Heterogeneity and statistical significance in meta-analysis: an empirical study of 125 meta-analyses

A Utilitarian Perspective on Risk Quantification for Clinical Significance in Binary Outcomes

Null hypothesis significance testing (NHST) in medical research is increasingly being supplemented by estimation statistics, focusing on effect sizes (ESs) and confidence intervals (CIs). This study evaluates the expression of ESs and CIs for binary outcomes. A utilitarian framework is proposed, emphasizing the number of beneficiaries and the impact level. To evaluate clinical significance, minimal clinically important risk difference (MCIRD) is proposed based on event magnitude (EM). Within this framework, risk difference (RD) is introduced as the primary measure. To assess the performance of RD, we compared its statistical power against other measures (risk ratio, RR; odds ratio, OR; Cohen's h) in individual study scenarios, and visual information conveyance in meta-analysis scenarios. RDs maintain statistical power in comparison to other measures in individual studies. They provide clarity on the true impact of clinical interventions without compromising statistical integrity. Meta-analytic results indicate that using RDs directly enhances transparency, uncovers heterogeneity, and addresses misaligned assumptions. This approach, by quantifying clinical effectiveness under a utilitarian perspective, facilitates the applicability of research to patient care and encourages shared decision-making. The study advocates for reporting baseline risks (BRs) with RDs and recommends a standardized presentation of these statistics. In a utilitarian perspective, adopting RD as the preferred ES can foster a transparent, patient-focused research ethos. This aids in accurately presenting the magnitude and variability of treatment effects, offering a new direction in methodology.

Effectiveness of Lifestyle Interventions during Pregnancy on Preventing Gestational Diabetes Mellitus in High-Risk Women: A Systematic Review and Meta-Analyses of Published RCTs

BACKGROUND

Until now, it is uncertain whether lifestyle interventions during pregnancy can prevent gestational diabetes mellites (GDM) in high-risk pregnant women.

OBJECTIVE

This study aims at investigating the effectiveness of dietary interventions and/or exercise interventions during pregnancy for preventing GDM in high-risk pregnant women.

MATERIALS AND METHODS

Eligible randomized controlled trials (RCTs) were selected after a search in CENTRAL, Scopus, and PubMed. Synthesis was performed for the outcome of GDM in women with any identified GDM risk factor. Separate meta-analyses (MA) were performed to assess the efficacy of either nutrition or physical activity (PA) interventions or both combined compared with standard prenatal care for preventing GDM. Subgroup and sensitivity analyses, as well as meta-regressions against OR, were performed to assess potentional heterogeneity. Overall quality, the quality of RCTs, and publication bias were also evaluated.

RESULTS

A total of 13,524 participants comprising high-risk pregnant women in 41 eligible RCTs were analyzed for GDM. Women receiving only a nutrition intervention during pregnancy were less likely to experience GDM compared with women following standard prenatal care. Among 3109 high-risk pregnant women undergoing only dietary intervention for preventing GDM, 553 (17.8%) developed GDM; however, the result of the MA was marginally not significant (OR 0.73, 95%CI 0.51, 1.03; p-value 0.07), (Q 21.29, p-value 0.01; I2 58% (95%CI 10, 78%)). Subgroup analyses demonstrated an effect for studies that were conducted in Great Britain (OR 0.65, 95%CI 0.49, 0.81; p-value 0.003), and in Spain (OR 0.50, 95%CI 0.27, 0.94; p-value 0.03), for studies with forms of the Mediterranean diet as the intervention's component (OR 0.61; 95%CI 0.46, 0.81; p-value 0.0005), and for studies including a motivation arm in the intervention (OR 0.71, 95%CI 0.58, 0.87; p-value 0.0008). Among 2742 high-risk pregnant women being analyzed for GDM outcome after receiving only an exercise intervention, 461 (16.8%) were diagnosed with GDM. Women after receiving PA intervention were less likely to develop GDM (OR 0.64, 95%CI 0.51, 0.80; p-value < 0.0001), (Q 11.27, p-value 0.51; I2 0% (95%CI 0, 99%)). Finally, 1308 (17%) cases of GDM were diagnosed among 7673 high-risk pregnant women undergoing both diet and PA intervention. Women in the group of mixed lifestyle intervention had a significant reduction in incidence of GDM (OR 0.70, 95%CI 0.55, 0.90; p-value 0.005), (Q 50.32, p-value < 0.0001, I2 66%, (95% CI 44, 79%)).

CONCLUSIONS

The results of this study support the efficacy of lifestyle interventions during pregnancy for preventing GDM in high-risk women if an exercise component is included in the intervention arm, either alone, or combined with diet. A combined lifestyle intervention including physical exercise and a Mediterranean diet accompanied by motivation support may be considered the most effective way to prevent GDM among high-risk women during pregnancy. Future research is needed to strengthen these findings.

The safety of digestive tract cancer surgery during COVID-19: A living systematic review and meta-analysis

Surgery is the primary curative treatment of solid cancers. However, its safety has been compromised by the outbreak of COVID-19. Therefore, it is necessary to evaluate the safety of digestive tract cancer surgery in the context of COVID-19. We used the Review Manager software (v.5.4) and Stata software (version 16.0) for meta-analysis and statistical analysis. Sixteen retrospective studies involving 17,077 patients met the inclusion criteria. The data indicates that performing digestive tract cancer surgery during the COVID-19 pandemic led to increased blood loss(MD = -11.31, 95%CI:-21.43 to -1.20, P = 0.03), but did not increase postoperative complications(OR = 1.03, 95%CI:0.78 to1.35, P = 0 0.86), anastomotic leakage (OR = 0.96, 95%CI:0.52 to1.77, P = 0 0.89), postoperative mortality (OR = 0.65, 95%CI:0.40 to1.07, P = 0 0.09), number of transfusions (OR = 0.74, 95%CI:0.30 to 1.80, P = 0.51), number of patients requiring ICU care(OR = 1.37, 95%CI:0.90 to 2.07, P = 0.14), postoperative 30-d readmission (OR = 0.94, 95%CI:0.82 to 1.07, P = 0 0.33), total hospital stay (MD = 0.11, 95%CI:-2.37 to 2.59, P = 0.93), preoperative waiting time(MD = - 0.78, 95%CI:-2.34 to 0.79, P = 0.33), postoperative hospital stay(MD = - 0.44, 95%CI:-1.61 to 0.74, P = 0.47), total operation time(MD = -12.99, 95%CI:-28.00 to 2.02, P = 0.09) and postoperative ICU stay (MD = - 0.02, 95%CI:-0.62 to 0.57, P = 0.94). Digestive tract cancer surgery can be safely performed during the COVID-19.

Vonoprazan versus lansoprazole in erosive esophagitis - A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Proton-pump inhibitors (PPIs) are the mainstay of treatment in erosive esophagitis (EE). An alternative to PPIs in EE is Vonoprazan, a potassium competitive acid blocker. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing vonoprazan to lansoprazole.

METHODS

Multiple databases searched through November 2022. Meta-analysis was performed to assess endoscopic healing at two, four and eight weeks, including for patients with severe EE (Los Angeles C/D). Serious adverse events (SAE) leading to drug discontinuation were assessed. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology.

RESULTS

Four RCTs with 2208 patients were included in the final analysis. Vonoprazan 20 mg once-daily was compared to lansoprazole 30 mg once-daily dosing. Among all patients, at two and eight weeks post-treatment, vonoprazan resulted in significantly higher rates of endoscopic healing as compared to lansoprazole, risk ratios (RR) 1.1, p<0.001 and RR 1.04, p=0.03. The same effect was not observed at four weeks, RR 1.03 (CI 0.99-1.06, I2=0%) following therapy. Among patients with severe EE, vonoprazan resulted in higher rates of endoscopic healing at two weeks, RR 1.3 (1.2-1.4, I2=47%), p=<0.001, at four weeks, RR 1.2 (1.1-1.3, I2=36%), p=<0.001 and at eight weeks post-treatment, RR 1.1 (CI 1.03-1.3, I2=79%), p=0.009. We found no significant difference in the overall pooled rate of SAE and pooled rate of adverse events leading to drug discontinuation. Finally, the overall certainty of evidence for our main summary estimates was rated as high (grade A).

CONCLUSION

Based on limited number of published non-inferiority RCTs, our analysis demonstrates that among patients with EE, vonoprazan 20 mg once-daily dosing achieves comparable and in those with severe EE, higher endoscopic healing rates as compared to lansoprazole 30 mg once-daily dosing. Both drugs have a comparable safety profile.

Safety and efficacy of underwater versus conventional endoscopic mucosal resection for colorectal polyps: Systematic review and meta-analysis of RCTs

Background and study aims Conventional endoscopic mucosal resection (C-EMR) is limited by low en-bloc resection rates, especially for large (> 20 mm) lesions. Underwater EMR (U-EMR) has emerged as an alternative for colorectal polyps and is being shown to improve en-bloc resection rates. We conducted a systematic review and meta-analysis comparing the two techniques. Methods Multiple databases were searched through November 2022 for randomized controlled trials (RCTs) comparing outcomes of U-EMR and C-EMR for colorectal polyps. Meta-analysis was performed to determine pooled proportions and relative risks (RRs) of R0 and en-bloc resection, polyp recurrence, resection time, and adverse events. Results Seven RCTs with 1458 patients (U-EMR: 739, C-EMR: 719) were included. The pooled rate of en-bloc resection was significantly higher with U-EMR vs C-EMR, 70.17% (confidence interval [CI] 46.68-86.34) vs 58.14% (CI 31.59-80.68), respectively, RR 1.21 (CI 1.01-1.44). R0 resection rates were higher with U-EMR vs C-EMR, 58.1% (CI 29.75-81.9) vs 44.6% (CI 17.4-75.4), RR 1.25 (CI 0.99-1.6). For large polyps (> 20 mm), en-bloc resection rates were comparable between the two techniques, RR 1.24 (CI 0.83-1.84). Resection times were comparable between U-EMR and C-EMR, standardized mean difference -1.21 min (CI -2.57 to -0.16). Overall pooled rates of perforation, and immediate and delayed bleeding were comparable between U-EMR and C-EMR. Pooled rate of polyp recurrence at surveillance colonoscopy was significantly lower with U-EMR than with C-EMR, RR 0.62 (CI 0.41-0.94). Conclusions Colorectal U-EMR results in higher en-bloc resection and lower recurrence rates when compared to C-EMR. Both techniques have comparable resection times and safety profiles.

The safety of colorectal cancer surgery during the COVID-19: a systematic review and meta-analysis

Background

The ongoing coronavirus disease 2019 (COVID-19) pandemic has placed unprecedented pressure on the healthcare systems. This study evaluated the safety of colorectal cancer (CRC) surgery during the COVID-19 pandemic.

Methods

A systematic review and meta-analysis were performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (PROSPERO ID: CRD 42022327968). Relevant articles were systematically searched in the PubMed, Embase, Web of Science, and Cochrane databases. The postoperative complications, anastomotic leakage, postoperative mortality, 30-day readmission, tumor stage, total hospitalization, postoperative hospitalization, preoperative waiting, operation time, and hospitalization in the intensive care unit (ICU) were compared between the pre-pandemic and during the COVID-19 pandemic periods.

Results

Among the identified 561 articles, 12 met the inclusion criteria. The data indicated that preoperative waiting time related to CRC surgery was higher during the COVID-19 pandemic (MD, 0.99; 95%CI, 0.71-1.28; p < 0.00001). A similar trend was observed for the total operative time (MD, 25.07; 95%CI, 11.14-39.00; p =0.0004), and on T4 tumor stage during the pandemic (OR, 1.77; 95%CI, 1.22-2.59; p=0.003). However, there was no difference in the postoperative complications, postoperative 90-day mortality, anastomotic leakage, and 30-day readmission times between pre-COVID-19 pandemic and during the COVID-19 pandemic periods. Furthermore, there was no difference in the total hospitalization time, postoperative hospitalization time, and hospitalization time in ICU related to CRC surgery before and during the COVID-19 pandemic.

Conclusion

The COVID-19 pandemic did not affect the safety of CRC surgery. The operation of CRC during the COVID-19 pandemic did not increase postoperative complications, postoperative 90-day mortality, anastomotic leakage, 30-day readmission, the total hospitalization time, postoperative hospitalization time, and postoperative ICU hospitalization time. However, the operation of CRC during COVID-19 pandemic increased T4 of tumor stage during the COVID-19 pandemic. Additionally, the preoperative waiting and operation times were longer during the COVID-19 pandemic. This provides a reference for making CRC surgical strategy in the future.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022327968.

Adverse Impact of Intimate Partner Violence Against HIV-Positive Women During Pregnancy and Post-Partum: Results From a Meta-Analysis of Observational Studies

Objectives: Intimate partner violence (IPV) against pregnant or human immunodeficiency virus (HIV)-positive women have been previously studied. However, data on the impact of IPV on HIV-positive pregnant women have not been systematically synthesized. We performed a meta-analysis to explore this issue and provide evidence regarding IPV prevention and HIV infection control. Method: The PubMed, Web of Science, Cochrane Library, and Embase databases were systematically searched. Studies that quantitatively assessed the association between IPV and its adverse impact on HIV-positive women during pregnancy and post-partum were eligible for inclusion. Pooled odds ratios (ORs) were calculated. Findings: Eight studies were identified to meet our eligibility criteria. The adverse impacts of IPV against HIV-positive pregnant women mainly included nonadherence to maternal antiretroviral treatment during pregnancy, nondisclosure of HIV-positive status to male partners, nonadherence to infant antiretroviral prophylaxis, and antenatal depression. IPV caused a 180% and 145% increase in the odds of antenatal depression and nonadherence to infant antiretroviral prophylaxis, respectively, among HIV-positive women, compared to the odds of their IPV-free counterparts [OR = 2.80, 95% confidence interval (CI): 1.66-4.74; OR = 2.45, 95% CI: 1.40-4.27]. Conclusion: Limited evidence has suggested that IPV against HIV-positive pregnant women caused maternal depression during pregnancy and led to the possible failure of HIV prophylaxis adherence in infants. Interventions to address IPV may ultimately reduce the risk of depression-related adverse birth outcomes and vertical transmission in infants exposed to maternal HIV. Prevention and control against IPV should be developed for HIV-positive pregnant women.

Intercellular adhesion molecule 4 and ischemic stroke: a two-sample Mendelian randomization study

BACKGROUND

Experimental studies suggested that intercellular adhesion molecule 4 (ICAM-4) might be implicated in ischemic stroke, but the population-based evidence on the relationship between ICAM-4 and ischemic stroke were limited. Herein, we performed a two-sample Mendelian randomization (MR) analysis to investigate the associations of genetically determined plasma ICAM-4 with the risks of ischemic stroke and its subtypes.

METHODS

A total of 11 single-nucleotide polymorphisms associated with ICAM-4 were selected as instrumental variables based on the genome-wide association studies (GWAS) with 3,301 European individuals. Summary-level data about ischemic stroke and its subtypes were obtained from the Multi-ancestry GWAS launched by the International Stroke Genetics Consortium. We used the inverse-variance weighted method followed by a series of sensitivity analyses to evaluate the associations of genetically determined ICAM-4 with the risks of ischemic stroke and its subtypes.

RESULTS

Genetically determined higher ICAM-4 levels were significantly associated with increased risks of ischemic stroke (in the IVW method fitted to multiplicative random effects model: odds ratio [OR] per standard deviation [SD] increase, 1.04; 95% confidence interval [CI], 1.01-1.07; P = 0.006; in the IVW analysis with fixed effects model: OR per SD increase, 1.04; 95% CI, 1.01-1.07; P = 0.003) and cardioembolic stroke (in multiplicative random effects model: OR per SD increase, 1.08; 95% CI, 1.02-1.14; P = 0.004; in fixed effects model: OR per SD increase, 1.08; 95% CI, 1.03-1.13; P = 0.003). There was no association of ICAM-4 with the risks of large artery stroke and small vessel stroke. MR-Egger regression showed no directional pleiotropy for all associations, and the sensitivity analyses with different MR methods further confirmed these findings.

CONCLUSIONS

We found positive associations of genetically determined plasma ICAM-4 with the risks of ischemic stroke and cardioembolic stroke. Future studies are needed to explore the detailed mechanism and investigate the targeting effect of ICAM-4 on ischemic stroke.

The Effectiveness of Trauma-Focused Interventions in Prison Settings: A Systematic Review and Meta-Analysis

BACKGROUND

Posttraumatic stress disorder (PTSD) is overrepresented in prison relative to community populations and can be difficult to manage in an environment which can inherently exacerbate trauma-related symptomology. Little is known about the effectiveness of trauma-focused interventions in prison and less is known about factors that moderate the effectiveness of these interventions.

AIM/METHODS

We examined the effectiveness of trauma-focused interventions in prison relative to prison controls using meta-analytic techniques. We further used meta-regression analysis to examine treatment, methodological and participant-level moderators to determine factors that increased the effectiveness of these interventions.

RESULTS

From 16 studies eligible for the meta-analysis, we found a small but significant effect size for trauma-focused interventions. Phase 2 trauma processing interventions and interventions delivered individually led to greater reductions in PTSD symptoms. Studies utilizing an active treatment control resulted in smaller effect sizes than those using waitlist or no contact controls. Treatment length, study quality, outcome type, and gender were not significant moderators of treatment effectiveness.

CONCLUSION

Findings from this review are encouraging but should be interpreted with caution. Results suggest that trauma processing therapies, and individual modality trauma-focused interventions can be effective and delivered successfully in prison. However, inadequate comparison groups do not allow a firm conclusion to be drawn. There is a need for high quality Randomized Controlled Trial's that additionally measure Complex PTSD, utilize a modular treatment approach, and include treatments recommended in the National Institute for health and Care Excellence (NICE) guidelines such as Trauma-focused CBT and Eye Movement Desensitization Reprocessing (EMDR).

Microvascular impairments detected by optical coherence tomography angiography in multiple sclerosis patients: A systematic review and meta-analysis

Purpose

A systematic review and meta-analysis was conducted to investigate changes in retinal and choroidal microvasculature in patients with multiple sclerosis (MS) using optical coherence tomography angiography (OCTA).

Methods

PubMed and Google Scholar were searched for studies that compared retinal and choroidal microvasculature between MS and healthy controls (HC) with OCTA. MS patients were divided into 2 groups: MS with (MSON) or without optic neuritis (MSNON).

Results

Totally, 13 studies including 996 MS eyes and 847 HC eyes were included. Compared with the HC, the vessel density of the whole superficial vascular complex (SVC) was reduced by 2.27% and 4.30% in the MSNON and MSON groups, respectively. The peripapillary vessel density was 2.28% lower and 4.96% lower in the MSNON and MSON groups, respectively, than in the HC. Furthermore, the MSON group had significant lower vessel density of the SVC (mean difference [MD] = -2.17%, P < 0.01) and lower peripapillary vessel density (MD = -2.02%, P = 0.02) than the MSNON group. No significant difference was found in the deep vascular complex or choriocapillaris densities among MSNON, MSON or HC groups (P > 0.05). Meta-regression analyses suggested that illness duration and the Expanded Disability Status Scale scores of MS patients were possible sources of heterogeneity (P < 0.05).

Conclusion

The retinal SVC and peripapillary vessel density decreased significantly in MS eyes, especially in eyes with optic neuritis. Retinal microvasculature is a potential biomarker of disease progression in MS.

Are risk-need-responsivity principles golden? A meta-analysis of randomized controlled trials of community correction programs

Objectives

Using meta-analysis to determine the effect size of the recidivism rate of participants in community correction programs that are conducted entirely in community settings.

Methods

Following the Preferred Reported Items for Systematic Reviews and Meta-analyses (PRISMA), 25 qualified studies contributed 35 independent effect sizes.

Results

Full participation in a program significantly reduced the recidivism rate. Participant age was a significant moderator of heterogeneity. Those aged over 18 have lower recidivism rates. Interventions that fully follow the Risk-Need-Responsivity (RNR) design principles achieved similar results to those that did not. Recidivism rates increase more than 12 months after the program ends.

Conclusions

The effectiveness of community correctional programs varies depending on the participant's age. The RNR principles are not golden. The above factors should be carefully considered when conducting intervention design in the future. Results should be interpreted with caution due to the literature's high heterogeneity and low quality.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11292-022-09550-w.

Effectiveness of exercise intervention during pregnancy on high-risk women for gestational diabetes mellitus prevention: A meta-analysis of published RCTs

Objective

We aimed at investigating the preventive role of exercise intervention during pregnancy, in high-risk women for gestational diabetes mellitus (GDM).

Materials and methods

We searched PubMed, CENTRAL, and Scopus for randomized controlled trials (RCTs) that evaluated exercise interventions during pregnancy on women at high risk for GDM. Data were combined with random effects models. Between study heterogeneity (Cochran’s Q statistic) and the extent of study effects variability [I² with 95% confidence interval (CI)] were estimated. Sensitivity analyses examined the effect of population, intervention, and study characteristics. We also evaluated the potential for publication bias.

Results

Among the 1,508 high-risk women who were analyzed in 9 RCTs, 374 (24.8%) [160 (21.4%) in intervention, and 214 (28.1%) in control group] developed GDM. Women who received exercise intervention during pregnancy were less likely to develop GDM compared to those who followed the standard prenatal care (OR 0.70, 95%CI 0.52, 0.93; P-value 0.02) [Q 10.08, P-value 0.26; I² 21% (95%CI 0, 62%]. Studies with low attrition bias also showed a similar result (OR 0.70, 95%CI 0.51, 0.97; P-value 0.03). A protective effect was also supported when analysis was limited to studies including women with low education level (OR 0.55; 95%CI 0.40, 0.74; P-value 0.0001); studies with exercise intervention duration more than 20 weeks (OR 0.54; 95%CI 0.40, 0.74; P-value 0.0007); and studies with a motivation component in the intervention (OR 0.69, 95%CI 0.50, 0.96; P-value 0.03). We could not exclude large variability in study effects because the upper limit of I² confidence interval was higher than 50% for all analyses. There was no conclusive evidence for small study effects (P-value 0.31).

Conclusions

Our study might support a protective effect of exercise intervention during pregnancy for high-risk women to prevent GDM. The protective result should be corroborated by large, high quality RCTs.

Tenets for the Proper Conduct and Use of Meta-Analyses: A Practical Guide for Neurosurgeons

Neurosurgeons today are inundated with rapidly amassing neurosurgical research publications. Systematic reviews and meta-analyses have consequently surged in popularity because, when executed properly, they constitute a high level of evidence and may save busy neurosurgeons many hours of combing and reviewing the literature for relevant articles. Meta-analysis refers to the quantitative (and discretionary) component of systematic reviews. It involves applying statistical techniques to combine effect sizes from multiple studies, which might offer more actionable insights than a systematic review without meta-analysis. Well-executed meta-analyses may prove instructive for clinical practice, but poorly conducted ones sow confusion and have the potential to cause harm. Unfortunately, recent audits have found the conduct and reporting of meta-analyses in neurosurgery (but also other surgical disciplines) to be relatively lackluster in methodologic rigor and compliance to established guidelines. Some of these deficiencies can be easily remedied through better awareness and adherence to prescribed standards-which will be reviewed in this article-but others stem from inherent problems with the source data (e.g., poor reporting of original research) as well as unique constraints faced by surgery as a field (e.g., lack of equipoise for randomized trials, or existence of learning curves for novel surgical procedures, which can lead to temporal heterogeneity), which may require unconventional tools (e.g., cumulative meta-analysis) to address. Therefore, it is also our goal to take stock of the unique issues encountered by surgeons who do meta-analysis and to highlight various techniques-some of which less well-known-to address such challenges.

SGLT2 Inhibitors and Kidney and Cardiac Outcomes According to Estimated GFR and Albuminuria Levels: A Meta-analysis of Randomized Controlled Trials

Rationale & Objective

There are few data on the absolute effects of sodium/glucose cotransporter 2 (SGLT2) inhibitors, despite their importance in treatment decision making. We investigated absolute treatment effects according to baseline kidney disease status.

Study Design

Meta-analysis.

Study Populations

Adults with type 2 diabetes, chronic kidney disease, or heart failure.

Selection Criteria for Studies

Randomized controlled trials of SGLT2 inhibitors (10 trials to November 20, 2020) for clinical outcomes of kidney disease progression, heart failure events, and major cardiovascular events.

Data Extraction

Publications of 10 trials to November 20, 2020.

Analytical Approach

The incidence rate difference (IRD) between SGLT2 inhibitor and placebo was compared across estimated glomerular filtration rate (eGFR) or urinary albumin-creatinine ratio (UACR) subgroups.

Results

Subgroup analyses included data from seven trials (61,821 participants with diabetes or chronic kidney disease). SGLT2 inhibitor treatment, in eGFR subgroups of <45, 45 to <60, and ≥60 mL/min/1.73 m², reduced 16.0, 9.5, and 1.9 heart failure events per 1,000 patient-year, respectively (P < 0.001 for heterogeneity). In urine UACR subgroups of >300, 30 to 300, and <30 mg/g, SGLT2 inhibitors reduced 17.3, 1.4, and 2.2 kidney disease events per 1,000 patient-year, respectively (P < 0.001 for heterogeneity), and 14.8, 8.7, and 2.1 heart failure events per 1,000 patient-year, respectively (P = 0.006 for heterogeneity). The pooled IRDs for major cardiovascular events were also greater in lower eGFR or overt albuminuria subgroups. In secondary analyses, risk differences calculated using pooled baseline and relative risks were comparable to the pooled IRDs, while the relative risk reductions for kidney and heart failure outcomes were consistent across the subgroups. For treatment-related harms, IRDs were similar between eGFR subgroups.

Limitations

Study-level data rather than individual patient data were used.

Conclusions

SGLT2 inhibitor treatment resulted in greater reductions of cardiovascular events in patients with lower eGFR and higher albuminuria and had substantially greater absolute benefits of renoprotection in patients with overt albuminuria than in their counterparts.

Efficacy and histologic accuracy of underwater versus conventional endoscopic mucosal resection for large (>20 mm) colorectal polyps: a comparative review and meta-analysis

BACKGROUND AND AIMS

Major limitations with conventional EMR (C-EMR) include high rates of polyp recurrence and low en-bloc resection rates, especially for lesions >20 mm in size. Underwater EMR (U-EMR) has emerged as an alternate technique for en-bloc resection of larger lesions. We conducted a systematic review and meta-analysis comparing the efficacy and safety of the 2 techniques.

METHODS

Multiple databases were searched through June 2020 for studies that compared outcomes of U-EMR and C-EMR for colorectal lesions. Meta-analysis was performed to determine pooled odds ratios (ORs) of successful R0, en-bloc, and piecemeal resection of colorectal lesions. We compared the rates of polyp recurrence at follow-up, diagnostic accuracy for colorectal cancer, and adverse events with the 2 techniques.

RESULTS

Eleven studies, including 4 randomized controlled trials (RCTs) with 1851 patients were included in the final analysis. A total of 1071 lesions were removed using U-EMR, and 1049 lesions were removed using C-EMR. Although U-EMR had an overall superior en-bloc resection rate compared with C-EMR (OR, 1.9; 95% confidence interval [CI], 1-3.5; P = .04), both techniques were comparable in terms of polyps >20 mm in size (OR, 0.8; 95% CI, 0.3-2.1; P = .75), R0 resection (OR, 3.1; 95% CI, 0.74-12.6; P = .14), piecemeal resection (OR, 3.1; 95% CI, 0.74-12.6; P = .13), and diagnostic accuracy for colorectal cancer (OR, 1.1; 95% CI, 0.6-1.8; P = .82). There were lower rates of polyp recurrence (OR, 0.3; 95% CI, 0.1-0.8; P = .01) and incomplete resection (OR, 0.4; 95% CI, 0.2-0.5; P = .001) with U-EMR. Both techniques have comparable resection times and safety profiles.

CONCLUSIONS

Our results support the use of U-EMR over C-EMR for successful resection of colorectal lesions. Further randomized controlled trials are needed to evaluate the efficacy of U-EMR for resecting polyps >20 mm in size.

Short versus standard esophageal myotomy in achalasia patients: a systematic review and meta-analysis of comparative studies

Background and study aims  Despite the clinical efficacy of peroral endoscopic myotomy (POEM), postoperative symptomatic gastroesophageal reflux disease (GERD) remains a major concern. While it is known that length of the gastric myotomy affects postoperative GERD, the clinical relevance of variation in esophageal myotomy length is not well known. We performed a systematic review and meta-analysis of studies comparing outcomes of short versus standard myotomy length in patients with achalasia. Patients and methods  We searched multiple databases from inception through November 2020 to identify studies that reported on outcomes of achalasia patients who underwent short compared with standard esophageal myotomy. Meta-analysis was performed to determine pooled odds ratio (OR) of clinical success, GERD outcomes, and adverse events with the two techniques. Results  5 studies with 474 patients were included in the final analysis (short myotomy group 214, standard myotomy group 260). There was no difference in clinical success (OR 1.17, 95 % confidence interval [CI] 0.54-2.52; I2 0 %; P  = 0.69), postoperative symptomatic GERD (OR 0.87, 95 %CI 0.44-1.74; I2 29 %; P  = 0.70), and overall adverse events (OR 0.52, 95 %CI 0.19-1.38; I2 40 %; P  = 0.19), between the two groups. Incidence of postoperative erosive esophagitis as determined by endoscopy was lower in the short myotomy group (OR 0.50, 95 %CI 0.24-1.03; I2 0 %; P  = 0.06). Conclusion  Our analysis showed that performing POEM with short esophageal myotomy in achalasia was as safe and effective as standard myotomy, with lower incidence of postoperative erosive esophagitis.

Multimedia based education on bowel preparation improves adenoma detection rate: Systematic review & meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Colorectal cancer (CRC) is the third most common cause of cancer worldwide. Studies have shown a strong association between screening colonoscopy and a reduced risk of death from colorectal cancers. The incidence of poor bowel preparation has been reported in up to 25% cases. We conducted a systematic review and comprehensive meta-analysis to evaluate the effect of patient education using multimedia platforms on adenoma detection rate and adequacy of bowel preparation.

METHODS

Multiple databases were searched through May 2020 for studies that reported the efficacy of multimedia education (smartphone app and online audio-visual aids) in improving quality of bowel preparation and its effect on adenoma detection rate (ADR). Meta-analysis was performed to determine whether multimedia based patient education (MM) helps improve ADR and bowel preparation quality as compared to controls (CT).

RESULTS

We included 13 randomized controlled trials with a total of 3754 patients. Eight studies reported outcomes on ADR and 12 reported on adequacy of bowel preparation. Overall ADR was higher in patients receiving multimedia based education as compared to CT (risk ratio (RR) 1.25, confidence interval (CI) 1.01-1.56, P = 0.04). A higher proportion of patients receiving multimedia based education achieved adequate bowel preparation (RR 1.2, CI 1.1-1.3, P = 0.001). In patients with mean age over 50 years, ADR was better in MM cohort as compared to controls (RR 1.3, CI 1.1-1.6, P = 0.001).

CONCLUSION

Pre-colonoscopy patient education using multimedia based platforms seems to improve ADR and the adequacy of bowel preparation.

Characteristics and quality of systematic reviews and meta-analyses of observational nutritional epidemiology: a cross-sectional study

BACKGROUND

Dietary recommendations and policies should be guided by rigorous systematic reviews. Reviews that are of poor methodological quality may be ineffective or misleading. Most of the evidence in nutrition comes from nonrandomized studies of nutritional exposures (usually referred to as nutritional epidemiology studies), but to date methodological evaluations of the quality of systematic reviews of such studies have been sparse and inconsistent.

OBJECTIVES

We aimed to investigate the quality of recently published systematic reviews and meta-analyses of nutritional epidemiology studies and to propose guidance addressing major limitations.

METHODS

We searched MEDLINE (January 2018-August 2019), EMBASE (January 2018-August 2019), and the Cochrane Database of Systematic Reviews (January 2018-February 2019) for systematic reviews of nutritional epidemiology studies. We included a random sample of 150 reviews.

RESULTS

Most reviews were published by authors from Asia (n = 49; 32.7%) or Europe (n = 43; 28.7%) and investigated foods or beverages (n = 60; 40.0%) and cancer morbidity and mortality (n = 54; 36%). Reviews often had important limitations: less than one-quarter (n = 30; 20.0%) reported preregistration of a protocol and almost one-third (n = 42; 28.0%) did not report a replicable search strategy. Suboptimal practices and errors in the synthesis of results were common: one-quarter of meta-analyses (n = 30; 26.1%) selected the meta-analytic model based on statistical indicators of heterogeneity and almost half of meta-analyses (n = 50; 43.5%) did not consider dose-response associations even when it was appropriate to do so. Only 16 (10.7%) reviews used an established system to evaluate the certainty of evidence.

CONCLUSIONS

Systematic reviews of nutritional epidemiology studies often have serious limitations. Authors can improve future reviews by involving statisticians, methodologists, and researchers with substantive knowledge in the specific area of nutrition being studied and using a rigorous and transparent system to evaluate the certainty of evidence.

Diagnostic Performance of Adjunctive Imaging Modalities Compared to Mammography Alone in Women with Non-Dense and Dense Breasts: A Systematic Review and Meta-Analysis

PURPOSE

To compare the diagnostic performance of mammography (MG) alone versus MG combined with adjunctive imaging modalities, including handheld ultrasound (HHUS), automated breast ultrasound (ABUS), digital breast tomosynthesis (DBT), contrast-enhanced mammography (CEM), and magnetic resonance imaging (MRI) in women with non-dense and dense breasts.

PATIENTS AND METHODS

Medline, Embase, PubMed, CINAHL, Scopus, and the Web of Science databases were searched up to October 2019. Quality assessment was performed using QUADAS-2. RevMan 5.3 was used to conduct a meta-analysis of the studies.

RESULTS

In dense breasts, adding adjunctive modalities significantly increased cancer detection rates (CDRs): HHUS (relative risk [RR] = 1.49; 95% confidence interval [CI], 1.19-1.86; P = .0005); ABUS (RR = 1.44; 95% CI, 1.16-1.78; P = .0008); DBT (RR = 1.38; 95% CI, 1.14-1.67; P = .001); CEM (RR = 1.37; 95% CI, 1.12-1.69; P = .003); and MRI (RR = 2.16; 95% CI, 1.81-2.58; P < .00001). The recall rate was significantly increased by HHUS (RR = 2.03; 95% CI, 1.89-2.17; P < .00001), ABUS (RR = 1.90; 95% CI, 1.81-1.99; P < .00001), and MRI (RR = 2.71; 95% CI, 1.73-4.25; P < .0001), but not by DBT (RR = 1.14; 95% CI, 0.95-1.36; P = .15). In non-dense breasts, HHUS and MRI showed significant increases in CDRs but not DBT: HHUS (RR = 1.14; 95% CI, 1.01-1.29; P = .04); MRI (RR = 1.78; 95% CI, 1.14-2.77; P = .01); and DBT (RR = 1.09; 95% CI, 1.13-1.75; P = .08). The recall rate was also significantly increased by HHUS (RR = 1.43; 95% CI, 1.28-1.59; P < .00001) and MRI (RR = 3.01; 95% CI, 1.68-5.39; P = .0002), whereas DBT showed a non-significant reduction (RR = 0.83; 95% CI, 0.65-1.05; P = .12).

CONCLUSION

Adding adjunctive modalities to MG increases CDRs in women with dense and non-dense breasts. Ultrasound and MRI increase recall rates across all breast densities; however, MRI results in higher values for both CDRs and recall rates.

A Comprehensive Meta-analysis on Short-term and Working Memory Dysfunction in Parkinson's Disease

A previous meta-analysis demonstrated short-term memory (STM) and working memory (WM) dysfunction in patients with Parkinson's disease (PD). However, considerable research on the topic that calls into question the extent of such impairments in PD has since been published. The aim of the present quantitative review was to provide the largest statistical overview on STM and WM dysfunction in Parkinson's disease (PD), while simultaneously providing novel insights on moderating factors of effect size heterogeneity in PD. The systematic literature search in PubMed, PsycINFO, PsycArticles, Scopus and Web of Science databases allowed us to estimate 350 effect sizes from 145 empirical studies that reported STM and WM scores for patients with PD against healthy controls. The outcomes indicated general dysfunction in the visuospatial domain and poor verbal WM in PD. Subgroup analyses suggested that mild cognitive impairment is associated with STM and WM difficulties in PD. Furthermore, meta-regression analyses revealed that disease duration accounted for more than 80% of the visuospatial STM effect size variance (β = 0.136, p < .001, R² = .8272), larger daily levodopa equivalent dose was associated with WM dysfunction (verbal: β = -0.001, p = .016, R² = .1812; visuospatial: β = 0.003, p = .069, R² = .2340), and years of education partially explained the verbal STM effect size variance (β = -0.027, p = .040, R² = .1171). Collectively, these findings advance our understanding of underlying factors that influence STM and WM functioning in PD, while at the same time providing novel directions for future research.

Prescription psychostimulants for the treatment of stimulant use disorder: a systematic review and meta-analysis

RATIONALE

Agonist-based pharmacologic intervention is an accepted approach in treatment of opioid and tobacco use disorders.

OBJECTIVES

We conducted a systematic review and meta-analysis to evaluate usefulness of an agonist approach as treatment of (psycho)stimulant use disorder (PSUD).

METHODS

We reviewed PubMed/Medline, LILACS, and ClinicalTrials.gov databases searching for randomized, double-blind, placebo-controlled, parallel-design studies evaluating outcomes of individuals treated for cocaine- or amphetamine-type substance use disorder. We combined results of all trials that included the following prescription psychostimulants (PPs): modafinil, methylphenidate, or amphetamines (mixed amphetamine salts, lisdexamphetamine, and dextroamphetamine). The combined sample consisted of 2889 patients. Outcomes of interest included the following: drug abstinence (defined as 2-3 weeks of sustained abstinence and the average maximum days of consecutive abstinence), percentage of drug-negative urine tests across trial, and retention in treatment. We conducted random-effects meta-analyses and assessed quality of evidence using the GRADE system.

RESULTS

Thirty-eight trials were included. Treatment with PPs increases rates of sustained abstinence [risk ratio (RR) = 1.45, 95% confidence interval (CI) = (1.10, 1.92)] and duration of abstinence [mean difference (MD) = 3.34, 95% CI = (1.06, 5.62)] in patients with PSUD, particularly those with cocaine use disorder (very low-quality evidence). Prescription amphetamines were particularly efficacious in promoting sustained abstinence in patients with cocaine use disorder [RR = 2.44, 95% CI = (1.66, 3.58)], and higher doses of PPs were particularly efficacious for treatment of cocaine use disorder [RR = 1.95, 95% CI = (1.38, 2.77)] (moderate-quality evidence). Treatment with prescription amphetamines also yielded more cocaine-negative urines [MD = 8.37%, 95% CI = (3.75, 12.98)]. There was no effect of PPs on the retention in treatment.

CONCLUSION

Prescription psychostimulants, particularly prescription amphetamines given in robust doses, have a clinically significant beneficial effect to promote abstinence in the treatment of individuals with PSUD, specifically the population with cocaine use disorder.

Advances in Management of Brain and Leptomeningeal Metastases

PURPOSE OF REVIEW

The management of brain and leptomeningeal metastases has changed significantly over the past decade.

RECENT FINDINGS

Historically, radiation therapy had been the mainstay of treatment. Several strategies to limit toxicities with radiation have been developed in the recent years. Increasingly systemic therapy options are being considered an important therapeutic option for CNS metastases. Numerous novel small molecule inhibitors and immunotherapy agents have intracranial activity to varying degrees, in addition to good extracranial disease control. Overall, the prognosis of select patients with CNS metastases has improved over the past several years with advent of new therapeutic strategies. Systemic therapy options with CNS benefit should be considered in select patients with small and asymptomatic CNS metastases. Further areas of research focus on molecular alterations predisposing to CNS metastases, identification of small molecule inhibitors with CNS activity, and the combination of radiation therapy and immunotherapy.

Comparison of four heterogeneity measures for meta-analysis

RATIONALE, AIMS, AND OBJECTIVES

Heterogeneity is a critical issue in meta-analysis, because it implies the appropriateness of combining the collected studies and impacts the reliability of the synthesized results. The Q test is a traditional method to assess heterogeneity; however, because it does not have an intuitive interpretation for clinicians and often has low statistical power, many meta-analysts alter to use some measures, such as the I² statistic, to quantify the extent of heterogeneity. This article aims at providing a summary of available tools to assess heterogeneity and comparing their performance.

METHODS

We reviewed four heterogeneity measures (I² , R ̂ I , R ̂ M , and R ̂ b ) and illustrated how they could be treated as test statistics like the Q statistic. These measures were compared with respect to statistical power based on simulations driven by three real-data examples. The pairwise agreement among the four measures was also evaluated using Cohen's κ coefficient.

RESULTS

Generally, R ̂ I was slightly more powerful than the Q test, while its type I error rate might be slightly inflated. The power of I² was fairly close to that of Q. The R ̂ M and R ̂ b statistics might have low powers in some cases. Because the differences between the powers of I² , R ̂ I , and Q were often tiny, meta-analysts might not expect I² and R ̂ I to yield significant heterogeneity if the Q test failed to do so. In addition, I² and R ̂ I had fairly good agreement based on the simulated meta-analyses, but all other pairs of heterogeneity measures generally had poor agreement.

CONCLUSION

The I² and R ̂ I statistics are recommended for measuring heterogeneity. Meta-analysts should use the heterogeneity measures as descriptive statistics which have intuitive interpretations from the clinical perspective, instead of determining the significance of heterogeneity simply based on their magnitudes.

The choice and definition of summary measure for meta-analysis of clinical studies with binary outcomes: effect on clinical interpretation

Many systematic reviews and meta-analyses concern the effect of a healthcare intervention on a binary outcome i.e. occurrence (or not) of a particular event. Usually, the overall effect, pooled across all studies included in the meta-analysis, is summarised using the odds ratio (OR) or the relative risk (RR). Under most circumstances, it is obvious how to identify what should be considered as the event of interest-for example, death or a clinically important side-effect. However, on occasion it may not be clear in which "direction" the event should be specified-such as attendance (vs non-attendance) at cancer screening. Usually, this choice is not critical to the overall conclusion of the meta-analysis, but occasionally it can lead to differences in how the included studies are pooled, ultimately affecting the overall meta-analytic result, particularly when using RRs rather than ORs. In this commentary, we will explain this phenomenon in more detail using examples from the literature, and explore how analysts and readers can avoid some potential pitfalls.

The Predictive Approaches to Treatment effect Heterogeneity (PATH) Statement: Explanation and Elaboration

The PATH (Predictive Approaches to Treatment effect Heterogeneity) Statement was developed to promote the conduct of, and provide guidance for, predictive analyses of heterogeneity of treatment effects (HTE) in clinical trials. The goal of predictive HTE analysis is to provide patient-centered estimates of outcome risk with versus without the intervention, taking into account all relevant patient attributes simultaneously, to support more personalized clinical decision making than can be made on the basis of only an overall average treatment effect. The authors distinguished 2 categories of predictive HTE approaches (a "risk-modeling" and an "effect-modeling" approach) and developed 4 sets of guidance statements: criteria to determine when risk-modeling approaches are likely to identify clinically meaningful HTE, methodological aspects of risk-modeling methods, considerations for translation to clinical practice, and considerations and caveats in the use of effect-modeling approaches. They discuss limitations of these methods and enumerate research priorities for advancing methods designed to generate more personalized evidence. This explanation and elaboration document describes the intent and rationale of each recommendation and discusses related analytic considerations, caveats, and reservations.

Clinical outcomes of laparoscopic versus open right hepatectomy for liver tumors: A meta-analysis

BACKGROUND

Laparoscopic right hepatectomy (LRH) is one of the most challenging procedures. Right liver resections have been always performed in open procedure and open right hepatectomy (ORH) was initially considered as routine way. Moreover, it is unclear how beneficial the minimally invasive technique is to patients; thus, we conducted a meta-analysis to acquire a more reliable conclusion about the feasibility and safety of LRH compared with ORH.

METHODS

We comprehensively searched the electronic databases of PubMed, Embase, and the Cochrane Library using the key words. Meta-analysis was performed using the Review Manager, with results expressed as odds ratio and weighted mean difference with 95% confidence intervals. The fixed-effect model was selected initially if high heterogeneity was not present between the studies; otherwise, the randomized-effect model was used. Subgroup analysis was performed based on different surgical methods of pure laparoscopic operation or hand-assisted operation.

RESULTS

Seven studies with 467 patients were included. In the overall analysis, less intraoperative blood loss (MD = -155.17; 95% CI, -238.89, -71.45; P = .0003) and a shorter length of stay (MD = -4.45; 95% CI, -5.84, -3.07; P < .00001) were observed in the LRH group compared to the ORH group. There were fewer overall complications (OR = 0.30; 95% CI, 0.10, 0.90; P = 0.03) and severe complications (OR = 0.24; 95% CI, 0.10, 0.58; P = .002;) in the LRH group than in the ORH group. The disadvantage of LRH was the longer operative time (MD = 49.39; 95% CI, 5.33, 93.45; P = .03). No significant difference was observed between the 2 groups in portal occlusion, rate of R0 resection, transfusion rate, mild complications, and postoperative mortality. In the subgroup analysis, intraoperative blood loss was significantly lower in the pure LRH group and hand-assist LRH group compared with ORH group. Length of stay was shorter by use of pure LRH and hand-assisted LRH manners than ORH. The incidence rate of complications was lower in the pure LRH group than in the ORH group. In contrast, there was no significant difference between hand-assisted LRH group and ORH group.

CONCLUSION

Compared to ORH, LRH has short-term surgical advantages and leads to a shorter recovery time in selected patients. We speculate that the operative time of LRH is closer with ORH. Overall, LRH can be considered a feasible choice in routine clinical practice with experienced surgeons, although more evidence is needed to make a definitive conclusion.

Can exergames contribute to improving walking capacity in older adults? A systematic review and meta-analysis

BACKGROUND

The accessibility, low cost and motivation generated by exergames has fostered its rapid expansion as a rehabilitation technique.

OBJECTIVE

To estimate the effectiveness of rehabilitation programs using IVGT in improving walking capacity of people aged 60 years and over.

MATERIALS AND METHODS

The electronic data research following the PRISMA Statement (Scopus, Cochrane, Web of Science, OT Seeker, National Guideline Clearinghouse, Trip Database, CSIC Spanish National Research Council) was completed in September 2018. The results of randomized clinical trials using exergames for rehabilitation of walking capacity were combined. The calculations have followed the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions. The Grading of Recommendations Assessment, Development and Evaluation system was used to evaluate the quality of the evidence.

RESULTS

We obtained data from 14 trials, including 11 meta-analysis studies. The size of exergames effects on walking capacity is moderate, but significant (SMD -0.56; 95 % CI: -0.90, -0.21; p = 0.002). Effectiveness was greater to recover the ability to transfer from one position or place to another (SMD -1.02; CI 95 %: -1.70, -0.35; P = 0.003). The intervention protocols, their duration and intensity varied considerably. The lack of masking, the allocation concealment, the absence of assessor blinding were the main causes of bias so the final grade of evidence has been low for walking and very low for transfers.

CONCLUSIONS

Positive clinical effects of exergames have been found to improve walking capacity, but the quality of evidence to refute its effectiveness is weak with risk of bias. Further research is needed in order to know the actual magnitude of its effect.

Many continuous variables should be analyzed using the relative scale: a case study of β2-agonists for preventing exercise-induced bronchoconstriction

BACKGROUND

The relative scale adjusts for baseline variability and therefore may lead to findings that can be generalized more widely. It is routinely used for the analysis of binary outcomes but only rarely for continuous outcomes. Our objective was to compare relative vs absolute scale pooled outcomes using data from a recently published Cochrane systematic review that reported only absolute effects of inhaled β₂-agonists on exercise-induced decline in forced-expiratory volumes in 1 s (FEV₁).

METHODS

From the Cochrane review, we selected placebo-controlled cross-over studies that reported individual participant data (IPD). Reversal in FEV₁ decline after exercise was modeled as a mean uniform percentage point (pp) change (absolute effect) or average percent change (relative effect) using either intercept-only or slope-only, respectively, linear mixed-effect models. We also calculated the pooled relative effect estimates using standard random-effects, inverse-variance-weighting meta-analysis using study-level mean effects.

RESULTS

Fourteen studies with 187 participants were identified for the IPD analysis. On the absolute scale, β₂-agonists decreased the exercise-induced FEV₁ decline by 28 pp., and on the relative scale, they decreased the FEV₁ decline by 90%. The fit of the statistical model was significantly better with the relative 90% estimate compared with the absolute 28 pp. estimate. Furthermore, the median residuals (5.8 vs. 10.8 pp) were substantially smaller in the relative effect model than in the absolute effect model. Using standard study-level meta-analysis of the same 14 studies, β₂-agonists reduced exercise-induced FEV₁ decline on the relative scale by a similar amount: 83% or 90%, depending on the method of calculating the relative effect.

CONCLUSIONS

Compared with the absolute scale, the relative scale captures more effectively the variation in the effects of β₂-agonists on exercise-induced FEV₁-declines. The absolute scale has been used in the analysis of FEV₁ changes and may have led to sub-optimal statistical analysis in some cases. The choice between the absolute and relative scale should be determined based on biological reasoning and empirical testing to identify the scale that leads to lower heterogeneity.

Interval estimation of proportion ratios for stratified bilateral correlated binary data

Confidence interval (CI) methods for the ratio of two proportions in the presence of correlated bilateral binary data are constructed for comparative clinical trials with stratified design. Simulations are conducted to evaluate the performance of the presented CIs with respect to mean coverage probability (MCP), mean interval width (MIW), and the ratio of mesial non-coverage probability to the distal non-coverage probability (RMNCP). Based on the empirical results, we suggest the use of the proposed CI method based on the complete score statistics (CS) for general applications. An example from a rheumatology study is used to demonstrate the proposed methodologies.

Clinical heterogeneity in random-effect meta-analysis: Between-study boundary estimate problem

Random-effect meta-analysis is commonly applied to estimate overall effects with unexplained heterogeneity across studies. However, standard methods, including (restricted) maximum likelihood (ML or REML), frequently produce (near) zero estimates for between-study variance parameters. Consequently, these methods are reduced to simple and unrealistic fixed-effect models, resulting in an ignorance of the substantial clinical heterogeneity and sometimes leading to incorrect conclusions. To solve the boundary estimate problem, we propose (1) an adjusted maximum likelihood method for the between-study variance that maximizes a likelihood defined as a product of a standard likelihood and a Gaussian class of adjustment factor and (2) a framework using sensitivity analysis by developing a new criterion to check for the occurrence of the boundary estimate. Although the adjustment introduces bias to the overall effects to ensure strictly positive estimates of the between-study variance when the number of studies K is small, the bias asymptotically approaches zero, resulting in the same estimates derived from the REML method. Moreover, the adjusted maximum likelihood estimator of the between-study variance is consistent for large K, and interestingly, the REML method and our method are equivalent in terms of mean squared error criterion, up to O(K^-1 ). We illustrate our approach with a motivating example to examine the controversial result of a meta-analysis for 24 randomized controlled trials of human albumin. Numerical evaluations show that our approach produces no boundary estimates but similar synthesized results with the standard maximum likelihood methods as those produced by conventional methods, especially with a small number of studies.

How does hard-to-reach status affect antiretroviral therapy adherence in the HIV-infected population? Results from a meta-analysis of observational studies

Background

Socially disadvantaged groups, such as drug users, sex workers and homeless individuals, are labelled as “hard-to-reach” (HTR) in public health and medical research. HIV disproportionately impacts these populations, but data on how the HTR status could affect antiretroviral therapy (ART) adherence among HIV-positive people are limited and have not been previously synthesized in a systematic manner. We performed a meta-analysis to explore the association between HTR status and optimal antiretroviral therapy adherence in the HIV-infected population to provide evidence and recommendations regarding ART adherence improvement and HIV infection control and prevention among HTR people.

Methods

The PubMed, EMBASE, and Cochrance Library databases and the bibliographies of relevant studies were systematically searched up to December 2018. Full-text studies published in English were included, and no geographic or race restrictions were applied. Studies that quantitatively assessed the association between HTR status and optimal ART adherence among HIV-infected populations with a status of homelessness, sex work, or drug use were eligible for inclusion. We estimated the pooled odds ratios (ORs) of HTR characteristics related to ART adherence from each eligible study using a random effects model. The sensitivity, heterogeneity and publication bias were assessed.

Results

Our search identified 593 articles, of which 29 studies were eligible and included in this meta-analysis. The studies were carried out between 1993 and 2017 and reported between 1999 and 2018. The results showed that HTR status resulted in a 45% reduction in the odds of achieving optimal ART adherence compared to odds in the general population (OR = 0.55, 95% confidential intervals (CIs) 0.49–0.62), and this significant inverse association was consistently found regardless of study design, exposure measurement, adherence cut-off points, etc. Subgroup analyses revealed that the HTRs tend to be suboptimal adhering during a longer observational period.

Conclusions

HIV treatment adherence is extremely negatively affected by HTR status. It is crucial to develop appropriate interventions to improve ART adherence and health outcomes among HTR people who are HIV-infected.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-7135-0) contains supplementary material, which is available to authorized users.

5-HTTLPR and COMT Val158Met are not associated with alexithymia: New evidence and meta-analyses

BACKGROUNDS

Alexithymia refers to the difficulties in identifying and describing one's own emotions, lacking of imagination, and an externally oriented thinking style. Studies up to date have examined the associations of 5-HTTLPR and COMT Val158Met polymorphisms with alexithymia. However, the previous findings were mixed.

METHODS

We replicated the associations by scoring on alexithymia with the 20-item Toronto Alexithymia Scale and genotyping the polymorphisms of 5-HTTLPR and COMT Val158Met in a large population of college students (N = 1698). Moreover, we also meta-analyzed the associations with five samples (N = 7517) for the 5-HTTLPR and with five samples (N = 2186) for the COMT Val158Met.

RESULTS

Neither the replicated study nor the meta-analyses indicated the 5-HTTLPR and COMT Val158Met were associated with alexithymia.

CONCLUSIONS

The findings suggest that the 5-HTTLPR and COMT Val158Met polymorphisms are not associated with alexithymia. However, genetic-environmental studies with different ethnicity and psychopathology should be carried in future.

Statistical properties of methods based on the Q-statistic for constructing a confidence interval for the between-study variance in meta-analysis

The effect sizes of studies included in a meta‐analysis do often not share a common true effect size due to differences in for instance the design of the studies. Estimates of this so‐called between‐study variance are usually imprecise. Hence, reporting a confidence interval together with a point estimate of the amount of between‐study variance facilitates interpretation of the meta‐analytic results. Two methods that are recommended to be used for creating such a confidence interval are the Q‐profile and generalized Q‐statistic method that both make use of the Q‐statistic. These methods are exact if the assumptions underlying the random‐effects model hold, but these assumptions are usually violated in practice such that confidence intervals of the methods are approximate rather than exact confidence intervals. We illustrate by means of two Monte‐Carlo simulation studies with odds ratio as effect size measure that coverage probabilities of both methods can be substantially below the nominal coverage rate in situations that are representative for meta‐analyses in practice. We also show that these too low coverage probabilities are caused by violations of the assumptions of the random‐effects model (ie, normal sampling distributions of the effect size measure and known sampling variances) and are especially prevalent if the sample sizes in the primary studies are small.

The number needed to treat and relevant between-trial comparisons of competing interventions

The number needed to treat (NNT) is considered an intuitive as well as popular effect measure. The aims of this review were to 1) explain why we cannot compare trial-specific NNT estimates for the competing treatments evaluated in different randomized controlled trials (RCTs) and 2) outline the principles of how relative treatment effects of different trials can be compared and results can be presented as NNT, without violating the principles of valid between-trial comparisons. Our premise is that ratio measures for relative treatment effects of response outcomes are less prone to effect modification than absolute difference measures of response outcomes. Accordingly, any between-trial comparisons of the efficacy of competing interventions using the study-specific ORs are less likely to be invalid or biased than comparisons based on the study-specific NNT estimates. However, treatment-specific ORs obtained from a meta-analysis or taken directly from an individual study can be transformed into consistent treatment-specific NNT estimates that allow for credible comparisons of treatments when these ratio measures are applied to the same reference response estimate. The theoretical discussion is illustrated with a relevant indirect comparison of biologics for the treatment of ulcerative colitis. Between-trial comparisons directly based on the NNT of individual trials may result in erroneous conclusions and should be avoided. Treatment-specific NNT estimates need to be based on the same probability of response with the common reference treatment against which the interventions are compared.

Oral isotretinoin for acne

BACKGROUND

Acne vulgaris, a chronic inflammatory disease of the pilosebaceous unit associated with socialisation and mental health problems, may affect more than 80% of teenagers. Isotretinoin is the only drug that targets all primary causal factors of acne; however, it may cause adverse effects.

OBJECTIVES

To assess efficacy and safety of oral isotretinoin for acne vulgaris.

SEARCH METHODS

We searched the following databases up to July 2017: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO and LILACS. We updated this search in March 2018, but these results have not yet been incorporated in the review. We also searched five trial registries, checked the reference lists of retrieved studies for further references to relevant trials, and handsearched dermatology conference proceedings. A separate search for adverse effects of oral isotretinoin was undertaken in MEDLINE and Embase up to September 2013.

SELECTION CRITERIA

Randomised clinical trials (RCTs) of oral isotretinoin in participants with clinically diagnosed acne compared against placebo, any other systemic or topical active therapy, and itself in different formulation, doses, regimens, or course duration.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 31 RCTs, involving 3836 participants (12 to 55 years) with mild to severe acne. There were twice as many male participants as females.Most studies were undertaken in Asia, Europe, and North America. Outcomes were generally measured between eight to 32 weeks (mean 19.7 weeks) of therapy.Assessed comparisons included oral isotretinoin versus placebo or other treatments such as antibiotics. In addition, different doses, regimens, or formulations of oral isotretinoin were assessed, as well as oral isotretinoin with the addition of topical agents.Pharmaceutical companies funded 12 included trials. All, except three studies, had high risk of bias in at least one domain.Oral isotretinoin compared with oral antibiotics plus topical agentsThese studies included participants with moderate or severe acne and assessed outcomes immediately after 20 to 24 weeks of treatment (short-term). Three studies (400 participants) showed isotretinoin makes no difference in terms of decreasing trial investigator-assessed inflammatory lesion count (RR 1.01 95% CI 0.96 to 1.06), with only one serious adverse effect found, which was Stevens-Johnson syndrome in the isotretinoin group (RR 3.00, 95% CI 0.12 to 72.98). However, we are uncertain about these results as they were based on very low-quality evidence.Isotretinoin may slightly improve (by 15%) acne severity, assessed by physician's global evaluation (RR 1.15, 95% CI 1.00 to 1.32; 351 participants; 2 studies), but resulted in more less serious adverse effects (67% higher risk) (RR 1.67, 95% CI 1.42 to 1.98; 351 participants; 2 studies), such as dry lips/skin, cheilitis, vomiting, nausea (both outcomes, low-quality evidence).Different doses/therapeutic regimens of oral isotretinoinFor our primary efficacy outcome, we found three RCTs, but heterogeneity precluded meta-analysis. One study (154 participants) reported 79%, 80% and 84% decrease in total inflammatory lesion count after 20 weeks of 0.05, 0.1, or 0.2 mg/kg/d of oral isotretinoin for severe acne (low-quality evidence). Another trial (150 participants, severe acne) compared 0.1, 0.5, and 1 mg/kg/d oral isotretinoin for 20 weeks and, respectively, 58%, 80% and 90% of participants achieved 95% decrease in total inflammatory lesion count. One RCT, of participants with moderate acne, compared isotretinoin for 24 weeks at (a) continuous low dose (0.25 to 0.4 mg/kg/day), (b) continuous conventional dose (0.5 to 0.7 mg/kg/day), and (c) intermittent regimen (0.5 to 0.7 mg/kg/day, for one week in a month). Continuous low dose (MD 3.72 lesions; 95% CI 2.13 to 5.31; 40 participants; one study) and conventional dose (MD 3.87 lesions; 95% CI 2.31 to 5.43; 40 participants; one study) had a greater decrease in inflammatory lesion counts compared to intermittent treatment (all outcomes, low-quality evidence).Fourteen RCTs (906 participants, severe and moderate acne) reported that no serious adverse events were observed when comparing different doses/therapeutic regimens of oral isotretinoin during treatment (from 12 to 32 weeks) or follow-up after end of treatment (up to 48 weeks). Thirteen RCTs (858 participants) analysed frequency of less serious adverse effects, which included skin dryness, hair loss, and itching, but heterogeneity regarding the assessment of the outcome precluded data pooling; hence, there is uncertainty about the results (low- to very-low quality evidence, where assessed).Improvement in acne severity, assessed by physician's global evaluation, was not measured for this comparison.None of the included RCTs reported birth defects.

AUTHORS' CONCLUSIONS

Evidence was low-quality for most assessed outcomes.We are unsure if isotretinoin improves acne severity compared with standard oral antibiotic and topical treatment when assessed by a decrease in total inflammatory lesion count, but it may slightly improve physician-assessed acne severity. Only one serious adverse event was reported in the isotretinoin group, which means we are uncertain of the risk of serious adverse effects; however, isotretinoin may result in more minor adverse effects.Heterogeneity in the studies comparing different regimens, doses, or formulations of oral isotretinoin meant we were unable to undertake meta-analysis. Daily treatment may be more effective than treatment for one week each month. None of the studies in this comparison reported serious adverse effects, or measured improvement in acne severity assessed by physician's global evaluation. We are uncertain if there is a difference in number of minor adverse effects, such as skin dryness, between doses/regimens.Evidence quality was lessened due to imprecision and attrition bias. Further studies should ensure clearly reported long- and short-term standardised assessment of improvement in total inflammatory lesion counts, participant-reported outcomes, and full safety accounts. Oral isotretinoin for acne that has not responded to oral antibiotics plus topical agents needs further assessment, as well as different dose/regimens of oral isotretinoin in acne of all severities.

Clubfoot Etiology: A Meta-Analysis and Systematic Review of Observational and Randomized Trials

BACKGROUND

Clubfoot is a common congenital anomaly with multiple potential risk factors. Identification of modifiable risk factors may minimize future incidence of clubfoot. The aim of this meta-analysis was to systematically review and analyze the best clinical evidence regarding risk factors associated with clubfoot.

METHODS

Medline, Embase, and Cochrane databases were systematically searched from 1967 to May 11, 2016 for studies reporting risk factors for clubfoot. Randomized trials and observational studies were eligible for inclusion, and assessed in duplicate. Study quality was assessed with the Newcastle-Ottawa Scale or Cochrane risk of bias tool; low quality studies were excluded, all randomized trials were included. Two reviewers extracted data independently. This meta-analysis was conducted in accordance with PRISMA guidelines. Pooled effect estimates for the odds of clubfoot were calculated using random or fixed-effects models based on heterogeneity.

RESULTS

Forty-two studies (28 case-control, 10 cohort, 4 randomized trials) comprising 31,844 clubfoot cases and 6,604,013 controls were included. Risk factors associated with increased odds of clubfoot included maternal smoking [odds ratio (OR)=1.65; 95% confidence interval (CI), 1.54-1.78], paternal smoking (OR=1.72; 95% CI, 1.05-2.84), maternal body mass index >30 (OR=1.46; 95% CI, 1.29-1.65), family history (OR=7.80; 95% CI, 4.04-15.04), amniocentesis (OR=2.08; 95% CI, 1.34-3.21), selective serotonin reuptake inhibitor exposure (OR=1.78; 95% CI, 1.34-2.37) maternal single status (OR=1.17; 95% CI, 1.11-1.23), gestational diabetes (OR=1.40; 95% CI, 1.13-1.72), nulliparity (OR=1.32; 95% CI, 1.19-1.45), male sex (OR=1.68; 95% CI, 1.48-1.94), and aboriginal Australian race (OR=2.35; 95% CI, 1.63-3.38).

CONCLUSIONS

Smoking, maternal obesity, family history, amniocentesis, and some selective serotonin reuptake inhibitor exposures are the most clinically relevant exposures associated with increased odds of clubfoot, with family history representing the greatest risk. Recognition of modifiable risk factors may help in counseling patients, and minimizing clubfoot incidence.

LEVEL OF EVIDENCE

Level II.

Considerations when assessing heterogeneity of treatment effect in patient-centered outcomes research

When baseline risk of an outcome varies within a population, the effect of a treatment on that outcome will vary on at least one scale (e.g., additive, multiplicative). This treatment effect heterogeneity is of interest in patient-centered outcomes research. Based on a literature review and solicited expert opinion, we assert the following: (1) Treatment effect heterogeneity on the additive scale is most interpretable to health-care providers and patients using effect estimates to guide treatment decision-making; heterogeneity reported on the multiplicative scale may be misleading as to the magnitude or direction of a substantively important interaction. (2) The additive scale may give clues about sufficient-cause interaction, although such interaction is typically not relevant to patients' treatment choices. (3) Statistical modeling need not be conducted on the same scale as results are communicated. (4) Statistical testing is one tool for investigations, provided important subgroups are identified a priori, but test results should be interpreted cautiously given nonequivalence of statistical and clinical significance. (5) Qualitative interactions should be evaluated in a prespecified manner for important subgroups. Principled analytic plans that take into account the purpose of investigation of treatment effect heterogeneity are likely to yield more useful results for guiding treatment decisions.

Number needed to treat in indirect treatment comparison

AIM

For dichotomous outcomes, odds ratio (OR) is one of the usual summary measures of indirect treatment comparison. A corresponding number needed to treat (NNT) estimate may facilitate understanding of the treatment effect.

METHODS

We show how to estimate NNT based on OR results of a matching adjusted indirect comparison. We also have derived the explicit formula of its 95% CIs by applying the delta method, and as an alternative, a simulation-based method.

RESULTS

The method was applied in a case study example in radioiodine-refractory differentiated thyroid cancer (RR-DTC) patients, comparing lenvatinib to sorafenib. For every two RR-DTC patients treated with lenvatinib instead of sorafenib, one fewer would have progressed and for every eight RR-DTC patients treated with lenvatinib instead of sorafenib, one fewer would have died.

CONCLUSION

Using NNT to summarize the results of a matching adjusted indirect comparison can help the clinicians to better understand the results in addition to OR.

Tumor necrosis factor alpha is a promising circulating biomarker for the development of obstructive sleep apnea syndrome: a meta-analysis

Obstructive sleep apnea syndrome (OSAS) is a chronic inflammatory disorder. The relationship between tumor necrosis factor alpha (TNF-alpha) and OSAS has been widely evaluated, but the results thus far remain inconclusive. We thereby decided to quantify the changes of TNF-alpha between OSAS patients and controls by a meta-analysis. This study complies with the MOOSE guidelines. Two reviewers independently searched articles and abstracted relevant data. In total, 47 articles (59 studies) were analyzed, including 2857 OSAS patients and 2115 controls. Overall, OSAS patients had a significantly higher level of circulating TNF-alpha than controls (weighted mean difference [WMD]: 9.66 pg/mL, 95% confidence interval [CI]: 8.66 to 11.24, P<0.001), but with significant heterogeneity (I²: 99.7%). After adjusting for potential missing studies, the overall estimate was weakened but still significant (filled WMD: 2.63 pg/mL, 95% CI: 2.56 to 2.70, P<0.001). When studies were stratified by OSAS severity, the changes in circulating TNF-alpha between patients and controls increased gradually with the more severe grades of OSAS. In patients with mild, mild-to-moderate, moderate, moderate-to-severe and severe OSAS, circulating TNF-alpha was higher than respective controls by 0.99, 1.48. 7.79, 10.08 and 8.85 pg/mL, with significant heterogeneity (I²: 91.2%, 74.5%, 97.6%, 99.0% and 98.1%). In conclusion, our findings demonstrated that circulating TNF-alpha was significantly higher in OSAS patients than in controls, and this difference became more pronounced with the more severe grades of OSAS, indicating that TNF-alpha might be a promising circulating biomarker for the development of OSAS.

Dose-Dependent Effects of Statins for Patients with Aneurysmal Subarachnoid Hemorrhage: Meta-Regression Analysis

OBJECTIVE

The study uses meta-regression analysis to quantify the dose-dependent effects of statin pharmacotherapy on vasospasm, delayed ischemic neurologic deficits (DIND), and mortality in aneurysmal subarachnoid hemorrhage.

METHODS

Prospective, retrospective observational studies, and randomized controlled trials (RCTs) were retrieved by a systematic database search. Summary estimates were expressed as absolute risk (AR) for a given statin dose or control (placebo). Meta-regression using inverse variance weighting and robust variance estimation was performed to assess the effect of statin dose on transformed AR in a random effects model. Dose-dependence of predicted AR with 95% confidence interval (CI) was recovered by using Miller's Freeman-Tukey inverse.

RESULTS

The database search and study selection criteria yielded 18 studies (2594 patients) for analysis. These included 12 RCTs, 4 retrospective observational studies, and 2 prospective observational studies. Twelve studies investigated simvastatin, whereas the remaining studies investigated atorvastatin, pravastatin, or pitavastatin, with simvastatin-equivalent doses ranging from 20 to 80 mg. Meta-regression revealed dose-dependent reductions in Freeman-Tukey-transformed AR of vasospasm (slope coefficient -0.00404, 95% CI -0.00720 to -0.00087; P = 0.0321), DIND (slope coefficient -0.00316, 95% CI -0.00586 to -0.00047; P = 0.0392), and mortality (slope coefficient -0.00345, 95% CI -0.00623 to -0.00067; P = 0.0352).

CONCLUSIONS

The present meta-regression provides weak evidence for dose-dependent reductions in vasospasm, DIND and mortality associated with acute statin use after aneurysmal subarachnoid hemorrhage. However, the analysis was limited by substantial heterogeneity among individual studies. Greater dosing strategies are a potential consideration for future RCTs.

Meta-research metrics matter: letter regarding article "indirect tolerability comparison of Deutetrabenazine and Tetrabenazine for Huntington disease"

Here we discuss the report by Claassen and colleagues describing an indirect treatment comparison between tetrabenazine and deutetrabenazine for chorea in Huntington’s disease using individual patient data. We note the potential for discrepancies in apparently statistically significant findings, due to the rank reversal phenomenon. We provide some cautionary observations and suggestions concerning the limitations of indirect comparisons and the low likelihood that good quality evidence will become available to guide clinical decision comparing these two agents.

Pentasaccharides for the treatment of deep vein thrombosis

BACKGROUND

Standard treatment of deep vein thrombosis (DVT) is based on antithrombotic therapy, initially with parenteral administration of unfractionated heparin or low molecular weight heparins (LMWH) for five to seven days, then subsequent long-term therapy with oral vitamin K antagonists (e.g. warfarin). Pentasaccharides are novel anticoagulants that may be favourable over standard therapy due to their predictable effect, no need for frequent monitoring or re-dosing, and few known drug interactions. Heparin-induced thrombocytopenia, a harmful effect of heparins, appears to be rare during treatment with pentasaccharides.

OBJECTIVES

To assess the efficacy and harms of pentasaccharides for the treatment of deep vein thrombosis.

SEARCH METHODS

The Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (22 March 2017) and the Cochrane Central Register of Controlled Trials (CENTRAL) (2017, Issue 2) (searched 22 March 2017). We searched clinical trials databases for details of ongoing or unpublished studies and the reference lists of relevant articles for additional citations.

SELECTION CRITERIA

We included randomised controlled trials in which people 18 years of age or older with a DVT confirmed by standard imaging techniques were allocated to receive a pentasaccharide (fondaparinux, idraparinux, or idrabiotaparinux) for the treatment of DVT in comparison with standard therapy or other treatments.

DATA COLLECTION AND ANALYSIS

We extracted data characterising the included trials according to the methods, participants, interventions, and outcomes. We assessed risk of bias using Cochrane's 'Risk of bias' tool and employed the GRADE methodology to evaluate the quality of the evidence.The main primary outcome for efficacy was recurrent venous thromboembolism (VTE), and the main primary outcome for harm was major and clinically relevant bleeding. Since our outcomes were dichotomous, we calculated the risk ratio (RR) with a 95% confidence interval (CI). We combined the effects of different comparisons through a meta-analysis using a fixed-effect model.

MAIN RESULTS

We included five randomised controlled trials of 6981 participants comparing pentasaccharides with standard therapy or other pentasaccharides. The quality of the evidence varied depending on the outcome and was judged as of moderate to very low quality. We downgraded the quality of the evidence due to risk of bias or imprecision, or both.Two studies evaluated fondaparinux, at doses of 5.0 mg, 7.5 mg, and 10.0 mg, plus vitamin K antagonist in comparison with standard therapy. A meta-analysis of these two studies showed no clear difference in the risk of recurrent VTE (RR 0.80, 95% CI 0.43 to 1.47; 2658 participants); moderate-quality evidence. The frequencies of major bleeding were similar between interventions in the initial period of treatment (approximately five days) (RR 1.15, 95% CI 0.39 to 3.44; 2645 participants) and at three months' follow-up (RR 1.05, 95% CI 0.64 to 1.71; 2645 participants). We judged the quality of the evidence as moderate.One study (757 participants) compared idrabiotaparinux (3.0 mg) with idraparinux (2.5 mg) and demonstrated no clear difference in the risk of recurrent VTE at six months' follow-up (RR 0.72, 95% CI 0.31 to 1.69); low-quality evidence. Major bleeding during the initial treatment period was not reported. Major bleeding at six-month follow-up was less frequent in participants receiving idrabiotaparinux versus participants treated with idraparinux (RR 0.21, 95% CI 0.06 to 0.71); low-quality evidence.The effect of an initial treatment with LMWH followed by three months of idraparinux (10 mg) showed no clear difference from standard therapy for risk of recurrent VTE (RR 1.51, 95% CI 0.26 to 8.90; 263 participants); very low-quality evidence; one study. Major bleeding during the initial treatment period was not reported. The frequency of major and other clinically relevant bleeding at three months' follow-up ranged from 2% to 15% in participants receiving LMWH and increasing doses of idraparinux of 2.5 mg, 5 mg, 7.5 mg, or 10 mg. When dosage groups were combined, there was no clear difference in major plus other clinically relevant bleeding or in major bleeding alone between the idraparinux treatment group and the standard therapy group (RR 1.30, 95% CI 0.70 to 2.40; 659 participants; RR 3.76, 95% CI 0.50 to 28.19; 659 participants, respectively); very low-quality evidence.One study (2904 participants) compared idraparinux (2.5 mg) to standard therapy. There was no clear difference in the risk of recurrent VTE at three months' follow-up (RR 0.98, 95% CI 0.64 to 1.48); low-quality evidence. Major bleeding during the initial treatment period was not reported. Major bleeding at three months of follow-up appeared to be similar in the idraparinux group and the standard therapy group (RR 0.71, 95% CI 0.34 to 1.47); very low-quality evidence.

AUTHORS' CONCLUSIONS

We found moderate-quality evidence that the effects of fondaparinux at doses of 5.0 mg, 7.5 mg, and 10.0 mg plus vitamin K antagonist are similar in terms of recurrent VTE and risk of major bleeding compared with standard treatment for DVT.Low-quality evidence suggests equal efficacy of idraparinux at 2.5 mg and the equimolar dose of 3.0 mg of idrabiotaparinux with regard to recurrent VTE, but a higher frequency of major bleeding was observed in participants treated with idraparinux.We judged evidence on the effectiveness of idraparinux compared with standard therapy, with or without initial treatment with LMWH, and on associated bleeding risk to be low to very low quality, therefore we have very limited confidence in the estimated effects.The observed similar effectiveness in terms of recurrent DVT and harmful effects in terms of bleeding risk with fondaparinux plus vitamin K antagonist compared to standard treatment for DVT suggest that it may be an alternative to conventional anticoagulants for the treatment of DVT in certain circumstances.

Social adversity and epigenetic aging: a multi-cohort study on socioeconomic differences in peripheral blood DNA methylation

Low socioeconomic status (SES) is associated with earlier onset of age-related chronic conditions and reduced life-expectancy, but the underlying biomolecular mechanisms remain unclear. Evidence of DNA-methylation differences by SES suggests a possible association of SES with epigenetic age acceleration (AA). We investigated the association of SES with AA in more than 5,000 individuals belonging to three independent prospective cohorts from Italy, Australia, and Ireland. Low SES was associated with greater AA (β = 0.99 years; 95% CI 0.39,1.59; p = 0.002; comparing extreme categories). The results were consistent across different SES indicators. The associations were only partially modulated by the unhealthy lifestyle habits of individuals with lower SES. Individuals who experienced life-course SES improvement had intermediate AA compared to extreme SES categories, suggesting reversibility of the effect and supporting the relative importance of the early childhood social environment. Socioeconomic adversity is associated with accelerated epigenetic aging, implicating biomolecular mechanisms that may link SES to age-related diseases and longevity.