Statistical primer: methodology and reporting of meta-analyses

Traditional and Complementary Medicine Use among Cancer Patients in Asian Countries: A Systematic Review and Meta-Analysis

Globally, cancer patients frequently use T&CM during their treatment for various reasons. The primary concerns regarding the use of T&CM among cancer patients are the potential risks associated with interactions between pharmaceuticals and T&CM, as well as the risk of noncompliance with conventional cancer treatments. Despite the higher prevalence of T&CM use in Asia, driven by cultural, historical, and resource-related factors, no prior review has tried to estimate the prevalence and influencing factors of T&CM use and disclosure among cancer patients in this region. This study aims to examine the prevalence and disclosure rates of T&CM use among cancer patients in Asia to assess various factors influencing its use across different cancer treatment settings in Asia. Systematic research on T&CM use was conducted using four databases (PubMed, EMBASE, Web of Science, and CINAHAL) from inception to January 2023. Quality was assessed using the Appraisal Tool for Cross-Sectional Studies (AXIS). A random effects model was used to estimate the pooled prevalence of T&CM use, and data analysis was performed using Stata Version 16.0. Among the 4849 records retrieved, 41 eligible studies conducted in 14 Asian countries were included, involving a total of 14,976 participants. The pooled prevalence of T&CM use was 49.3%, ranging from 24.0% to 94.8%, and the disclosure rate of T&CM use was 38.2% (11.9% to 82.5%). The most commonly used T&CM modalities were herbal medicines and traditional medicine. Females were 22.0% more likely to use T&CM than males. A subgroup analysis revealed the highest prevalence of T&CM use was found in studies conducted in East Asia (62.4%) and those covered by both national and private insurance (55.8%). The disclosure rate of T&CM use to physicians remains low. Moreover, the factors influencing this disclosure are still insufficiently explored. Since the disclosure of T&CM use is a crucial indicator of patient safety and the quality of cancer treatment prognosis, future research should focus on identifying the determinants of non-disclosure.

Meta-Analysis of the Therapeutic Effects of Stem Cell-Derived Extracellular Vesicles in Rodent Models of Hemorrhagic Stroke

Background

Stem cell-derived extracellular vesicles (SCEVs) have emerged as a potential therapy for hemorrhagic stroke. However, their effects are not fully understood. The aim of this study was to comprehensively evaluate the effects of SCEVs therapy in rodent models of hemorrhagic stroke, including subarachnoid hemorrhage (SAH) and intracerebral hemorrhage (ICH).

Materials and Methods

We conducted a comprehensive search of PubMed, EMBASE, and Web of Science until May 2023 to identify studies investigating the effects of SCEVs therapy in rodent models of ICH. The functional outcomes were assessed using neurobehavioral scores. Standardized mean differences (SMDs) and confidence intervals (CIs) were calculated using a random-effects model. Three authors independently screened the articles based on inclusion and exclusion criteria. All statistical analyses were performed using Revman 5.3 and Stata 17.0.

Results

Twelve studies published between 2018 and 2023 met the inclusion criteria. Our results showed that SCEVs therapy improved neurobehavioral scores in the rodent SAH model (SMD = -3.49, 95% CI: -4.23 to -2.75; p < 0.001). Additionally, SCEVs therapy improved the chronic neurobehavioral scores of the rodent ICH model (SMD = 2.38, 95% CI: 0.36-4.40; p=0.02) but did not have a significant impact on neurobehavioral scores in the acute and subacute phases. Significant heterogeneity was observed among the studies, and further stratification and sensitivity analyses failed to identify the source of heterogeneity.

Conclusions

Our findings suggest that SCEVs therapy may improve neurofunctional behavior after hemorrhagic stroke and provide important insights into the design of preclinical trials.

Statistical primer: individual patient data meta-analysis and meta-analytic approaches in case of non-proportional hazards

Individual patient data (IPD) meta-analyses build upon traditional (aggregate data) meta-analyses by collecting IPD from the individual studies rather than using aggregated summary data. Although both traditional and IPD meta-analyses produce a summary effect estimate, IPD meta-analyses allow for the analysis of data to be performed as a single dataset. This allows for standardization of exposure, outcomes, and analytic methods across individual studies. IPD meta-analyses also allow the utilization of statistical methods typically used in cohort studies, such as multivariable regression, survival analysis, propensity score matching, uniform subgroup and sensitivity analyses, better management of missing data, and incorporation of unpublished data. However, they are more time-intensive, costly, and subject to participation bias. A separate issue relates to the meta-analytic challenges when the proportional hazards assumption is violated. In these instances, alternative methods of reporting time-to-event estimates, such as restricted mean survival time should be used. This statistical primer summarizes key concepts in both scenarios and provides pertinent examples.

Biomechanical and physical determinants of bowling speed in cricket: a novel approach to systematic review and meta-analysis of correlational data

This systematic review and meta-analysis examined the influence of biomechanical and physical characteristics on ball release speed in cricket using correlation data. Search was conducted across PubMed, Cinhal, Scopus, SportDiscus and Web of Science, with eighteen studies included. The ball release speed had a moderate correlation with overall biomechanical (r = 0.42, p < 0.001) parameters and a strong correlation with physical (r = 0.65, p < 0.001) characteristics. Furthermore, individual biomechanical and physical parameters were also correlated with ball release speed. The run-up speed had a strong correlation (r = 0.50, p < 0.001) and front knee angle at ball release had a moderate correlation (r = 0.40, p < 0.001). Poorer correlations were identified for centre of mass velocity at ball release (r = 0.16, p = 0.134), front knee angle at front foot contact (r = 0.26, p = 0.015) 25 and vertical ground reaction force (r = 0.13, p = 0.659). Strong and significant correlation was found for total arm length (r = 0.65, p < 0.001) and shoulder strength (r = 0.58, p < 0.001). This review highlights the biomechanical and physical parameters that are major determinants of faster ball release speed.

Antidotal Effects of the Antihistamine Diphenhydramine Against Cholinesterase Inhibitor Poisoning: A Meta-Analysis of Median Lethal Doses in Experimental Animals

The H1-antihistamine diphenhydramine antagonizes cholinesterase inhibitor poisoning in various animal species. One aspect of acute antidotal actions of diphenhydramine is increasing the median lethal doses (LD50) of toxicants. The objective of this meta-analysis was to assess the antidotal action of diphenhydramine against short-term toxicity (LD50) of cholinesterase inhibitors in experimental animals. The experimental studies selected were according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. They were conducted in laboratory animals (mice, rats, and chicks) to determine acute LD50 values of cholinesterase inhibitors (organophosphates, carbamates, and imidocarb) under the influence of diphenhydramine vs. controls. Twenty-eight records were selected from 12 studies on mice (n= 242), rats (n= 27), and young chicks (n= 128). The forest plot of randomized two-group meta-analysis assessed effect size, subgroup analysis, drapery prediction, heterogeneity, publication bias-funnel plot as well as one-group proportions meta-analysis of percent protection. Diphenhydramine significantly increased the combined effect size (i.e. increased LD50) in intoxicated experimental animals in comparison to controls (-3.71, standard error (SE) 0.36, 95%CI -4.46, -2.97). The drapery plot proposed a wide range of confidence intervals. The I2 index of heterogeneity of the combined effect size was high at 81.03% (Q= 142.3, p < 0.0001). Galbraith regression also indicated data heterogeneity; however, the normal quantile plot indicated no outliers. Subgroup analysis indicated significantly high heterogeneity with organophosphates (I2 = 63.72%) and carbamates (I2 = 76.41%), but low with imidocarb (I2 = 51.48%). The funnel plot and Egger regression test (t= -13.7, p < 0.0001) revealed publication bias. The median of the diphenhydramine protection ratio was 1.655, and the related forest plot of one group proportion meta-analysis revealed a statistically high level of protection (0.594, SE 0.083, 95%CI 0.432, 0.756), with high heterogeneity (I2= 99.86). The risk of bias assessment was unclear, while the total score (16 out of 20) of each study leaned towards the side of the low risk of bias. In conclusion, the meta-analysis of LD50 values indicated that diphenhydramine unequivocally protected experimental animals from the acute toxicity of cholinesterase inhibitors. The drug could be an additional antidote against acute poisoning induced by cholinesterase inhibitors, but a word of caution: it is not to be considered as a replacement for the standard antidote atropine sulfate. Further studies are needed to examine the action of diphenhydramine on adverse chronic effects of cholinesterase inhibitors.

Comparison of Femtosecond Laser Assistance and Manual Trephination in Deep Anterior Lamellar Keratoplasty in the Treatment of Keratoconus: A Meta-Analysis

PURPOSE

To compare the efficacy and safety of femtosecond laser-assisted deep anterior lamellar keratoplasty (F-DALK) with those of manual-trephination DALK (M-DALK) in treating keratoconus.

DESIGN

Systematic review and meta-analysis.

METHODS

Through November 2022, we comprehensively searched PubMed, EMBASE, the Cochrane Library, and 4 Chinese databases. Studies that involved comparisons between F-DALK and M-DALK groups and that reported on relevant efficacy and/or safety parameters were included. Primary outcomes were uncorrected- and corrected-distance visual acuity and intraoperative complication rates. Secondary outcomes were spherical equivalent, topographic astigmatism, refractive cylinder, mean keratometry, endothelial cell density, suture removal time, and postoperative complication rates. These data were analyzed using Cochrane Review Manager software version 5.3.

RESULTS

This meta-analysis included 9 nonrandomized controlled studies involving 1713 eyes. In eyes treated with F-DALK, corrected-distance visual acuity at 1 to 6 months (weighted mean difference = -0.07 [95% confidence interval {CI} -0.10 to -0.03]; I2 = 0%; P < .001) after surgery was better and intraoperative Descemet membrane perforation occurred less often (odds ratio = 0.53 [95% CI 0.31-0.92]; I2 = 6%; P = .02) than in eyes treated with M-DALK. No clinically significant differences in other outcomes were found among the groups.

CONCLUSIONS

Both F-DALK and M-DALK are safe and efficacious for patients with keratoconus. Compared with M-DALK, F-DALK can provide better early visual acuity and reduce the intraoperative perforation rate, and its likely improvements to long-term visual quality and endothelial cell preservation warrant further investigation. In addition, the 2 techniques seem to be comparable regarding refractive outcomes and other complications.

Association of Reduced Maternal Plasma Cholinesterase Activity With Preeclampsia: A Meta-Analysis

Blood butyrylcholinesterase (BChE) activity has been found to decrease during pregnancy and reportedly decrease even more in preeclampsia (PE). The purpose of the present meta-analysis was to answer a specific question of whether BChE activity (in the plasma, serum, or whole blood) is reduced in pregnant women suffering from PE compared to those with normal pregnancy. The meta-analysis included 15 studies with 20 records of BChE activity in 608 women compared to 569 healthy pregnant (control) ones. The studies were subjected to quality assessment using the Newcastle-Ottawa Scale (NOS). Using the Meta-Essentials software program 1.5, the one-group random effects model and forest plot revealed that the percentage of BChE activity in pregnant women with PE was 84.84% of the control value, with a standard error of 4.09 and 95% C.I. of 76.28, 93.41, indicating a significant 15.16% reduction in BChE activity in comparison to healthy pregnancy. No significant heterogeneity was seen in the analyzed data and the funnel plot did show publication bias. Subgroup (mild, severe, and unclassified PE) forest plot analysis revealed that the % BChE activities in PE compared to respective healthy pregnancies were 96.28%, 97.08%, and 76.62%, respectively with no heterogeneity. The median NOS score of the 15 studies included in the meta-analysis was 7, ranging from 5 to 8 (medium to high quality), and the forest plot showed an effect size of 0.735. This meta-analysis shows that BChE activity is reduced in PE compared with normal pregnancy and its value as a biomarker warrants further clinical studies.

Effects of tranquilization therapy in elderly patients suffering from chronic non-communicable diseases: A meta-analysis

The current meta-analysis searched the literature connected to different tranquilizers used to treat elderly people and assessed it in terms of dose, types of outcomes and adverse effects, to determine a safe and acceptable tranquilizer and its optimal dose. A systematic literature review was undertaken for randomized controlled trials, case-control, retrospective and prospective studies on the use of tranquilizers in elderly patients, using PubMed, Ebsco, SCOPUS and Web of Science. PICOS criteria were used to select studies, and pertinent event data was collected. This meta-analysis includes 16 randomized control trials spanning the years 2000 to 2022, using the data from 2224 patients. The trials that were included used various tranquilizers such as diazepam, alprazolam, temazepam and lorazepam, and indicated high treatment efficacy and low adverse effects. With a p-value of 0.853 for Egger's test and 0.13 for Begg's test, the current meta-analysis shows a minimal probability of publication bias. A recent meta-analysis supports the use of tranquilizers in older people to treat sleeplessness, epilepsy or anxiety, but only at modest doses, because large doses are harmful and produce numerous withdrawal symptoms.

Reassessment of Historical Clinical Trials Supports the Effectiveness of Phage Therapy

Phage therapy has become a hot topic in medical research due to the increasing prevalence of antibiotic-resistant bacteria strains. In the treatment of bacterial infections, bacteriophages have several advantages over antibiotics, including strain specificity, lack of serious side effects, and low development costs. However, scientists dismissed the clinical success of early clinical trials in the 1940s, slowing the adoption of this promising antibacterial application in Western countries. The current study used statistical methods commonly used in modern meta-analysis to reevaluate early 20th-century studies and compare them with clinical trials conducted in the last 20 years. Using a random effect model, the development of disease after treatment with or without phages was measured in odds ratios (OR) with 95% confidence intervals (CI). Based on the findings of 17 clinical trials conducted between 1921 and 1940, phage therapy was effective (OR = 0.21, 95% CI = 0.10 to 0.44, P value < 0.0001). The current study includes a topic review on modern clinical trials; four could be analyzed, indicating a noneffective therapy (OR = 2.84, 95% CI = 1.53 to 5.27, P value = 0.0009). The results suggest phage therapy was surprisingly less effective than standard treatments in resolving bacterial infections. However, the results were affected by the small sample set size. This work also contextualizes the development of phage therapy in the early 20th century and highlights the expansion of phage applications in the last few years. In conclusion, the current review shows phage therapy is no longer an underestimated tool in the treatment of bacterial infections.

Assessment of prognostic factors in pediatric adrenocortical tumors: a systematic review and evaluation of a modified S-GRAS score

OBJECTIVE

Pediatric adrenocortical carcinoma (pACC) is rare and prognostic stratification remains challenging. We summarized the clinical prognostic factors of pACC and determined the prognostic value of the pediatric scoring system (pS-GRAS) in adaption to the recommendation (S-GRAS) of the European Network for the Study of Adrenal Tumors for the classification of adult ACC.

DESIGN

Analysis of pACC patients of 33 available retrospective studies in the literature.

METHODS

We searched the PubMed and Embase databases for manuscripts regarding pACC. The pS-GRAS score was calculated as a sum of tumor stage (1 = 0; 2-3 = 1; 4 = 2 points), grade (Ki67 index/rate of mitosis 0-9%/low = 0; 10-19%/intermediate = 1; ≥20%/high = 2 points), resection status (R0 = 0; RX = 1; R1 = 2; R2 = 3 points), age (<4 years = 0; ≥4 years = 1 point), hormone-related symptoms (androgen production = 0; glucocorticoid/mixed/no hormone production = 1 point) generating 10 scores and 4 groups (1: 0-2, 2: 3-4, 3: 5, 4: 6-9). The primary endpoint was overall survival (OS).

RESULTS

We included 733 patients. The median age was 2.5 years and >85% of pACC showed hormone activity (mixed 50%, androgen 29%, glucocorticoid 21%). Androgen production was associated with a superior OS. Increasing age correlated with higher rates of inactive or only glucocorticoid-producing tumors, advanced tumor stage, and case fatality. Especially infants < 4 years showed more often low-risk constellations with an increased OS for all tumor stages. The pS-GRAS score correlated with clinical outcome; median OS was 133 months (95% CI: 36-283) in group 1 (n = 49), 110 months (95% CI: 2.9-314) in group 2 (n = 57), 49 months (95% CI: 5.8-278) in group 3 (n = 18), and 16 months (95% CI: 2.4-267) in group 4; (n = 11) P < 0.05).

CONCLUSION

The pS-GRAS score seems to have a high predictive value in the pACC patients, may serve as a helpful tool for risk stratification in future studies, and should be evaluated prospectively in an international context.

Incidence of postoperative symptomatic spinal epidural hematoma requiring surgical evacuation: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis aimed to determine the incidence of symptomatic spinal epidural hematoma (SSEH) following spine surgery.

METHODS

We systematically searched for all relevant articles that mentioned the incidence of SSEH following the spine surgery published in the PubMed, Embase, and Cochrane Library databases through March 2022 and manually searched the reference lists of included studies. The Newcastle-Ottawa quality assessment scale (NOS) was used to assess the quality of the included studies. A fixed-effects or random-effects model was performed to calculate the pooled incidence of the totality and subgroups based on the heterogeneity. The potential publication bias was assessed by Egger's linear regression and a funnel plot. Sensitivity analysis was also conducted.

RESULTS

A total of 40 studies were included in our meta-analysis based on our inclusion and exclusion criteria. The overall pooled incidence of SSEH was 0.52% (95% CI 0.004-0.007). In the subgroup analysis, the pooled incidence of SSEH in males and females was 0.86% (95% CI 0.004-0.023) and 0.68% (95% CI 0.003-0.017). Among the different indications, a higher incidence (2.9%, 95% CI 0.006-0.084) was found in patients with deformity than degeneration (1.12%, 95% CI 0.006-0.020) and tumor (0.30%, 95% CI 0.006-0.084). For different surgical sites, the incidences of SSEH in cervical, thoracic and lumbar spine were 0.32% (95% CI 0.002-0.005), 0.84% (95% CI 0.004-0.017) and 0.63% (95% CI 0.004-0.010), respectively. The incidences of SSEH in anterior and posterior approach were 0.24% (95% CI 0.001-0.006) and 0.70% (95% CI 0.004-0.011), respectively. The pooled incidence of SSEH was five times higher with minimally invasive surgery (1.94%, 95% CI 0.009-0.043) than with open surgery (0.42%, 95% CI 0.003-0.006). Delayed onset of SSEH had a lower incidence of 0.16% (95% CI 0.001-0.002) than early onset. There were no significant variations in the incidence of SSEH between patients who received perioperative anticoagulation therapy and those who did not or did not report getting chemopreventive therapy (0.44%, 95% CI 0.006-0.084 versus 0.42%, 95% CI 0.003-0.006).

CONCLUSION

We evaluated the overall incidence proportion of SSEH after spine surgery and performed stratified analysis, including sex, surgical indication, site, approach, minimally invasive surgery, and delayed onset of SSEH. Our research would be helpful for patients to be accurately informed of their risk and for spinal surgeons to estimate the probability of SSEH after spine surgery.

Running economy and lower extremity stiffness in endurance runners: A systematic review and meta-analysis

Background: Lower extremity stiffness simulates the response of the lower extremity to landing in running. However, its relationship with running economy (RE) remains unclear. This study aims to explore the relationship between lower extremity stiffness and RE. Methods: This study utilized articles from the Web of Science, PubMed, and Scopus discussing the relationships between RE and indicators of lower extremity stiffness, namely vertical stiffness, leg stiffness, and joint stiffness. Methodological quality was assessed using the Joanna Australian Centre for Evidence-Based Care (JBI). Pearson correlation coefficients were utilized to summarize effect sizes, and meta-regression analysis was used to assess the extent of this association between speed and participant level. Result: In total, thirteen studies involving 272 runners met the inclusion criteria and were included in this review. The quality of the thirteen studies ranged from moderate to high. The meta-analysis results showed a negative correlation between vertical stiffness (r = -0.520, 95% CI, -0.635 to -0.384, p < 0.001) and leg stiffness (r = -0.568, 95% CI, -0.723 to -0.357, p < 0.001) and RE. Additional, there was a small negative correlation between knee stiffness and RE (r = -0.290, 95% CI, -0.508 to -0.037, p = 0.025). Meta-regression results showed that the extent to which leg stiffness was negatively correlated with RE was influenced by speed (coefficient = -0.409, p = 0.020, r 2 = 0.79) and participant maximal oxygen uptake (coefficient = -0.068, p = 0.010, r 2 = 0.92). Conclusion: The results of this study suggest that vertical, leg and knee stiffness were negatively correlated with RE. In addition, maximum oxygen uptake and speed will determine whether the runner can take full advantage of leg stiffness to minimize energy expenditure.

Does robotic-assisted thymectomy have advantages over video-assisted thymectomy in short-term outcomes? A systematic view and meta-analysis

OBJECTIVES

A thymic epithelial tumour is the most common primary tumour in the anterior mediastinum of adults. A few retrospective studies compared the short-term outcomes between robotic-assisted thymectomy (RAT) and video-assisted thymectomy (VAT). So, it is necessary to conduct a meta-analysis to further compare these 2 surgical techniques.

METHODS

EMBASE, Medline and Web of Science were used. Thesaurus terms and medical subject headings were used in Medline and EMBASE, respectively. The Newcastle-Ottawa scale was used for grading because the included studies were all case-control studies.

RESULTS

Nine studies were included in the meta-analysis with a total of 723 patients, including 315 patients in the RAT group and 408 patients in the VAT group. The meta-analysis [odds ratio (OR) 0.24, 95% confidence interval (CI) 0.06-0.94; P = 0.041], indicating that RAT yielded a significantly lower rate of conversion compared with VAT. Duration of drainage with RAT was significantly less than that with VAT (weighted mean difference = -1.10; 95% CI -1.98 to -0.22; P = 0.014). The pooled analysis (weighted mean difference = -103.6; 95% CI -199.21 to -7.98; P = 0.034) suggested that patients in the RAT group had less drainage than those in the VAT group. The recurrence rates in both groups were comparable (OR 0.19, 95% CI 0.03-1.20; P = 0.078).

CONCLUSIONS

RAT has advantages over VAT in terms of short-term outcomes such as shorter duration of drainage, less total drainage and a lower rate of conversion. The recurrence rate was comparable between the 2 techniques. Therefore, RAT could be considered as an alternative treatment for diseases of the thymus.

Depression as a predictor of postoperative delirium after cardiac surgery: a systematic review and meta-analysis

OBJECTIVES

Depression is common in patients with cardiac disease. The importance of preoperative depression for development of postoperative delirium (POD) following cardiac surgery is not well known. The aim is to provide a summary estimate of depression as a predictor of POD following cardiac surgery.

METHODS

Systematic search of MEDLINE, EMBASE, Cochrane Library, Web of Science Core Collection and Psycinfo (Ovid) was performed from inception to October 2019, including cohort studies reporting odds ratios (ORs) and 95% confidence intervals (CIs) for POD following cardiac surgery in patients with preoperative depression compared to patients without depression. ORs and 95% CIs for POD were calculated using random-effects meta-analyses. Subgroup and sensitivity analyses were performed.

RESULTS

Seven studies were included with a combined study population of 2066 patients. The pooled prevalence of POD in the combined study population was 26% and preoperative depression was present in ∼9% of the total study population. All studies showed a positive association between preoperative depression and POD; and in 5 studies, the association was statistically significant. Patients with depression had a pooled OR of 2.31 (95% CI 1.37-3.90) for POD.

CONCLUSIONS

This systematic review and meta-analysis confirm the findings that the previous association between preoperative depression and increased risk for developing POD reported for other patient groups is found also in cardiac surgery. Depression screening prior to cardiac surgery may be effective in identifying patients at higher risk for POD.

Evolving Concepts in Chronic Obstructive Pulmonary Disease Blood-Based Biomarkers

In recent years, there has been a great deal of interest in the identification and validation of blood-based biomarkers for clinical use in chronic obstructive pulmonary disease (COPD). We now have panels of blood biomarkers that potentially hold great promise as they show statistically significant associations with COPD, but biomarkers for the diagnosis of COPD remain elusive. In fact, they are yet to demonstrate sufficient accuracy to be accepted in clinical use, and many are not specific to COPD but more related to inflammation (e.g. interleukin-6) or associated with other chronic diseases such as diabetes (e.g. soluble receptor for advanced glycation endproducts [sRAGE]). Although no single blood-based biomarker has demonstrated clinical utility for either the diagnosis or progression of COPD, it has been suggested that combinations of individual markers may provide important diagnostic or prognostic information; however, the interpretation of COPD biomarker results still requires thought and many questions remain unanswered.

Comparative efficacy and safety of antithrombotic therapy for transcatheter aortic valve replacement: a systematic review and network meta-analysis

OBJECTIVES

We sought to determine the optimal antithrombotic therapy after transcatheter aortic valve replacement.

METHODS

Related scientific databases were searched until December 2018. We conducted a pairwise and a network meta-analysis within a frequentist framework, measuring 30-day bleeding, stroke and all-cause mortality. The surface under the cumulative ranking (SUCRA) curve was estimated to rank the therapies. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was performed. The protocol was registered with PROSPERO (CRD42018111163).

RESULTS

Eight studies comprising 2173 patients were analysed. The risk of 30-day bleeding was higher for dual antiplatelet therapy (DAPT) than single antiplatelet therapy (SAPT) [odds ratio (OR) 1.90 (1.10-3.28); P = 0.02], whereas there was no difference in the risk of 30-day stroke [OR 1.27 (0.38-4.20); P = 0.69] and mortality [OR 1.46 (0.67-3.22); P = 0.34] between DAPT and SAPT. In the network meta-analysis, DAPT + oral anticoagulant (OAC) increased the risk of 30-day bleeding compared with SAPT [OR 6.21 (1.74-22.17); P = 0.005], DAPT [OR 3.27 (1.04-10.32); P = 0.043], SAPT + OAC [OR 4.87 (2.51-9.45); P < 0.001] and OAC [OR 14.4 (1.3-154.7); P = 0.028]. Additionally, patients receiving DAPT + OAC had the highest risks for 30-day bleeding (SUCRA 1.0%). OAC seemed to be superior to SAPT and DAPT in terms of 30-day bleeding (SUCRA OAC: 86.3%, SAPT: 72.3%, DAPT: 32.3%) and stroke (SUCRA 54.2%, 47.4%, 40.5%), but not mortality (SUCRA 69.6%, 74.1%, 43.4%).

CONCLUSIONS

There is a trend towards less bleeding with the application of SAPT, but no mortality benefit with the application of DAPT is shown. The comparison of SAPT, DAPT and OAC shows that OAC may improve the balance between stroke and bleeding, which can reduce the risk of mortality. In addition, the application of DAPT + OAC was ranked the worst amongst all treatment modalities and should be avoided due to an increased risk of bleeding.

CLINICAL TRIAL REGISTRATION NUMBER

PROSPERO (International Prospective Register of Systematic Reviews, CRD42018111163).