Effect Sizes Of Individual Studies Research Articles

P261 Clinical outcomes of high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) and electroconvulsive therapy (ECT) in the treatment of major depression. An overview of findings from meta-analyses

Background Meta-analyses comparing the short-term clinical outcomes of high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) and electroconvulsive therapy (ECT) in major depression produced conflicting results. The aim of the current study was to summarise the results of these meta-analyses. Methods A systematic literature search of PubMed and PsycInfo (any time – 13.01.2016) identified k = 4 systematic reviews (published in 2010–2014) comparing the clinical outcomes of ECT and HF-rTMS in major depression using quantitative meta-analysis. The short-term outcomes were the standardised mean change scores (baseline – last stimulation) on depression scales and odds or risk ratios of response, remission, and acceptability (dropout) rates. Since different meta-analytical approaches were used, we have pooled the effects using random-effects model with inverse-variance weights based on data shown in reviews. Results The k = 4 reviews included different combinations of k = 8 open-label or single-blind, randomised primary studies with major depression patients. Most studies utilised right unilateral ECT (2.5 times the seizure threshold, 6–12 sessions) and HF-rTMS (10–20 Hz) of the left dorsolateral prefrontal cortex (90–110% of the resting motor threshold, 10–20 sessions). The pooled weighted effects favoured ECT over HF-rTMS in terms of reduction in depression severity (change scores in k = 2 reviews), while response and acceptability rates of both methods were similar (in k = 2 and k = 3 reviews respectively), and remission rates were inconsistent in k = 3 reviews (possibly due to heterogeneous definitions of remission). The individual study effect sizes favoured ECT over HF-rTMS in terms of reduction in depression severity and remission rate in studies with psychotic major depression patients. Conclusion Uniform meta-analytical approaches suggest that ECT might be clinically superior to HF-rTMS in psychotic major depression, while the clinical outcomes tend to be similar in non-psychotic major depression in the short-term treatment. Future blinded randomised trials are required to compare the long-term clinical outcomes of both methods in clinically-homogeneous samples with major depression.

Effects of low-level laser therapy on pain in patients with musculoskeletal disorders: a systematic review and meta-analysis.

This meta-analysis investigated the effectiveness of low-level laser therapy (LLLT) on pain in adult patients with musculoskeletal disorders. A systematic literature search was conducted in the Medline and PEDro databases. Two researchers independently screened titles and abstracts of the retrieved studies for eligibility. Quality assessment of the eligible studies was conducted using the PEDro rating scale. Studies that scored ≥4 were included. A random-effects model was used for this meta-analysis. Subgroup meta-analyses were conducted to evaluate the influence of the adherence of the applied LLLT to the World Association of Laser Therapy (WALT) guidelines, the anatomical site under investigation and the study design on the overall weighted mean effect size. Meta regression was used to assess the possible influence of the study quality on the individual study effect sizes. Eighteen studies allowing for 21 head-to-head comparisons (totaling N.=1462 participants) were included. The pooled raw mean difference (D) in pain between LLLT and the control groups was -0.85 (95% CI: -1.22 to -0.48). There was high (I²=85.6%) and significant between study heterogeneity (Cochran's Q =139.2; df=20; P<0.001). The subgroup meta-analysis of the comparisons not following the WALT guidelines revealed a D=-0.68 (95% CI: -1.09 to -0.27). In this group, heterogeneity decreased to I²=72.6% (Q=51.2; df=14; P<0.001). In the WALT subgroup D equaled -1.52 (95% CI: -2.34 to -0.70). This between groups difference was clinically relevant although statistically not significant (Q=3.24; df=1; P=0.072). This meta-analysis presents evidence that LLLT is an effective treatment modality to reduce pain in adult patients with musculoskeletal disorders. Adherence to WALT dosage recommendations seems to enhance treatment effectiveness.

The effect of polymer burs on microbiological reduction of carious dentin in deciduous teeth: a systematic review

Background. Polymer bur is a new technology that proposes to conserve the dentin that is capable of remineralization. Aim: To conduct a quantitative systematic review to evaluate the effect of polymer burs on the reduction of Streptococcus mutans and Lactobacillus after dentin carious excavation in deciduous teeth. Methods and Material: Two reviewers performed the database to identify the relevant clinical papers. Only papers in English that compared polymer burs with other caries removal techniques with the microbiological aspects as an outcome were included. Papers that evaluated only permanent teeth were excluded. Risk of bias was also assessed. Individual study effect sizes were calculated using Cohen’s d formula for the comparisons of microorganism reduction before and after carious excavation. Results: The search resulted in 12 non-duplicated papers. After the revision, only 2 were selected. The quantitative evaluation demonstrated that polymer bur reduces microorganism levels in carious dentin. The larger effect size observed was for Streptococcus mutans in the polymer bur technique (r=0.84; d=3.12), followed by Lactobacillus in the carbide bur technique (r=0.83; d=3.03). Conclusion: Polymer burs promoted a significant reduction of microorganism levels, mainly Streptococcus mutans in carious dentin.

Increased levels of vascular endothelial growth factor in patients with major depressive disorder: A meta-analysis

The regulation of neurotrophic factors plays an important role in the pathophysiology of major depressive disorder (MDD). Vascular endothelial growth factor (VEGF) has been shown to promote neurogenesis, neuroprotection, and influence synaptic transmission. Many studies have examined the VEGF levels in patients with depression, however the results have been inconsistent. In the current meta-analysis, we compared blood VEGF levels between MDD patients and control subjects (16 articles including 872 patients and 882 control subjects). The effect sizes of individual studies were synthesized using a random effect model. We found that the blood VEGF levels in the patients with MDD were significantly higher than those in the healthy controls (p<0.001), and the difference was negatively correlated with mean age (p=0.01). Other variables including proportion of female subjects, body mass index, severity of depression, duration of illness, and age at onset were not significantly correlated with the difference. Our results highlight that elevated blood VEGF levels may be a disease marker in patients with MDD. Further studies are needed to examine the relationship between VEGF levels in central and peripheral environments, and clarify the role of VEGF in the pathophysiology of MDD.

Increasing Physical Activity With Mobile Devices: A Meta-Analysis

BackgroundRegular physical activity has established physical and mental health benefits; however, merely one quarter of the U.S. adult population meets national physical activity recommendations. In an effort to engage individuals who do not meet these guidelines, researchers have utilized popular emerging technologies, including mobile devices (ie, personal digital assistants [PDAs], mobile phones). This study is the first to synthesize current research focused on the use of mobile devices for increasing physical activity.ObjectiveTo conduct a meta-analysis of research utilizing mobile devices to influence physical activity behavior. The aims of this review were to: (1) examine the efficacy of mobile devices in the physical activity setting, (2) explore and discuss implementation of device features across studies, and (3) make recommendations for future intervention development.MethodsWe searched electronic databases (PubMed, PsychINFO, SCOPUS) and identified publications through reference lists and requests to experts in the field of mobile health. Studies were included that provided original data and aimed to influence physical activity through dissemination or collection of intervention materials with a mobile device. Data were extracted to calculate effect sizes for individual studies, as were study descriptives. A random effects meta-analysis was conducted using the Comprehensive Meta-Analysis software suite. Study quality was assessed using the quality of execution portion of the Guide to Community Preventative Services data extraction form.ResultsFour studies were of “good” quality and seven of “fair” quality. In total, 1351 individuals participated in 11 unique studies from which 18 effects were extracted and synthesized, yielding an overall weight mean effect size of g = 0.54 (95% CI = 0.17 to 0.91, P = .01).ConclusionsResearch utilizing mobile devices is gaining in popularity, and this study suggests that this platform is an effective means for influencing physical activity behavior. Our focus must be on the best possible use of these tools to measure and understand behavior. Therefore, theoretically grounded behavior change interventions that recognize and act on the potential of smartphone technology could provide investigators with an effective tool for increasing physical activity.

Four decades of research on the effects of detracking reform: Where do we stand?—A systematic review of the evidence

To review and synthesize evidence about academic and non-academic effects of detracking reform. Fifteen studies conducted from 1972 to 2006 were located and reviewed, including 4 experimental studies, 2 quasi-experimental studies, 7 observational studies, and 2 qualitative studies. Meta-analyses using fixed effects and random effects models were conducted for all and subsets of selected studies (by the academic ability of students and research design), followed by extensive discussion of individual studies. Generally speaking, students in detracked groups performed slightly better academically than their equivalent-ability peers in tracked groups (d = 0.087, k = 22, N = 15,577, p < 0.0001), using a fixed effects model. A random effects model also indicated the overall positive effects of detracking (d = 0.202, k = 22, N = 15,577, p < 0.01). However, the effect sizes of individual studies are generally heterogeneous with I(2)(21) = 94.033. Using a random effects model, the study shows that average or high ability students in detracked groups performed no differently than their equivalent-ability peers in tracked groups with a 95% confidence interval of (-0.047, 0.388). For low-achieving students, both the fixed effects model [d = 0.113, k = 8, p < 0.0001, 95% CI (0.056, 0.169)] and random effects model [d = 0.283, k = 8, p < 0.005, 95% CI (0.087, 0.479)] revealed positive effects of detracking on student achievement for the 8 low-ability subgroups in 6 studies. The evidence with respect to the non-academic impact of detracking is mixed. The findings suggest that the detracking reform had appreciable effects on low-ability student achievement and no effects on average and high-ability student achievement. Therefore, detracking should be encouraged, especially in schools where the lower-track classes have been traditionally assigned fewer resources.

WITHDRAWN: Dieting to reduce body weight for controlling hypertension in adults.

As early as the 1920's, researchers noted a relationship between caloric restriction, weight loss and a decreased incidence of hypertension (Terry 1922, Preble 1923, Bauman 1928, Master 1929). In 1988 a meta-analysis of aggregate data from 12 prospective studies, including 5 randomized controlled trials (RCTs), found that on average each 1 kilogram decrease in body weight in obese hypertensive patients was associated with a 2.4 mm Hg systolic and 1.5 mm Hg diastolic decrease in blood pressure (Staessen 1988). Blood pressure reductions were not dependent upon degree of baseline obesity.This review aims to: 1) update the work of Staessen (Staessen 1988) looking specifically at randomized controlled trials, and 2) assess whether any of the trials assess effects of weight-reducing diets on clinical outcomes such as quality of life, morbidity or mortality. Evaluate whether weight-loss diets are more effective than regular diets or other antihypertensive therapies in controlling blood pressure and preventing morbidity and mortality in hypertensive adults. MEDLINE and The Cochrane Library were searched through November 1997. Trials known to experts in the field were included through June 1998. For inclusion in the review, trials were required to meet each of the following criteria: 1) randomized controlled trials with one group assigned to a weight-loss diet and the other group assigned to either normal diet or antihypertensive therapy; 2) ambulatory adults with a mean blood pressure of at least 140 mm Hg systolic and/or 90 mm Hg diastolic; 3) active intervention consisting of a calorie-restricted diet intended to produce weight loss (excluded studies simultaneously implementing multiple lifestyle interventions where the effects of weight loss could not be disaggregated); and 4) outcome measures included weight loss and blood pressure. Studies were dual abstracted by two independent reviewers using a standardized form designed specifically for this review. The primary mode of analysis was qualitative; graphs of effect sizes for individual studies were also used. Eighteen trials were found. Only one small study of inadequate power reported morbidity and mortality outcomes. None addressed quality of life or general well being issues. In general, participants assigned to weight-reduction groups lost weight compared to control groups.Six trials involving 361 participants assessed a weight-reducing diet versus a normal diet. The data suggested weight loss in the range of 4% to 8% of body weight was associated with a decrease in blood pressure in the range of 3 mm Hg systolic and diastolic. Three trials involving 363 participants assessed a weight-reducing diet versus treatment with antihypertensive medications. These suggested that a stepped-care approach with antihypertensive medications produced greater decreases in blood pressure (in the range of 6/5 mm Hg systolic/diastolic) than did a weight-loss diet. Trials that allowed adjustment of participants' antihypertensive regimens suggested that patients required less intensive antihypertensive drug therapy if they followed a weight-reducing diet. Data was insufficient to determine the relative efficacy of weight-reduction versus changes in sodium or potassium intake or exercise. Weight-reducing diets in overweight hypertensive persons can affect modest weight loss in the range of 3-9% of body weight and are probably associated with modest blood pressure decreases of roughly 3 mm Hg systolic and diastolic. Weight-reducing diets may decrease dosage requirements of persons taking antihypertensive medications.

Sole searching—wasting our time?

Sole searching—wasting our time?

An update of a systematic review of controlled clinical trials on the primary prevention of back pain at the workplace.

To update the evidence on the effectiveness of lumbar supports, education and exercise in the primary prevention of low back pain at the workplace. A computerized search for controlled clinical trials published between 1997 and 2002 was conducted, and the methodological quality of the studies was assessed using a criteria list. The available evidence was graded with a rating system for the level of evidence. Effect sizes of individual studies were combined if the studies were sufficiently similar. Five new papers were identified for the update. These trials were added to the previously available trials (n = 11). The methodological quality of most studies was low. Since three of four RCTs on lumbar supports reported no effect, there is no evidence for the effectiveness of lumbar supports. No evidence for education could be found either, since all six RCTs showed negative results. The four RCTs on exercise consistently reported a positive effect, indicating limited evidence for the effectiveness of exercise. There is no evidence for the effectiveness of lumbar supports or education in the primary prevention of low back pain at the workplace. There is limited evidence for the efficacy of exercise, and the effect that can be obtained is moderate. There is still a need for methodologically sound studies and studies on the cost-effectiveness of exercise. Also the possible effect of lumbar supports in the treatment of back pain needs further investigation.

History of depression and smoking cessation outcome: a meta-analysis.

The authors conducted a meta-analysis of published studies to (a) evaluate the premise that a history of major depression is associated with failure to quit smoking and (b) identify factors that moderate the relationship between history of depression and cessation outcome. Fifteen studies met the selection requirements and were coded for various study methodology and treatment characteristics. DSTAT was used to calculate individual study effect sizes, determine the mean effect size across studies, and test for moderator effects. No differences in either short-term (< or = 3 months) or long-term abstinence rates (> or = 6 months) were observed between smokers positive versus negative for history of depression. Lifetime history of major depression does not appear to be an independent risk factor for cessation failure in smoking cessation treatment.

Dieting to reduce body weight for controlling hypertension in adults.

Evaluate whether weight-loss diets are more effective than regular diets or other antihypertensive therapies in controlling blood pressure and preventing morbidity and mortality in hypertensive adults. MEDLINE and The Cochrane Library were searched through November 1997. Trials known to experts in the field were included through June 1998. For inclusion in the review, trials were required to meet each of the following criteria: 1) randomized controlled trials with one group assigned to a weight-loss diet and the other group assigned to either normal diet or antihypertensive therapy; 2) ambulatory adults with a mean blood pressure of at least 140 mm Hg systolic and/or 90 mm Hg diastolic; 3) active intervention consisting of a calorie-restricted diet intended to produce weight loss (excluded studies simultaneously implementing multiple lifestyle interventions where the effects of weight loss could not be disaggregated); and 4) outcome measures included weight loss and blood pressure. Studies were dual abstracted by two independent reviewers using a standardized form designed specifically for this review. The primary mode of analysis was qualitative; graphs of effect sizes for individual studies were also used. Eighteen trials were found. Only one small study of inadequate power reported morbidity and mortality outcomes. None addressed quality of life or general well being issues. In general, participants assigned to weight-reduction groups lost weight compared to control groups. Six trials involving 361 participants assessed a weight-reducing diet versus a normal diet. The data suggested weight loss in the range of 4% to 8% of body weight was associated with a decrease in blood pressure in the range of 3 mm Hg systolic and diastolic. Three trials involving 363 participants assessed a weight-reducing diet versus treatment with antihypertensive medications. These suggested that a stepped-care approach with antihypertensive medications produced greater decreases in blood pressure (in the range of 6/5 mm Hg systolic/diastolic) than did a weight-loss diet. Trials that allowed adjustment of participants' antihypertensive regimens suggested that patients required less intensive antihypertensive drug therapy if they followed a weight-reducing diet. Data was insufficient to determine the relative efficacy of weight-reduction versus changes in sodium or potassium intake or exercise. Weight-reducing diets in overweight hypertensive persons can affect modest weight loss in the range of 3-9% of body weight and are probably associated with modest blood pressure decreases of roughly 3 mm Hg systolic and diastolic. Weight-reducing diets may decrease dosage requirements of persons taking antihypertensive medications.

A systematic review of controlled clinical trials on the prevention of back pain in industry.

OBJECTIVE: To assess the effectiveness of lumbar supports, education, and exercise in the prevention of back pain in industry. METHODS: A computerised search for controlled clinical trials was conducted. A...

Empirical Bayes Meta-Analysis

As interest in quantitative research synthesis grows, investigators increasingly seek to use information about study features—study contexts, designs, treatments, and subjects—to account for variation in study outcomes. To facilitate analysis of diverse study findings, a mixed linear model with fixed and random effects is presented and illustrated with data from teacher expectancy experiments. This strategy enables the analyst to (a) estimate the variance of the effect size parameters by means of maximum likelihood; (b) pose a series of linear models to explain the effect parameter variance; (c) use information about study characteristics to derive improved empirical Bayes estimates of individual study effect sizes; and (d) examine the sensitivity of all substantive inferences to likely errors in the estimation of variance components.