Combining randomized and non-randomized evidence in network meta-analysis

crossnma: An R package to synthesize cross-design evidence and cross-format data using network meta-analysis and network meta-regression

BACKGROUND

Although aggregate data (AD) from randomised clinical trials (RCTs) are used in the majority of network meta-analyses (NMAs), other study designs (e.g., cohort studies and other non-randomised studies, NRS) can be informative about relative treatment effects. The individual participant data (IPD) of the study, when available, are preferred to AD for adjusting for important participant characteristics and to better handle heterogeneity and inconsistency in the network.

RESULTS

We developed the R package crossnma to perform cross-format (IPD and AD) and cross-design (RCT and NRS) NMA and network meta-regression (NMR). The models are implemented as Bayesian three-level hierarchical models using Just Another Gibbs Sampler (JAGS) software within the R environment. The R package crossnma includes functions to automatically create the JAGS model, reformat the data (based on user input), assess convergence and summarize the results. We demonstrate the workflow within crossnma by using a network of six trials comparing four treatments.

CONCLUSIONS

The R package crossnma enables the user to perform NMA and NMR with different data types in a Bayesian framework and facilitates the inclusion of all types of evidence recognising differences in risk of bias.

Calcium versus cabergoline for prevention of ovarian hyperstimulation syndrome: A systematic review and meta-analysis

AIM

To conduct the first-ever systematic review and meta-analysis evaluating calcium infusion versus cabergoline in preventing ovarian hyperstimulation syndrome (OHSS) among high-risk women undergoing assisted reproductive technology.

METHODS

Six databases were screened from inception until April 1, 2024. The included randomized and non-randomized controlled studies were assessed for quality. The endpoints included the severity of OHSS and selected pregnancy-related outcomes. Endpoints were summarized as risk ratios (RRs) and 95% confidence intervals (CIs) in a random-effects model.

RESULTS

Six studies were analyzed, including 1687 patients (828 in the calcium group and 859 in the cabergoline group). The quality of the studies varied and reflected low risk and high risk of bias in two and four studies, respectively, according to the revised Cochrane risk of bias tool. No significant differences were noted between both groups regarding the rates of overall (n = 5, RR = 0.65, 95 % CI [0.39, 1.07], p = 0.09), mild (n = 4, RR = 1.05, 95 % CI [0.59, 1.89], p = 0.86), moderate (n = 5, RR = 0.41, 95 % CI [0.15, 1.08], p = 0.07), and severe (n = 6, RR = 0.36, 95 % CI [0.11, 1.22], p = 0.1) cases of OHSS. Leave-one-out sensitivity analysis of an outlier study revealed that calcium significantly reduced the occurrence of severe OHSS compared with cabergoline (n = 5, RR = 0.16, 95 % CI [0.09, 0.43], p < 0.001, Higgins I2 = 0 %). No significant differences were observed between both groups regarding the rates of clinical pregnancy (n = 4, RR = 0.97, 95 % CI [0.88, 1.07], p = 0.57), ongoing pregnancy, live birth, and spontaneous abortion (Higgins I2 < 50 % for all).

CONCLUSION

Both agents yielded similar pregnancy-related outcomes. However, calcium infusion could potentially be more effective than cabergoline in reducing the rate of severe OHSS. Additional high-quality and well-controlled trials are essential to draw firm conclusions.

Drug exposure as a predictor in diabetic retinopathy risk prediction models; a systematic review and meta-analysis

PURPOSE

To conduct a systematic review to assess drug exposure handling in diabetic retinopathy (DR) risk prediction models, a network-meta-analysis to identify drugs associated with DR and a meta-analysis to determine which drugs contributed to enhanced model performance.

DESIGN

Systematic review and meta-analysis.

METHODS

We included studies presenting DR models incorporating drug exposure as a predictor. We searched EMBASE, MEDLINE and SCOPUS from inception to December 2023. We evaluated the quality of studies using the Prediction model Risk of Bias Assessment Tool and certainty using GRADE. We conducted network meta-analysis and meta-analysis to estimate the odds ratio (OR) and pooled C-statistic, respectively, and 95% confidence intervals (CI) (PROSPERO: CRD42022349764).

RESULTS

Of 5,653 records identified, we included 28 studies of 678,837 type 1 or 2 diabetes participants, of which 38,579 (5.7%) had DR. A total of 19, 3 and 7 studies were at high, unclear, and low risk of bias, respectively. Drugs included in models as predictors were: insulin (n=24), antihypertensives (n=5), oral antidiabetics (n=12), lipid-lowering drugs (n=7), antiplatelets (n=2). Drug exposure was modelled primarily as a categorical variable (n=23 studies). Two studies handled drug exposure as time-varying covariates, and one as a time-dependent covariate. Insulin was associated with an increased risk of DR (OR= 2.50; 95%-CI: 1.61-3.86). Models that included insulin (n=9) had a higher pooled C-statistic (C-statistic=0.84, CI: 0.80-0.88), compared to models (n=9) that incorporated a combination of drugs alongside insulin (C-statistic= 0.79, CI:0.74-0.84), as well as models (n=3) not including insulin (C-statistic =0.70, CI: 0.64-0.75). Limitations include the high risk of bias and significant heterogeneity in reviewed studies.

CONCLUSION

This is the first review assessing drug exposure handling in DR prediction models. Drug exposure was primarily modelled as a categorical variable, with insulin associated with improved model performance. However, due to suboptimal drug handling, associations between other drugs and model performance may have been overlooked. This review proposes the following for future DR prediction models: 1) evaluation of drug exposure as a variable, 2) use of time-varying methodologies, and 3) consideration of drug regimen details. Improving drug exposure handling could potentially unveil novel variables capable of significantly enhancing the predictive capability of prediction models.

Protocol for a systematic review and network meta-analysis of the use of prophylactic antibiotics in hand trauma surgery

BACKGROUND

The use of prophylactic antibiotics in surgery is contentious. With the rise in antimicrobial resistance, evidence-based antibiotic use should be followed. This systematic review and network meta-analysis will assess the effectiveness of different antibiotics on the prevention of surgical site infection (SSI) following hand trauma surgery.

METHODS AND ANALYSIS

The databases Embase, MEDLINE, CINAHL and CENTRAL, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform will be searched. Abstracts will be screened by two persons independently to identify eligible studies. This systematic review will include both randomised and non-randomised prospective comparative studies in participants with hand and/or wrist injuries requiring surgery; bite injuries will be excluded. The network meta-analysis will compare the use of different prophylactic antibiotics against each other, placebo and/or no antibiotics on the development of SSI within 30 days of surgery (or 90 days if there is an implanted device). The Cochrane risk-of-bias tool 2 will be used to assess the risk of methodological bias in randomised controlled trials, and the Newcastle-Ottowa scale (NOS) will be used to assess the risk of bias in non-randomised studies. A random-effects network meta-analysis will be conducted along with subgroup analyses looking at antibiotic timing, injury type, and operation location. Sensitivity analyses including only low risk-of-bias studies will be conducted, and the confidence in the results will be assessed using Confidence in Network Meta-Analysis (CINEMA).

DISCUSSION

This systematic review and network meta-analysis aims to provide an up-to-date synthesis of the studies assessing the use of antibiotics following hand and wrist trauma to enable evidence-based peri-operative prescribing.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023429618.

Compare the efficacy of antifungal agents as primary therapy for invasive aspergillosis: a network meta-analysis

BACKGROUND

Several antifungal agents are available for primary therapy in patients with invasive aspergillosis (IA). Although a few studies have compared the effectiveness of different antifungal agents in treating IA, there has yet to be a definitive agreement on the best choice. Herein, we perform a network meta-analysis comparing the efficacy of different antifungal agents in IA.

METHODS

We searched PubMed, Embase, and the Cochrane Central Register of Controlled Clinical Trials databases to find studies (both randomized controlled trials [RCTs] and observational) that reported on treatment outcomes with antifungal agents for patients with IA. The study quality was assessed using the revised tool for risk of bias and the Newcastle Ottawa scale, respectively. We performed a network meta-analysis (NMA) to summarize the evidence on antifungal agents' efficacy (favourable response and mortality).

RESULTS

We found 12 studies (2428 patients) investigating 11 antifungal agents in the primary therapy of IA. There were 5 RCTs and 7 observational studies. When treated with monotherapy, isavuconazole was associated with the best probability of favourable response (SUCRA, 77.9%; mean rank, 3.2) and the best reduction mortality against IA (SUCRA, 69.1%; mean rank, 4.1), followed by voriconazole and posaconazole. When treated with combination therapy, Liposomal amphotericin B plus caspofungin was the therapy associated with the best probability of favourable response (SUCRA, 84.1%; mean rank, 2.6) and the best reduction mortality (SUCRA, 88.2%; mean rank, 2.2) against IA.

CONCLUSION

These findings suggest that isavuconazole, voriconazole, and posaconazole may be the best antifungal agents as the primary therapy for IA. Liposomal amphotericin B plus caspofungin could be an alternative option.

Palliative procedures for malignant gastric outlet obstruction: a network meta-analysis

BACKGROUND

The optimal treatment for malignant gastric outlet obstruction (GOO) remains uncertain. This systematic review aimed to comprehensively investigate the efficacy and safety of four palliative treatments for malignant GOO: gastrojejunostomy, endoscopic ultrasound-guided gastroenterostomy (EUS-GE), stomach-partitioning gastrojejunostomy (PGJ), and endoscopic stenting.

METHODS

We searched PubMed, Embase, Cochrane Library, Scopus, and Web of Science databases, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform for randomized controlled trials (RCTs) and cohort studies comparing the four treatments for malignant GOO. We included studies that reported at least one of the following clinical outcomes: clinical success, 30-day mortality, reintervention rate, or length of hospital stay. Evidence from RCTs and non-RCTs was naïve combined to perform network meta-analysis through the frequentist approach using an inverse variance model. Treatments were ranked by P score.

RESULTS

This network meta-analysis included 3617 patients from 4 RCTs, 4 prospective cohort studies, and 32 retrospective cohort studies. PGJ was the optimal approach in terms of clinical success and reintervention (P scores: 0.95 and 0.90, respectively). EUS-GE had the highest probability of being the optimal treatment in terms of 30-day mortality and complications (P scores: 0.82 and 0.99, respectively). Cluster ranking to combine the P scores for 30-day mortality and reintervention indicated the benefits of PGJ and EUS-GE (cophenetic correlation coefficient: 0.94; PGJ and EUS-GE were in the same cluster).

CONCLUSION

PGJ and EUS-GE are recommended for malignant GOO. PGJ could be the alternative choice in centers with limited resources or in patients who are unsuitable for EUS-GE.

Cervical Osmotic Dilators versus Dinoprostone for Cervical Ripening during Labor Induction: A Systematic Review and Meta-analysis of 14 Controlled Trials

OBJECTIVE

This study aimed to conduct a systematic review and meta-analysis of all randomized and nonrandomized controlled trials (RCTs and NCTs, respectively) that explored the maternal-neonatal outcomes of cervical osmotic dilators versus dinoprostone in promoting cervical ripening during labor induction.

STUDY DESIGN

Six major databases were screened until August 27, 2022. The quality of included studies was evaluated. The data were summarized as mean difference or risk ratio (RR) with 95% confidence interval (CI) in a random-effects model.

RESULTS

Overall, 14 studies with 15 arms were analyzed (n = 2,380 patients). Ten and four studies were RCTs and NCTs, respectively. The overall quality for RCTs varied (low risk n = 2, unclear risk n = 7, and high risk n = 1), whereas all NCTs had good quality (n = 4). For the primary endpoints, there was no significant difference between both groups regarding the rate of normal vaginal delivery (RR = 1.04, 95% CI: 0.95-1.14, p = 0.41) and rate of cesarean delivery (RR = 1.04, 95% CI: 0.93-1.17, p = 0.51). Additionally, there was no significant difference between both groups regarding the mean change in Bishop score and mean time from intervention to delivery. The rate of uterine hyperstimulation was significantly lower in the cervical osmotic dilator group. For the neonatal outcomes, during cervical ripening, the rate of fetal distress was significantly lower in the cervical osmotic dilator group. There was no significant difference between both groups regarding the mean Apgar scores, rate of meconium-stained amniotic fluid, rate of umbilical cord metabolic acidosis, rate of neonatal infection, and rate of neonatal intensive care unit admission.

CONCLUSION

During labor induction, cervical ripening with cervical osmotic dilators and dinoprostone had comparable maternal-neonatal outcomes. Cervical osmotic dilators had low risk of uterine hyperstimulation compared with dinoprostone. Overall, cervical osmotic dilators might be more preferred over dinoprostone in view of their analogous cervical ripening effects, comparable maternal-neonatal outcomes, and lack of drug-related adverse events.

KEY POINTS

· This is the first analysis of cervical osmotic dilators versus PGE2 for cervical ripening during labor.. · There was no difference between both arms regarding the rates of normal vaginal/cesarean deliveries.. · There was no difference between both arms regarding the rates of neonatal adverse events.. · Cervical osmotic dilators had significant lower risk of uterine hyperstimulation compared with PGE2.. · Cervical osmotic dilators may be superior to PGE2 in view of their similar efficacy and better safety..

Comparative study of venous thromboembolic prophylaxis strategies in hemorrhagic stroke: A systematic review and network meta-analysis

BACKGROUND

Venous thromboembolic events, including deep vein thrombosis (DVT) and pulmonary embolism (PE), are frequent complications in patients with intracerebral hemorrhage (ICH). Various prophylactic strategies have been employed to mitigate this risk, such as heparin, intermittent pneumatic compression (IPC), and graduated compression stockings (GCS). The optimal thromboembolic prophylaxis approach remains uncertain due to the lack of randomized controlled trials (RCTs) comparing all interventions.

AIMS

We conducted a network meta-analysis and meta-analysis to systematically review and synthesize evidence from RCTs and non-randomized studies on the efficacy and safety of thromboembolic prophylaxis strategies in hospitalized ICH patients.

SUMMARY OF FINDINGS

Our study followed a registered protocol (PROSPERO CRD42023489217) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines incorporating the extension for network meta-analyses. Search for eligible studies was performed up to December 2023. We considered the occurrence of DVT, PE, hematoma expansion (HE), and all-cause mortality as outcome measures. A total of 16 studies, including 7 RCTs and 9 non-randomized studies, were included in the analysis. Network meta-analysis revealed that IPC demonstrated the highest efficacy in reducing DVT incidence (odds ratios (OR) 0.30, 95% confidence interval (CI) 0.08-1.16), particularly considering only RCTs (OR 0.33, 95% CI 0.16-0.67). GCS showed the highest safety profile for HE (OR 0.67, 95% CI 0.14-3.13), but without efficacy. Chemoprophylaxis did not reduce the risk of PE events (OR 1.10, 95% CI 0.17-7.19) with a higher occurrence of HE (OR 1.33, 95% CI 0.60-2.96), but the differences were not significant.

CONCLUSION

Our study supports the use of IPC as the primary thromboembolic prophylaxis measure in ICH patients. Further research, including head-to-head RCTs, is needed to strengthen the evidence base and optimize clinical decision-making for thromboembolic prophylaxis in this vulnerable patient population.

Sharing information across patient subgroups to draw conclusions from sparse treatment networks

Network meta-analysis (NMA) usually provides estimates of the relative effects with the highest possible precision. However, sparse networks with few available studies and limited direct evidence can arise, threatening the robustness and reliability of NMA estimates. In these cases, the limited amount of available information can hamper the formal evaluation of the underlying NMA assumptions of transitivity and consistency. In addition, NMA estimates from sparse networks are expected to be imprecise and possibly biased as they rely on large-sample approximations that are invalid in the absence of sufficient data. We propose a Bayesian framework that allows sharing of information between two networks that pertain to different population subgroups. Specifically, we use the results from a subgroup with a lot of direct evidence (a dense network) to construct informative priors for the relative effects in the target subgroup (a sparse network). This is a two-stage approach where at the first stage, we extrapolate the results of the dense network to those expected from the sparse network. This takes place by using a modified hierarchical NMA model where we add a location parameter that shifts the distribution of the relative effects to make them applicable to the target population. At the second stage, these extrapolated results are used as prior information for the sparse network. We illustrate our approach through a motivating example of psychiatric patients. Our approach results in more precise and robust estimates of the relative effects and can adequately inform clinical practice in presence of sparse networks.

Efficacy and safety of basal insulins in people with type 2 diabetes mellitus: a systematic review and network meta-analysis of randomized clinical trials

Aim

The comparative effectiveness of basal insulins has been examined in several studies. However, current treatment algorithms provide a list of options with no clear differentiation between different basal insulins as the optimal choice for initiation.

Methods

A comprehensive search of MEDLINE, Embase, Cochrane Library, ISI, and Scopus, and a reference list of retrieved studies and reviews were performed up to November 2023. We identified phase III randomized controlled trials (RCTs) comparing the efficacy and safety of basal insulin regimens. The primary outcomes evaluated were HbA1c reduction, weight change, and hypoglycemic events. The revised Cochrane ROB-2 tool was used to assess the methodological quality of the included studies. A random-effects frequentist network meta-analysis was used to estimate the pooled weighted mean difference (WMD) and odds ratio (OR) with 95% confidence intervals considering the critical assumptions in the networks. The certainty of the evidence and confidence in the rankings was assessed using the GRADE minimally contextualized approach.

Results

Of 20,817 retrieved studies, 44 RCTs (23,699 participants) were eligible for inclusion in our network meta-analysis. We found no significant difference among various basal insulins (including Neutral Protamine Hagedorn (NPH), ILPS, insulin glargine, detemir, and degludec) in reducing HbA1c. Insulin glargine, 300 U/mL (IGlar-300) was significantly associated with less weight gain (mean difference ranged from 2.9 kg to 4.1 kg) compared to other basal insulins, namely thrice-weekly insulin degludec (IDeg-3TW), insulin degludec, 100 U/mL (IDeg-100), insulin degludec, 200 U/mL (IDeg-200), NPH, and insulin detemir (IDet), but with low to very low certainty regarding most comparisons. IDeg-100, IDeg-200, IDet, and IGlar-300 were associated with significantly lower odds of overall, nocturnal, and severe hypoglycemic events than NPH and insulin lispro protamine (ILPS) (moderate to high certainty evidence). NPH was associated with the highest odds of overall and nocturnal hypoglycemia compared to others. Network meta-analysis models were robust, and findings were consistent in sensitivity analyses.

Conclusion

The efficacy of various basal insulin regimens is comparable. However, they have different safety profiles. IGlar-300 may be the best choice when weight gain is a concern. In contrast, IDeg-100, IDeg-200, IDet, and IGlar-300 may be preferred when hypoglycemia is the primary concern.

Perioperative Dexmedetomidine Infusion Improves Perioperative Care of Bariatric-Metabolic Surgery: A Single Center Experience with Meta-Analysis

PURPOSE

This study aims to determine the effects of perioperative dexmedetomidine infusion (PDI) on Asian patients undergoing bariatric-metabolic surgery (BMS), focusing on the need for pain medications and management of postoperative nausea and vomiting (PONV), and to investigate the association with these variables, including patients' characteristics and BMS data.

MATERIALS AND METHODS

A retrospective review of prospectively collected data was conducted in an Asian weight management center from August 2016 to October 2021. A total of 147 native patients with severe obesity were enrolled. All patients were informed of the full support of perioperative pain medications for BMS. The pain numeric rating scale scores, events of PONV, needs for pain medications, and the associated patients' characteristics were analyzed. A p-value of < 0.05 was considered statistically significant. Furthermore, to verify the effects of perioperative usage of dexmedetomidine for BMS, a systematic review with meta-analysis of currently available randomized control trials was performed.

RESULTS

Among the 147 enrolled patients, 107 underwent laparoscopic sleeve gastrectomy and 40 underwent laparoscopic Roux-en-Y gastric bypass. PDI has been used as an adjunct multimodal analgesia for BMS in our institution since June 2017 (group D; n = 114). In comparison with those not administered with perioperative dexmedetomidine (group C; n = 33), lower pain numeric rating scale scores (2.52 ± 2.46 vs. 4.27 ± 2.95, p = 0.007) in the postanesthesia care unit, fewer PONV (32.46% vs. 51.52%; p = 0.046), and infrequent needs of additional pain medications (19.47% vs. 45.45%; p = 0.003) were observed in group D. Multivariable analysis demonstrated that type II diabetes mellitus was correlated with the decreased need of pain medications other than PDI (p = 0.035). Moreover, dexmedetomidine seemed to have a better analgesic effect for patients with longer surgical time based on our meta-analysis.

CONCLUSION

Based on our limited experience, PDI could be a practical solution to alleviate pain and PONV in Asian patients undergoing BMS. Moreover, it might reduce the need for rescue painkillers with better postoperative pain management for patients with type II diabetes mellitus or longer surgical time.

Twenty years of network meta-analysis: Continuing controversies and recent developments

Network meta-analysis (NMA) is an extension of pairwise meta-analysis (PMA) which combines evidence from trials on multiple treatments in connected networks. NMA delivers internally consistent estimates of relative treatment efficacy, needed for rational decision making. Over its first 20 years NMA's use has grown exponentially, with applications in both health technology assessment (HTA), primarily re-imbursement decisions and clinical guideline development, and clinical research publications. This has been a period of transition in meta-analysis, first from its roots in educational and social psychology, where large heterogeneous datasets could be explored to find effect modifiers, to smaller pairwise meta-analyses in clinical medicine on average with less than six studies. This has been followed by narrowly-focused estimation of the effects of specific treatments at specific doses in specific populations in sparse networks, where direct comparisons are unavailable or informed by only one or two studies. NMA is a powerful and well-established technique but, in spite of the exponential increase in applications, doubts about the reliability and validity of NMA persist. Here we outline the continuing controversies, and review some recent developments. We suggest that heterogeneity should be minimized, as it poses a threat to the reliability of NMA which has not been fully appreciated, perhaps because it has not been seen as a problem in PMA. More research is needed on the extent of heterogeneity and inconsistency in datasets used for decision making, on formal methods for making recommendations based on NMA, and on the further development of multi-level network meta-regression.

Cognitive stimulation and psychosocial results in older adults: A systematic review and meta-analysis

INTRODUCTION

Cognitive stimulation (CS) is a popular and cost-effective intervention, which applies different types of techniques focused on cognitive skills and can be administered by different professionals. CS can be defined as activities that involve cognitive processing usually conducted in a social context and often in a group. Therefore, CS can improve psychosocial functioning and quality of life (QoL), depression, anxiety and activities of daily living (ADLs) independent of the pharmacological treatment such as acetylcholinesterase inhibitors. The objective of this systematic review and meta-analysis was to evaluate the effects of CS on psychosocial outcomes in older adults (aged 65 years or over), with healthy cognitive ageing, mild cognitive impairment (MCI), and dementia.

METHODS

PubMed, Scopus and Web of Science databases were examined from inception to October 2021. A total of 1,997 studies were initially identified in these databases. After discarding studies that did not meet the inclusion criteria, 30 studies were finally included in the systematic review and the meta-analysis performed with robust variance estimator (RVE) due the inclusion of studies with repeated measurements. The quality assessment tools from the National Institutes of Health were used to evaluate the quality of the studies.

RESULTS

CS was significantly associated with a higher QoL in participants who received personalized/adapted CS (RVE = 0.11±0.19 [-0.76, 0.99], t(1.86) = 0.6, p = 0.61). .

CONCLUSION

Personalized/adapted CS seems to improve QoL in older adults.

Evaluating treatments in rare indications warrants a Bayesian approach

Evaluating efficacy and real-world effectiveness for novel therapies targeting rare mutations or patient subpopulations with unmet needs is a growing challenge in health economics and outcomes research (HEOR). In these settings it may be difficult to recruit enough patients to run adequately powered randomized clinical trials, resulting in greater reliance on single-arm trials or basket trial designs. Additionally, evidence networks for performing network meta-analysis may be sparse or disconnected when comparing available treatments in narrower patient populations. These challenges create an increased need for use of appropriate methods for handling small sample sizes, structural modelling assumptions and more nuanced decision rules to arrive at "best-available evidence" on comparative and non-comparative efficacy/effectiveness. We advocate for greater use of Bayesian methods to address these challenges as they can facilitate efficient and transparent borrowing of information across varied data sources under flexible modelling assumptions, probabilistic sensitivity analysis to assess model assumptions, and more nuanced decision-making where limited power reduces the utility of classical frequentist hypothesis testing. We illustrate how Bayesian methods have been recently used to overcome several challenges of rare indications in HEOR, including approaches to borrowing information from external data sources, evaluation of efficacy in basket trials, and incorporating non-randomized studies into network meta-analysis. Lastly, we provide several recommendations for HEOR practitioners on appropriate use of Bayesian methods to address challenges in the rare disease setting.

Survival benefit of perioperative locoregional adjuvant treatment for hepatocellular carcinoma with portal vein tumor thrombosis: A systematic review and Bayesian network meta-analysis

BACKGROUND

To identify the optimal strategy for hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT) by comparing the oncological prognosis of different perioperative locoregional adjuvant treatments.

METHODS

Electronic database were searched for relevant studies. Overall survival (OS) and recurrence-free survival (RFS) were pooled by pairwise and network meta-analysis.

RESULTS

Fourteen eligible trials with 1927 patients and covering four adjuvant treatments were included. All adjuvant therapies in combination with surgery were shown to be superior to surgery alone. Adjuvant therapy with radiotherapy had the lowest hazard ratio (HR) for both OS (HR: 0.38, 95% CrI: 0.25-0.57) and RFS (HR: 0.27, 95% CrI: 0.11-0.65) compared with other combination treatments, with estimated surface under the cumulative ranking of 93.2% and 82.7%, respectively.

CONCLUSIONS

Perioperative locoregional adjuvant therapy provides OS benefits and reduces the risk of recurrence for patients suffering from HCC with PVTT. Radiotherapy is likely to be the most effective adjuvant regimen.

Methodological and reporting quality assessment of network meta-analyses in anesthesiology: a systematic review and meta-epidemiological study

PURPOSE

The scientific rigour of the conduct and reporting of anesthesiology network meta-analyses (NMAs) is unknown. This systematic review and meta-epidemiological study assessed the methodological and reporting quality of NMAs in anesthesiology.

METHODS

We searched four databases, including MEDLINE, PubMed, Embase, and the Cochrane Systematic Reviews Database, for anesthesiology NMAs published from inception to October 2020. We assessed the compliance of NMAs against A Measurement Tool to Assess Systematic Reviews (AMSTAR-2), Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement for Network Meta-Analyses (PRISMA-NMA), and PRISMA checklists. We measured the compliance across various items in AMSTAR-2 and PRISMA checklists and provided recommendations to improve quality.

RESULTS

Using the AMSTAR-2 rating method, 84% (52/62) of NMAs were rated "critically low." Quantitatively, the median [interquartile range] AMSTAR-2 score was 55 [44-69]%, while the PRISMA score was 70 [61-81]%. Methodological and reporting scores showed a strong correlation (R = 0.78). Anesthesiology NMAs had a higher AMSTAR-2 score and PRISMA score if they were published in higher impact factor journals (P = 0.006 and P = 0.01, respectively) or followed PRISMA-NMA reporting guidelines (P = 0.001 and P = 0.002, respectively). Network meta-analyses from China had lower scores (P < 0.001 and P < 0.001, respectively). Neither score improved over time (P = 0.69 and P = 0.67, respectively).

CONCLUSION

The current study highlights numerous methodological and reporting deficiencies in anesthesiology NMAs. Although the AMSTAR tool has been used to assess the methodological quality of NMAs, dedicated tools for conducting and assessing the methodological quality of NMAs are urgently required.

STUDY REGISTRATION

PROSPERO (CRD42021227997); first submitted 23 January 2021.

Comparison of statistical methods for integrating real-world evidence in a rare events meta-analysis of randomized controlled trials

Rare events meta-analyses of randomized controlled trials (RCTs) are often underpowered because the outcomes are infrequent. Real-world evidence (RWE) from non-randomized studies may provide valuable complementary evidence about the effects of rare events, and there is growing interest in including such evidence in the decision-making process. Several methods for combining RCTs and RWE studies have been proposed, but the comparative performance of these methods is not well understood. We describe a simulation study that aims to evaluate an array of alternative Bayesian methods for including RWE in rare events meta-analysis of RCTs: the naïve data synthesis, the design-adjusted synthesis, the use of RWE as prior information, the three-level hierarchical models, and the bias-corrected meta-analysis model. The percentage bias, root-mean-square-error, mean 95% credible interval width, coverage probability, and power are used to measure performance. The various methods are illustrated using a systematic review to evaluate the risk of diabetic ketoacidosis among patients using sodium/glucose co-transporter 2 inhibitors as compared with active-comparators. Our simulations show that the bias-corrected meta-analysis model is comparable to or better than the other methods in terms of all evaluated performance measures and simulation scenarios. Our results also demonstrate that data solely from RCTs may not be sufficiently reliable for assessing the effects of rare events. In summary, the inclusion of RWE could increase the certainty and comprehensiveness of the body of evidence of rare events from RCTs, and the bias-corrected meta-analysis model may be preferable.

Efficacy and Safety of Oral Anticoagulants in Older Adult Patients With Atrial Fibrillation: Pairwise and Network Meta-Analyses

OBJECTIVE

To evaluate the efficacy and safety of oral anticoagulants for older adult patients with atrial fibrillation (AF).

DESIGN

Pairwise and network meta-analyses.

SETTING AND PARTICIPANTS

Patients with AF aged ≥75 years.

METHODS

PubMed, Embase, and the Cochrane library were searched for published randomized controlled trials and adjusted observational studies evaluating the use of a non-vitamin K antagonist oral anticoagulants (NOACs), vitamin K antagonist, or antiplatelet drug for the prevention of stroke. The primary efficacy and safety outcomes were the composite of stroke and systemic embolism (SSE) and major bleedings.

RESULTS

This study included 38 studies enrolling 1,022,908 older adult patients with AF. Results from pairwise meta-analyses showed that NOACs were superior to warfarin for all outcomes, except that dabigatran increased the risk of gastrointestinal (GI) bleedings. Aspirin was associated with a higher risk of SSE and ischemic stroke than warfarin or NOACs. Results of network meta-analyses indicated that apixaban significantly reduced the risk of SSE, major bleedings, and GI bleedings than warfarin, rivaroxaban, and dabigatran. Apixaban, edoxaban, rivaroxaban, and dabigatran reduced the risk of ischemic stroke and intracranial bleeding compared to warfarin. Dabigatran showed lower risk of all-cause mortality than warfarin and of intracranial bleeding than rivaroxaban.

CONCLUSIONS AND IMPLICATIONS

NOACs are of at least equal efficacy, or even superior to warfarin. The safety profile of individual NOAC agents was significantly different, as apixaban performs better than the other oral anticoagulants in reducing major bleeding and GI bleeding, whereas dabigatran increased the risk of GI bleeding.

Efficacy and safety of botulinum toxin for treating motor dysfunction in patients with Parkinson's disease: a systematic review and meta-analysis

OBJECTIVE

To evaluate the efficacy and safety of botulinum toxin (BTX) for motor dysfunction in Parkinson's disease (PD).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Searches of PubMed, EMBASE and the Cochrane Library, from database inception to 20 October 2022.

ELIGIBILITY CRITERIA

Studies reported in English with adult PD patients treated with BTX.

DATA EXTRACTION AND SYNTHESIS

Primary outcomes were United Parkinson's Disease Rate Scale Section (UPDRS) III (or its items) and Visual Analogue Scale (VAS). Secondary outcomes were UPDRS-II (or its items), Freezing of Gait Questionnaire (FOG-Q), Timed Up and Go test (TUG) and treatment-related adverse events (TRAEs). Mean difference (MD) or standardised MD (SMD) before and after treatment with 95% CIs were used for continuous variables and risk ratios (RRs) with 95% CIs was used for TRAEs.

RESULTS

Six randomised controlled trials (RCTs) and six non-RCTs (case series) were included (ntotal=224 participants, nRCT=165). No significant difference was found in pooled results of UPDRS-III (available in four RCTs and two non-RCTs, SMD=-0.19, 95% CI -0.98 to 0.60), UPDRS-II (four RCTs and one non-RCT, SMD=-0.55, 95% CI -1.22 to 0.13), FOG-Q (one RCT and one non-RCT, SMD=0.53, 95% CI -1.93 to 2.98) or the risk of TRAEs (five RCTs, RR 0.87, 95% CI 0.37 to 2.01). Significant decreases were found in pooled VAS score (three RCTs and five non-RCTs, MD=-2.14, 95% CI -3.05 to -1.23) and TUG (MD=-2.06, 95% CI -2.91 to -1.20) after BTX treatment.

CONCLUSIONS

BTX may not be associated with motor symptoms alleviation, although it benefits pain alleviation and functional mobility improvement.

Analgesic Efficacy of Intraoperative Superior Hypogastric Plexus (SHP) Block during Abdominal Hysterectomy: A Systematic Review and Meta-Analysis of Controlled Trials

Background and Objectives: Abdominal hysterectomy is a major surgery that is often associated with pronounced postsurgical pain. The objective of this research is to conduct a systematic review and meta-analysis of all randomized controlled trials (RCTs) and nonrandomized comparative trials (NCTs) that have surveyed the analgesic benefits and morbidity of intraoperative superior hypogastric plexus (SHP) block (intervention) compared with no SHP block (control) during abdominal hysterectomy. Materials and Methods: The Cochrane Central Register of Controlled Trials (CENTRAL), Google Scholar, Web of Science, PubMed, Scopus, and Embase were searched from inception until 8 May 2022. The Cochrane Collaboration tool and Newcastle-Ottawa Scale were used to evaluate the risk of bias of RCTs and NCTs, respectively. In a random effects mode, the data were pooled as risk ratio (RR) or mean difference (MD) with 95% confidence interval (CI). Results: Five studies (four RCTs and one NCT) comprising 210 patients (SHP block = 107 and control = 103) were analyzed. The overall postsurgical pain score (n = 5 studies, MD = -1.08, 95% CI [-1.41, -0.75], p < 0.001), postsurgical opioid consumption (n = 4 studies, MD = -18.90 morphine milligram equivalent, 95% CI, [-22.19, -15.61], p < 0.001), and mean time to mobilization (n = 2 studies, MD = -1.33 h, 95% CI [-1.98, -0.68], p < 0.001) were significantly decreased in the SHP block group contrasted with the control arm. Nevertheless, there was no significant variance between both arms regarding operation time, intraoperative blood loss, postsurgical NSAID consumption, and hospital stay. There were no major side effects or sympathetic block-related aftermaths in both groups. Conclusions: During abdominal hysterectomy and receiving perioperative multimodal analgesia, the administration of intraoperative SHP block is largely safe and exhibits better analgesic effects compared to cases without administration of SHP block.

Hierarchical network meta-analysis models for synthesis of evidence from randomised and non-randomised studies

BACKGROUND

With the increased interest in the inclusion of non-randomised data in network meta-analyses (NMAs) of randomised controlled trials (RCTs), analysts need to consider the implications of the differences in study designs as such data can be prone to increased bias due to the lack of randomisation and unmeasured confounding. This study aims to explore and extend a number of NMA models that account for the differences in the study designs, assessing their impact on the effect estimates and uncertainty.

METHODS

Bayesian random-effects meta-analytic models, including naïve pooling and hierarchical models differentiating between the study designs, were extended to allow for the treatment class effect and accounting for bias, with further extensions allowing for bias terms to vary depending on the treatment class. Models were applied to an illustrative example in type 2 diabetes; using data from a systematic review of RCTs and non-randomised studies of two classes of glucose-lowering medications: sodium-glucose co-transporter 2 inhibitors and glucagon-like peptide-1 receptor agonists.

RESULTS

Across all methods, the estimated mean differences in glycated haemoglobin after 24 and 52 weeks remained similar with the inclusion of observational data. The uncertainty around these estimates reduced when conducting naïve pooling, compared to NMA of RCT data alone, and remained similar when applying hierarchical model allowing for class effect. However, the uncertainty around these effect estimates increased when fitting hierarchical models allowing for the differences in study design. The impact on uncertainty varied between treatments when applying the bias adjustment models. Hierarchical models and bias adjustment models all provided a better fit in comparison to the naïve-pooling method.

CONCLUSIONS

Hierarchical and bias adjustment NMA models accounting for study design may be more appropriate when conducting a NMA of RCTs and observational studies. The degree of uncertainty around the effectiveness estimates varied depending on the method but use of hierarchical models accounting for the study design resulted in increased uncertainty. Inclusion of non-randomised data may, however, result in inferences that are more generalisable and the models accounting for the differences in the study design allow for more detailed and appropriate modelling of complex data, preventing overly optimistic conclusions.

Synthesizing cross-design evidence and cross-format data using network meta-regression

In network meta-analysis (NMA), we synthesize all relevant evidence about health outcomes with competing treatments. The evidence may come from randomized clinical trials (RCT) or non-randomized studies (NRS) as individual participant data (IPD) or as aggregate data (AD). We present a suite of Bayesian NMA and network meta-regression (NMR) models allowing for cross-design and cross-format synthesis. The models integrate a three-level hierarchical model for synthesizing IPD and AD into four approaches. The four approaches account for differences in the design and risk of bias (RoB) in the RCT and NRS evidence. These four approaches variously ignoring differences in RoB, using NRS to construct penalized treatment effect priors and bias-adjustment models that control the contribution of information from high RoB studies in two different ways. We illustrate the methods in a network of three pharmacological interventions and placebo for patients with relapsing-remitting multiple sclerosis. The estimated relative treatment effects do not change much when we accounted for differences in design and RoB. Conducting network meta-regression showed that intervention efficacy decreases with increasing participant age. We also re-analysed a network of 431 RCT comparing 21 antidepressants, and we did not observe material changes in intervention efficacy when adjusting for studies' high RoB. We re-analysed both case studies accounting for different study RoB. In summary, the described suite of NMA/NMR models enables the inclusion of all relevant evidence while incorporating information on the within-study bias in both observational and experimental data and enabling estimation of individualized treatment effects through the inclusion of participant characteristics.

Methods for the Inclusion of Real-World Evidence in a Rare Events Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Many rare events meta-analyses of randomized controlled trials (RCTs) have lower statistical power, and real-world evidence (RWE) is becoming widely recognized as a valuable source of evidence. The purpose of this study is to investigate methods for including RWE in a rare events meta-analysis of RCTs and the impact on the level of uncertainty around the estimates.

METHODS

Four methods for the inclusion of RWE in evidence synthesis were investigated by applying them to two previously published rare events meta-analyses: the naïve data synthesis (NDS), the design-adjusted synthesis (DAS), the use of RWE as prior information (RPI), and the three-level hierarchical models (THMs). We gauged the effect of the inclusion of RWE by varying the degree of confidence placed in RWE.

RESULTS

This study showed that the inclusion of RWE in a rare events meta-analysis of RCTs could increase the precision of the estimates, but this depended on the method of inclusion and the level of confidence placed in RWE. NDS cannot consider the bias of RWE, and its results may be misleading. DAS resulted in stable estimates for the two examples, regardless of whether we placed high- or low-level confidence in RWE. The results of the RPI approach were sensitive to the confidence level placed in RWE. The THM was effective in allowing for accommodating differences between study types, while it had a conservative result compared with other methods.

CONCLUSION

The inclusion of RWE in a rare events meta-analysis of RCTs could increase the level of certainty of the estimates and enhance the decision-making process. DAS might be appropriate for inclusion of RWE in a rare event meta-analysis of RCTs, but further evaluation in different scenarios of empirical or simulation studies is still warranted.

Effectiveness of educational and behavioural interventions for reducing fear of hypoglycaemia among adults with type 1 diabetes: Systematic review and meta-analyses

AIMS

To summarize and critically appraise evidence regarding the effectiveness of educational and/or behavioural interventions in reducing fear of hypoglycaemia among adults with type 1 diabetes.

METHODS

Systematic searches of medical and psychology databases were conducted. Risk-of-bias was assessed using the Joanna Briggs Institute Critical Appraisal Tools. Data were synthesized using random-effects meta-analyses for randomized controlled trials (RCTs) and narrative synthesis for observational studies.

RESULTS

Five RCTs (N = 682) and seven observational studies (N = 1519) met the inclusion criteria, reporting on behavioural, structured education and cognitive-behavioural therapy (CBT) interventions. Most studies assessed fear of hypoglycaemia using the Hypoglycaemia Fear Survey Worry (HFS-W) and Behaviour (HFS-B) subscales. Mean fear of hypoglycaemia at baseline was relatively low across studies. Meta-analyses showed a significant effect of interventions on HFS-W (SMD = -0.17, p = 0.032) but not on HFS-B scores (SMD = -0.34, p = 0.113). Across RCTs, Blood Glucose Awareness Training (BGAT) had the largest effect on HFS-W and HFS-B scores, and one CBT-based program was as effective as BGAT in reducing HFS-B scores. Observational studies showed that Dose Adjustment for Normal Eating (DAFNE) was associated with significant fear of hypoglycaemia reductions.

CONCLUSIONS

Current evidence suggests that educational and behavioural interventions can reduce fear of hypoglycaemia. However, no study to date has examined these interventions among people with high fear of hypoglycaemia.

Unit information prior for incorporating real-world evidence into randomized controlled trials

Randomized controlled trials (RCTs) have been widely recognized as the gold standard to infer the treatment effect in clinical research. Recently, there has been growing interest in enhancing and complementing the result in an RCT by integrating real-world evidence from observational studies. The unit information prior (UIP) is a newly proposed technique that can effectively borrow information from multiple historical datasets. We extend this generic approach to synthesize the non-randomized evidence into a current RCT. Not only does the UIP only require summary statistics published from observational studies for ease of implementation, but it also has clear interpretations and can alleviate the potential bias in the real-world evidence via weighting schemes. Extensive numerical experiments show that the UIP can improve the statistical efficiency in estimating the treatment effect for various types of outcome variables. The practical potential of our UIP approach is further illustrated with a real trial of hydroxychloroquine for treating COVID-19 patients.

Exercise in patients with repaired tetralogy of Fallot: a systematic review and meta-analysis

OBJECTIVE

Children and adults with repaired tetralogy of Fallot (rTOF) have an impaired exercise capacity, a less active lifestyle and an increased long-term risk of adverse outcomes compared with healthy peers. This study aimed to summarise the current evidence for the effectiveness and safety of exercise training interventions in patients with rTOF.

METHODS

PubMed/MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, Scopus and reference lists of relevant articles were searched for prospective studies published by November 2021. Random-effects meta-analysis and descriptive synthesis were performed to assess the effectiveness and safety of exercise training in patients with rTOF.

RESULTS

Of the 9677 citations identified, 12 articles were included that reported on 10 unique studies and covered 208 patients with rTOF (range of mean/median age: 7.4-43.3 years). All studies implemented 2 to 7 aerobic or respiratory training sessions per week with durations ranging from 6 to 26 weeks. Meta-analysis of the included randomised controlled trials showed that exercise training was associated with a significant improvement in peak VO₂ (pooled mean difference: +3.1 mL/min/kg; 95% CI: 0.76 to 5.36 mL/min/kg, p=0.019). Cardiac imaging studies revealed no subclinical adverse remodelling after the exercise interventions. No serious adverse events including arrhythmias were reported in these studies.

CONCLUSION

Current evidence suggests that exercise training can improve exercise capacity in patients with rTOF with a low risk for adverse events. Exercise prescription may be a safe and effective tool to help improving outcomes in patients with rTOF.

PROSPERO REGISTRATION NUMBER

CRD42021292809.

Management of Chronic Subdural Hematoma: A Systematic Review and Component Network Meta-analysis of 455 Studies With 103 645 Cases

BACKGROUND

Chronic subdural hematoma (CSDH) is a common neurosurgical condition with a high risk of recurrence after treatment.

OBJECTIVE

To assess and compare the risk of recurrence, morbidity, and mortality across various treatments for CSDH.

METHODS

A systematic review and meta-analysis was performed. PubMed/MEDLINE, EMBASE, SCOPUS, and Web of Science were searched from January 01, 2000, to July 07, 2021. The primary outcome was recurrence, and secondary outcomes were morbidity and mortality. Component network meta-analyses (CNMAs) were performed for surgical and medical treatments, assessing recurrence and morbidity. Incremental risk ratios (iRRs) with 95% CIs were estimated for each component.

RESULTS

In total, 12 526 citations were identified, and 455 studies with 103 645 cases were included. Recurrence occurred in 11 491/93 525 (10.8%, 95% CI 10.2-11.5, 418 studies) cases after surgery. The use of a postoperative drain (iRR 0.53, 95% CI 0.44-0.63) and middle meningeal artery embolization (iRR 0.19, 95% CI 0.05-0.83) reduced recurrence in the surgical CNMA. In the pharmacological CNMA, corticosteroids (iRR 0.47, 95% CI 0.36-0.61) and surgical intervention (iRR 0.11, 95% CI 0.07-0.15) were associated with lower risk. Corticosteroids were associated with increased morbidity (iRR 1.34, 95% CI 1.05-1.70). The risk of morbidity was equivalent across surgical treatments.

CONCLUSION

Recurrence after evacuation occurs in approximately 10% of cSDHs, and the various surgical interventions are approximately equivalent. Corticosteroids are associated with reduced recurrence but also increased morbidity. Drains reduce the risk of recurrence, but the position of drain (subdural vs subgaleal) did not influence recurrence. Middle meningeal artery embolization is a promising treatment warranting further evaluation in randomized trials.

Structured expert elicitation to inform long-term survival extrapolations using alternative parametric distributions: a case study of CAR T therapy for relapsed/ refractory multiple myeloma

Background

Our aim was to extend traditional parametric models used to extrapolate survival in cost-effectiveness analyses (CEAs) by integrating individual-level patient data (IPD) from a clinical trial with estimates from experts regarding long-term survival. This was illustrated using a case study evaluating survival of patients with triple-class exposed relapsed/refractory multiple myeloma treated with the chimeric antigen receptor (CAR) T cell therapy idecabtagene vicleucel (ide-cel, bb2121) in KarMMa (a phase 2, single-arm trial).

Methods

The distribution of patients expected to be alive at 3, 5, and 10 years given the observed survival from KarMMa (13.3 months of follow-up) was elicited from 6 experts using the SHeffield ELicitation Framework. Quantities of interest were elicited from each expert individually, which informed the consensus elicitation including all experts. Estimates for each time point were assumed to follow a truncated normal distribution. These distributions were incorporated into survival models, which constrained the expected survival based on standard survival distributions informed by IPD from KarMMa.

Results

Models for ide-cel that combined KarMMa data with expert opinion were more consistent in terms of survival as well as mean survival at 10 years (survival point estimates under different parametric models were 29–33% at 3 years, 5–17% at 5 years, and 0–6% at 10 years) versus models with KarMMa data alone (11–39% at 3 years, 0–25% at 5 years, and 0–11% at 10 years).

Conclusion

This case study demonstrates a transparent approach to integrate IPD from trials with expert opinion using traditional parametric distributions to ensure long-term survival extrapolations are clinically plausible.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01745-z.

Bridging disconnected networks of first and second lines of biologic therapies in rheumatoid arthritis with registry data: bayesian evidence synthesis with target trial emulation

OBJECTIVES

We aim to use real-world data in evidence synthesis to optimize an evidence base for the effectiveness of biologic therapies in rheumatoid arthritis to allow for evidence on first-line therapies to inform second-line effectiveness estimates.

STUDY DESIGN AND SETTING

We use data from the British Society for Rheumatology Biologics Register for Rheumatoid Arthritis to supplement randomized controlled trials evidence obtained from the literature, by emulating target trials of treatment sequences to estimate treatment effects in each line of therapy. Treatment effects estimates from the target trials inform a bivariate network meta-analysis (NMA) of first-line and second-line treatments.

RESULTS

Summary data were obtained from 21 trials of biologic therapies including two for second-line treatment and results from six emulated target trials of both treatment lines. Bivariate NMA resulted in a decrease in uncertainty around the effectiveness estimates of the second-line therapies, when compared to the results of univariate NMA, and allowed for predictions of treatment effects not evaluated in second-line randomized controlled trials.

CONCLUSION

Bivariate NMA provides effectiveness estimates for all treatments in first and second line, including predicted effects in second line where these estimates did not exist in the data. This novel methodology may have further applications; for example, for bridging networks of trials in children and adults.

Comparative effectiveness and risk of preterm birth of local treatments for cervical intraepithelial neoplasia and stage IA1 cervical cancer: a systematic review and network meta-analysis

Background

The trade-off between comparative effectiveness and reproductive morbidity of different treatment methods for cervical intraepithelial neoplasia (CIN) remains unclear. We aimed to determine the risks of treatment failure and preterm birth associated with various treatment techniques.

Methods

In this systematic review and network meta-analysis, we searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials database for randomised and non-randomised studies reporting on oncological or reproductive outcomes after CIN treatments from database inception until March 9, 2022, without language restrictions. We included studies of women with CIN, glandular intraepithelial neoplasia, or stage IA1 cervical cancer treated with excision (cold knife conisation [CKC], laser conisation, and large loop excision of the transformation zone [LLETZ]) or ablation (radical diathermy, laser ablation, cold coagulation, and cryotherapy). We excluded women treated with hysterectomy. The primary outcomes were any treatment failure (defined as any abnormal histology or cytology) and preterm birth (<37 weeks of gestation). The network for preterm birth also included women with untreated CIN (untreated colposcopy group). The main reference group was LLETZ for treatment failure and the untreated colposcopy group for preterm birth. For randomised controlled trials, we extracted group-level summary data, and for observational studies, we extracted relative treatment effect estimates adjusted for potential confounders, when available, and we did random-effects network meta-analyses to obtain odds ratios (ORs) with 95% CIs. We assessed within-study and across-study risk of bias using Cochrane tools. This systematic review is registered with PROSPERO, CRD42018115495 and CRD42018115508.

Findings

7880 potential citations were identified for the outcome of treatment failure and 4107 for the outcome of preterm birth. After screening and removal of duplicates, the network for treatment failure included 19 240 participants across 71 studies (25 randomised) and the network for preterm birth included 68 817 participants across 29 studies (two randomised). Compared with LLETZ, risk of treatment failure was reduced for other excisional methods (laser conisation: OR 0·59 [95% CI 0·44–0·79] and CKC: 0·63 [0·50–0·81]) and increased for laser ablation (1·69 [1·27–2·24]) and cryotherapy (1·84 [1·33–2·56]). No differences were found for the comparison of cold coagulation versus LLETZ (1·09 [0·68–1·74]) but direct data were based on two small studies only. Compared with the untreated colposcopy group, risk of preterm birth was increased for all excisional techniques (CKC: 2·27 [1·70–3·02]; laser conisation: 1·77 [1·29–2·43]; and LLETZ: 1·37 [1·16–1·62]), whereas no differences were found for ablative methods (laser ablation: 1·05 [0·78–1·41]; cryotherapy: 1·01 [0·35–2·92]; and cold coagulation: 0·67 [0·02–29·15]). The evidence was based mostly on observational studies with their inherent risks of bias, and the credibility of many comparisons was low.

Interpretation

More radical excisional techniques reduce the risk of treatment failure but increase the risk of subsequent preterm birth. Although there is uncertainty, ablative treatments probably do not increase risk of preterm birth, but are associated with higher failure rates than excisional techniques. Although we found LLETZ to have balanced effectiveness and reproductive morbidity, treatment choice should rely on a woman's age, size and location of lesion, and future family planning.

Funding

National Institute for Health and Care Research: Research for Patient Benefit.

Effects of the ketogenic diet on performance and body composition in athletes and trained adults: a systematic review and Bayesian multivariate multilevel meta-analysis and meta-regression

This systematic review with meta-analysis aimed to determine the effects of the ketogenic diet (KD) against carbohydrate (CHO)-rich diets on physical performance and body composition in trained individuals. The MEDLINE, EMBASE, CINAHL, SPORTDiscus, and The Cochrane Library were searched. Randomized and non-randomized controlled trials in athletes/trained adults were included. Meta-analytic models were carried out using Bayesian multilevel models. Eighteen studies were included providing estimates on cyclic exercise modes and strength one-maximum repetition (1-RM) performances and for total, fat, and free-fat masses. There were more favorable effects for CHO-rich than KD on time-trial performance (mode [95% credible interval]; -3.3% [-8.5%, 1.7%]), 1-RM (-5.7% [-14.9%, 2.6%]), and free-fat mass (-0.8 [-3.4, 1.9] kg); effects were more favorable to KD on total (-2.4 [-6.2, 1.8] kg) and fat mass losses (-2.4 [-5.4, 0.2] kg). Likely modifying effects on cyclic performance were the subject's sex and VO2max, intervention and performance durations, and mode of exercise. The intervention duration and subjects' sex were likely to modify effects on total body mass. KD can be a useful strategy for total and fat body losses, but a small negative effect on free-fat mass was observed. KD was not suitable for enhancing strength 1-RM or high-intensity cyclic performances.

Surgical resection, radiotherapy and percutaneous thermal ablation for treatment of stage 1 non-small cell lung cancer: protocol for a systematic review and network meta-analysis

INTRODUCTION

Non-small cell lung cancer (NSCLC) makes up the majority of lung cancer cases. Currently, surgical resection is the gold standard of treatment. However, as patients are becoming medically more complex presenting with advanced disease, minimally invasive image-guided percutaneous ablations are gaining popularity. Therefore, comparison of surgical, ablative and second-line external beam therapies will help clinicians, as management of NSCLC changes. We will conduct a meta-analysis, reviewing literature investigating these therapies in adult patients diagnosed with stage 1 NSCLC, with neither hilar nor mediastinal nodal involvement, confirmed either through cytology or histology regardless of type.

METHODS AND ANALYSIS

We will search electronic databases (MEDLINE, Embase, Web of Science, Scopus, ClinicalTrials.gov, Cochrane) from their inception to January 2021 to identify randomised controlled trials (RCTs), cluster RCTs and cohort studies comparing survival and clinical outcomes between any two interventions (lobectomy, wedge resection, video-assisted thoracoscopic surgery/robot-assisted thoracoscopic surgery, radiofrequency ablation, microwave ablation, cryoablation and consolidated radiation therapies (external beam radiation therapy, stereotactic body radiation therapy, and 3D conformal radiation therapy). The primary outcomes will include cancer-specific survival, lung disease-free survival, locoregional recurrence, death, toxicity and non-target organ injury. We will also search published and unpublished studies in trial registries and will review references of included studies for possible inclusion. Risk of bias will be assessed using tools developed by the Cochrane collaboration. Two reviewers will independently assess the eligibility of studies and conduct the corresponding risk of bias assessments. For each outcome, given enough studies, we will conduct a network meta-analysis. Finally, we will use the Confidence in Network Meta-Analysis tool to assess quality of the evidence for each of the primary outcomes.

ETHICS AND DISSEMINATION

We aim to share our findings through high-impact peer review. As interventional techniques become more popular, it will be important for providers in multidisciplinary teams caring for these patients to receive continuing medical education related to these interventions. Data will be made available to readers.

PROSPERO REGISTRATION NUMBER

CRD42021276629.

Efficacy and Safety of Various First-Line Therapeutic Strategies for Fetal Tachycardias: A Network Meta-Analysis and Systematic Review

Background: Fetal arrhythmias are common cardiac abnormalities associated with high mortality due to ventricular dysfunction and heart failure, particularly when accompanied by hydrops. Although several types of common fetal tachycardias have been relatively identified medications, such as digoxin, flecainide, and sotalol, there is no first-line drug treatment protocol established for the treatment of various types of fetal tachycardias.

Methods: We conducted a network meta-analysis using a Bayesian hierarchical framework to obtain a model for integrating both direct and indirect evidence. All tachycardia types (Total group), supraventricular tachycardia (SVT subgroup), atrial flutter (AF subgroup), hydrops subgroup, and non-hydrops subgroup fetuses were analyzed, and five first-line regimens were ranked according to treatment outcomes: digoxin monotherapy (D), flecainide monotherapy (F), sotalol monotherapy (S), digoxin plus flecainide combination therapy (DF), and digoxin plus sotalol combination therapy (DS). Effectiveness and safety were determined according to the cardioversion rate and intrauterine death rate.

Results: The pooled data indicated that DF combination therapy was always superior to D monotherapy, regardless of the tachycardia type or the presence of hydrops: Total, 2.44 (95% CrI: 1.59, 3.52); SVT, 2.77 (95% CrI: 1.59, 4.07); AF, 67.85 (95% CrI: 14.25, 168.68); hydrops, 6.03 (95% CrI: 2.54, 10.68); and non-hydrops, 5.06 (95% CrI: 1.87, 9.88). DF and F had a similar effect on control of fetal tachycardias. No significant differences were observed when comparing S, DS with D therapies across the subgroup analyses for the SVT, hydrops, and non-hydrops groups. No significant differences in mortality risks were among the various treatment regimens for the total group. And no significant differences were found in rates of intrauterine death rates at the same cardioversion amount.

Conclusion The flecainide monotherapy and combination of digoxin and flecainide should be considered the most superior therapeutic strategies for fetal tachycardia.

Systematic Review Registration: (https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=288997), identifier (288997).

Safety of general anaesthetics on the developing brain: are we there yet?

Thirty years ago, neurotoxicity induced by general anaesthetics in the developing brain of rodents was observed. In both laboratory-based and clinical studies, many conflicting results have been published over the years, with initial data confirming both histopathological and neurodevelopmental deleterious effects after exposure to general anaesthetics. In more recent years, animal studies using non-human primates and new human cohorts have identified some specific deleterious effects on neurocognition. A clearer pattern of neurotoxicity seems connected to exposure to repeated general anaesthesia. The biochemistry involved in this neurotoxicity has been explored, showing differential effects of anaesthetic drugs between the developing and developed brains. In this narrative review, we start with a comprehensive description of the initial concerning results that led to recommend that any non-essential surgery should be postponed after the age of 3 yr and that research into this subject should be stepped up. We then focus on the neurophysiology of the developing brain under general anaesthesia, explore the biochemistry of the observed neurotoxicity, before summarising the main scientific and clinical reports investigating this issue. We finally discuss the GAS trial, the importance of its results, and some potential limitations that should not undermine their clinical relevance. We finally suggest some key points that could be shared with parents, and a potential research path to investigate the biochemical effects of general anaesthesia, opening up perspectives to understand the neurocognitive effects of repetitive exposures, especially in at-risk children.

A comparison of methods for enriching network meta-analyses in the absence of individual patient data

During drug development, a biomarker is sometimes identified as separating a patient population into those with more and those with less benefit from evaluated treatments. Consequently, later studies might be targeted, while earlier ones are performed in mixed patient populations. This poses a challenge in evidence synthesis, especially if only aggregated data are available. Starting from this scenario, we investigate three commonly used network meta-analytic estimation methods, the naive estimation approach, the stand-alone analysis, and the network meta-regression. Additionally, we adapt and modify two methods which are used in evidence synthesis to combine randomized controlled trials with observational studies, the enrichment-through-weighting approach and the informative prior estimation. We evaluate all five methods in a simulation study with 32 scenarios using bias, RMSE, coverage, precision, and power. Additionally, we re-visit a clinical data set to exemplify and discuss the application. In the simulation study, none of the methods was observed to be clearly favorable over all investigated scenarios. However, the stand-alone analysis and the naive estimation performed comparably or worse than the other methods in all evaluated performance measures and simulation scenarios and are therefore not recommended. While substantial between-trial heterogeneity is challenging for all estimation approaches, the performance of the network meta-regression, the enriching-through weighting approach and the informative prior approach was dependent on the simulation scenario and the performance measure of interest. Furthermore, as these estimation methods are drawing slightly different assumptions, some of which require the presence of additional information for estimation, we recommend sensitivity-analyses wherever possible. This article is protected by copyright. All rights reserved.

Combining individual patient data from randomized and non-randomized studies to predict real-world effectiveness of interventions

Meta-analysis of randomized controlled trials is generally considered the most reliable source of estimates of relative treatment effects. However, in the last few years, there has been interest in using non-randomized studies to complement evidence from randomized controlled trials. Several meta-analytical models have been proposed to this end. Such models mainly focussed on estimating the average relative effects of interventions. In real-life clinical practice, when deciding on how to treat a patient, it might be of great interest to have personalized predictions of absolute outcomes under several available treatment options. This paper describes a general framework for developing models that combine individual patient data from randomized controlled trials and non-randomized study when aiming to predict outcomes for a set of competing medical interventions applied in real-world clinical settings. We also discuss methods for measuring the models' performance to identify the optimal model to use in each setting. We focus on the case of continuous outcomes and illustrate our methods using a data set from rheumatoid arthritis, comprising patient-level data from three randomized controlled trials and two registries from Switzerland and Britain.

Framework for the synthesis of non-randomised studies and randomised controlled trials: a guidance on conducting a systematic review and meta-analysis for healthcare decision making

INTRODUCTION

High-quality randomised controlled trials (RCTs) provide the most reliable evidence on the comparative efficacy of new medicines. However, non-randomised studies (NRS) are increasingly recognised as a source of insights into the real-world performance of novel therapeutic products, particularly when traditional RCTs are impractical or lack generalisability. This means there is a growing need for synthesising evidence from RCTs and NRS in healthcare decision making, particularly given recent developments such as innovative study designs, digital technologies and linked databases across countries. Crucially, however, no formal framework exists to guide the integration of these data types.

OBJECTIVES AND METHODS

To address this gap, we used a mixed methods approach (review of existing guidance, methodological papers, Delphi survey) to develop guidance for researchers and healthcare decision-makers on when and how to best combine evidence from NRS and RCTs to improve transparency and build confidence in the resulting summary effect estimates.

RESULTS

Our framework comprises seven steps on guiding the integration and interpretation of evidence from NRS and RCTs and we offer recommendations on the most appropriate statistical approaches based on three main analytical scenarios in healthcare decision making (specifically, 'high-bar evidence' when RCTs are the preferred source of evidence, 'medium,' and 'low' when NRS is the main source of inference).

CONCLUSION

Our framework augments existing guidance on assessing the quality of NRS and their compatibility with RCTs for evidence synthesis, while also highlighting potential challenges in implementing it. This manuscript received endorsement from the International Society for Pharmacoepidemiology.

Comparative effectiveness of N95, surgical or medical, and non-medical facemasks in protection against respiratory virus infection: A systematic review and network meta-analysis

The aim of this systematic review and network meta‐analysis is to evaluate the comparative effectiveness of N95, surgical/medical and non‐medical facemasks as personal protective equipment against respiratory virus infection. The study incorporated 35 published and unpublished randomized controlled trials and observational studies investigating specific mask effectiveness against influenza virus, SARS‐CoV, MERS‐CoV and SARS‐CoV‐2. We searched PubMed, Google Scholar and medRxiv databases for studies published up to 5 February 2021 (PROSPERO registration: CRD42020214729). The primary outcome of interest was the rate of respiratory viral infection. The quality of evidence was estimated using the GRADE approach. High compliance to mask‐wearing conferred a significantly better protection (odds ratio [OR], 0.43; 95% confidence interval [CI], 0.23–0.82) than low compliance. N95 or equivalent masks were the most effective in providing protection against coronavirus infections (OR, 0.30; CI, 0.20–0.44) consistently across subgroup analyses of causative viruses and clinical settings. Evidence supporting the use of medical or surgical masks against influenza or coronavirus infections (SARS, MERS and COVID‐19) was weak. Our study confirmed that the use of facemasks provides protection against respiratory viral infections in general; however, the effectiveness may vary according to the type of facemask used. Our findings encourage the use of N95 respirators or their equivalents (e.g., P2) for best personal protection in healthcare settings until more evidence on surgical and medical masks is accrued. This study highlights a substantial lack of evidence on the comparative effectiveness of mask types in community settings.

Real World Data in Health Technology Assessment of Complex Health Technologies

The available evidence on relative effectiveness and risks of new health technologies is often limited at the time of health technology assessment (HTA). Additionally, a wide variety in real-world data (RWD) policies exist among HTA organizations. This study assessed which challenges, related to the increasingly complex nature of new health technologies, make the acceptance of RWD most likely. A questionnaire was disseminated among 33 EUnetHTA member HTA organizations. The questions focused on accepted data sources, circumstances that allowed for RWD acceptance and barriers to acceptance. The questionnaire was validated and tested for reliability by an expert panel, and pilot-tested before dissemination via LimeSurvey. Twenty-two HTA organizations completed the questionnaire (67%). All reported accepting randomized clinical trials. The most accepted RWD source were patient registries (19/22, 86%), the least accepted were editorials and expert opinions (8/22, 36%). With orphan treatments or companion diagnostics, organizations tended to be most likely to accept RWD sources, 4.3–3.2 on a 5-point Likert scale, respectively. Additional circumstances were reported to accept RWD (e.g., a high disease burden). The two most important barriers to accepting RWD were lacking necessary RWD sources and existing policy structures. European HTA organizations seem positive toward the (wider) use of RWD in HTA of complex therapies. Expanding the use of patient registries could be potentially useful, as a large share of the organizations already accepts this source. However, many barriers still exist to the widespread use of RWD. Our results can be used to prioritize circumstances in which RWD might be accepted.

Integrative Analysis of Randomized Clinical Trial and Observational Study Data to Inform Post-marketing Safety Decision-Making

Safety evaluation is a continual and iterative process throughout the drug development life cycle and requires long time horizons and large amounts of data to fully understand the safety profile of a medical product. Although randomized clinical trials (RCT) provide high-quality data for an initial assessment of safety signals, the safety signals may not all have been known at the time of approval because safety data collected from RCT only involve a relatively small number of subjects during a relatively short follow-up period. The increased accumulation of post-marketing real-world data (RWD) presents an opportunity to utilize them for safety decision-making; these include identifying new safety signals, further characterization of safety concerns that are raised in pre-marketing RCT, and further generalization of RCT findings to the broader patient populations not previously studied in RCT. In this paper, we use cardiovascular safety outcome trial for antidiabetic therapies as an illustrative example and discuss how integrative analysis of RCT and observational study data can answer regulatory concerns about cardiovascular risk in a post-marketing setting. A novel statistical analysis strategy is proposed to combine both sources of safety data in a data fusion approach. The proposed approach includes three stages: (1) feasibility analysis that uses an RCT to validate an observational study, applying estimand framework and emulating RCT with RWD; (2) integrative analysis that combines evidence from the RCT and observational study data cooperatively; and (3) sensitivity analysis that examines the consistency of the previous analyses. Two potential utilities of the proposed integrative analysis for the cardiovascular safety outcome trial are discussed.

Supermicrosurgical treatment for lymphedema: a systematic review and network meta-analysis protocol

BACKGROUND

Lymphedema is a condition that affects up to 130 million subjects worldwide. Since it is related to several complications and a significant reduction in terms of quality of life, it is a heavy burden not only to the patients but also for the healthcare system worldwide. Despite the development of supermicrosurgery, such as vascularized lymph node transfer (VLNT) and lymphovenous anastomosis LVA, the indications and outcomes of these complex groups of interventions remain a controversial topic in the field of reconstructive plastic surgery.

METHODS

This systematic review and network meta-analysis aims to assess the evidence of outcomes of LVA and VLNT in patients with lymphedema. Secondary aims of the project are to determine if for any outcomes, LVA or VLNT is superior to conservative therapy alone, and whether the available evidence favors any kind of supermicrosurgical interventions for lymphedema patients. This study will include original studies of patients with lymphedema on the extremities indexed in PubMed, EMBASE, CENTRAL, PASCAL, FRANCIS, ISTEX, LILACS, CNKI, and IndMED that reported microsurgery (supermicrosurgery) of all techniques aiming the re-functionalization of the lymphatic system. As comparators, mere observation, conservative treatment of any kind, and the other subgroups of supermicrosurgery are planned. The primary outcome of this systematic review and network meta-analysis is the difference of the limb volume, while the secondary outcomes of interest will be erysipelas rates, major and minor complications, postoperative necessity of continuous compression garments, and patient satisfaction, measured by already published and validated scores for quality of life.

DISCUSSION

We will provide an overview and evidence grade analysis of the scientific literature available on the effectiveness of the subcategories of supermicrosurgical interventions for lymphedema.

Network Meta-Analysis

There are often multiple potential interventions to treat a disease; therefore, we need a method for simultaneously comparing and ranking all of these available interventions. In contrast to pairwise meta-analysis, which allows for the comparison of one intervention to another based on head-to-head data from randomized trials, network meta-analysis (NMA) facilitates simultaneous comparison of the efficacy or safety of multiple interventions that may not have been directly compared in a randomized trial. NMAs help researchers study important and previously unanswerable questions, which have contributed to a rapid rise in the number of NMA publications in the biomedical literature. However, the conduct and interpretation of NMAs are more complex than pairwise meta-analyses: there are additional NMA model assumptions (i.e., network connectivity, homogeneity, transitivity, and consistency) and outputs (e.g., network plots and surface under the cumulative ranking curves [SUCRAs]). In this chapter, we will: (1) explore similarities and differences between pairwise and network meta-analysis; (2) explain the differences between direct, indirect, and mixed treatment comparisons; (3) describe how treatment effects are derived from NMA models; (4) discuss key criteria predicating completion of NMA; (5) interpret NMA outputs; (6) discuss areas of ongoing methodological research in NMA; (7) outline an approach to conducting a systematic review and NMA; (8) describe common problems that researchers encounter when conducting NMAs and potential solutions; and (9) outline an approach to critically appraising a systematic review and NMA.

Effectiveness and Safety of Two Consecutive Cycles of Single Embryo Transfer Compared With One Cycle of Double Embryo Transfer: A Systematic Review and Meta-Analysis

OBJECTIVE

To date, evidence regarding the effectiveness and safety of two consecutive cycles of single embryo transfer (2SETs) compared with one cycle of double embryo transfer (DET) has been inadequate, particularly considering infertile women with different prognostic factors. This study aimed to comprehensively summarize the evidence by comparing 2SETs with DET.

METHODS

PubMed, Embase, Cochrane Library databases, ClinicalTrails.gov, and the WHO International Clinical Trials Registry Platform were searched up to March 22, 2022. Peer-reviewed, English-language randomized controlled trials (RCTs) and observational studies (OS) comparing the outcomes of 2SETs with DET in infertile women with their own oocytes and embryos were included. Two authors independently conducted study selection, data extraction, and bias assessment. The Mantel-Haenszel random-effects model was used for pooling RCTs, and a Bayesian design-adjusted model was conducted to synthesize the results from both RCTs and OS.

MAIN RESULTS

Twelve studies were finally included. Compared with the DET, 2SETs were associated with a similar cumulative live birth rate (LBR; 48.24% vs. 48.91%; OR, 0.97; 95% credible interval (CrI), 0.89-1.13, τ^{2 =} 0.1796; four RCTs and six observational studies; 197,968 women) and a notable lower cumulative multiple birth rate (MBR; 0.87% vs. 17.72%; OR, 0.05; 95% CrI, 0.02-0.10, τ^{2 =} 0.1036; four RCTs and five observational studies; 197,804 women). Subgroup analyses revealed a significant increase in cumulative LBR (OR, 1.33; 95% CrI, 1.29-1.38, τ^{2 =} 0) after two consecutive cycles of single blastocyst transfer compared with one cycle of double blastocyst transfer. Moreover, a lower risk of cesarean section, antepartum hemorrhage, preterm birth, low birth weight, and neonatal intensive care unit admission but a higher gestational age at birth and birth weight were found in the 2SETs group.

CONCLUSION

Compared to the DET strategy, 2SETs result in a similar LBR while simultaneously reducing the MBR and improving maternal and neonatal adverse outcomes. The 2SETs strategy appears to be especially beneficial for women aged ≤35 years and for blastocyst transfers.

Effects of Different Treatment Regimens on Primary Spontaneous Pneumothorax: A Systematic Review and Network Meta-Analysis

PURPOSE

The best treatment strategy for primary spontaneous pneumothorax is controversial and varies widely in practice.

METHODS

Literatures were searched from databases till 24 August 2021. A Bayesian network meta-analysis was conducted to compare the outcomes of various treatments with the following endpoints: recurrence rate, postoperative chest tube duration, postoperative air leakage duration, length of hospital stay, and complications rate.

RESULTS

In all, 7210 patients of 20 randomized controlled trials and 17 cohort studies were included. Surgery had a significantly lower recurrence rate compared to other treatments. Besides, bullectomy (BT) combined with chemical pleurodesis (CP), mechanical pleurodesis, or staple line coverage (SLC) can reduce the recurrence rate compared to BT alone, but none of them were statistically significant. In terms of reducing chest tube duration, BT with tubular Neoveil outperformed BT + pleural abrasion (mean difference [MD], 95% confidence interval [CI]: -2.5 [-4.63, -0.35]) and BT + apical pleurectomy (MD, 95% CI: -2.72 [-5.16, -0.27]).

CONCLUSIONS

Surgical methods were superior to manual aspiration (MA), chest tube drainage (CTD), and conservative treatment in terms of recurrence reduction. There was no significant difference between MA and CTD in reducing the recurrence rate. Among surgical methods, CP is more effective than mechanical pleurodesis and SLC among the additional procedures based on BT.

BRIDGING RANDOMIZED CONTROLLED TRIALS AND SINGLE-ARM TRIALS USING COMMENSURATE PRIORS IN ARM-BASED NETWORK META-ANALYSIS

Network meta-analysis (NMA) is a powerful tool to compare multiple treatments directly and indirectly by combining and contrasting multiple independent clinical trials. Because many NMAs collect only a few eligible randomized controlled trials (RCTs), there is an urgent need to synthesize different sources of information, e.g., from both RCTs and single-arm trials. However, single-arm trials and RCTs may have different populations and quality, so that assuming they are exchangeable may be inappropriate. This article presents a novel method using a commensurate prior on variance (CPV) to borrow variance (rather than mean) information from single-arm trials in an arm-based (AB) Bayesian NMA. We illustrate the advantages of this CPV method by reanalyzing an NMA of immune checkpoint inhibitors in cancer patients. Comprehensive simulations investigate the impact on statistical inference of including single-arm trials. The simulation results show that the CPV method provides efficient and robust estimation even when the two sources of information are moderately inconsistent.

Comparing Single- and Dual Antiplatelet Therapies Following Transcatheter Aortic Valve Implantation

BACKGROUND

Transcatheter aortic valve implantation has been an established treatment in patients with symptomatic severe aortic stenosis. However, the postoperative antiplatelet regimen after transcatheter aortic valve implantation was not established certainly. The aim of this meta-analysis is to compare the safety and efficacy of single- (SAPT) and dual-antiplatelet therapies (DAPT) in patients undergoing transcatheter aortic valve implantation.

METHODS

Eligible randomized controlled trials and cohort studies published before February 2021 were retrieved from PubMed, Embase, and the Cochrane Library. We calculated odds ratios with 95% confidence intervals.

RESULTS

Nine articles, involving 19,277 patients, met the selection criteria. In the short-term outcome, compared with SAPT, DAPT was associated with a significantly higher rate of bleeding (odds ratios, 95% confidence intervals: 3.00, 1.67-5.38) and showed no significant differences in thrombotic events (odds ratios, 95% confidence intervals: 1.25, 0.74-2.11) and all-cause mortality (odds ratios, 95% confidence intervals: 0.84; 0.42-1.69). In the long-term outcome, DAPT was associated with a significantly higher bleeding rate (odds ratios, 95% confidence intervals: 1.85, 1.24-2.78) and showed no differences in thrombotic events (odds ratios, 95% confidence intervals: 1.13, 0.86-1.48) and all-cause mortality (odds ratios, 95% confidence intervals: 1.12, 0.95-1.32). Our trial sequential analysis confirmed DAPT didn't confer any benefit for reducing all-cause mortality and thrombotic events, and carried a higher risk of bleeding than SAPT.

CONCLUSIONS

SAPT should be a sufficient antiplatelet strategy in post- transcatheter aortic valve implantation patients without indications for oral anticoagulation medication, especially in the long-term follow-up period.

Stepwise-Hierarchical Pooled Analysis for Synergistic Interpretation of Meta-analyses Involving Randomized and Observational Studies: Methodology Development

Background

The necessity of including observational studies in meta-analyses has been discussed in the literature, but a synergistic analysis method for combining randomized and observational studies has not been reported. Observational studies differ in validity depending on the degree of the confounders’ influence. Combining interpretations may be challenging, especially if the statistical directions are similar but the magnitude of the pooled results are different between randomized and observational studies (the ”gray zone”).

Objective

To overcome these hindrances, in this study, we aim to introduce a logical method for clinical interpretation of randomized and observational studies.

Methods

We designed a stepwise-hierarchical pooled analysis method to analyze both distribution trends and individual pooled results by dividing the included studies into at least three stages (eg, all studies, balanced studies, and randomized studies).

Results

According to the model, the validity of a hypothesis is mostly based on the pooled results of randomized studies (the highest stage). Ascending patterns in which effect size and statistical significance increase gradually with stage strengthen the validity of the hypothesis; in this case, the effect size of the observational studies is lower than that of the true effect (eg, because of the uncontrolled effect of negative confounders). Descending patterns in which decreasing effect size and statistical significance gradually weaken the validity of the hypothesis suggest that the effect size and statistical significance of the observational studies is larger than the true effect (eg, because of researchers’ bias).

Conclusions

We recommend using the stepwise-hierarchical pooled analysis approach for meta-analyses involving randomized and observational studies.