scholarly journals Influence of Methodological Variables on Fracture Strength Tests Results of Premolars with Different Number of Residual Walls. A Systematic Review with Meta-Analysis

2021 ◽  
Vol 9 (12) ◽  
pp. 146
Author(s):  
Carlo Gaeta ◽  
Crystal Marruganti ◽  
Emanuele Mignosa ◽  
Giovanni Franciosi ◽  
Edoardo Ferrari ◽  
...  
Keyword(s):  
Fracture Strength ◽  
Ex Vivo ◽  
Meta Analysis ◽  
Study Groups ◽  
Breaking Load ◽  
Outcome Variable ◽  
Strength Tests ◽  
Meta Regression ◽  
Tip Position ◽  
The Impact

The aim of the current meta-analysis was to assess the impact of methodological variables in performing fracture strength tests of upper premolars. Medline (Pubmed), Embase and Google Scholar were screened for studies performing ex vivo fracture strength tests of intact upper premolars or premolars with 0, 1 or 2 walls lost. The outcome variable for each study was the maximum breaking load expressed in Newton (kg × m/s2). Methodological variables (i.e., simulation of the periodontal ligament, load inclination, tip position, tip diameter and thermocycling) were registered to perform subgroup analyses and meta-regression. Overall, 25 studies and 78 study groups were included in the meta-analysis. Intact premolars (17 study groups) were not significantly influenced by any of the methodological variables considered. Subgroup analysis for load inclination (30°/45° vs. 90°/150°) was significant for premolars with 0 (10 study groups), 1 (6 study groups) and 2 (45 study groups) walls lost; thermocycling was significant for premolars with 1 and 2 walls lost. A strong methodological heterogeneity across studies evaluating the fracture strength of upper premolars was highlighted, especially when 0, 1 or 2 walls were lost. Further studies are needed to standardize the methodology used in order to allow for across-studies comparisons.

scholarly journals Vitamin D2 and D3 Supplementation Effect on Serum 25(OH)D Levels: A Meta-Analysis

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1782-1782
Author(s):  
Meline Chakalian ◽  
Joyce Cao ◽  
Jiang Hu ◽  
Casey Vanous ◽  
Simon Sum
Keyword(s):  
Vitamin D ◽  
Meta Analysis ◽  
Small Sample ◽  
Relative Potency ◽  
Health Concern ◽  
Outcome Variable ◽  
Vitamin D2 ◽  
Baseline Serum ◽  
Meta Regression ◽  
The Impact

Abstract Objectives Vitamin D insufficiency is a global health concern that affects nearly 50% of the population worldwide. Growing demand for vegan/vegetarian products has aroused interest in the plant-sourced D2 form for use in dietary supplements. However, vitamin D2’s ability to raise serum 25(OH)D levels in relation to D3 among existing scientific literature is inconclusive. This study sought to compare vitamin D2 to D3 in increasing serum 25(OH)D levels in order to better understand the relative potency and dosage required to address vitamin D insufficiencies. Methods PubMed and Embase databases were searched through July of 2018. Randomized controlled trials comparing D2 and D3 supplementation of equivalent dosages and the resulting increase in serum 25(OH)D levels in adults were eligible for this meta-analysis. A meta regression was conducted to compare the impact of both vitamin D forms on serum 25(OH)D levels. The outcome variable evaluated was the serum 25(OH)D levels. Results Nine RCTs (n = 628) with vitamin D dose ranging from 10 mcg per day to 1250 mcg per week, and an intervention duration from 2 to 16 weeks were eligible. Subjects included healthy adults as well as those with chronic kidney disease. There was substantial heterogeneity among the studies (I2 = 78.07%). The meta-regression showed vitamin D supplementation regardless of form was effective in raising serum 25(OH)D levels (P < 0.0001). The mean effect size expressed as the standardized mean difference (SMD) from baseline serum 25(OH)D levels was 1.16 [95% CI: 0.83, 1.49] for D2 and 1.52 [95% CI: 0.99, 2.04] for D3. While there was a trend of greater increase caused by D3 numerically, the difference between D2 and D3 was not statistically significant. When duration and frequency of supplementation were examined, similar trends of non-significant greater increases for D3 relative to D2 were observed. Conclusions This research shows both vitamin D2 and D3 supplementation can significantly increase serum 25(OH)D levels. Though the results did not reach statistical significance, there is a consistent trend of vitamin D3 offering additional effectiveness relative to D2. The high heterogeneity across studies and small sample size likely contributed to the non-significant results and limited the ability to identify a quantitative relative potency that can be used for a D2 dosage recommendation. Funding Sources None.

scholarly journals When does the use of individual patient data in network meta-analysis make a difference? A simulation study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Steve Kanters ◽  
Mohammad Ehsanul Karim ◽  
Kristian Thorlund ◽  
Aslam Anis ◽  
Nick Bansback
Keyword(s):  
Simulation Study ◽  
Treatment Effect ◽  
Mean Squared Error ◽  
Individual Patient Data ◽  
Meta Analysis ◽  
Model Performance ◽  
Patient Data ◽  
Meta Regression ◽  
Treatment Comparisons ◽  
The Impact

Abstract Background The use of individual patient data (IPD) in network meta-analyses (NMA) is rapidly growing. This study aimed to determine, through simulations, the impact of select factors on the validity and precision of NMA estimates when combining IPD and aggregate data (AgD) relative to using AgD only. Methods Three analysis strategies were compared via simulations: 1) AgD NMA without adjustments (AgD-NMA); 2) AgD NMA with meta-regression (AgD-NMA-MR); and 3) IPD-AgD NMA with meta-regression (IPD-NMA). We compared 108 parameter permutations: number of network nodes (3, 5 or 10); proportion of treatment comparisons informed by IPD (low, medium or high); equal size trials (2-armed with 200 patients per arm) or larger IPD trials (500 patients per arm); sparse or well-populated networks; and type of effect-modification (none, constant across treatment comparisons, or exchangeable). Data were generated over 200 simulations for each combination of parameters, each using linear regression with Normal distributions. To assess model performance and estimate validity, the mean squared error (MSE) and bias of treatment-effect and covariate estimates were collected. Standard errors (SE) and percentiles were used to compare estimate precision. Results Overall, IPD-NMA performed best in terms of validity and precision. The median MSE was lower in the IPD-NMA in 88 of 108 scenarios (similar results otherwise). On average, the IPD-NMA median MSE was 0.54 times the median using AgD-NMA-MR. Similarly, the SEs of the IPD-NMA treatment-effect estimates were 1/5 the size of AgD-NMA-MR SEs. The magnitude of superior validity and precision of using IPD-NMA varied across scenarios and was associated with the amount of IPD. Using IPD in small or sparse networks consistently led to improved validity and precision; however, in large/dense networks IPD tended to have negligible impact if too few IPD were included. Similar results also apply to the meta-regression coefficient estimates. Conclusions Our simulation study suggests that the use of IPD in NMA will considerably improve the validity and precision of estimates of treatment effect and regression coefficients in the most NMA IPD data-scenarios. However, IPD may not add meaningful validity and precision to NMAs of large and dense treatment networks when negligible IPD are used.

A meta-analysis of the capitalisation of CAP direct payments into land prices

2021 ◽  
Author(s):  
Alessandro Varacca ◽  
Giovanni Guastella ◽  
Stefano Pareglio ◽  
Paolo Sckokai
Keyword(s):  
Agricultural Policy ◽  
Meta Analysis ◽  
Extensive Review ◽  
The European Union ◽  
Decoupled Payments ◽  
Land Prices ◽  
Implementation Scheme ◽  
Direct Payments ◽  
Meta Regression ◽  
The Impact

Abstract The impact of the European Union common agricultural policy direct payments on land prices has received substantial attention in recent years, leading to heterogeneous evidence of capitalisation for both coupled and decoupled payments. In this paper, we provide an extensive review of the empirical works addressing this issue econometrically and compare their results through a Bayesian meta-regression model, focussing on the impact of decoupling and its implementation schemes. We find that the introduction of decoupled payments increased the capitalisation rate, although the extent of this increment hinges on the implementation scheme adopted by the member state.

scholarly journals The Use of Telehealth Technology in Assessing the Accuracy of Self-Reported Weight and the Impact of a Daily Immediate-Feedback Intervention among Obese Employees

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Nicolaas P. Pronk ◽  
A. Lauren Crain ◽  
Jeffrey J. VanWormer ◽  
Brian C. Martinson ◽  
Jackie L. Boucher ◽  
...  
Keyword(s):  
Body Weight ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Controlled Trial ◽  
Intervention Group ◽  
Study Groups ◽  
Outcome Variable ◽  
Control Group ◽  
Immediate Feedback ◽  
The Impact

Objective.To determine the accuracy of self-reported body weight prior to and following a weight loss intervention including daily self-weighing among obese employees.Methods.As part of a 6-month randomized controlled trial including a no-treatment control group, an intervention group received a series of coaching calls, daily self-weighing, and interactive telemonitoring. The primary outcome variable was the absolute discrepancy between self-reported and measured body weight at baseline and at 6 months. We used general linear mixed model regression to estimate changes and differences between study groups over time.Results.At baseline, study participants underreported their weight by an average of 2.06 (se=0.33) lbs. The intervention group self-reported a smaller absolute body weight discrepancy at followup than the control group.Conclusions.The discrepancy between self-reported and measured body weight appears to be relatively small, may be improved through daily self-monitoring using immediate-feedback telehealth technology, and negligibly impacts change in body weight.

Carbapenem Resistance, Initial Antibiotic Therapy, and Mortality inKlebsiella pneumoniaeBacteremia: A Systematic Review and Meta-Analysis

2017 ◽  
Vol 38 (11) ◽  
pp. 1319-1328 ◽  
Author(s):  
Philipp P. Kohler ◽  
Cheryl Volling ◽  
Karen Green ◽  
Elizabeth M. Uleryk ◽  
Prakesh S. Shah ◽  
...  
Keyword(s):  
Systematic Review ◽  
Antibiotic Therapy ◽  
Meta Analysis ◽  
Carbapenem Resistance ◽  
Carbapenem Resistant ◽  
Initial Antibiotic Therapy ◽  
Meta Regression ◽  
The Difference ◽  
Meta Regression Analysis ◽  
The Impact

BACKGROUNDMortality associated with infections caused by carbapenem-resistantEnterobacteriaceae(CRE) is higher than mortality due to carbapenem-sensitive pathogens.OBJECTIVETo examine the association between mortality from bacteremia caused by carbapenem-resistant (CRKP) and carbapenem-sensitiveKlebsiella pneumoniae(CSKP) and to assess the impact of appropriate initial antibiotic therapy (IAT) on mortality.DESIGNSystematic review and meta-analysisMETHODSWe searched MEDLINE, EMBASE, CINAHL, and Wiley Cochrane databases through August 31, 2016, for observational studies reporting mortality among adult patients with CRKP and CSKP bacteremia. Search terms were related toKlebsiella, carbapenem-resistance, and infection. Studies including fewer than 10 patients per group were excluded. A random-effects model and meta-regression were used to assess the relationship between carbapenem-resistance, appropriateness of IAT, and mortality.RESULTSMortality was higher in patients who had CRKP bacteremia than in patients with CSKP bacteremia (15 studies; 1,019 CRKP and 1,148 CSKP patients; unadjusted odds ratio [OR], 2.2; 95% confidence interval [CI], 1.8–2.6; I2=0). Mortality was lower in patients with appropriate IAT than in those without appropriate IAT (7 studies; 658 patients; unadjusted OR, 0.5; 95% CI, 0.3–0.8; I2=36%). CRKP patients (11 studies; 1,326 patients; 8-year period) were consistently less likely to receive appropriate IAT (unadjusted OR, 0.5; 95% CI, 0.3–0.7; I2=43%). Our meta-regression analysis identified a significant association between the difference in appropriate IAT and mortality (OR per 10% difference in IAT, 1.3; 95% CI, 1.0–1.6).CONCLUSIONSAppropriateness of IAT is an important contributor to the observed difference in mortality between patients with CRKP bacteremia and patients with CSKP bacteremia.Infect Control Hosp Epidemiol2017;38:1319–1328

scholarly journals Infrastructure and Trade: A Meta-Analysis

REGION ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 25 ◽  
Author(s):  
Guney Celbis ◽  
Peter Nijkamp ◽  
Jacques Poot
Keyword(s):  
Regression Models ◽  
Meta Analysis ◽  
Public Infrastructure ◽  
Transport Costs ◽  
Panel Data Estimation ◽  
Regression Techniques ◽  
Meta Regression ◽  
Low Levels ◽  
The Impact ◽  
Data Estimation

Low levels of infrastructure quality and quantity can create trade impediments through increased transport costs. Since the late 1990s an increasing number of trade studies have taken infrastructure into account. The purpose of the present paper is to quantify the importance of infrastructure for trade by means of meta-analysis and meta-regression techniques that synthesize various studies. The type of infrastructure that we focus on is mainly public infrastructure in transportation and communication. We examine the impact of infrastructure on trade by means of estimates obtained from 36 primary studies that yielded 542 infrastructure elasticities of trade. We explicitly take into account that infrastructure can be measured in various ways and that its impact depends on the location of the infrastructure. We estimate several meta-regression models that control for observed heterogeneity in terms of variation across different methodologies, infrastructure types, geographical areas and their economic features, model specifications, and publication characteristics. Additionally, random effects account for between-study unspecified heterogeneity, while publication bias is explicitly addressed by means of the Hedges model.  After controlling for all these issues we find that a 1 percent increase in own infrastructure increases exports by about 0.6 percent and imports by about 0.3 percent. Such elasticities are generally larger for developing countries, land infrastructure, IV or panel data estimation, and macro-level analyses. They also depend on the inclusion or exclusion of various common covariates in trade regressions.

scholarly journals ART initiations following community-based distribution of HIV self-tests: meta-analysis and meta-regression of STAR Initiative data

2021 ◽  
Vol 6 (Suppl 4) ◽  
pp. e004986
Author(s):  
Melissa Neuman ◽  
Katherine L Fielding ◽  
Helen Ayles ◽  
Frances M Cowan ◽  
Bernadette Hensen ◽  
...  
Keyword(s):  
Meta Analysis ◽  
National Level ◽  
Population Level ◽  
Hiv Care ◽  
People Living With Hiv ◽  
Community Based ◽  
Variable Effect ◽  
Standard Testing ◽  
Meta Regression ◽  
The Impact

IntroductionMeasuring linkage after community-based testing, particularly HIV self-testing (HIVST), is challenging. Here, we use data from studies of community-based HIVST distribution, conducted within the STAR Initiative, to assess initiation of antiretroviral therapy (ART) and factors driving differences in linkage rates.MethodsFive STAR studies evaluated HIVST implementation in Malawi, Zambia and Zimbabwe. New ART initiations during the months of intervention at clinics in HIVST and comparison areas were presented graphically, and study effects combined using meta-analysis. Meta-regression was used to estimate associations between the impact of community-based HIVST distribution and indicators of implementation context, intensity and reach. Effect size estimates used (1) prespecified trial definitions of ART timing and comparator facilities and (2) exploratory definitions accounting for unexpected diffusion of HIVST into comparison areas and periods with less distribution of HIVST than was expected.ResultsCompared with arms with standard testing only, ART initiations were higher in clinics in HIVST distribution areas in 4/5 studies. The prespecified meta-analysis found positive but variable effects of HIVST on facility ART initiations (RR: 1.14, 95% CI 0.93 to 1.40; p=0.21). The exploratory meta-analysis found a stronger impact of HIVST distribution on ART initiations (RR: 1.29, 95% CI 1.08 to 1.55, p=0.02).ART initiations were higher in studies with greater self-reported population-level intensity of HIVST use (RR: 1.12; 95% CI 1.04 to 1.21; p=0.02.), but did not differ by national-level indicators of ART use among people living with HIV, number of HIVST kits distributed per 1000 population, or self-reported knowledge of how to link to care after a reactive HIVST.ConclusionCommunity-based HIVST distribution has variable effect on ART initiations compared with standard testing service alone. Optimising both support for and approach to measurement of effective and timely linkage or relinkage to HIV care and prevention following HIVST is needed to maximise impact and guide implementation strategies.

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