surgical and alternative approaches for the treatment of perforated peptic ulcers regarding morta…

During drug development, evidence can emerge to suggest a treatment is more effective in a specific patient subgroup. Whilst early trials may be conducted in biomarker-mixed populations, later trials are more likely to enroll biomarker-positive patients alone, thus leading to trials of the same treatment investigated i…

There is a rapid increase in trials assessing healthcare interventions consisting of a combination of drugs (polytherapies) or multiple components. In the latter type of interventions (also known as complex interventions), the aspect of complexity is of paramount importance. For example, nonpharmacological intervention…

Network meta-analysis is a commonly used tool to combine direct and indirect evidence in systematic reviews of multiple treatments to improve estimation compared to traditional pairwise meta-analysis. Unlike the contrast-based network meta-analysis approach, which focuses on estimating relative effects such as odds rat…

OBJECTIVE: The objective of the study is to examine the analytic approach of meta-analyses that include noninferiority or equivalence (NI/EQ) trials. STUDY DESIGN AND SETTING: We used Scopus to identify meta-analyses including NI/EQ trials. We extracted data from the meta-analyses and their included randomized clinica…

In random-effects meta-analysis the between-study variance ( τ) has a key role in assessing heterogeneity of study-level estimates and combining them to estimate an overall effect. For odds ratios the most common methods suffer from bias in estimating τand the overall effect and produce confidence intervals…

INTRODUCTION: The optimal dose-fractionation schedule of palliative radiotherapy has been debated in patients with bone metastases. Our objective is to comprehensively compare multiple fraction schedules with single fraction radiotherapy in terms of efficacy and toxicities by performing a systematic review and network…

INTRODUCTION: Inguinal hernia mesh repair is the standard care for symptomatic inguinal hernia. Mesh fixation is used to keep mesh in place for which various mesh fixation techniques have been used in open and laparoscopic inguinal hernia repair, but their effectiveness has remained inconclusive. Therefore, we develope…

Meta-analyses of clinical trials targeting rare events face particular challenges when the data lack adequate numbers of events for all treatment arms. Especially when the number of studies is low, standard random-effects meta-analysis methods can lead to serious distortions because of such data sparsity. To overcome t…

INTRODUCTION: Mild cognitive impairment (MCI) often represents the earliest stage of Alzheimer's disease. There has been considerable research investigating specific risk factors regarding the progression from normal cognition to MCI. However, different studies have come to different conclusions on the impact of partic…

Missing data result in less precise and possibly biased effect estimates in single studies. Bias arising from studies with incomplete outcome data is naturally propagated in a meta-analysis. Conventional analysis using only individuals with available data is adequate when the meta-analyst can be confident that the data…

Network meta-analysis (NMA) uses both direct and indirect evidence to compare the efficacy and harm between several treatments. Structural equation modeling (SEM) is a statistical method that investigates relations among observed and latent variables. Previous studies have shown that the contrast-based Lu-Ades model fo…

OBJECTIVES: We aimed to develop and evaluate an algorithm for automatically screening citations when updating living network meta-analysis (NMA). STUDY DESIGN AND SETTING: Our algorithm learns from the initial screening of citations conducted when creating an NMA to automatically identify eligible citations (i.e., nee…

The use of data from multiple studies or centers for the validation of a clinical test or a multivariable prediction model allows researchers to investigate the test's/model's performance in multiple settings and populations. Recently, meta-analytic techniques have been proposed to summarize discrimination and calibrat…

INTRODUCTION: Gliomas, the most commonly diagnosed primary brain tumours, are associated with varied survivals based, in part, on their histological subtype. Therefore, accurate pretreatment tumour grading is essential for patient care and clinical trial design. METHODS AND ANALYSIS: We will perform an individual-leve…

Network meta-analysis (NMA) is gaining popularity for comparing multiple treatments in a single analysis. Generalized linear mixed models provide a unifying framework for NMA, allow us to analyze datasets with dichotomous, continuous or count endpoints, and take into account multiarm trials, potential heterogeneity bet…

Percentage study weights in meta-analysis reveal the contribution of each study toward the overall summary results and are especially important when some studies are considered outliers or at high risk of bias. In meta-analyses of test accuracy reviews, such as a bivariate meta-analysis of sensitivity and specificity,…

Network meta-analysis (NMA) combines direct and indirect evidence from trials to calculate and rank treatment estimates. While modelling approaches for continuous and binary outcomes are relatively well developed, less work has been done with time-to-event outcomes. Such outcomes are usually analysed using Cox proporti…

BACKGROUND: Many reviews aim to compare numerous treatments and report results stratified by subgroups (eg, by disease severity). In such cases, a network meta-analysis model including treatment by covariate interactions can estimate the relative effects of all treatment pairings for each subgroup of patients. Two key…

An important question for clinicians appraising a meta-analysis is: are the findings likely to be valid in their own practice-does the reported effect accurately represent the effect that would occur in their own clinical population? To this end we advance the concept of statistical validity-where the parameter being e…