Cumulating evidence from randomized trials: utilizing sequential monitoring boundaries for cumulative meta-analysis

Decisive gene strategy on osteoarthritis: a comprehensive whole-literature based approach for conclusive gene targets

BACKGROUND

Previous meta-analyses only examined the association between single or several gene polymorphisms and osteoarthritis (OA), whereas no studies have concluded that there are existing all gene loci that associate with OA.

OBJECTIVE

To assess whether a definite conclusion of the association between the gene loci and OA can be drawn.

METHODS

Decisive gene strategy (DGS), a literature-based approach, was used to search PubMed, Embase, and Cochrane databases for all meta-analyses that associated gene polymorphisms and OA. Trial Sequential Analysis (TSA) examined the sufficiency of the cumulative sample size. Finally, we assessed the importance of gene loci in OA based on whether there were enough sample sizes and the heterogeneity of the literatures with I2 value.

RESULTS

After excluding 179 irrelevant publications, 80 meta-analysis papers were recruited. Among Caucasians, SMAD3 rs12901499 (OR = 1.20, 95% CI: 1.12-1.29) was a risk factor with validation of sufficient sample sizes through TSA model. Among Asians, there were 3 gene loci risk factors with validation of sufficient sample sizes through TSA model: ESR1 rs2228480, SMAD3 rs12901499, and MMP-1 rs1799750 (OR = 1.35, 95% CI: 1.08-1.69; OR = 1.34, 95% CI: 1.07-1.69; OR = 1.43, 95% CI: 1.18-1.74, respectively). Besides, 3 gene loci, DVWA rs7639618, GDF5 rs143383, and VDR rs7975232 (OR = 0.78, 95% CI: 0.67-0.90; OR = 0.74, 95% CI: 0.67-0.81; OR = 0.56, 95% CI: 0.35-0.90, respectively) were identified as protective factors through TSA model.

CONCLUSIONS

We used DGS to identify conclusive gene loci associated with OA. These findings provide implications of precision medicine in OA and may potentially advance genetic therapy.

Different doses and courses of omalizumab for patients with chronic spontaneous urticaria: A systematic review with meta-analysis and trial sequential analysis

Background

The stability, efficacy, and safety of omalizumab at different doses and regimens for chronic spontaneous urticaria (CSU) are yet to be studied.

Objective

A systematic review (SR) with meta-analysis (MA) and trial sequential analysis (TSA) was performed to assess the efficacy and safety of omalizumab in CSU.

Methods

Randomised controlled trials (RCTs) of administering omalizumab versus placebo for CSU were searched. Random-effects MAs were performed using planned subgroup analyses. TSA was performed to control for the risk of random errors and assess the stability of our MA results. Publication bias was visually assessed using a contour-enhanced funnel plot and the trim-and-fill method. The quality of RCTs was assessed using the Cochrane Risk of Bias Tool 2.

Results

Twelve studies met the inclusion criteria. Omalizumab had remarkable effects on the patient percentage of the weekly urticaria activity score is zero (UAS = 0) [RR 4.64, 95% CI (3.38, 6.37)], percentage of no angioedema-burdened days [MD 3.15, 95% CI (0.10, 6.19], patient percentage of UAS ≤6 [RR 3.05, 95% CI (2.46, 3.78)], and patient percentage of the weekly itch severity score minimally important difference (ISS7 MID) [RR 1.50, 95% CI (1.36, 1.66)]. Omalizumab was well tolerated across studies [RR 0.98, 95% CI (0.90, 1.08)]. TSA confirmed the above results, except for "the percentage of no angioedema-burdened day".

Conclusion

Among the different doses and courses assessed, omalizumab (300 mg, 12 weeks) can be recommended as an effective treatment for patients with CSU. However, whether omalizumab improves angioedema requires further investigation. The clinical management of angioedema accompanying CSU requires further attention.

Prevalence of and factors associated with potentially redundant randomized controlled trials: a cross-sectional study

OBJECTIVES

To investigate the prevalence of meta-analyses containing potentially redundant randomized controlled trials (RCTs) and the factors associated with the presence of redundancy.

STUDY DESIGN AND SETTING

This is a cross-sectional study, based on a random sample of references (n = 4500) that were published during 2020 and 2021, indexed in PubMed, Embase, or the Cochrane Database of Systematic Reviews, and retrieved through comprehensive searches using terms about systematic reviews and meta-analysis. From each systematic review, one meta-analysis fulfilling all the following criteria, if available, was included in this study: (1) assessing the effect of the intervention on a primary outcome of the systematic review; (2) combining RCTs only. The primary outcome was prevalence of meta-analyses containing potentially redundant RCTs. Potentially redundant RCTs referred to the trials that started 1 year after the overall effect estimate from cumulative meta-analysis had been statistically robust, as determined by trial sequential analysis when appropriate. The number of potentially redundant trials (if any) in each eligible meta-analysis and the number of participants involved in those trials were documented and contrasted across groups. Logistic regression analysis was conducted to explore the factors associated with presence of potential redundancy.

RESULTS

Of the 448 eligible meta-analyses, 57 (12.7%, 95% confidence interval (CI) 9.8-16.2%) contained potentially redundant RCTs. When limited to the 333 low-heterogeneity meta-analyses, the prevalence was 17.1% (95% CI 13.5-21.5%). The total number of potentially redundant RCTs was 295 (involving 85,385 participants), accounting for 38.5% of the RCTs (and 30.3% of the participants) included in the 57 meta-analyses. In these meta-analyses, the median number of potentially redundant RCTs and the participants involved were 2 (range: 1-50) and 352 (range: 17-26997), respectively. Potentially redundant RCTs were more likely to be present in the meta-analyses evaluating pharmaceutical intervention (odds ratio [OR] 2.31, 95% CI 1.16-4.49), assessing efficacy outcomes (OR 7.25, 95% CI 0.85-61.87), containing more than 5 RCTs (OR 6.47, 95% CI 3.22-12.99), or with the earliest RCT reporting statistically significant effect estimate (OR 5.30, 95% CI 2.64-10.64).

CONCLUSION

This study found that 12.7% to 17.1% of recently published meta-analyses contained potentially redundant RCTs, highlighting the importance of conducting or examining systematic reviews of existing evidence to justify new RCTs. More importantly, the study identified some scenarios in which redundancy was more likely to occur and thus has implications for trialists, funding agencies, ethics committees, and journal editors.

Determining the conclusiveness of a meta-analysis

The pursuit of conclusive evidence related to an unanswered foreground (decision-making) question has been the driving factor behind multiple ongoing and planned randomized controlled trials as well as meta-analyses. However, a fundamental challenge lies in establishing robust methods for ascertaining whether a collection of synthesized trials has yielded a definitive answer to that foreground question through the process of meta-analysis. This article explores the evolution of methods that attempt to address this challenge. These methods have primarily focused on defining and measuring the sufficiency and stability of evidence within a meta-analytic context. Cumulative meta-analysis and trial sequential analysis are the tools currently used, but they both come with limitations and challenges. We further discuss methods aimed at evaluating the evolution of effects over time more directly, such as the recursive cumulative meta-analysis. The latter method can be considered a better alternative, as it serves to demonstrate whether there is a true underlying treatment effect to which the meta-analysis is converging. However, recursive cumulative meta-analysis falls short of a specific indicator that establishes whether convergence has been reached. We coin the term exit for a meta-analysis where convergence can be demonstrated. Developing methods to determine the exit status of a meta-analysis is the next priority in research synthesis methods, as it will indicate that the research journey has concluded on a particular foreground question with no expectation of a different result with the addition of future trials.

Amantadine for functional improvement in patients with traumatic brain injury: A systematic review with meta-analysis and trial sequential analysis

Introduction

TBIs contribute in over one-third of injury-related deaths with mortality rates as high as 50% in trauma centers serving the most severe TBI. The effect of TBI on mortality is about 10% across all ages. Amantadine hydrochloride is one of the most commonly prescribed medications for patients undergoing inpatient neurorehabilitation who have disorders of consciousness.6 It is a dopamine (DA) receptor agonist and a N-Methyl-D-aspartate (NMDA) receptor antagonist via dopamine release and dopamine reuptake inhibition. The current study will synthesize the current available evidence and show the effect of Amantadine in functional improvement after TBI.

Research question

Does Amantadine have an effect on functional improvement of TBI patients?

Material and methods

This systematic review included all randomized placebo-controlled trials that compare the use of Amantadine versus placebo for functional improvement of patients after TBI. Outcome measures included DRS, GCS and/or GOS scores.

Results

Three studies with a total of 281 patients were included in the quantitative analyses. GRADE assessments show that there was a high certainty of evidence for functional improvement in terms of DRS scores.

Discussion and conclusion

Evidence of this review show that the use of Amantadine may have a beneficial effect on functional outcome in moderate to severe traumatic brain injuries among adult patients. Given the still-limited body of knowledge, more relevant studies must be made exploring the impact of Amantadine therapies on promoting functional recovery within the brain injury rehabilitation care continuum, with the goals of achieving larger sample sizes and establishing the early- or later-treatment beneficial effects.

The safety of remimazolam versus propofol in gastroscopic sedation: a meta-analysis

BACKGROUND

This meta-analysis was designed to compare the safety and efficiency of remimazolam with those of propofol in patients undergoing gastroscope sedation.

METHODS

We searched PubMed, Cochrane Library, Embase, Ovid, Wanfang Database, China National Knowledge Infrastructure, SINOMED, and ClinicalTrials.gov for studies that reported on remimazolam versus propofol for gastroscope sedation from establishment to February 25, 2023. The sedative efficiency and the incidence of adverse events were assessed as outcomes. Version 2 of the Cochrane risk-of-bias assessment tool was used to assess the risk of bias. Review Manager 5.4 and STATA 17 were used to perform all statistical analyses.

RESULTS

A total of 26 randomized controlled trials involving 3,641 patients were included in this meta-analysis. The results showed that remimazolam had a significantly lower incidence of respiratory depression (risk ratio [RR] = 0.40, 95% confidence interval [CI]: 0.28-0.57; p < 0.01, GRADE high), hypoxemia (RR = 0.34, 95% CI: 0.23-0.49; p < 0.01, GRADE high), bradycardia (RR = 0.34, 95% CI: 0.23-0.51; p < 0.01, GRADE high), dizziness (RR = 0.45, 95% CI: 0.31-0.65; p < 0.01, GRADE high), injection site pain (RR = 0.06, 95% CI: 0.03-0.13; p < 0.01, GRADE high), nausea or vomiting (RR = 0.79, 95% CI: 0.62-1.00; p = 0.05, GRADE moderate), and hypotension (RR = 0.36, 95% CI: 0.26-0.48; p < 0.01, GRADE low).

CONCLUSIONS

Remimazolam can be used safely in gastroscopic sedation and reduces the incidence of respiratory depression, hypoxemia, bradycardia, injection site pain, and dizziness compared with propofol, and doesn't increase the incidence of nausea and vomiting.

Motivational interviewing for substance use reduction

BACKGROUND

Substance use is a global issue, with around 30 to 35 million individuals estimated to have a substance-use disorder. Motivational interviewing (MI) is a client-centred method that aims to strengthen a person's motivation and commitment to a specific goal by exploring their reasons for change and resolving ambivalence, in an atmosphere of acceptance and compassion. This review updates the 2011 version by Smedslund and colleagues.

OBJECTIVES

To assess the effectiveness of motivational interviewing for substance use on the extent of substance use, readiness to change, and retention in treatment.

SEARCH METHODS

We searched 18 electronic databases, six websites, four mailing lists, and the reference lists of included studies and reviews. The last search dates were in February 2021 and November 2022.

SELECTION CRITERIA

We included randomised controlled trials with individuals using drugs, alcohol, or both. Interventions were MI or motivational enhancement therapy (MET), delivered individually and face to face. Eligible control interventions were no intervention, treatment as usual, assessment and feedback, or other active intervention.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane, and assessed the certainty of evidence with GRADE. We conducted meta-analyses for the three outcomes (extent of substance use, readiness to change, retention in treatment) at four time points (post-intervention, short-, medium-, and long-term follow-up).

MAIN RESULTS

We included 93 studies with 22,776 participants. MI was delivered in one to nine sessions. Session durations varied, from as little as 10 minutes to as long as 148 minutes per session, across included studies. Study settings included inpatient and outpatient clinics, universities, army recruitment centres, veterans' health centres, and prisons. We judged 69 studies to be at high risk of bias in at least one domain and 24 studies to be at low or unclear risk. Comparing MI to no intervention revealed a small to moderate effect of MI in substance use post-intervention (standardised mean difference (SMD) 0.48, 95% confidence interval (CI) 0.07 to 0.89; I2 = 75%; 6 studies, 471 participants; low-certainty evidence). The effect was weaker at short-term follow-up (SMD 0.20, 95% CI 0.12 to 0.28; 19 studies, 3351 participants; very low-certainty evidence). This comparison revealed a difference in favour of MI at medium-term follow-up (SMD 0.12, 95% CI 0.05 to 0.20; 16 studies, 3137 participants; low-certainty evidence) and no difference at long-term follow-up (SMD 0.12, 95% CI -0.00 to 0.25; 9 studies, 1525 participants; very low-certainty evidence). There was no difference in readiness to change (SMD 0.05, 95% CI -0.11 to 0.22; 5 studies, 1495 participants; very low-certainty evidence). Retention in treatment was slightly higher with MI (SMD 0.26, 95% CI -0.00 to 0.52; 2 studies, 427 participants; very low-certainty evidence). Comparing MI to treatment as usual revealed a very small negative effect in substance use post-intervention (SMD -0.14, 95% CI -0.27 to -0.02; 5 studies, 976 participants; very low-certainty evidence). There was no difference at short-term follow-up (SMD 0.07, 95% CI -0.03 to 0.17; 14 studies, 3066 participants), a very small benefit of MI at medium-term follow-up (SMD 0.12, 95% CI 0.02 to 0.22; 9 studies, 1624 participants), and no difference at long-term follow-up (SMD 0.06, 95% CI -0.05 to 0.17; 8 studies, 1449 participants), all with low-certainty evidence. There was no difference in readiness to change (SMD 0.06, 95% CI -0.27 to 0.39; 2 studies, 150 participants) and retention in treatment (SMD -0.09, 95% CI -0.34 to 0.16; 5 studies, 1295 participants), both with very low-certainty evidence. Comparing MI to assessment and feedback revealed no difference in substance use at short-term follow-up (SMD 0.09, 95% CI -0.05 to 0.23; 7 studies, 854 participants; low-certainty evidence). A small benefit for MI was shown at medium-term (SMD 0.24, 95% CI 0.08 to 0.40; 6 studies, 688 participants) and long-term follow-up (SMD 0.24, 95% CI 0.07 to 0.41; 3 studies, 448 participants), both with moderate-certainty evidence. None of the studies in this comparison measured substance use at the post-intervention time point, readiness to change, and retention in treatment. Comparing MI to another active intervention revealed no difference in substance use at any follow-up time point, all with low-certainty evidence: post-intervention (SMD 0.07, 95% CI -0.15 to 0.29; 3 studies, 338 participants); short-term (SMD 0.05, 95% CI -0.03 to 0.13; 18 studies, 2795 participants); medium-term (SMD 0.08, 95% CI -0.01 to 0.17; 15 studies, 2352 participants); and long-term follow-up (SMD 0.03, 95% CI -0.07 to 0.13; 10 studies, 1908 participants). There was no difference in readiness to change (SMD 0.15, 95% CI -0.00 to 0.30; 5 studies, 988 participants; low-certainty evidence) and retention in treatment (SMD -0.04, 95% CI -0.23 to 0.14; 12 studies, 1945 participants; moderate-certainty evidence). We downgraded the certainty of evidence due to inconsistency, study limitations, publication bias, and imprecision.

AUTHORS' CONCLUSIONS

Motivational interviewing may reduce substance use compared with no intervention up to a short follow-up period. MI probably reduces substance use slightly compared with assessment and feedback over medium- and long-term periods. MI may make little to no difference to substance use compared to treatment as usual and another active intervention. It is unclear if MI has an effect on readiness to change and retention in treatment. The studies included in this review were heterogeneous in many respects, including the characteristics of participants, substance(s) used, and interventions. Given the widespread use of MI and the many studies examining MI, it is very important that counsellors adhere to and report quality conditions so that only studies in which the intervention implemented was actually MI are included in evidence syntheses and systematic reviews. Overall, we have moderate to no confidence in the evidence, which forces us to be careful about our conclusions. Consequently, future studies are likely to change the findings and conclusions of this review.

Concentrations, Number of Doses, and Formulations of Aluminium Adjuvants in Vaccines: A Systematic Review with Meta-Analysis and Trial Sequential Analysis of Randomized Clinical Trials

Aluminium adjuvants are commonly used in vaccines to boost the effects of vaccination. Here, we assessed the benefits and harms of different aluminium adjuvants vs. other aluminium adjuvants or vs. the same aluminium adjuvant at other concentrations, administered a different number of doses, or at different particle sizes used in vaccines or vaccine excipients. We conducted a systematic review with meta-analysis and Trial Sequential Analysis to assess the certainty of evidence with Grading of Recommendations Assessment, Development and Evaluation (GRADE). We obtained data from major medical databases until 20 January 2023 and included 10 randomized clinical trials of healthy volunteers. The comparisons assessed higher vs. lower aluminium adjuvant concentrations; higher vs. lower number of doses of aluminium adjuvant; and aluminium phosphate adjuvant vs. aluminium hydroxide adjuvant. For all three comparisons, meta-analyses showed no evidence of a difference on all-cause mortality, serious adverse events, and adverse events considered non-serious. The certainty of evidence was low to very low. None of the included trials reported on quality of life or proportion of participants who developed the disease being vaccinated against. The benefits and harms of different types of aluminium adjuvants, different aluminium concentrations, different number of doses, or different particle sizes, therefore, remain uncertain.

Efficacy and safety of the Chinese herbal medicine Xiao Yao San for treating anxiety: a systematic review with meta-analysis and trial sequential analysis

Introduction: The effectiveness and safety of the Chinese herbal medicine (CHM) Xiao Yao San (XYS) used for treating anxiety disorders are still unknown. Thus, we conducted this systematic review with meta-analysis and trial sequential analysis (TSA) to determine its safety and efficacy. Methods: We searched 12 databases for relevant studies from the inception of each database till 10 August 2023. We selected randomized controlled trials to compare the efficacy and safety of XYS (including XYS only and XYS + anxiolytics) to those of anxiolytics in patients with anxiety. Results: We found 14 trials with 1,256 patients in total that met the requirements for inclusion. We assessed the majority of studies (8 out of 14) as being at high risk of bias; 6 were assessed as having a moderate risk of bias. Three trials compared oral XYS to anxiolytic medication, and 11 trials compared oral XYS plus anxiolytics to anxiolytic treatment alone. The pooled results showed that the efficacy of treatment in the XYS + anxiolytics groups was significantly higher than that of the anxiolytics alone group (RR = 1.19; 95% CI: [1.13, 1.26]; p < 0.00001; I2 = 0) and the adverse event rates in the XYS + anxiolytics groups were significantly lower than those in the anxiolytics alone group (RR = 0.44; 95% CI: [0.28, 0.82]; p = 0.001 < 0.05; I2 = 13). The efficacy of treatment in the XYS alone groups was also significantly higher than that of the anxiolytics alone groups (RR = 5.41; 95% CI: [2.23, 13.11]; p < 0.0001; I2 = 0). However, there was no statistical difference between the adverse events of the XYS alone group and the anxiolytics alone group, although the incidence of adverse events in the XYS alone group was lower than that in the anxiolytics alone group. The results of the TSA confirmed the above findings. Conclusion: The use of XYS combined with anxiolytics for treating anxiety was found to be safe and effective. However, although XYS alone is effective in the treatment of anxiety disorder, more large-scale research is needed to investigate adverse events. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=350358, identifier CRD42022350358.

Proposed triggers for retiring a living systematic review

Living systematic reviews (LSRs) are systematic reviews that are continually updated, incorporating relevant new evidence as it becomes available. LSRs are critical for decision-making in topics where the evidence continues to evolve. It is not feasible to continue to update LSRs indefinitely; however, guidance on when to retire LSRs from the living mode is not clear. We propose triggers for making such a decision. The first trigger is to retire LSRs when the evidence becomes conclusive for the outcomes that are required for decision-making. Conclusiveness of evidence is best determined based on the GRADE certainty of evidence construct, which is more comprehensive than solely relying on statistical considerations. The second trigger to retire LSRs is when the question becomes less pertinent for decision-making as determined by relevant stakeholders, including people affected by the problem, healthcare professionals, policymakers and researchers. LSRs can also be retired from a living mode when new studies are not anticipated to be published on the topic and when resources become unavailable to continue updating. We describe examples of retired LSRs and apply the proposed approach using one LSR about adjuvant tyrosine kinase inhibitors in high-risk renal cell carcinoma that we retired from a living mode and published its last update.

Higher versus lower fractions of inspired oxygen or targets of arterial oxygenation for adults admitted to the intensive care unit

BACKGROUND

This is an updated review concerning 'Higher versus lower fractions of inspired oxygen or targets of arterial oxygenation for adults admitted to the intensive care unit'. Supplementary oxygen is provided to most patients in intensive care units (ICUs) to prevent global and organ hypoxia (inadequate oxygen levels). Oxygen has been administered liberally, resulting in high proportions of patients with hyperoxemia (exposure of tissues to abnormally high concentrations of oxygen). This has been associated with increased mortality and morbidity in some settings, but not in others. Thus far, only limited data have been available to inform clinical practice guidelines, and the optimum oxygenation target for ICU patients is uncertain. Because of the publication of new trial evidence, we have updated this review.

OBJECTIVES

To update the assessment of benefits and harms of higher versus lower fractions of inspired oxygen (FiO2) or targets of arterial oxygenation for adults admitted to the ICU.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Science Citation Index Expanded, BIOSIS Previews, and LILACS. We searched for ongoing or unpublished trials in clinical trial registers and scanned the reference lists and citations of included trials. Literature searches for this updated review were conducted in November 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared higher versus lower FiO2 or targets of arterial oxygenation (partial pressure of oxygen (PaO2), peripheral or arterial oxygen saturation (SpO2 or SaO2)) for adults admitted to the ICU. We included trials irrespective of publication type, publication status, and language. We excluded trials randomising participants to hypoxaemia (FiO2 below 0.21, SaO2/SpO2 below 80%, or PaO2 below 6 kPa) or to hyperbaric oxygen, and cross-over trials and quasi-randomised trials.

DATA COLLECTION AND ANALYSIS

Four review authors independently, and in pairs, screened the references identified in the literature searches and extracted the data. Our primary outcomes were all-cause mortality, the proportion of participants with one or more serious adverse events (SAEs), and quality of life. We analysed all outcomes at maximum follow-up. Only three trials reported the proportion of participants with one or more SAEs as a composite outcome. However, most trials reported on events categorised as SAEs according to the International Conference on Harmonisation Good Clinical Practice (ICH-GCP) criteria. We, therefore, conducted two analyses of the effect of higher versus lower oxygenation strategies using 1) the single SAE with the highest reported proportion in each trial, and 2) the cumulated proportion of participants with an SAE in each trial. Two trials reported on quality of life. Secondary outcomes were lung injury, myocardial infarction, stroke, and sepsis. No trial reported on lung injury as a composite outcome, but four trials reported on the occurrence of acute respiratory distress syndrome (ARDS) and five on pneumonia. We, therefore, conducted two analyses of the effect of higher versus lower oxygenation strategies using 1) the single lung injury event with the highest reported proportion in each trial, and 2) the cumulated proportion of participants with ARDS or pneumonia in each trial. We assessed the risk of systematic errors by evaluating the risk of bias in the included trials using the Risk of Bias 2 tool. We used the GRADEpro tool to assess the overall certainty of the evidence. We also evaluated the risk of publication bias for outcomes reported by 10b or more trials.

MAIN RESULTS

We included 19 RCTs (10,385 participants), of which 17 reported relevant outcomes for this review (10,248 participants). For all-cause mortality, 10 trials were judged to be at overall low risk of bias, and six at overall high risk of bias. For the reported SAEs, 10 trials were judged to be at overall low risk of bias, and seven at overall high risk of bias. Two trials reported on quality of life, of which one was judged to be at overall low risk of bias and one at high risk of bias for this outcome. Meta-analysis of all trials, regardless of risk of bias, indicated no significant difference from higher or lower oxygenation strategies at maximum follow-up with regard to mortality (risk ratio (RR) 1.01, 95% confidence interval (C)I 0.96 to 1.06; I2 = 14%; 16 trials; 9408 participants; very low-certainty evidence); occurrence of SAEs: the highest proportion of any specific SAE in each trial RR 1.01 (95% CI 0.96 to 1.06; I2 = 36%; 9466 participants; 17 trials; very low-certainty evidence), or quality of life (mean difference (MD) 0.5 points in participants assigned to higher oxygenation strategies (95% CI -2.75 to 1.75; I2 = 34%, 1649 participants; 2 trials; very low-certainty evidence)). Meta-analysis of the cumulated number of SAEs suggested benefit of a lower oxygenation strategy (RR 1.04 (95% CI 1.02 to 1.07; I2 = 74%; 9489 participants; 17 trials; very low certainty evidence)). However, trial sequential analyses, with correction for sparse data and repetitive testing, could reject a relative risk increase or reduction of 10% for mortality and the highest proportion of SAEs, and 20% for both the cumulated number of SAEs and quality of life. Given the very low-certainty of evidence, it is necessary to interpret these findings with caution. Meta-analysis of all trials indicated no statistically significant evidence of a difference between higher or lower oxygenation strategies on the occurrence of lung injuries at maximum follow-up (the highest reported proportion of lung injury RR 1.08, 95% CI 0.85 to 1.38; I2 = 0%; 2048 participants; 8 trials; very low-certainty evidence). Meta-analysis of all trials indicated harm from higher oxygenation strategies as compared with lower on the occurrence of sepsis at maximum follow-up (RR 1.85, 95% CI 1.17 to 2.93; I2 = 0%; 752 participants; 3 trials; very low-certainty evidence). Meta-analysis indicated no differences regarding the occurrences of myocardial infarction or stroke.

AUTHORS' CONCLUSIONS

In adult ICU patients, it is still not possible to draw clear conclusions about the effects of higher versus lower oxygenation strategies on all-cause mortality, SAEs, quality of life, lung injuries, myocardial infarction, stroke, and sepsis at maximum follow-up. This is due to low or very low-certainty evidence.

Efficacy of acupuncture for tension-type headache prophylaxis: systematic review and meta-analysis with trial sequential analysis

BACKGROUND

Acupuncture has been shown to reduce tension-type headache (TTH) frequency in previous studies. Nevertheless, repeated significance testing might inflate type I error. We aimed to verify the effectiveness and safety of acupuncture in reducing TTH frequency by meta-analysis and trial sequential analysis (TSA).

METHODS

Ovid Medline, Embase, and Cochrane Library were searched until September 29, 2022. Randomized controlled trials comparing acupuncture with sham acupuncture, no acupuncture, or other active therapies in adults with TTH were included. The primary outcome was TTH frequency. The secondary outcomes were responder rate and adverse event.

RESULTS

Fourteen studies involving 2795 participants were included. Acupuncture had more reduction than sham acupuncture in TTH frequency, both after treatment (standardized mean difference [SMD] - 0.80, 95% CI - 1.36 to - 0.24, P = 0.005) and at the follow-up period (SMD - 1.33, 95% CI - 2.18 to - 0.49, P = 0.002), while TSA showed the included sample size did not exceed required information size (RIS). Acupuncture was superior over no acupuncture after treatment (SMD - 0.52, 95% CI - 0.63 to - 0.41, P < 0.001), and cumulative sample size reached RIS. In terms of responder rate, acupuncture had a higher responder rate compared with sham acupuncture both after treatment (relative ratio [RR] 1.28, 95% CI 1.12 to 1.46, P = 0.0003) and the follow-up period (RR 1.37, 95% CI 1.19 to 1.58, P < 0.0001), but the sample size is inadequate.

CONCLUSION

Acupuncture is an efficacious and safe treatment for TTH prevention, but this conclusion might be limited by the generally very low to low quality evidence. TSA suggested that high-quality trials are needed to verify the efficacy and safety of acupuncture compared to sham acupuncture.

Systemic glucocorticoids as an adjunct to treatment of postoperative pain after total hip and knee arthroplasty: A systematic review with meta-analysis and trial sequential analysis

BACKGROUND

Postoperative analgesic effects of systemic glucocorticoids given as an adjunct to treatment are largely undetermined in alloplastic procedures.

OBJECTIVES

To investigate the beneficial and harmful effects of peri-operative systemic glucocorticoid treatment for pain after total hip arthroplasty (THA) or total knee arthroplasty (TKA).

DESIGN

A systematic review of randomised clinical trials (RCTs) with meta-analyses, trial sequential analyses and GRADE. Primary outcome was 24 h intravenous (i.v.) morphine (or equivalent) consumption with a predefined minimal important difference (MID) of 5 mg. Secondary outcomes included pain at rest and during mobilisation (MID, VAS 10 mm), adverse and serious adverse events (SAEs).

DATA SOURCES

We searched EMBASE, Cochrane CENTRAL, PubMed and Google Scholar up to October 2021.

ELIGIBILITY CRITERIA

RCTs investigating peri-operative systemic glucocorticoid versus placebo or no intervention, for analgesic pain management of patients at least 18 years undergoing planned THA or TKA, irrespective of publication date and language.

RESULTS

We included 32 RCTs with 3521 patients. Nine trials were at a low risk of bias. Meta-analyses showed evidence of a reduction in 24 h cumulative morphine consumption with glucocorticoids by 5.0 mg (95% CI 2.2 to 7.7; P  = 0.0004). Pain at rest was reduced at 6 h by 7.8 mm (95% CI 5.5 to 10.2; P  < 0.00001), and at 24 h by 6.3 mm (95% CI 3.8 to 8.8; P  < 0.00001). Pain during mobilisation was reduced at 6 h by 9.8 mm (95% CI 6.9 to 12.8; P  < 0.00001), and at 24 h by 9.0 mm (95% CI 5.5 to 12.4, P  < 0.00001). Incidence of adverse events was generally lower in the glucocorticoid treatment group. SAEs were rarely reported. The GRADE rated quality of evidence was low to very low.

CONCLUSION

Peri-operative systemic glucocorticoid treatment reduced postoperative morphine consumption to an individually relevant level following hip and knee arthroplasty. Pain levels were reduced but were below the predefined MID. The quality of evidence was generally low.

REGISTRATION

PROSPERO ID: CRD42019135034.

Protocol for a Systematic Review and Individual Participant Data Meta-Analysis of Randomized Trials of Screening for Atrial Fibrillation to Prevent Stroke

INTRODUCTION

 Atrial fibrillation (AF) is a common cause of stroke. Timely diagnosis of AF and treatment with oral anticoagulation (OAC) can prevent up to two-thirds of AF-related strokes. Ambulatory electrocardiographic (ECG) monitoring can identify undiagnosed AF in at-risk individuals, but the impact of population-based ECG screening on stroke is uncertain, as ongoing and published randomized controlled trials (RCTs) have generally been underpowered for stroke.

METHODS AND ANALYSIS

 The AF-SCREEN Collaboration, with support from AFFECT-EU, have begun a systematic review and individual participant data meta-analysis of RCTs evaluating ECG screening for AF. The primary outcome is stroke. Secondary outcomes include AF detection, OAC prescription, hospitalization, mortality, and bleeding.After developing a common data dictionary, anonymized data will be collated from individual trials into a central database. We will assess risk of bias using the Cochrane Collaboration tool, and overall quality of evidence with the Grading of Recommendations Assessment, Development and Evaluation approach.We will pool data using random effects models. Prespecified subgroup and multilevel meta-regression analyses will explore heterogeneity. We will perform prespecified trial sequential meta-analyses of published trials to determine when the optimal information size has been reached, and account for unpublished trials using the SAMURAI approach.

IMPACT AND DISSEMINATION

 Individual participant data meta-analysis will generate adequate power to assess the risks and benefits of AF screening. Meta-regression will permit exploration of the specific patient, screening methodology, and health system factors that influence outcomes.

TRIAL REGISTRATION NUMBER

 PROSPERO CRD42022310308.

When we shouldn't borrow information from an existing network of trials for planning a new trial

Introduction: To achieve higher power or increased precision for a new trial, methods based on updating network meta-analysis (NMA) have been proposed by researchers. However, this approach could potentially lead to misinterpreted results and misstated conclusions. This work aims to investigate the potential inflation of type I error risk when a new trial is conducted only when, based on a p-value of the comparison in the existing network, a "promising" difference between two treatments is noticed. Methods: We use simulations to evaluate the scenarios of interest. In particular, a new trial is to be conducted independently or depending on the results from previous NMA in various scenarios. Three analysis methods are applied to each simulation scenario: with the existing network, sequential analysis and without the existing network. Results: For the scenario that the new trial will be conducted only when a promising finding (p-value <5%) is indicated by the existing network, the type I error risk increased dramatically (38.5% in our example data) when analyzed with the existing network and sequential analysis. The type I error is controlled at 5% when analyzing the new trial without the existing network. Conclusion: If the intention is to combine a trial result with an existing network of evidence, or if it is expected that the trial will eventually be included in a network meta-analysis, then the decision that a new trial is performed should not depend on a statistically "promising" finding indicated by the existing network.

Perioperative oxygen therapy: a protocol for an overview of systematic reviews and meta-analyses

BACKGROUND

Oxygen is routinely given to patients during and after surgery. Perioperative oxygen administration has been proposed as a potential strategy to prevent and treat hypoxaemia and reduce complications, such as surgical site infections, pulmonary complications and mortality. However, uncertainty exists as to which strategies in terms of amount, delivery devices and timing are clinically effective. The aim of this overview of systematic reviews and meta-analyses is to answer the research question, 'For which types of surgery, at which stages of care, in which sub-groups of patients and delivered under what conditions are different types of perioperative oxygen therapy clinically effective?'.

METHODS

We will search key electronic databases (MEDLINE, EMBASE, the Cochrane Database of Systematic Reviews, CENTRAL, Epistemonikos, PROSPERO, the INAHTA International HTA Database and DARE archives) for systematic reviews and randomised controlled trials comparing perioperative oxygen strategies. Each review will be mapped according to type of surgery, surgical pathway timepoints and clinical comparison. The highest quality reviews with the most comprehensive and up-to-date coverage of relevant literature will be chosen as anchoring reviews. Standardised data will be extracted from each chosen review, including definition of oxygen therapy, summaries of interventions and comparators, patient population, surgical characteristics and assessment of overall certainty of evidence. For clinical outcomes and adverse events, the overall pooled findings and results of subgroup and sensitivity analyses (where available) will be extracted. Trial-level data will be extracted for surgical site infections, mortality, and potential trial-level effect modifiers such as risk of bias, outcome definition and type of surgery to facilitate quantitative data analysis. This analysis will adopt a multiple indication review approach with panoramic meta-analysis using review-level data and meta-regression using trial-level data. An evidence map will be produced to summarise our findings and highlight any research gaps.

DISCUSSION

There is a need to provide a panoramic overview of systematic reviews and meta-analyses describing peri-operative oxygen practice to both inform clinical practice and identify areas of ongoing uncertainty, where further research may be required. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021272361.

Anticoagulants for thrombosis prophylaxis in acutely ill patients admitted to hospital: systematic review and network meta-analysis

OBJECTIVE

To assess the benefits and harms of different types and doses of anticoagulant drugs for the prevention of venous thromboembolism in patients who are acutely ill and admitted to hospital.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

Cochrane CENTRAL, PubMed/Medline, Embase, Web of Science, clinical trial registries, and national health authority databases. The search was last updated on 16 November 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Published and unpublished randomised controlled trials that evaluated low or intermediate dose low-molecular-weight heparin, low or intermediate dose unfractionated heparin, direct oral anticoagulants, pentasaccharides, placebo, or no intervention for the prevention of venous thromboembolism in acutely ill adult patients in hospital.

MAIN OUTCOME MEASURES

Random effects, bayesian network meta-analyses used four co-primary outcomes: all cause mortality, symptomatic venous thromboembolism, major bleeding, and serious adverse events at or closest timing to 90 days. Risk of bias was also assessed using the Cochrane risk-of-bias 2.0 tool. The quality of evidence was graded using the Confidence in Network Meta-Analysis framework.

RESULTS

44 randomised controlled trials that randomly assigned 90 095 participants were included in the main analysis. Evidence of low to moderate quality suggested none of the interventions reduced all cause mortality compared with placebo. Pentasaccharides (odds ratio 0.32, 95% credible interval 0.08 to 1.07), intermediate dose low-molecular-weight heparin (0.66, 0.46 to 0.93), direct oral anticoagulants (0.68, 0.33 to 1.34), and intermediate dose unfractionated heparin (0.71, 0.43 to 1.19) were most likely to reduce symptomatic venous thromboembolism (very low to low quality evidence). Intermediate dose unfractionated heparin (2.63, 1.00 to 6.21) and direct oral anticoagulants (2.31, 0.82 to 6.47) were most likely to increase major bleeding (low to moderate quality evidence). No conclusive differences were noted between interventions regarding serious adverse events (very low to low quality evidence). When compared with no intervention instead of placebo, all active interventions did more favourably with regard to risk of venous thromboembolism and mortality, and less favourably with regard to risk of major bleeding. The results were robust in prespecified sensitivity and subgroup analyses.

CONCLUSIONS

Low-molecular-weight heparin in an intermediate dose appears to confer the best balance of benefits and harms for prevention of venous thromboembolism. Unfractionated heparin, in particular the intermediate dose, and direct oral anticoagulants had the least favourable profile. A systematic discrepancy was noted in intervention effects that depended on whether placebo or no intervention was the reference treatment. Main limitations of this study include the quality of the evidence, which was generally low to moderate due to imprecision and within-study bias, and statistical inconsistency, which was addressed post hoc.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020173088.

Benefits of more intensive versus less intensive blood pressure control. Updated trial sequential analysis

Outcome data from randomized trials which compared different blood pressure (BP) targets grew impressively after publication of recent trials. We conducted a cumulative updated trial sequential analysis of studies which compared a more versus less intensive BP control strategy, for a total of 60,870 randomized patients. The compared BP targets differed across the trials. Outcome measures were stroke, heart failure, myocardial infarction and cardiovascular death. The average duration of follow-up was 3.95 years and achieved systolic BP was 7.69 mmHg lower with the more intensive than the less intensive BP control strategy. The more intensive BP control strategy significantly reduced the risk of stroke (OR 0.79; 95% CI 0.67-0.93), heart failure (OR 0.73; 95% CI 0.55-0.96), myocardial infarction (OR 0.81; 95% CI 0.73-0.91) and cardiovascular death (OR 0.81; 95% CI 0.68-0.98) as compared to the less intensive strategy. In a trial sequential analysis, the more intensive BP control strategy provided conclusive benefits over the less intensive strategy on the risk of stroke, heart failure and myocardial infarction by definitely crossing the efficacy monitoring boundary. For cardiovascular death, the cumulative Z-curve of the sequential analysis touched the efficacy monitoring boundary, but did not cross it. In conclusion, data accrued from randomized trials conclusively demonstrate the superiority of a more intensive over a less intensive BP control strategy for the prevention of stroke, heart failure and myocardial infarction. Results also suggest a significant benefit, albeit not yet conclusive, of a more intensive over a less intensive strategy for prevention of cardiovascular death.

Loop diuretics in adult intensive care patients with fluid overload: a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis

BACKGROUND

Fluid overload is a risk factor for organ dysfunction and death in intensive care unit (ICU) patients, but no guidelines exist for its management. We systematically reviewed benefits and harms of a single loop diuretic, the predominant treatment used for fluid overload in these patients.

METHODS

We conducted a systematic review with meta-analysis and Trial Sequential Analysis (TSA) of a single loop diuretic vs. other interventions reported in randomised clinical trials, adhering to our published protocol, the Cochrane Handbook, and PRISMA statement. We assessed the risks of bias with the ROB2-tool and certainty of evidence with GRADE. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42020184799).

RESULTS

We included 10 trials (804 participants), all at overall high risk of bias. For loop diuretics vs. placebo/no intervention, we found no difference in all-cause mortality (relative risk (RR) 0.72, 95% confidence interval (CI) 0.49-1.06; 4 trials; 359 participants; I2 = 0%; TSA-adjusted CI 0.15-3.48; very low certainty of evidence). Fewer serious adverse events were registered in the group treated with loop diuretics (RR 0.81, 95% CI 0.66-0.99; 6 trials; 476 participants; I2 = 0%; very low certainty of evidence), though contested by TSA (TSA-adjusted CI 0.55-1.20).

CONCLUSIONS

The evidence is very uncertain about the effect of loop diuretics on mortality and serious adverse events in adult ICU patients with fluid overload. Loop diuretics may reduce the occurrence of these outcomes, but large randomised placebo-controlled trials at low risk of bias are needed.

Decisive gene strategy on osteoporosis: a comprehensive whole-literature-based approach for conclusive candidate gene targets

Purpose: Previous meta-analyses only examined the association between single gene polymorphisms and osteoporosis; there is no compilation of all gene loci that correlate with osteoporosis in the literature. In this study, we develop a new literature-based approach, a decisive gene strategy (DGS), to examine the sufficiency of the cumulative sample size for each gene locus and to assess whether a definite conclusion of the association between the gene locus and osteoporosis can be drawn.

Methods: The DGS was used to search PubMed, Embase, and Cochrane databases for all meta-analyses that correlated gene polymorphisms with osteoporosis. Trial sequential analysis was employed to examine the sufficiency of the cumulative sample size. Finally, we assessed the importance of gene loci in osteoporosis based on whether there were enough sample sizes and the heterogeneity of the literature with the I² value.

Results: After excluding 169 irrelevant publications, 39 meta-analysis papers were obtained. Among Caucasians, in 17 gene loci, there were eight gene loci (e.g., vitamin D Receptor ApaI rs7975232) with sufficient cumulative sample size to confirm that they were unrelated to the disease. Among Asians, in 15 gene loci, four gene loci that had sufficient sample sizes were risk factors: VDR FokI rs2228570 (odds ratio (OR) = 1.44, 95% confidence interval (CI) = 1.22–1.70), TGF β1 rs1800470 (OR = 1.35, 95% CI = 1.10–1.65), IGF1 rs2288377 (OR = 1.44, 95% CI = 1.28–1.62), and IGF1 rs35767 (OR = 1.20, 95% CI = 1.06–1.36), respectively, whereas one gene locus, ESR2 RsaI rs1256049 (OR = 0.69, 95% CI = 0.59–0.81), was a protective factor.

Conclusions: The DGS successfully identified five gene loci in osteoporosis that will apply to other diseases to find causal genes, which may contribute to further genetic therapy.

Systematic reviews do not (yet) represent the 'gold standard' of evidence: A position paper

The low quality of included trials, insufficient rigour in review methodology, ignorance of key pain issues, small size, and over-optimistic judgements about the direction and magnitude of treatment effects all devalue systematic reviews, supposedly the 'gold standard' of evidence. Available evidence indicates that almost all systematic reviews in the published literature contain fatal flaws likely to make their conclusions incorrect and misleading. Only 3 in every 100 systematic reviews are deemed to have adequate methods and be clinically useful. Examples of research waste and questionable ethical standards abound: most trials have little hope of providing useful results, and systematic review of hopeless trials inspires no confidence. We argue that results of most systematic reviews should be dismissed. Forensically critical systematic reviews are essential tools to improve the quality of trials and should be encouraged and protected.

Pre-treatment neutrophil-to-lymphocyte ratio is an independent prognostic factor in head and neck squamous cell carcinoma: Meta-analysis and trial sequential analysis

Inflammation seems to play a critical role in the development and progression of different cancers. Neutrophil-to-lymphocyte ratio (NLR) is an easily measurable marker of systemic inflammation. The purpose of this systematic review and meta-analysis was to evaluate the prognostic role of the pre-treatment NLR, in terms of overall survival (OS) and disease-free survival (DFS), in patients with primary head and neck squamous cell carcinoma (HNSCC) treated by surgery alone or followed by chemo/radiotherapy. This systematic review was performed according to the guidelines reported in the Cochrane Handbook and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. Meta-analysis of OS and DFS was performed using the inverse of variance test. Fixed-effect models were used on the basis of the presence of heterogeneity. Risk of bias assessment and trial sequential analysis (TSA) were also performed; the quality of the evidence was evaluated via the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. The analysis revealed that a higher value of pre-treatment NLR correlates with a statistically significant decrease of OS (HR, 1.56; 95% CI: [1.35, 1.80]; p < 0.00001) and a lower DFS (HR, 1.64; 95% CI: [1.30, 2.07]; p < 0.0001) in HNSCC patients.

Living Systematic Reviews

Systematic reviews are difficult to keep up to date, but failure to do so leads to poor review currency and accuracy. "Living systematic review" (LSR) is an approach that aims to continually update a review, incorporating relevant new evidence as it becomes available. LSRs may be particularly important in fields where research evidence is emerging rapidly, current evidence is uncertain, and new research may change policy or practice decisions.This chapter describes the concept and processes of living systematic reviews. It describes the general principles of LSRs, when they might be of particular value, and how their procedures differ from conventional systematic reviews. The chapter focuses particularly on two methods of sequential meta-analysis that may be particularly useful for LSRs: Trial Sequential Analysis and Sequential Meta-Analysis, which both control for Type I error, Type II error (failing to detect a genuine effect) and take account of heterogeneity.

Antibiotics for hospital-acquired pneumonia in neonates and children

BACKGROUND

Hospital-acquired pneumonia is one of the most common hospital-acquired infections in children worldwide. Most of our understanding of hospital-acquired pneumonia in children is derived from adult studies. To our knowledge, no systematic review with meta-analysis has assessed the benefits and harms of different antibiotic regimens in neonates and children with hospital-acquired pneumonia.

OBJECTIVES

To assess the beneficial and harmful effects of different antibiotic regimens for hospital-acquired pneumonia in neonates and children.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, three other databases, and two trial registers to February 2021, together with reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

We included randomised clinical trials comparing one antibiotic regimen with any other antibiotic regimen for hospital-acquired pneumonia in neonates and children.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We assessed the certainty of the evidence using the GRADE approach. Our primary outcomes were all-cause mortality and serious adverse events; our secondary outcomes were health-related quality of life, pneumonia-related mortality, non-serious adverse events, and treatment failure. Our primary time point of interest was at maximum follow-up.

MAIN RESULTS

We included four randomised clinical trials (84 participants). We assessed all trials as having high risk of bias. We did not conduct any meta-analyses, as the included trials did not compare similar antibiotic regimens. Each of the four trials assessed a different comparison, as follows: cefepime versus ceftazidime; linezolid versus vancomycin; meropenem versus cefotaxime; and ceftobiprole versus cephalosporin. Only one trial reported our primary outcomes of all-cause mortality and serious adverse events. Three trials reported our secondary outcome of treatment failure. Two trials primarily included community-acquired pneumonia and hospitalised children with bacterial infections, hence the children with hospital-acquired pneumonia constituted subgroups of the total sample sizes. Where outcomes were reported, the certainty of the evidence was very low for each of the comparisons. We are unable to draw meaningful conclusions from the numerical results. None of the included trials assessed health-related quality of life, pneumonia-related mortality, or non-serious adverse events.

AUTHORS' CONCLUSIONS

The relative beneficial and harmful effects of different antibiotic regimens remain unclear due to the very low certainty of the available evidence. The current evidence is insufficient to support any antibiotic regimen being superior to another. Randomised clinical trials assessing different antibiotic regimens for hospital-acquired pneumonia in children and neonates are warranted.

Evidence-based Urology: When Is a Study or Meta-analysis Big Enough?

Both designing a clinical study and drawing conclusions from studies about the effect of treatments require justification of the sample size via judicious choice of the endpoint and power. Such an a priori power calculation limits the chances of mistakenly claiming a lack of clinical significance if no statistically significant difference between two treatments can be detected. Calculating the sample size for a new trial furthermore requires assessment of existing evidence to determine if its results will contribute to an updated meta-analysis. To rate the power of a meta-analysis, determination of the optimal information size is suggested, following the same principles as for calculating the power of a single trial. Even though these sample size considerations might seem like an additional hurdle, they are necessary to conduct clinical studies and meta-analysis that provide the optimal benefit for both clinicians and patients. PATIENT SUMMARY: Before conducting a clinical trial, researchers should determine how many patients need to be included to detect a difference between treatments. Even though a study might find a statistical difference between treatments, this does not necessarily mean that the difference is relevant for clinical use. These analyses before starting a study are important for producing worthwhile usable evidence for clinicians and patients.

Risk of complications due to antithrombotic agents in cutaneous surgery: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

We aimed to determine the risk of complications during cutaneous surgery for the perioperative discontinuation in comparison to the continuation of antithrombotic agents and the bridging of vitamin K antagonists with heparin in comparison to their continuation.

METHODS

We conducted a systematic review, searching three databases for eligible studies. Methods followed the Cochrane Handbook. We used RoB 2 and ROBINS-I to assess risk of bias. The quality of evidence was judged (GRADE). Fixed-effect meta-analyses were performed.

RESULTS

Two randomized-controlled trials and 19 prospective cohort studies were included. It is uncertain whether, compared to its discontinuation, continuing acetylsalicylic acid (risk difference (RD) 0.004, 95 % confidence interval (CI) -0.003 to 0.019) perioperatively increases the risk of significant postoperative bleedings (SPB). Compared to its discontinuation, continuing phenprocoumon perioperatively may increase the risk of SPB (RD 0.02, 95 % CI 0.00 to 0.05). Bridging phenprocoumon with heparin perioperatively may increase the risk of SPB when compared to its continuation (RD 0.07, 95 % CI 0.01 to 0.22). No evidence was found regarding bleeding risks for direct oral anticoagulants.

CONCLUSIONS

No clear indications of major risks of bleedings when continuing antithrombotic agents during minor skin surgeries were identified. However, the quality of evidence was very low.

Systematic review and trial sequential analysis of high-intensity focused ultrasound combined with chemotherapy versus chemotherapy in the treatment of unresectable pancreatic ductal adenocarcinoma

PURPOSE

This study aimed to compare the survival benefits between high-intensity focused ultrasound (HIFU) combined with chemotherapy and chemotherapy alone in patients with unresectable pancreatic ductal adenocarcinoma (PDAC).

METHODS

All randomized clinical trials (RCTs) and observational studies were systematically searched through the databases of PubMed, EMBASE, CNKi and CQVIP up to December 2020. Case reports, case series and nonsystematic reviews were excluded. A meta-analysis was conducted to generate combined hazard ratios (HRs) with 95% confidence intervals (CI) for overall survival (OS).

RESULTS

Seven trials, containing a total of 992 patients, were included in this study. The meta-analysis showed that a combination of HIFU and chemotherapy increased overall survival compared with chemotherapy alone, with a pooled HR of 0.40 (95% confidence interval [CI], 0.28-0.58). The combined therapy group had a significant advantage in 1-year survival rate (OR: 0.35, 95% CI: 0.22-0.53, p = 0.00). The trial sequence analysis (TSA) showed that there were enough trials to control for random errors.

CONCLUSION

Our analysis suggests that HIFU combined with chemotherapy intravenously will prolong survival for unresectable PDAC patients. The TSA showed that the survival benefit of combined therapy was definitive and there was no need to expand the sample size for repetitive exploration.

Cumulative meta-analysis: What works

To present time-varying evidence, cumulative meta-analysis (CMA) updates results of previous meta-analyses to incorporate new study results. We investigate the properties of CMA, suggest possible improvements and provide the first in-depth simulation study of the use of CMA and CUSUM methods for detection of temporal trends in random-effects meta-analysis. We use the standardized mean difference (SMD) as an effect measure of interest. For CMA, we compare the standard inverse-variance-weighted estimation of the overall effect using REML-based estimation of between-study variance τ 2 with the sample-size-weighted estimation of the effect accompanied by Kulinskaya-Dollinger-Bjørkestøl (Biometrics. 2011; 67:203-212) (KDB) estimation of τ 2 . For all methods, we consider Type 1 error under no shift and power under a shift in the mean in the random-effects model. To ameliorate the lack of power in CMA, we introduce two-stage CMA, in which τ 2 is estimated at Stage 1 (from the first 5-10 studies), and further CMA monitors a target value of effect, keeping the τ 2 value fixed. We recommend this two-stage CMA combined with cumulative testing for positive shift in τ 2 . In practice, use of CMA requires at least 15-20 studies.

Effectiveness and safety of adjunctive inhaled antibiotics for ventilator-associated pneumonia: A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

The efficacy and safety of adjunctive inhaled antibiotic therapy for ventilator-associated pneumonia (VAP) was systematically reviewed based on updated studies.

METHODS

We searched four databases and four clinical trial registration platforms to identify relevant studies published prior to May 19, 2020. Randomized controlled trials (RCTs) assessing adjunctive antibiotic inhalation treatment for VAP patients were eligible for this review. Two reviewers independently screened the articles and extracted the data. Information on inhaled therapy and clinical outcomes was collected. Study quality was assessed with the Cochrane risk of bias tool. The meta-analysis was conducted with Review Manager and R software. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines were used to evaluate the quality of evidence for each pooled outcome.

RESULTS

Eleven RCTs and 1210 patients were included in this analysis after the application of the inclusion and exclusion criteria. Compared with the use of intravenous injection alone, the use of adjunctive inhaled antibiotic therapy improved the rates of clinical cure (relative risk (RR) 1.13, 95% CI [1.02,1.26]) and microbiological eradication (RR 1.45, 95% CI [1.19,1.76]) in VAP patients. However, despite these improvements, mortality was not reduced (RR 1.00, 95% CI [0.82,1.21]). Adjunctive antibiotics delivered through the respiratory tract were not associated with a higher risk of renal impairment but were associated with an increased risk of bronchospasm (RR 2.74, 95% CI [1.31,5.73] during treatment.

CONCLUSIONS

Adjunctive inhaled antibiotics improved the clinical outcomes in VAP patients, but the increased rates clinical cure and microbiological eradication were not associated with reduced mortality. The use of nebulized antibiotics is not supported by the currently available evidence as a routine therapeutic strategy for VAP.

PROSPERO REGISTRATION NUMBER

CRD42020186970.

A framework for prospective, adaptive meta-analysis (FAME) of aggregate data from randomised trials

BACKGROUND

The vast majority of systematic reviews are planned retrospectively, once most eligible trials have completed and reported, and are based on aggregate data that can be extracted from publications. Prior knowledge of trial results can introduce bias into both review and meta-analysis methods, and the omission of unpublished data can lead to reporting biases. We present a collaborative framework for prospective, adaptive meta-analysis (FAME) of aggregate data to provide results that are less prone to bias. Also, with FAME, we monitor how evidence from trials is accumulating, to anticipate the earliest opportunity for a potentially definitive meta-analysis.

METHODOLOGY

We developed and piloted FAME alongside 4 systematic reviews in prostate cancer, which allowed us to refine the key principles. These are to: (1) start the systematic review process early, while trials are ongoing or yet to report; (2) liaise with trial investigators to develop a detailed picture of all eligible trials; (3) prospectively assess the earliest possible timing for reliable meta-analysis based on the accumulating aggregate data; (4) develop and register (or publish) the systematic review protocol before trials produce results and seek appropriate aggregate data; (5) interpret meta-analysis results taking account of both available and unavailable data; and (6) assess the value of updating the systematic review and meta-analysis. These principles are illustrated via a hypothetical review and their application to 3 published systematic reviews.

CONCLUSIONS

FAME can reduce the potential for bias, and produce more timely, thorough and reliable systematic reviews of aggregate data.

Liver Resection Versus Local Ablation Therapies for Hepatocellular Carcinoma Within the Milan Criteria: A Systematic Review and Meta-analysis

OBJECTIVE

To compare the oncologic outcomes of liver resection (LR) and local ablation therapies for HCC.

SUMMARY OF BACKGROUND DATA

Although several studies have compared LR and local ablation therapies, the optimal treatment of choice for HCC within the Milan criteria remains controversial.

METHODS

We systemically searched the MEDLINE, Embase, and Cochrane Library databases for randomized control trials (RCTs) and matched nonrandomized trials (NRTs) that compared LR and local ablation therapies for HCC within the Milan criteria. The primary outcome was overall survival (OS). Secondary outcomes were recurrence free survival (RFS) and recurrence pattern.

RESULTS

A total of 7 RCTs and 18 matched NRTs, involving 2865 patients in the LR group and 2764 patients in the local ablation therapy group [RFA, MWA, RFA plus trans-arterial chemoembolization (TACE)], were included. Although there was no significant difference in OS between LR and RFA, LR showed a significantly better 5-year RFS than RFA in the analysis of RCTs (hazards ratio: 0.75; 95% confidence interval: 0.62-0.92; P = 0.006). The RFA group showed a significantly higher local recurrence than the LR group in both analyses of RCTs and NRTs. Additionally, the LR group showed better OS and RFS than the MWA or RFA plus TACE groups.

CONCLUSION

Our meta-analysis showed that LR was superior to RFA in terms of RFS and incidence of local recurrence. Moreover, LR showed better oncologic outcomes than MWA or RFA plus TACE.

Prophylactic acid suppressants in children in the intensive care unit: a systematic review with meta-analysis and trial sequential analysis

BACKGROUND

Critically ill children are at risk of stress-induced gastrointestinal ulceration. Acid suppressants are frequently used in intensive care units even though there is uncertainty about the benefits and harms. With this systematic review, we aimed to assess patient-important benefits and harms of stress ulcer prophylaxis (SUP) in children in intensive care.

METHODS

We conducted the review according to the PRISMA statement, the Cochrane Handbook, and GRADE, using conventional meta-analysis and trial sequential analysis (TSA). We included randomised clinical trials comparing SUP with histamine-2-receptor antagonists or proton pump inhibitors vs placebo/no prophylaxis in children admitted for intensive care. Primary outcomes were all-cause mortality and overt gastrointestinal bleeding. Secondary outcomes were serious adverse events, hospital-acquired pneumonia, Clostridium difficile enteritis, myocardial ischemia, acute kidney injury and quality of life.

RESULTS

We included a total of seven trials (n = 504) with eight trial comparisons. We found no statistically significant difference in all-cause mortality (relative risk (RR) 1.43, 95% confidence interval (CI) 0.86-2.37), overt gastrointestinal bleeding (RR 0.75, 95% CI 0.42-1.35) or hospital-acquired pneumonia (RR 1.18, 95% CI 0.77-1.82) between SUP vs placebo/no prophylaxis. No trials reported on remaining secondary outcomes. TSA was unable to draw firm conclusions for all outcomes and certainty of evidence for all outcomes was "very low."

CONCLUSIONS

We found no difference in all-cause mortality, overt gastrointestinal bleeding or hospital-acquired pneumonia in children in intensive care receiving acid suppressants compared with placebo/no prophylaxis. However, the quantity and quality of evidence was very low with no firm evidence for benefit or harm.

[How to interpret the certainty of evidence based on GRADE (Grading of Recommendations, Assessment, Development and Evaluation)]

BACKGROUND

GRADE (Grading of Recommendations, Assessment, Development and Evaluation) is a widely used approach in the fields of medicine and public health to assess the outcome-specific certainty of the evidence in systematic reviews.

OBJECTIVES

To make the GRADE approach comprehensible in order to facilitate the reading, understanding and interpretation of GRADE assessments in systematic reviews.

MATERIALS AND METHODS

Presentation of the procedure of the GRADE approach using the example of a Cochrane review on selenium supplements in the prevention of prostate cancer.

RESULTS

GRADE provides criteria for rating the certainty of evidence. GRADE's approach to rating the certainty of the evidence is based on a four-level system (high, moderate, low, very low). The GRADE approach classifies bodies of randomized controlled trials as initially starting at high certainty and bodies of observational studies at initially starting at low certainty. By assessing the five domains (risk for bias, inconsistency, indirectness, insufficient precision and publication bias), certainty can be rated down or, in the case of large effects, existing dose-response relationships or plausible confounders, rated up.

CONCLUSIONS

GRADE is a consistent and transparent approach for rating the certainty of a body of evidence by offering explicit key questions.

Nonaspirin nonsteroidal anti-inflammatory drugs and gastric cancer risk after Helicobacter pylori eradication: A territory-wide study

BACKGROUND

Despite Helicobacter pylori (HP) eradication, individuals can still develop gastric cancer (GC). Prior studies have demonstrated that nonaspirin nonsteroidal anti-inflammatory drugs (NA-NSAIDs) reduce the risk of GC, but this may be caused by immortal time bias and failure to adjust for HP status. The objective of this study was to investigate whether NA-NSAIDs reduced the risk of GC in patients who undergo H. pylori eradication.

METHODS

Adult patients who had received clarithromycin-based triple therapy between 2003 and 2016 were identified from a territory-wide health care database. Exclusion criteria included prior GC or GC diagnosed <6 months after HP eradication, prior gastrectomy, gastric ulcer after HP eradication, and failure of triple therapy. Covariates included age, sex, prior peptic ulcer disease, other comorbidities, and concurrent medications (aspirin, proton pump inhibitors, statins, and metformin). To avoid immortal time bias, NA-NSAID use (≥90 days) was treated as a time-dependent variable in a multivariable Cox model (time-dependent analysis). Time-independent analysis was also performed.

RESULTS

During a median follow-up of 8.9 years (interquartile range, 5.4-12.6 years), 364 of 92,017 patients (0.4%) who underwent HP eradication developed GC. NA-NSAID use was associated with a significant reduction in the risk of GC in time-fixed analysis (adjusted hazard ratio [aHR], 0.65; 95% CI, 0.47-0.90), but not in time-dependent multivariable analysis (aHR, 1.35; 95% CI, 0.97-1.87). Time-dependent subgroup analyses also did not indicate any significant association between NA-NSAID use and either cardia GC (aHR, 0.75; 95% CI, 0.27-2.06) or noncardia GC (aHR, 1.28; 95% CI, 0.83-1.98).

CONCLUSIONS

NA-NSAID use was not associated with a reduced risk of GC among patients who underwent HP eradication. The chemopreventive effect of NA-NSAIDs observed in prior studies may have been confounded by immortal time bias.

Using Trial Sequential Analysis for estimating the sample sizes of further trials: example using smoking cessation intervention

Background

Assessing benefits and harms of health interventions is resource-intensive and often requires feasibility and pilot trials followed by adequately powered randomised clinical trials. Data from feasibility and pilot trials are used to inform the design and sample size of the adequately powered randomised clinical trials. When a randomised clinical trial is conducted, results from feasibility and pilot trials may be disregarded in terms of benefits and harms.

Methods

We describe using feasibility and pilot trial data in the Trial Sequential Analysis software to estimate the required sample size for one or more trials investigating a behavioural smoking cessation intervention. We show how data from a new, planned trial can be combined with data from the earlier trials using trial sequential analysis methods to assess the intervention’s effects.

Results

We provide a worked example to illustrate how we successfully used the Trial Sequential Analysis software to arrive at a sensible sample size for a new randomised clinical trial and use it in the argumentation for research funds for the trial.

Conclusions

Trial Sequential Analysis can utilise data from feasibility and pilot trials as well as other trials, to estimate a sample size for one or more, similarly designed, future randomised clinical trials. As this method uses available data, estimated sample sizes may be smaller than they would have been using conventional sample size estimation methods.

Effects of vitamin E on stroke: a systematic review with meta-analysis and trial sequential analysis

There are several previous studies on the association of vitamin E with prevention of stroke but the findings remain controversial. We have conducted a systematic review, meta-analysis together with trial sequential analysis of randomised controlled trials to evaluate the effect of vitamin E supplementation versus placebo/no vitamin E on the risk reduction of total, fatal, non-fatal, haemorrhagic and ischaemic stroke. Relevant studies were identified by searching online databases through Medline, PubMed and Cochrane Central Register of Controlled Trials. A total of 18 studies with 148 016 participants were included in the analysis. There was no significant difference in the prevention of total stroke (RR (relative risk)=0.98, 95% CI 0.92-1.04, p=0.57), fatal stroke (RR=0.96, 95% CI 0.77-1.20, p=0.73) and non-fatal stroke (RR=0.96, 95% CI 0.88-1.05, p=0.35). Subgroup analyses were performed under each category (total stroke, fatal stroke and non-fatal stroke) and included the following subgroups (types of prevention, source and dosage of vitamin E and vitamin E alone vs control). The findings in all subgroup analyses were statistically insignificant. In stroke subtypes analysis, vitamin E showed significant risk reduction in ischaemic stroke (RR=0.92, 95% CI 0.85-0.99, p=0.04) but not in haemorrhagic stroke (RR=1.17, 95% CI 0.98-1.39, p=0.08). However, the trial sequential analysis demonstrated that more studies were needed to control random errors. Limitations of this study include the following: trials design may not have provided sufficient power to detect a change in stroke outcomes, participants may have had different lifestyles or health issues, there were a limited number of studies available for subgroup analysis, studies were mostly done in developed countries, and the total sample size for all included studies was insufficient to obtain a meaningful result from meta-analysis. In conclusion, there is still a lack of statistically significant evidence of the effects of vitamin E on the risk reduction of stroke. Nevertheless, vitamin E may offer some benefits in the prevention of ischaemic stroke and additional well-designed randomised controlled trials are needed to arrive at a definitive finding. PROSPERO registration number: CRD42020167827.

Loop diuretics in adult intensive care patients with fluid overload: A protocol for a systematic review of randomised clinical trials with meta-analysis and Trial Sequential Analysis

BACKGROUND

In the intensive care unit, fluid overload is frequent and a risk factor for organ dysfunction and increased mortality. Primarily, lung and kidney functions may be impaired by fluid overload resulting in acute respiratory failure and acute kidney injury. No clinical guidelines exist for treatment of fluid overload in intensive care patients. Loop diuretics, most often furosemide, appear to be the most frequently used pharmacological intervention. The aim of this protocol is to describe the methods of a systematic review assessing the evidence of treatment with loop diuretics in adult intensive care patients with fluid overload.

METHODS

We will conduct a systematic review with meta-analysis and report it according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statements, use the recommendations of the Cochrane Handbook and assess the quality of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. We will include randomised clinical trials identified through searches of major international databases and trial registers. Two authors will independently screen and select trials for inclusion, extract data and assess the methodological quality using the Cochrane risk of bias tool. Extracted data will be analysed using Review Manager and Trial Sequential Analysis. The protocol is registered at PROSPERO.

DISCUSSION

We aim to provide reliable evidence on the use of loop diuretics in adult intensive care patients with fluid overload to guide clinicians, decision makers and trialists on clinical practice.

Early head-up mobilisation versus standard care for patients with severe acquired brain injury: A systematic review with meta-analysis and Trial Sequential Analysis

BACKGROUND

There is increasing focus on earlier rehabilitation in patients with traumatic or hypoxic brain injury or stroke. This systematic review evaluates the benefits and harms of early head-up mobilisation versus standard care in patients with severe acquired brain injury.

METHODS

We searched Medline, CENTRAL, EMBASE, four other databases and 13 selected clinical trial registries until April 2020. Eligible randomised clinical trials compared early head-up mobilisation versus standard care in patients with severe acquired brain injury and were analysed conducting random- and fixed-effects meta-analyses and Trial Sequential Analysis (TSA). Certainty of evidence was assessed by GRADE.

MAIN RESULTS

We identified four randomised clinical trials (total n = 385 patients) with severe acquired brain injury (stroke 86% and traumatic brain injury 13%). Two trials were at low risk and two at high risk of bias. We found no evidence of a difference between early mobilisation vs. standard care on mortality or poor functional outcome at end of the intervention (relative risk (RR) 1.19, 95% CI 0.93 to 1.53; I2 0%; very low certainty) or at maximal follow-up (RR 1.03, 95% CI 0.89 to 1.21; I2 0%; very low certainty). We found evidence against an effect on quality of life at maximal follow-up. The proportion of patients with at least one serious adverse event did not differ at end of intervention or at maximal follow-up. For most comparisons, TSA suggested that further trials are needed.

CONCLUSIONS

We found no evidence of a difference between early mobilisation versus standard care for patients with severe acquired brain injury. Early mobilisation appeared not to exert a major impact on quality of life. This systematic review highlights the insufficient evidence in patients with severe brain injury, and no firm conclusions can be drawn from these data.

TRIAL REGISTRATION

Protocol uploaded to PROSPERO: April 2018 (revised October 2018, CRD42018088790).

Remote Ischemic Conditioning in Patients with Acute Coronary Syndromes: A Systematic Review with Meta-Analysis and Trial Sequential Analysis

Objective

To evaluate the efficacy of remote ischemic conditioning (RIC) as compared to no conditioning on clinical endpoints in acute coronary syndromes (ACS) patients undergoing percutaneous coronary intervention (PCI).

Design

Systematic review of randomized clinical trials (RCTs).

Material and Methods

Literature was searched up to September 13, 2019, and we identified a total of 13 RCTs. The efficacy of RIC on incidence of clinical events during follow-up was quantified by the rate ratio (RR) with its 95% confidence interval (CI), and we used fixed and random effects models to synthetize the results. Small-study effect was evaluated, and controlled for by the trim-and-fill method. Heterogeneity between studies was examined by subgroup and meta-regression analyses. The risk of false-positive results in meta-analysis was evaluated by trial sequential analysis (TSA).

Results

Pooled analysis of 13 trials (7183 patients) showed that RIC compared to no conditioning revealed a non-significant risk reduction on endpoint mortality (RR=0.81, 95% CI: 0.56–1.17) during a median follow-up time of 1 year (range: 0.08–3.8) with low heterogeneity (I²=16%). Controlling for small-study effect showed no efficacy of RIC (adjusted RR: 1.03, 95% CI: 0.66–1.59). Pooled effect of RIC on the incidence of myocardial infarction (MI) from 11 trials (6996 patients) was non-significant too (RR=0.85, 95% CI: 0.62–1.18), with no observed heterogeneity (I²=0%) or small-study effect. A similar lack of efficacy was found in endpoint congestive heart failure (CHF) from 6 trials including 6098 patients (RR=0.71, 95% CI: 0.44–1.15), with moderate heterogeneity (I²=30%). TSAs showed that the pooled estimates from the cumulative meta-analyses were true negative with adequate power.

Conclusion

Evidence from this updated systematic review demonstrates no beneficial effect of RIC on the incidence of clinical endpoint mortality, MI and CHF during a median follow-up of 1 year in ACS patients undergoing PCI.

The effect of Bushen Huoxue method in treating glaucoma: A protocol for systematic review and meta-analysis

BACKGROUND

Glaucoma is a common ophthalmic neurodegenerative disease and the main cause of blindness, which seriously affects the life and work of patients, without more effective treatment for optic nerve damage. Bushen Huoxue (BSHX) method is a traditional Chinese medicine (TCM) therapy that has been widely used as an alternative therapy to treat optic nerve damage in glaucoma patients with growing beneficial effect evidence, however, there is no current systematic review has addressed its effect for glaucoma. This study will conduct a systematic review and meta-analysis of the currently published randomized controlled trials (RCTs) of BSHX method for the treatment of glaucoma, aim to assess the efficacy and safety of BSHX method for patients with glaucoma.

METHODS

We will thoroughly search literatures of RCTs related to BSHX method for glaucoma in PubMed, Medline, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), VIP and Wanfang database and other databases from the establishment of the database to November 2019, with no language restriction. After reviewing the title, abstract and full text, 2 reviewers will independently select the study, extract the data, after assess the risk of bias, we will conduct a meta-analysis of the data extracted from the included RCTs, including total effective rate, intraocular pressure (IOP), visual acuity, visual field, TCM syndrome score, and adverse events. The meta-analysis will be performed using Review Manager 5.3 software and the results will be based on either random effects or fixed effects models, depending on the heterogeneity. Trial sequential analysis (TSA) and Grading of Recommendations, Development and Evaluate system (GRADE) will be conduct to evaluate the reliability and quality of evidence.

RESULTS

The results of the study will be published in a peer-reviewed journal, and provide a reasonable and high-quality evidence for the efficacy and safety of BSHX method for glaucoma.

CONCLUSION

This study will be the first meta-analysis to evaluate the efficacy of BSHX method in the treatment of glaucoma comprehensively, and will to provide helpful evidence for the clinical treatment of this disease.

REGISTRATION

PROSPERO CRD42020159897.

Prophylactic use of acid suppressants in adult acutely ill hospitalised patients: A systematic review with meta-analysis and trial sequential analysis

BACKGROUND

Acutely ill patients are at risk of stress-related gastrointestinal (GI) bleeding and prophylactic acid suppressants are frequently used. In this systematic review, we assessed the effects of stress ulcer prophylaxis (SUP) with proton pump inhibitors (PPIs) or histamine-2 receptor antagonists (H2RAs) versus placebo or no prophylaxis in acutely ill hospitalised patients.

METHODS

We conducted the review according to the PRISMA statement, the Cochrane Handbook and GRADE, using conventional meta-analysis and trial sequential analysis (TSA). The primary outcomes were all-cause mortality, clinically important GI bleeding and serious adverse events (SAEs). The primary analyses included overall low risk of bias trials.

RESULTS

We included 65 comparisons from 62 trials (n = 9713); 43 comparisons were from intensive care units. Only three trials (n = 3596) had overall low risk of bias. We did not find an effect on all-cause mortality (RR 1.03, 95% CI 0.94 to 1.14; TSA-adjusted CI 0.90 to 1.18; high certainty). The rate of clinically important GI bleeding was lower with SUP (RR 0.62, 95% CI 0.43 to 0.89; TSA-adjusted CI 0.14 to 2.81; moderate certainty). We did not find a difference in pneumonia rates (moderate certainty). Effects on SAEs, Clostridium difficile enteritis, myocardial ischaemia and health-related quality of life (HRQoL) were inconclusive due to sparse data. Analyses of all trials regardless of risk of bias were consistent with the primary analyses.

CONCLUSIONS

We did not observe a difference in all-cause mortality or pneumonia with SUP. The incidence of clinically important GI bleeding was reduced with SUP, whereas any effects on SAEs, myocardial ischaemia, Clostridium difficile enteritis and HRQoL were inconclusive.

STUDY REGISTRATION

PROSPERO registration number CRD42017055676; published study protocol: Marker, et al 2017 in Systematic Reviews.