Conducting Meta-Analyses in<i>R</i>with the<b>metafor</b>Package

Viechtbauer, Wolfgang

doi:10.18637/jss.v036.i03

Cited by 14,356 publications

(12,051 citation statements)

References 79 publications

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“…Subgroup analyses also were performed by sex for bone mineral content outcomes, but the number of studies providing sex-specific data for bone area and aBMD were too small to test for sex-specific effects. All meta-analyses were performed using the metafor Package from R Statistical Computing [46,53].…”

Section: Resultsmentioning

confidence: 99%

Does Exercise Influence Pediatric Bone? A Systematic Review

Specker

Thiex

Sudhagoni

2015

Clinical Orthopaedics &Amp; Related Research

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Background Periods of growth are thought to be the best time to increase bone mineral content, bone area, and areal bone mineral density (aBMD) through increased loading owing to high rates of bone modeling and remodeling. However, questions remain regarding whether a benefit of exercise is seen at all bone sites, is dependent on pubertal status or sex of the child, or whether other factors such as diet modify the response to exercise. Questions/purposes We asked: (1) Does bone-loading exercise in childhood consistently increase bone mineral content, bone area, or aBMD? (2) Do effects of exercise differ depending on pubertal status or sex? (3) Does calcium intake modify the bone response to exercise? Methods A literature search identified 22 unique trials for inclusion in this meta-analysis of the effect of exercise on bone changes by bone site, pubertal status, and sex. Sample sizes ranged from 16 to 410 subjects 3 to 18 years old with length of intervention ranging from 3 to 36 months. Fifteen of 22 trials were randomized (child randomized in nine, classroom/school randomized in six) and seven were observational trials. Ten trials were Level 2 and 11 were Level 3 based on the Oxford Centre for Evidence-Based Medicine criteria. Random effects models tested the difference (intervention mean effect-control mean effect) in percent change in bone mineral content, bone area, and aBMD. Meta-regression was used to identify sources of heterogeneity and funnel plots were used to assess publication bias. Results Children assigned to exercise had greater mean percent changes in bone mineral content and aBMD than children assigned to the control groups. Mean differences (95% CI) in bone mineral content percent change between intervention and control groups at total body (0.8; 95% CI, 0.3-1.3; p = 0.003), femoral neck (1.5; 95% CI, 0.5-2.5; p = 0.003), and spine (1.7; 95% CI, 0.4-3.1; p = 0.01) were significant with no differences in bone area (all p [ 0.05). There were greater percent changes in aBMD in intervention than control groups at the femoral neck (0.6; 95% CI, 0.2-1.1; p = 0.006) and spine (1.2; 95% CI, 0.6-1.8; p \ 0.001). Benefit of exercise was limited to children who were prepubertal (bone mineral content: total body [0.9; 95% CI, 0.2-1.7; p = 0.01], femoral neck [1.8; 95% CI, 0.0-3.5; p = 0.047], spine [3.7; 95% CI, 0.8-6.6; p = 0.01], and aBMD: femoral neck [0.6; 95% CI, À0.1-1.2; p = 0.07], spine [1.5; 95% CI, 0.7-2.3; p \ 0.001]), with no differences among children who were pubertal (all p [ 0.05). Changes in aBMD did not differ by sex (all p [ 0.05), although the number of studies providing malespecific results was small (six of 22 eligible studies included boys). There was significant heterogeneity in bone

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Section: Resultsmentioning

confidence: 99%

Does Exercise Influence Pediatric Bone? A Systematic Review

Specker

Thiex

Sudhagoni

2015

Clinical Orthopaedics &Amp; Related Research

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“…A meta-analysis was conducted over these effect sizes using the rma function in the R package metaphor (Viechtbauer, 2010). We metaanalyzed the estimates across sites by weighting Fisher's r-to-z transformed effect size values by sample size in a random-effects model using the default restricted maximum-likelihood (REML) estimator.…”

Section: Meta-analysesmentioning

confidence: 99%

Prefrontal cortical thinning links to negative symptoms in schizophrenia via the ENIGMA consortium

et al. 2017

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Background. Our understanding of the complex relationship between schizophrenia symptomatology and etiological factors can be improved by studying brain-based correlates of schizophrenia. Research showed that impairments in value processing and executive functioning, which have been associated with prefrontal brain areas [particularly the medial orbitofrontal cortex (MOFC)], are linked to negative symptoms. Here we tested the hypothesis that MOFC thickness is associated with negative symptom severity. Results. Meta-analytical results showed that left, but not right, MOFC thickness was significantly associated with negative symptom severity (β std = −0.075; p = 0.019) after accounting for age, gender, and site. This effect remained significant (p = 0.036) in a model including overall illness severity. Covarying for duration of illness, age of onset, antipsychotic medication or handedness weakened the association of negative symptoms with left MOFC thickness. As part of a secondary analysis including 10 other prefrontal regions further associations in the left lateral orbitofrontal gyrus and pars opercularis emerged.Conclusions. Using an unusually large cohort and a meta-analytical approach, our findings point towards a link between prefrontal thinning and negative symptom severity in schizophrenia. This finding provides further insight into the relationship between structural brain abnormalities and negative symptoms in schizophrenia.

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“…For the statistical analysis, we used R statistical software for Windows [16] and the package 'metaphor' [17]. We classified the studies into two groups: The first group consisted of studies for which outcome was assessed at pre-specified time points (e.g., 3 days after randomization); in the second group, outcome was assessed at different days during a specific time frame (e.g., 7 to 12 days after randomization).…”

Section: Resultsmentioning

confidence: 99%

Antibiotic efficacy in patients with a moderate probability of acute rhinosinusitis: a systematic review

Burgstaller

Steurer

Holzmann

et al. 2015

Eur Arch Otorhinolaryngol

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The aim of this systematic review was to synthesize the results of original studies assessing antibiotic efficacy at different time points after initiating treatment in patients with a moderate probability of acute bacterial rhinosinusitis. We searched the Cochrane library for systematic reviews on the efficacy of antibiotic treatment in patients with acute rhinosinusitis (ARS). Only randomized controlled trials (RCTs) that compared treatment of any antibiotic with placebo were included. The synthesis of the results of six RCTs showed a benefit of antibiotic treatment compared to placebo for the rate of improvement after 3 [pooled odds ratio (OR) 2.78 (95 % confidence interval (CI) 1.39-5.58)] and 7 [OR 2.29 (95 % CI 1.19-4.41)] days after initiation in patients with symptoms and signs of ARS lasting for 7 or more days. After 10 days [pooled OR 1.36 (95 % CI 0.66-2.90)], improvement rates did not differ significantly between patients treated with or without antibiotics. Compared to placebo, antibiotic treatment relieves symptoms in a significantly higher proportion of patients within the first days of treatment. Reporting an overall average treatment efficacy may underestimate treatment benefits in patients with a self-limiting illness.

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Conducting Meta-Analyses inRwith themetaforPackage

Cited by 14,356 publications

References 79 publications

Does Exercise Influence Pediatric Bone? A Systematic Review

Does Exercise Influence Pediatric Bone? A Systematic Review

Prefrontal cortical thinning links to negative symptoms in schizophrenia via the ENIGMA consortium

Antibiotic efficacy in patients with a moderate probability of acute rhinosinusitis: a systematic review

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