Peer effects in weight-related behaviours of young people: A systematic literature review

Individual preferences and beliefs are perpetually shaped by environmental influences, with peers playing a key role in this dynamic process. Compelling evidence from qualitative and quantitative studies has highlighted the significant impact of peer influence on health-related decisions. This systematic literature review critically synthesises findings from 45 studies published between 2011 and 2022, providing a comprehensive understanding of the nature of peer effects on dietary, physical activity and sleep behaviours during youth. The majority of studies indicated that social norms drive directional changes in eating and physical activity. Yet, our analysis revealed a notable gap in exploring alternative mechanisms, including social comparison and social identity, despite their potential relevance. Studies, generally classified as moderate to high quality, predominantly relied on self-reported data, potentially affecting the validity and reliability of measures. Meta-regression analyses suggest a small, but significant association of sample size with the magnitude, sign and significance of the reported peer effects. Moreover, studies focusing on physical activity are more likely to report significant outcomes, whereas findings on peer influence on sleep-related studies tend to reveal less pronounced effects, compared to studies on dietary behaviours. Experimental designs do not appear to increase the likelihood of finding significant effects when compared to other study designs. In conclusion, this synthesis emphasises the need for further research into the underlying mechanisms on peer effects to better inform policy-makers in designing effective policies for improving weight-related behaviours in young people.

Prevalence Ratio of Primary Angle-Closure and Primary Open-Angle Glaucoma in Asian Population: A Meta-Analysis and Multiple Meta-Regression Analysis

PURPOSE

To investigate the prevalence ratio of primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG) in the Asian population.

METHODS

Systematic searches of PubMed, Embase, and Cochrane databases for population-based studies in Asia published until August 5, 2022. We conducted a meta-analysis for PACG to POAG prevalence ratio using inverse variance-weighted random-effects meta-analyses so as to combine the study-specific measures of association. Between-study outcome variation (i.e., heterogeneity) was quantified with the I2 statistic. The multiple meta-regression analyses were performed in order to further account for the reasons for heterogeneity.

RESULTS

Twenty studies, with a total study population of 52,522 individuals, had been conducted in 13 countries. The pooled PACG to POAG prevalence ratio was 2.204 (95% confidence interval, 1.617-3.004) with high heterogeneity (p < 0.001). In multiple meta-regression model, prevalence of POAG is the most important predictor for heterogeneity (model importance, 0.954), followed continent (0.508), and publication year (0.222). For every additional elevation of POAG prevalence (i.e., increase of 1.0%), the PACG to POAG prevalence ratio is expected to rise by 0.471.

CONCLUSIONS

We estimated the pooled PACG to POAG prevalence ratio in the Asian population. The POAG prevalence is the most important factor to determine the PACG to POAG prevalence ratio.

Effects of urbanisation on PM2.5 concentrations: A systematic review and meta-analysis

While urbanisation greatly improves a population's quality of life, it also has significant effects on urban air pollution. Previous studies have determined how urbanisation affects PM2.5 concentrations; the findings, however, have not been consistent. This study conducts a meta-analysis to systematically organise existing research and draw more conclusive and broadly applicable results regarding the impact of different factors of urbanisation on PM2.5 concentrations. The main research findings are as follows: (1) the Environmental Kuznets Curve (EKC) is proven to hold true in terms of the effect of population and land urbanisation on PM2.5 concentrations, while there is no consistent conclusion on the non-linear relationship between economic urbanisation and PM2.5 concentrations; (2) publication bias is evident in research on the economic and comprehensive urbanisation dimensions under linear assumptions; (3) there are notable heterogeneities in existing research in this field. The meta-regression model further indicates that model design, sample design, and publication characteristics might be responsible for these heterogeneities. This study innovatively applies a meta-analysis to investigate the effect of urbanisation on PM2.5 concentrations. The findings will contribute to scholars designing more rigorous research frameworks in this field.

Capital endowments and adoption of agricultural green production technologies in China: A meta-regression analysis review

The promotion of agricultural green production technologies (AGPTs) is a fundamental channel of agricultural sustainable development, and the capital endowments that drive farmers to adopt AGPTs have sparked an enormous interest. Given the mixed findings of 237 primary empirical studies on the link between capital endowments - AGPTs adoption, this systematic quantitative review conducts a meta-regression analysis method to estimate the genuine effects of different capital endowments in terms of eleven proxy factors on AGPTs adoption in China. Combining the estimation strategies of Weighted Least Squares (WLS) and Bayesian Model Averaging (BMA), our findings reveal that three proxy factors (Technical training, Family income, and Government subsidies) are infected by publication bias, and the study-to-study variation between those published studies that focus on these proxy factors stems from several heterogeneity features, such as the types of AGPTs, measurements of adoption decision, and model specification. After controlling the above issues, there are still six proxy factors attached to five types of capital endowments-Technical training, Labor force, Assets, Land size, Social network, and Government subsidies-present positive and significant genuine effects on AGPTs adoption. These effects are robust to different estimation strategies or model specifications. As farmers normally possess a low level of capital endowment and willingness to adopt AGPTs in most developing countries, such study findings are expected to provide some enlightenment for future research and policies related to the effective promotion of AGPTs, which may contribute to carbon reduction, environmental protection of farmland, and agricultural sustainable development.

Placebo Effect and Its Determinants in Ocular Hypotensive Therapy: Meta-analysis and Multiple Meta-regression Analysis

TOPIC

The placebo effect and its potential determinants in ocular hypotensive therapy.

CLINICAL RELEVANCE

The placebo effect has been studied and documented within a wide clinical context. It remains unclear whether placebo is effective in glaucoma treatment or, if so, which factors are determinative of effect size (ES).

METHODS

Randomized controlled trials (RCTs) of topical ocular hypotensive therapy for patients with open-angle glaucoma or ocular hypertension, conducted through June 2, 2022, were included. First, a perceived placebo effect was measured as the overall intraocular pressure (IOP) change from the baseline. It was evaluated in terms of the ES (mean difference between the baseline and the end point) and then was compared with the ES, as obtained from the untreated control participant to obtain a true placebo effect. The primary outcome was ES based on 4 weeks of treatment. Meta-analysis-based statistical pooling was performed where appropriate, and 95% confidence intervals (CIs) were used for comparison. Potential placebo effect determinants were scrutinized using a multiple meta-regression model (PROSPERO identifier, CRD42022348098).

RESULTS

A total of 40 RCTs (7829 eyes) with 33 placebo groups (2055 eyes) along with 7 untreated groups (1184 eyes) were included. Among placebo-controlled trials, placebo was determined to be effective in lowering IOP (ES, -1.30 mmHg; 95% CI, -1.75 to -0.84 mmHg). Using NMA, the ES for placebo was -2.27 mmHg (95% CI, -3.52 to -1.01 mmHg) greater than ES for untreated control participants.. According to the multiple meta-regression model, the active treatment ES was a significant factor to predict the amount of placebo effect. Placebo additionally lowered IOP by -0.45 mmHg per -1 mmHg of active treatment effect. Add-on study design and larger sample size also were associated with greater amount of placebo effect. No publication bias was evident in either a funnel plot or the Begg and Mazumdar adjusted rank correlation test results (P = 0.24).

DISCUSSION

This meta-analysis indicated that placebo is effective in lowering IOP and is superior to the effect observed for the untreated control participants. However, caution is required in interpreting the results because of the small number of untreated controlled trials and potential bias from the lack of direct comparison between the placebo and untreated arms.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Heterogeneity in cardiovascular death or hospitalization for heart failure benefits with flozins is linked to weight

AIMS

Cardiovascular outcome trials with sodium-glucose cotransporter 2 inhibitors (SGLT-2is) have documented a positive impact on micro- and macrovascular complications of type 2 diabetes (T2D). Most analyses suggest that these benefits are independent of achieving metabolic control. This meta-regression analysis was undertaken to explore the relationship between metabolic components positively influenced by SGLT-2is and a reduction in cardiovascular death (CV death) or hospitalization due to heart failure (hHF).

METHODS AND RESULTS

A database search was conducted using the Cochrane Library to identify relevant studies. Analysis was conducted using CMA and RStudio (2022.07.1) software. The hazard ratios of the individual studies were used to compute the random effects model mean effect size for CV death or hHF, and the prediction interval was used to identify the uncertainty in the summary treatment effect. Heterogeneity was quantified using Q statistics. A pooled population of 46 969 patients from five studies was included for analysis. The Cochrane risk of bias tool was used to assess the quality of the studies. There was a significant 23% reduction in CV deaths or hHFs in the SGLT-2i arm compared with the placebo arm [hazard ratio (HR): 0.77, 95% confidence interval (CI) 0.70-0.85]. However, the prediction interval (0.57-1.05) and the Q statistics [8.06 > degrees of freedom (df) of 4] were indicative of uncertainty in the true effect or heterogeneity. Nearly 50% of the variance of the observed effects were related to the true effects (I²  = 50%). Among the moderators selected, a significant correlation of the outcomes was found with the weight variable (P < 0.01). Weight differential could explain the entire variance in true effect size (R²  = 1.00) ruling out any sampling error.

CONCLUSIONS

The results of this meta-regression analysis suggest that the beneficial effects of SGLT-2is in reducing CV deaths and hHFs are related to the weight variable.

Willingness to pay for cleaning up beach litter: A meta-analysis

At the global level, the UN 2030 Agenda for Sustainable Development Goal 14 calls for action to significantly reduce marine litter pollution by 2025. To understand the non-market benefits of removing marine litter, researchers have conducted numerous studies on Willingness to Pay (WTP) for reductions in beach litter. This paper estimates the overall effect size of WTP for a worldwide dataset of 63 primary studies over 22 years by applying a meta-regression technique to assess the variability in WTP estimates. The results show an annual mean effect size of $US0.71 (or $US35.29) per person for a 1 % (for a corresponding 50 %) reduction in all types of beach litter. The observed heterogeneity is associated with WTP elicitation methods, beach attributes, geographic locations, and per-capita income. This study yields valuable information for policy makers to develop cost-effective policies and recommends standardised measurements to benchmark changes in marine litter pollution.

The effect of health on economic growth: a meta-regression analysis

The main objective of this study is to examine the effect of health on economic growth based on 719 estimates obtained from 64 studies from all over the world. We find evidence of a publication bias towards a positive estimated effect of health on economic growth. After accounting for heterogeneity of the estimates, we show that health has a genuine positive effect on economic growth. Less developed countries seem to enjoy a higher effect of health on growth driven by the ongoing economic-demographic transition in those countries. The variation of the health effect on economic growth is also influenced by the available data, estimation procedure, model specification, publication channel, and country characteristics in each study. Studies that do not account for endogeneity seem to create an upward bias. Studies with more comprehensive variables seem to increase the estimated effect of health on growth. A higher number of years of compulsory education, longer working experience, and more favourable environmental conditions also increase the effect size. Overall, our results confirm the key role of the health factor in explaining economic growth across countries.

The cardiovascular benefits of GLP1-RAs are related to their positive effect on glycemic control: A meta-regression analysis

BACKGROUNDS AND AIMS

Glucagon-like-peptides 1 receptor analogues (GLP1-RAs) have gained primacy in the management of type 2 diabetes (T2D).However, in contrast to the CVOT conducted with sodium glucose cotransporter-2 inhibitors (SGLT-2i)there was a significant reduction in glycated haemoglobin (HbA1c) in some of the CVOT with GLP1-RA. The aim of this analysis is to explore the possible association between cardiovascular outcome benefits with GLP1-RA and HbA1c reduction.

METHODS

A Cochrane library based web search yielded 9 eligible citations for this analysis. The analysis was performed using the comprehensive meta-analysis (CMA) software.A meta-regression analysis was performed using HbA1c, weight, and systolic blood pressure reduction as moderators.

RESULT

The meta-regression analysis was conducted on a pooled population of 64,236 patients. There was a significant heterogeneity associated with the MACE benefits (Q = 16.88, I2: 52.59, df = 7, p = 0.03). Among the moderators selected to explain the variance in true effects, HbA1c reduction was significant (Q = 7.00, P=<0.001, R²:1.0). Additional meta-regression analysis using 0.9% reduction of HbA1c from baseline indicated an association with MACE benefit (95% CI -0.23 to -0.02, P = 0.01, R²: 0.98).

CONCLUSION

The MACE benefits associated with GLP1-RAs are dependent on the reduction of HbA1c levels.

The relationship between the level of exercise and hemoglobin A1c in patients with type 2 diabetes mellitus: a systematic review and meta-analysis

PURPOSE

The aim of the study was to evaluate the relationship between changes in hemoglobin A₁c (HbA_1c) and exercise levels in type 2 diabetes mellitus (T2DM) patients when performing various types of exercise.

METHODS

The inclusion criteria were randomized controlled trials involving adults with T2DM, intervention involving exercise alone, the overall duration of intervention ≥12 weeks, and reporting HbA_1c. Weighted mean difference (WMD) was defined as the mean difference between the intervention group and the control group weighted by the inverse of the squared standard error for each study, and all WMDs were pooled as overall effects. A meta-regression analysis was performed to evaluate the relationship between the exercise level and the WMD in HbA_1c.

RESULTS

Forty-eight studies (2395 subjects) were analyzed. The pooled WMD in HbA_1c decreased significantly (-0.5% [95% confidence intervals: -0.6 to -0.4]) but contained significant heterogeneity (Q = 103.8, P < 0.01; I² = 36.6%). A meta-regression analysis showed that the intensity (metabolic equivalents [METs]), time (min/session), or frequency (sessions/week) of the exercise was not associated with the HbA_1c. However, the overall duration of exercise (weeks) was significantly associated with the WMD in HbA_1c (meta-regression coefficient: 0.01 [95% confidence intervals: 0.002-0.016]; R² = 70.0%), and that result did not contain significant heterogeneity (P > 0.05; I² = 14.7%).

CONCLUSIONS

The exercise intervention decreases HbA_1c in T2DM patients. In addition, exercise for an extended duration was associated with an increase in HbA_1c, so the effects of exercise may be evident early on, but results suggested that exercise for a prolonged period alone may increase HbA_1c.

Descriptive statistics of dataset from the meta-analysis and meta-regression analysis on prognostic significance of pre-treatment systemic hemato-immunological indices of cervical cancer patients

In this study, we perform a meta-analysis and meta-regression analysis for the article entitled “Prognostic value of systemic hemato-immunological indices in uterine cervical cancer: A systemic review, meta-analysis, and meta-regression of observational studies.” [1] We implemented quantitative meta-analyses and time series meta-regression analysis to determine whether systemic hemato-immunological indices, such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), thrombocyte-to-lymphocyte ratio (TLR), and C-reactive protein/albumin ratio (CAR) are associated with an increased risk of cervical collision cancer. In all, 9558 patients from 22 studies were included after a systematic data search, performed comprehensively using the following databases: MEDLINE, Web of Science, Embase, and Cochrane. The meta-analysis was conducted with a random-effects model using the Review Manager software (Revman version 5.3). The overall survival (OS), disease-free survival (DFS), and progression-free survival (PFS) data were compared among each observational study. All data are expressed as hazard ratios (HRs) and 95% confidence intervals (CIs), and were calculated using the generic inverse of variance method. Statistical heterogeneity was quantified using Cochrane's Q statistic and Higgins I² statistic. Subgroup analysis was performed to investigate the sources of heterogeneity. Furthermore, quality assessment of the included datasets was presented according to the Newcastle-Ottawa Scale method. Additionally, sensitivity analysis was conducted to explore the sources of heterogeneity and analyze whether the results were stable and reliable. Meta-analysis random-effect approach was used for the regression to evaluate the effect of age, presence of squamous cell carcinoma patients, and number of evaluated NLR and PLR parameters on patient survival.

Is the evidence on the effectiveness of pay for performance schemes in healthcare changing? Evidence from a meta-regression analysis

BACKGROUND

This study investigated if the evidence on the success of the Pay for Performance (P4P) schemes in healthcare is changing as the schemes continue to evolve by updating a previous systematic review.

METHODS

A meta-regression analysis using 116 studies evaluating P4P schemes published between January 2010 to February 2018. The effects of the research design, incentive schemes, use of incentives, and the size of the payment to revenue ratio on the proportion of statically significant effects in each study were examined.

RESULTS

There was evidence of an increase in the range of countries adopting P4P schemes and weak evidence that the proportion of studies with statistically significant effects have increased. Factors hypothesized to influence the success of schemes have not changed. Studies evaluating P4P schemes which made payments for improvement over time, were associated with a lower proportion of statistically significant effects. There was weak evidence of a positive association between the incentives' size and the proportion of statistically significant effects.

CONCLUSION

The evidence on the effectiveness of P4P schemes is evolving slowly, with little evidence that lessons are being learned concerning the design and evaluation of P4P schemes.

Association between discontinuation due to withdrawal of consent and use of long-acting injectable antipsychotics: A meta-analysis of randomized trials for schizophrenia

We investigated the association between discontinuation due to withdrawal of consent (DWC) in schizophrenia trials and the use of long-acting injectable antipsychotics (LAI-APs). In two categorical meta-analyses of randomized controlled trials, we compared DWC: individual and pooled LAI-APs vs. (1) placebo and (2) oral antipsychotics (OAPs). We also performed conducted a single-group meta-analysis to calculate the average DWC and a meta-regression analysis to examine the association between the results of the meta-analyses and factors related to study design, treatment, and patients. We identified 52 studies (total adult patients = 18,675, LAI-APs = 12,613, placebo = 2,083, and OAPs = 3,979; median study duration = 32 weeks). DWC was higher for LAI-aripiprazole than for the placebo [risk ratio (95% confidence interval) = 1.70 (1.23-2.39)]. Neither pooled nor individual LAI-APs differed from the placebo for fluphenazine, olanzapine, paliperidone, and risperidone or from the OAPs for aripiprazole, fluphenazine, haloperidol, olanzapine, paliperidone, risperidone, and zuclopenthixol. The average DWC of each LAI-AP was as follows: LAI-aripiprazole = 10.98%, LAI-fluphenazine = 7.65%, LAI-flupenthixol = 3.33%, LAI-haloperidol = 6.71%, LAI-olanzapine = 10.50%, LAI-paliperidone = 10.38%, LAI-perphenazine = 7.06%, LAI-risperidone = 10.39%, LAI-zuclopenthixol = 4.45%, pooled LAI-APs = 9.88%, and placebo = 11.17%. Meta-regression analysis demonstrated that publication year (β = 0.02), percentage of males (β = 0.02), and mean age (β = 0.05) were associated with an average DWC for pooled LAI-APs. Study duration (β = -0.03), percentage of males (β = 0.08), and patient status (β = -0.85) were associated with an average DWC for LAI-aripiprazole. Presence of a placebo arm (β = 1.60) was associated with an average DWC for LAI-fluphenazine. LAI-AP use was unlikely to be associated with DWC. Although the LAI-aripiprazole had a higher DWC than did the placebo, its average DWC was similar to other those of LAI-APs.

Dose-effect response in image-guided adaptive brachytherapy for cervical cancer: A systematic review and meta-regression analysis

PURPOSE

This study aimed to integrate and update the dose-effect relationship between volumetric dose and local control for cervical cancer brachytherapy.

METHODS AND MATERIALS

We identified studies that reported high-risk clinical target volume (HR-CTV) D₉₀ and local control probability by searching PubMed, Web of Science, and the Cochrane Library databases through Oct 27, 2019. The regression analyses were performed using a probit model between HR-CTV D₉₀, D₁₀₀, intermediate-risk clinical target volume (IR-CTV) D₉₀, and dose to Point A vs. local control probability. Subgroup analyses were performed according to stratification: time of local control, income level of the country or region, stage of cancer, pathology, mean volume of HR-CTV, dose rate, image modality, concurrent chemoradiotherapy proportion, interstitial proportion, and mean overall treatment time.

RESULTS

Thirty-three studies encompassing 2893 patients were included. The probit model showed a significant relationship between the HR-CTV D₉₀ value and the local control probability, p < 0.0001. The D₉₀ corresponding to a probability of 90% local control was 83.7 Gy_EQD2,10 (80.6-87.8 Gy_EQD2,10). Of the 33 studies included in our analysis, eight studies, including 1172 patients, reported the IR-CTV D₉₀ value, ranging from 59.1 Gy_EQD2,10 to 72.3 Gy_EQD2,10. The probit model also showed a significant relationship between the IR-CTV D₉₀ value and the local control probability, p = 0.0464. The 60 Gy_EQD2,10 for IR-CTV D₉₀ corresponded to an 86.1% local control probability (82.0%-89.8%).

CONCLUSIONS

A significant dependence of local control on HR-CTV D₉₀ and IR-CTV D₉₀ was found. A tumor control probability of >90% can be expected at doses >84 Gy_EQD2,10 and 69 Gy_EQD2,10, respectively, based on an updated meta-regression analysis.

Effectiveness of various innovative learning methods in health science classrooms: a meta-analysis

This study reports the results of a meta-analysis of the available literature on the effectiveness of various forms of innovative small-group learning methods on student achievement in undergraduate college health science classrooms. The results of the analysis revealed that most of the primary studies supported the effectiveness of the small-group learning methods in improving students' academic achievement with an overall weighted average effect-size of 0.59 in standard deviation units favoring small-group learning methods. The subgroup analysis showed that the various forms of innovative and reform-based small-group learning interventions appeared to be significantly more effective for students in higher levels of college classes (sophomore, junior, and senior levels), students in other countries (non-U.S.) worldwide, students in groups of four or less, and students who choose their own group. The random-effects meta-regression results revealed that the effect sizes were influenced significantly by the instructional duration of the primary studies. This means that studies with longer hours of instruction yielded higher effect sizes and on average every 1 h increase in instruction, the predicted increase in effect size was 0.009 standard deviation units, which is considered as a small effect. These results may help health science and nursing educators by providing guidance in identifying the conditions under which various forms of innovative small-group learning pedagogies are collectively more effective than the traditional lecture-based teaching instruction.

Is pancreaticogastrostomy safer than pancreaticojejunostomy after pancreaticoduodenectomy? A meta-regression analysis of randomized clinical trials

OBJECTIVE

To evaluate the clinically relevant POPF rate between Pancreatogastrostomy (PG) and pancreaticojejunostomy (PJ) after pancreaticoduodenectomy (PD). To evaluate the confounding factors affecting meta-analytic results.

METHODS

A systematic literature search of randomized clinical trials (RCTs) comparing PG to PJ with an International Study Group of Pancreatic Fistula (ISGPF) definition of postoperative pancreatic fistula (POPF). Risk difference (RD) and number needed to treat or harm (NNT and NNH) were used. Fixed and random-effect models were applied. Impact of confounding covariates on the meta-analytic results was evaluated using meta-regression analysis, reporting β coefficient ± standard error (SE).

RESULTS

Seven RCTs were identified involving 1184 patients: 603 PG and 581 PJ. RD in the fixed model of clinically relevant POPFs suggested that PG was superior to PJ (RD-0.07; 95% CI: -0.11 to -0.03) with an NNT of 14 (95% CI: 9 to 33). In random model, PG was not superior to PJ (RD-0.06; 95% CI: -0.13 to 0.01) with an NNT of 17 and a possibility of harm in some cases (NNH = 100). Meta-regression suggested that the increase in the proportion of "soft pancreas" in the PG arm corresponded to a more positive value of RD (β = 0.47 ± 0.19; P value: 0.045 ± 0.003).

CONCLUSION

A PG could be slightly superior to PJ in the prevention of clinically relevant POPF. The presence of high risk pancreatic remnant remains the main limitation of PG.

Placebo and nocebo reactions in randomized trials of pharmacological treatments for persistent depressive disorder. A meta-regression analysis

BACKGROUND

We aimed to investigate placebo and nocebo reactions in randomized controlled trials (RCT) of pharmacological treatments for persistent depressive disorder (PDD).

METHODS

We conducted a systematic electronic search and included RCTs investigating antidepressants for the treatment of PDD. Outcomes were the number of patients experiencing response and remission in placebo arms (=placebo reaction). Additional outcomes were the incidence of patients experiencing adverse events and related discontinuations in placebo arms (=nocebo reaction). A priori defined effect modifiers were analyzed using a series of meta-regression analyses.

RESULTS

Twenty-three trials were included in the analyses. We found a pooled placebo response rate of 31% and a placebo remission rate of 22%. The pooled adverse event rate and related discontinuations were 57% and 4%, respectively. All placebo arm outcomes were positively associated with the corresponding medication arm outcomes. Placebo response rate was associated with a greater proportion of patients with early onset depression, a smaller chance to receive placebo and a larger sample size. The adverse event rate in placebo arms was associated with a greater proportion of patients with early onset depression, a smaller proportion of females and a more recent publication.

CONCLUSIONS

Pooled placebo and nocebo reaction rates in PDD were comparable to those in episodic depression. The identified effect modifiers should be considered to assess unbiased effects in RCTs, to influence placebo and nocebo reactions in practice.

LIMITATIONS

Limitations result from the methodology applied, the fact that we conducted only univariate analyses, and the number and quality of included trials.

Tumor dose-volume response in image-guided adaptive brachytherapy for cervical cancer: A meta-regression analysis

PURPOSE

Image-guided adaptive brachytherapy is a high precision technique that allows dose escalation and adaptation to tumor response. Two monocentric studies reported continuous dose-volume response relationships, however, burdened by large confidence intervals. The aim was to refine these estimations by performing a meta-regression analysis based on published series.

METHODS AND MATERIALS

Eligibility was limited to series reporting dosimetric parameters according to the Groupe Européen de Curiethérapie-European SocieTy for Radiation Oncology recommendations. The local control rates reported at 2-3 years were confronted to the mean D90 clinical target volume (CTV) in 2-Gy equivalent using the probit model. The impact of each series on the relationships was pondered according to the number of patients reported.

RESULTS

An exhaustive literature search retrieved 13 series reporting on 1299 patients. D90 high-risk CTV ranged from 70.9 to 93.1 Gy. The probit model showed a significant correlation between the D90 and the probability of achieving local control (p < 0.0001). The D90 associated to a 90% probability of achieving local control was 81.4 Gy (78.3-83.8 Gy). The planning aim of 90 Gy corresponded to a 95.0% probability (92.8-96.3%). For the intermediate-risk CTV, less data were available, with 873 patients from eight institutions. Reported mean D90 intermediate-risk CTV ranged from 61.7 to 69.1 Gy. A significant dose-volume effect was observed (p = 0.009). The D90 of 60 Gy was associated to a 79.4% (60.2-86.0%) local control probability.

CONCLUSION

Based on published data from a high number of patients, significant dose-volume effect relationships were confirmed and refined between the D90 of both CTV and the probability of achieving local control. Further studies based on individual data are required to develop nomograms including nondosimetric prognostic criteria.

Japanese elderly persons walk faster than non-Asian elderly persons: a meta-regression analysis

[Purpose] The purpose of this study was to clarify ethnic differences in walking speed by comparing walking speed in both Japanese and non-Asian elderly individuals and to investigate the necessity of consideration of ethnic differences in walking speed. [Subjects and Methods] Articles that reported comfortable walking speeds for community-dwelling elderly individuals were identified from electronic databases. Articles that involved community-dwelling individuals who were 60 years old or older and well functioning were included in the study. Articles that involved Asians were excluded. Weighted means for 5-m walking times were calculated as walking speeds from the Japanese and non-Asian sample data. The effects of age, gender, and ethnicity on 5-m walking times were then investigated using meta-regression analysis. [Results] Twenty studies (34 groups) were included for Japanese, and 16 studies (28 groups) were included for non-Asians. The weighted mean 5-m walking time was estimated to be 4.15 sec (95% confidence interval [CI]: 3.87-4.44) for Japanese and 4.24 sec (95% CI: 4.09-4.40) for non-Asians. Furthermore, using meta-regression analysis adjusted for age and gender, the 5-m walking time was 0.40 sec faster (95% CI: 0.03-0.77) for Japanese than for non-Asian elderly individuals. [Conclusion] Walking speed appeared faster for Japanese community-dwelling elderly individuals than for non-Asian elderly individuals.

Meta-analysis of the efficacy and safety of bortezomib re-treatment in patients with multiple myeloma

INTRODUCTION

Bortezomib is administered for a finite course; thus, patients might remain sensitive to bortezomib-based therapy at relapse. We report a meta-analysis of bortezomib-based retreatment in relapsed/refractory myeloma.

PATIENTS AND METHODS

A systematic literature review identified studies of bortezomib-based retreatment in relapsed/refractory myeloma. Proportions of bortezomib-refractory patients and additional prognostic factors were extracted and used in weighted stratified analyses of TTP and OS. Random-effect pooled estimates were calculated for overall response rate (ORR) and rates of common AEs.

RESULTS

Twenty-three studies (n = 1051 patients) were identified. Bortezomib was administered intravenously in all studies. Across studies in which data were available, pooled, weighted average ORR was 39.1% (95% confidence interval, 30.8%-47.4%), and pooled, weighted average median TTP and OS were 7.5 and 16.6 months, respectively. Patients with fewer previous therapies (≤ 4) and relapsed (not refractory) patients achieved higher ORRs, of 43.4% and 57.2%, respectively. Random-effects meta-regression analysis confirmed that relapsed patients were associated with a higher ORR by 28 to 41 percentage points versus refractory patients. In relapsed patients, median TTP and OS were 8.5 and 19.7 months, respectively. Common Grade 3/4 AEs included thrombocytopenia (35%), neutropenia (15%), anemia (14%), pneumonia (10%), and peripheral neuropathy (3%).

CONCLUSION

Based on these findings, bortezomib retreatment is well tolerated and appears efficacious in relapsed patients. In an era of new and emerging treatment options for relapsed and/or refractory myeloma, these data indicate that bortezomib retreatment might be a highly effective option in previously treated patients.

Publication selection and the income elasticity of the value of a statistical life

Estimates of the value of a statistical life (VSL) establish the price government agencies use to value fatality risks. Transferring these valuations to other populations often utilizes the income elasticity of the VSL, which typically draw on estimates from meta-analyses. Using a data set consisting of 101 estimates of the income elasticity of VSL from 14 previously reported meta-analyses, we find that after accounting for potential publication bias the income elasticity of value of a statistical life is clearly and robustly inelastic, with a value of approximately 0.25-0.63. There is also clear evidence of the importance of controlling for levels of risk, differential publication selection bias, and the greater income sensitivity of VSL from stated preference surveys.

Social inequality in infant mortality: what explains variation across low and middle income countries?

Growing work demonstrates social gradients in infant mortality within countries. However, few studies have compared the magnitude of these inequalities cross-nationally. Even fewer have assessed the determinants of social inequalities in infant mortality across countries. This study provides a comprehensive and comparative analysis of social inequalities in infant mortality in 53 low-and-middle-income countries (LMICs). We used the most recent nationally representative household samples (n = 874,207) collected through the Demographic Health Surveys (DHS) to calculate rates of infant mortality. The relative and absolute concentration indices were used to quantify social inequalities in infant mortality. Additionally, we used meta-regression analyses to examine whether levels of inequality in proximate determinants of infant mortality were associated with social inequalities in infant mortality across countries. Estimates of both the relative and the absolute concentration indices showed a substantial variation in social inequalities in infant mortality among LMICs. Meta-regression analyses showed that, across countries, the relative concentration of teenage pregnancy among poorer households was positively associated with the relative concentration of infant mortality among these groups (beta = 0.333, 95% CI = 0.115 0.551). Our results demonstrate that the concentration of infant deaths among socioeconomically disadvantaged households in the majority of LMICs remains an important health and social policy concern. The findings suggest that policies designed to reduce the concentration of teenage pregnancy among mothers in lower socioeconomic groups may mitigate social inequalities in infant mortality.