Assessing the consistency assumptions underlying network meta-regression using aggregate data

Which antiseptic to use for a caesarean section? A systematic review and network meta-analysis of randomized controlled trials

Guidelines for pre-operative skin antisepsis recommend using chlorhexidine in an alcohol-based solution. However, other antiseptics such as aqueous povidone-iodine or alcohol-based solutions continue to be used. Randomized controlled trials (RCTs) in caesarean section are rare and do not include all possible comparisons of antiseptics. The aim of this study was to assess the efficacy (reduction of surgical site infections) of chlorhexidine at two different concentrations (0.3% and 2%) and povidone-iodine in aqueous or alcohol-based solutions using a network meta-analysis, including only RCTs of caesarean sections. Fragility indices and prediction intervals were also estimated. A systematic literature review and network meta-analysis were performed. RCTs published up to February 2024 were collected from PubMed, ScienceDirect and the Cochrane Library. Interventions included alcohol-based povidone-iodine, aqueous povidone-iodine, and alcohol-based chlorhexidine 2% and 0.3%. The primary outcome measure was surgical site infection. Nine RCTs with 4915 patients and four interventions were included in the network meta-analysis. All credible intervals of the compared interventions overlapped. Alcohol-based 2% chlorhexidine had the highest probability of being effective in preventing surgical site infections, followed by alcohol-based povidone-iodine. The fragility index ranged from 4 to 18. The prediction intervals were wide. On the basis of rank probabilities, chlorhexidine 2% in an alcohol-based solution was most likely to be effective in preventing surgical site infections after caesarean section, followed by alcohol-based povidone-iodine. Given the paucity of literature and the relatively small difference between povidone-iodine and chlorhexidine found in our meta-analysis, we suggest that either can be used in an alcohol-based solution as antisepsis for planned or emergency caesarean section.

Individual participant data from digital sources informed and improved precision in the evaluation of predictive biomarkers in Bayesian network meta-analysis

OBJECTIVES

We aimed to develop a network meta-analytic model for the evaluation of treatment effectiveness within predictive biomarker subgroups, by combining evidence from individual participant data (IPD) from digital sources (in the absence of randomized controlled trials) and aggregate data (AD).

STUDY DESIGN AND SETTING

A Bayesian framework was developed for modeling time-to-event data to evaluate predictive biomarkers. IPD were sourced from electronic health records, using a target trial emulation approach, or digitized Kaplan-Meier curves. The model is illustrated using two examples: breast cancer with a hormone receptor biomarker, and metastatic colorectal cancer with the Kirsten Rat Sarcoma (KRAS) biomarker.

RESULTS

The model allowed for the estimation of treatment effects in two subgroups of patients defined by their biomarker status. Effectiveness of taxanes did not differ in hormone receptor positive and negative breast cancer patients. Epidermal growth factor receptor inhibitors were more effective than chemotherapy in KRAS wild type colorectal cancer patients but not in patients with KRAS mutant status. Use of IPD reduced uncertainty of the subgroup-specific treatment effect estimates by up to 49%.

CONCLUSION

Utilization of IPD allowed for more detailed evaluation of predictive biomarkers and cancer therapies and improved precision of the estimates compared to use of AD alone.

Early parenting interventions to prevent internalising problems in children and adolescents: a global systematic review and network meta-analysis

QUESTION

We compared the effectiveness of different types of parenting interventions based on an a priori taxonomy, and the impact of waitlists versus treatment as usual (TAU), in reducing child internalising problems.

STUDY SELECTION AND ANALYSIS

We conducted a systematic review and network meta-analysis of published and unpublished randomised controlled trials (RCTs) until 1 October 2022 that investigated parenting interventions with children younger than 4 years.

EXCLUSION CRITERIA

studies with children born preterm, with intellectual disabilities, or families receiving support for current abuse, neglect, and substance misuse. We assessed the certainty of evidence using the Confidence in Network Meta-Analysis framework. We used random-effects network meta-analysis to estimate standardised mean differences (SMDs) with 95% credible intervals (CrIs).

FINDINGS

Of 20 520 citations identified, 59 RCTs (18 349 participants) were eligible for the network meta-analysis. Parenting interventions focusing on the dyadic relationship (SMD: -0.26, 95% CrI: -0.43 to -0.08) and those with mixed focus (-0.09, -0.17 to -0.02) were more effective in reducing internalising problems than TAU at the first time point available. All interventions were more effective than waitlist, which increased the risk of internalising problems compared with TAU (0.36, 0.19 to 0.52). All effects attenuated at later follow-ups. Most studies were rated as with 'high risk' or 'some concerns' using the Risk of Bias Assessment Tool V.2. There was no strong evidence of effect modification by theoretically informed components or modifiers.

CONCLUSIONS

We found preliminary evidence that relationship-focused and mixed parenting interventions were effective in reducing child internalising problems, and the waitlist comparator increased internalising problems with implications for waiting times between referral and support. Considering the high risk of bias of most studies included, the findings from this meta-analysis should be interpreted with caution. PROSPERO registration number CRD42020172251.

Comparative efficacy and acceptability of non-pharmacological interventions for depression among people living with HIV: A protocol for a systematic review and network meta-analysis

BACKGROUND

Improving depression is critical to the success of HIV treatment. Concerns about the adverse effects of pharmacotherapy have led to non-pharmacological treatments for depression in people living with HIV (PLWH) becoming increasingly popular. However, the most effective and acceptable non-pharmacological treatments for depression in PLWH have not yet been determined. This protocol for a systematic review and network meta-analysis aims to compare and rank all available non-pharmacological treatments for depression in PLWH in the global network of countries as well as in the network of low-income and middle-income countries (LMICs) only.

METHODS

We will include all randomized controlled trials of any non-pharmacological treatments for depression in PLWH. The primary outcomes will consider efficacy (the overall mean change scores in depression) and acceptability (all-cause discontinuation). Published and unpublished studies will be systematically searched through the relevant databases (PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), PsycINFO, CINAHL, ProQuest, and OpenGrey), international trial registers, and websites. There is no restriction by language and publication year. All study selection, quality evaluation, and data extraction will be independently conducted by at least two investigators. We will perform a random-effects network meta-analysis to synthesize all available evidence for each outcome and obtain a comprehensive ranking of all treatments for the global network of countries as well as for the network of LMICs only. We will employ validated global and local approaches to evaluate inconsistency. We will use OpenBUGS (version 3.2.3) software to fit our model within a Bayesian framework. We will evaluate the strength of evidence using the Confidence in Network Meta-Analysis (CINeMA) tool, a web application based on the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system.

ETHICS AND DISSEMINATION

This study will use secondary data and therefore does not require ethical approval. The results of this study will be disseminated through peer-reviewed publication.

TRIAL REGISTRATION

PROSPERO registration number: CRD42021244230.

Comparison of complications and bowel function among different reconstruction techniques after low anterior resection for rectal cancer: a systematic review and network meta-analysis

BACKGROUND

Anastomosis for gastrointestinal reconstruction has been contentious after low anterior resection of rectal cancer for the past 30 years. Despite the abundance of randomized controlled trials (RCTs) on colon J-pouch (CJP), straight colorectal anastomosis (SCA), transverse coloplast (TCP), and side-to-end anastomosis (SEA), most studies are small and lack reliable clinical evidence. We conducted a systematic review and network meta-analysis to evaluate the effects of the four anastomoses on postoperative complications, bowel function, and quality of life in rectal cancer.

METHODS

We assessed the safety and efficacy of CJP, SCA, TCP, and SEA in adult patients with rectal cancer after surgery by searching the Cochrane Library, Embase, and PubMed databases to collect RCTs from the date of establishment to May 20, 2022. Anastomotic leakage and defecation frequency were the main outcome indicators. We pooled data through a random effects model in a Bayesian framework and assessed model inconsistency using the deviance information criterion (DIC) and node-splitting method and inter-study heterogeneity using the I-squared statistics (I²). The interventions were ranked according to the surface under the cumulative ranking curve (SUCRA) to compare each outcome indicator.

RESULTS

Of the 474 studies initially evaluated, 29 were eligible RCTs comprising 2631 patients. Among the four anastomoses, the SEA group had the lowest incidence of anastomotic leakage, ranking first (SUCRA_SEA = 0.982), followed by the CJP group (SUCRA_CJP = 0.628). The defecation frequency in the SEA group was comparable to those in the CJP and TCP groups at 3, 6, 12, and 24 months postoperatively. In comparison, the defecation frequency in the SCA group 12 months after surgery all ranked fourth. No statistically significant differences were found among the four anastomoses in terms of anastomotic stricture, reoperation, postoperative mortality within 30 days, fecal urgency, incomplete defecation, use of antidiarrheal medication, or quality of life.

CONCLUSIONS

This study demonstrated that SEA had the lowest risk of complications, comparable bowel function, and quality of life compared to the CJP and TCP, but further research is required to determine its long-term consequences. Furthermore, we should be aware that SCA is associated with a high defecation frequency.

Comparative efficacy and safety of the artemisinin derivatives compared to quinine for treating severe malaria in children and adults: A systematic update of literature and network meta-analysis

BACKGROUND

The artemisinin derivatives are the preferred antimalaria drugs for treating severe Plasmodium falciparum malaria. However, their clinical effectiveness compared to each other is unknown. Our objective, therefore, was to evaluate the efficacy and safety of the artemisinin derivatives and quinine for treating severe P. falciparum malaria in children and adults using a network meta-analysis.

METHODS AND FINDINGS

Review protocol was registered with PROSPERO, CRD42020218190. We updated the search strategies of three Cochrane systematic reviews which included published and unpublished randomised control trials (RCTs) that have compared specific artemisinin derivatives to quinine in treating severe malaria. Search included CENTRAL, MEDLINE, Embase, LILACS, ISI Web of Science and trial registries up to February 2021. We screened studies, extracted data, assessed risk of bias, and quality of evidence in duplicate. Separate network meta-analyses in the frequentist framework, using a random effects model, with quinine as reference, were conducted for adults and children, and rankings were produced using p-scores to assess mortality, parasite clearance, coma recovery, fever clearance, neurological sequela and adverse events. Searches identified 818 citations, 33 RCTs were eligible. We pooled 7795 children and 3182 adults. The networks involved artesunate, artemether, rectal artemisinin, arteether and quinine. Compared to quinine, artesunate reduced mortality in children (risk ratio (RR), 0.76; 95%CI [0.65 to 0.89], moderate quality), adults (RR, 0.55; 95%CI [0.40 to 0.75], moderate quality) and in cerebral malaria (RR, 0.72; 95%CI [0.55 to 0.94], moderate quality). Compared to rectal artemisinin and intramuscular arteether, the efficacy and safety of parenteral artesunate, and intramuscular artemether in treating severe malaria are not clear. Rankings showed that none of the artemisinin drugs were consistently superior in all the outcomes assessed. Indirect evidence produced were of very low ratings due to suspected publication bias and imprecision.

CONCLUSIONS

Artesunate reduces mortality compared to quinine for both adults and children in Asia and Africa including cerebral malaria. The artemisinin derivatives remain the best treatment for severe malaria but their comparative clinical effectiveness is yet to be fully explored.

Evidence inconsistency degrees of freedom in Bayesian network meta-analysis

Network meta-analysis (NMA) is a popular tool to synthesize direct and indirect evidence for simultaneously comparing multiple treatments, while evidence inconsistency greatly threatens its validity. One may use the inconsistency degrees of freedom (ICDF) to assess the potential that an NMA might suffer from inconsistency. Multi-arm studies provide intrinsically consistent evidence and complicate the ICDF's calculation; they commonly appear in NMAs. The existing ICDF measure may not feasibly handle multi-arm studies. Motivated from the effective numbers of parameters of Bayesian hierarchical models, we propose new ICDF measures in generic NMAs that may contain multi-arm studies. Under the fixed- or random-effects setting, the new ICDF measure is the difference between the effective numbers of parameters of the consistency and inconsistency NMA models. We used artificial NMAs created based on an illustrative example and 39 empirical NMAs to evaluate the performance of the existing and new measures. In NMAs with two-arm studies only, the proposed ICDF measure under the fixed-effects setting was nearly the same with the existing measure. Among the empirical NMAs, 27 (69%) contained at least one multi-arm study. The existing measure was not applicable to them, while the proposed measures led to interpretable ICDFs in all NMAs.

Analgesic medicines for adults with low back pain: protocol for a systematic review and network meta-analysis

BACKGROUND

There is limited evidence for the comparative effectiveness of analgesic medicines for adults with low back pain. This systematic review and network meta-analysis aims to determine the analgesic effect, safety, acceptability, effect on function, and relative rank according to analgesic effect, safety, acceptability, and effect on function of a single course of [an] analgesic medicine(s) or combination of these medicines for people with low back pain.

METHODS

We will include published and unpublished randomised trials written in any language that compare an analgesic medicine to either another medicine, placebo/sham, or no intervention in adults with low back pain, grouped according to pain duration: acute (fewer than 6 weeks), sub-acute (6 to 12 weeks), and chronic (greater than 12 weeks). The co-primary outcomes are pain intensity following treatment and safety (adverse events). The secondary outcomes are function and acceptability (all-cause dropouts). We will perform a network meta-analysis to compare and rank analgesic medicines. We will form judgements of confidence in the results using the Confidence in Network Meta-Analysis (CINeMA) methodology.

DISCUSSION

This network meta-analysis will establish which medicine, or combination of medicines, is most effective for reducing pain and safest for adults with low back pain.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019145257.

Assessing the consistency assumptions underlying network meta-regression using aggregate data

When numerous treatments exist for a disease (Treatments 1, 2, 3, etc), network meta‐regression (NMR) examines whether each relative treatment effect (eg, mean difference for 2 vs 1, 3 vs 1, and 3 vs 2) differs according to a covariate (eg, disease severity). Two consistency assumptions underlie NMR: consistency of the treatment effects at the covariate value 0 and consistency of the regression coefficients for the treatment by covariate interaction. The NMR results may be unreliable when the assumptions do not hold. Furthermore, interactions may exist but are not found because inconsistency of the coefficients is masking them, for example, when the treatment effect increases as the covariate increases using direct evidence but the effect decreases with the increasing covariate using indirect evidence.

We outline existing NMR models that incorporate different types of treatment by covariate interaction. We then introduce models that can be used to assess the consistency assumptions underlying NMR for aggregate data. We extend existing node‐splitting models, the unrelated mean effects inconsistency model, and the design by treatment inconsistency model to incorporate covariate interactions. We propose models for assessing both consistency assumptions simultaneously and models for assessing each of the assumptions in turn to gain a more thorough understanding of consistency.

We apply the methods in a Bayesian framework to trial‐level data comparing antimalarial treatments using the covariate average age and to four fabricated data sets to demonstrate key scenarios.

We discuss the pros and cons of the methods and important considerations when applying models to aggregated data.