Evaluating the Risk of Bias of a Study

The impact of bias of underlying literature in guidelines on its recommendations: assessment of the German fluoride guideline

PURPOSE

The significance of the underlying literature in clinical guidelines can be weakened by the risk of bias, which could negatively affect the recommendations. Especially in controversial matters, such as fluoride use for caries prevention in children, biased results may be not reliable and lead to incorrect conclusions. This study was performed to detect bias in underlying literature of the German guideline for caries prevention using fluoride in children, where no consensus was reached between paediatricians and paediatric dentists.

METHODS

Three tools used for risk of bias assessments of different study designs were RoB 2 for RCTs, ROBINS-I for non-randomized studies, and ROBIS for systematic reviews. For each study cited in the guideline two independent risk of bias assessments were performed. Disagreements were resolved by consensus.

RESULTS

Out of 58 papers, 48.3% (n = 28) showed high risk of bias, with the majority in sections regarding fluoride tablets, fluoridated toothpaste, and paediatricians' recommendations. 9 out of 20 recommendations and statements were based on studies with high risk of bias, all of which were in these three controversial sections. 13 out of 29 RCTs showed high risk of bias (44.8%), as all 13 non-randomized trials did, while only 2 of 16 (12.5%) systematic reviews had high risk of bias.

CONCLUSION

Considering risk of bias of cited studies in clinical guidelines may result in substantial changes in its recommendations and aid in reaching consensus. Efforts should be made to assess risk of bias of underlying literature in future clinical guidelines.

Clinical Effectiveness of Artificial Disc Replacement in Comparison With Anterior Cervical Discectomy and Fusion in the Patients With Cervical Myelopathy: Systematic Review and Meta-analysis

OBJECTIVE

Cervical myelopathy (CM) describes the compressive cervical spinal cord state, often accompanied by serious clinical condition, by herniated disc or hypertrophied spurs or ligament. Anterior cervical discectomy and fusion (ACDF) has been frequently employed as conventional surgical solution for this CM despite its inherent biomechanical handicap. Alternatively, an artificial disc replacement (ADR) preserves cervical motion while still decompressing the spinal canal and neural foramen. This analysis elaborated to clarify the potential benefits of ADR application to CM over ACDF from the conglomerated results of the past references.

METHODS

A literature search was performed using MEDLINE, Embase, Cochrane review, and KMbase databases from the studies published until March 2023. Six studies (3 randomized controlled study [RCTs] and 3 non-RCTs) were included in a qualitative and quantitative synthesis. Data were extracted and analyzed using a random effects model to obtain effect size and its statistical significance. Quality assessment and evidence level were established in accordance with the GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology.

RESULTS

Among 6 studies, 2 studies showed that ADR group achieved significantly better clinical improvement than the ACDF group, while the rest 4 studies revealed no significant difference. A meta-analysis showed better clinical outcomes with or without statistical significance. The level of evidence was low because of inconsistency and imprecision.

CONCLUSION

ADR was superior or at least, not inferior to ACDF in terms of functional recovery. However, its application to the CM patients is merely empowered with weak strength due to low level of evidence.

Comparison of the Effects of Metformin and Thiazolidinediones on Bone Metabolism: A Systematic Review and Meta-Analysis

OBJECTIVES

Studies have shown that people with diabetes have a high risk of osteoporosis and fractures. The effect of diabetic medications on bone disease cannot be ignored. This meta-analysis aimed to compare the effects of two types of glucose-lowering drugs, metformin and thiazolidinediones (TZD), on bone mineral density and bone metabolism in patients with diabetes mellitus.

METHODS

This systematic review and meta-analysis were prospectively registered on PROSPERO, and the registration number is CRD42022320884. Embase, PubMed, and Cochrane Library databases were searched to identify clinical trials comparing the effects of metformin and thiazolidinediones on bone metabolism in patients with diabetes. The literature was screened by inclusion and exclusion criteria. Two assessors independently assessed the quality of the identified studies and extracted relevant data.

RESULTS

Seven studies involving 1656 patients were finally included. Our results showed that the metformin group had a 2.77% (SMD = 2.77, 95%CI [2.11, 3.43]; p < 0.00001) higher bone mineral density (BMD) than the thiazolidinedione group until 52 weeks; however, between 52 and 76 weeks, the metformin group had a 0.83% (SMD = -0.83, 95%CI: [-3.56, -0.45]; p = 0.01) lower BMD. The C-terminal telopeptide of type I collagen (CTX) and procollagen type I N-terminal propeptide (PINP) were decreased by 18.46% (MD = -18.46, 95%CI: [-27.98, -8.94], p = 0.0001) and 9.94% (MD = -9.94, 95%CI: [-16.92, -2.96], p = 0.005) in the metformin group compared with the TZD group.

The therapeutic effect of capsaicin on oropharyngeal dysphagia: A systematic review and meta-analysis

Objectives

Capsaicin is a specific agonist of TRPV1 (multimodal sensory receptor), which improves oropharyngeal dysphagia by increasing sensory input from the oropharynx and hypopharynx and by increasing repetitive stimulation of the cerebral cortex. The aim of this systematic review was to evaluate the therapeutic effect of capsaicin on swallowing disorders in stroke patients and the elderly.

Method

We searched Medline, Embase, PubMed, and Cochrane Library databases. We used the Mesh terms search database to screen all clinical trials that complied with the inclusion criteria. Studies were subjected to literature screening, quality assessment, and data extraction to remove studies that did not meet the inclusion criteria. After literature screening, quality assessment, and data extraction, a systematic review and meta-analysis of the included study were performed.

Results

This systematic review and meta-analysis were prospectively registered on PROSPERO under registration number CRD42022313958. Five high-quality randomized controlled trials were ultimately included. The results of our meta-analysis showed a more significant reduction in swallowing function score change in the capsaicin group compared to the control group [SMD = -1.30, 95% CI: (-2.35, -0.25), P = 0.01] and on the Water swallowing test the improvement was significantly higher in the capsaicin group [RR = 2.46, 95% CI: (1.73, 3.50), P < 0.0001].

Conclusions

Although the results of our meta-analysis showed that capsaicin improved swallowing function, most studies had an unclear bias and included few studies. More studies are needed to support this in the future.

Systematic review registration

www.crd.york.ac.uk/prospero/display_record.php?RecordID=304061, identifier: 304061.

Neoadjuvant immunotherapy for resectable esophageal cancer: A protocol of meta-analysis

BACKGROUND

Esophageal cancer is a highly malignant cancer with a very poor prognosis. For resectable esophageal cancer, neoadjuvant treatment could improve the prognosis of esophageal cancer. However, current clinical neoadjuvant treatment options for esophageal cancer are still limited. The application of immunotherapy is a potentially beneficial new neoadjuvant treatment option for esophageal cancer. The objective of this meta-analysis is to evaluate the efficacy and safety of immunotherapy for the neoadjuvant treatment of esophageal cancer.

METHODS

We will search Wanfang Database, SinoMed, China National Knowledge Infrastructure, Embase, Web of Science, Pubmed, and Cochrane Library for relevant articles published before July, 2021. We will also search the unpublished clinical trials of neoadjuvant immunotherapy in esophageal cancer in preprint website (such as bioRXiv and medRxiv) up to July, 2021. We will perform a meta-analysis to evaluate the efficacy and safety of neoadjuvant immunotherapy for resectable esophageal cancer. Randomized controlled trials (RCTs) will be included in this study. The risk of bias will be evaluated for each included study using the Cochrane Handbook for Systematic Reviews of Interventions. We will use RevMan 5.3 software for statistical analysis of the data.

RESULTS

The results of this study will provide evidence of immunotherapy using as neoadjuvant treatment for esophageal cancer. This meta-analysis will be submitted to a peer-reviewed journal seeking for publication.

CONCLUSION

The results of this study will provide a reliable basis for clinicians and patients to formulate the best pre-surgical treatment plan for resectable esophageal cancer.

SYSTEMATIC REVIEW REGISTRATION

INPLASY202120026.

Anlotinib-containing regimen for advanced small-cell lung cancer: A protocol of meta-analysis

Background

Small cell lung cancer (SCLC) is a highly malignant lung cancer with a very poor prognosis. Clinical treatment options for SCLC are still limited, especially for patients who have failed first or second line therapy. Anlotinib is a potentially beneficial new treatment option for SCLC. The aim of this meta-analysis is to evaluate the efficacy and safety of anlotinib-containing regimen for the treatment of SCLC.

Methods

We will search SinoMed, Wanfang Database, China National Knowledge Infrastructure, Embase, Cochrane Library, and PubMed for relevant articles that may meet the criteria published before March 31, 2021. We will perform a meta-analysis to evaluate the efficacy and safety of anlotinib-containing regimen for the treatment of SCLC. Clinical randomized controlled trials comparing anlotinib-containing regimens with other treatment regimens for advanced SCLC will be included in this study. The risk of bias will be evaluated for each included study using the Cochrane Handbook for Systematic Reviews of Interventions. We will use RevMan 5.3 software for statistical analysis of the data.

Results

The results of this study will provide evidence of anlotinib-containing regimens for advanced SCLC, and provide clinicians and patients with another convenient and effective treatment regimen for SCLC. This meta-analysis will be submitted to a peer-reviewed journal for publication.

Conclusion

This meta-analysis will provide clinical evidence of anlotinib-containing regimens for advanced SCLC, which may or may not be found for anlotinib use.

Systematic review registration

INPLASY202110034.

Anlotinib for refractory advanced non-small-cell lung cancer: A systematic review and meta-analysis

Objective

To assess the efficacy and toxicity of anlotinib for the treatment of refractory advanced non-small-cell lung cancer (NSCLC).

Methods

We systematically searched databases for randomized controlled trials on anlotinib treatment for patients with advanced NSCLC published until November 6, 2020. Articles were assessed and data were extracted independently by two investigators. Further, we analyzed hazard ratios (HRs) for progression-free and overall survival (PFS and OS, respectively). In addition, we analyzed risk ratio (RR) for overall response and disease control rates (ORR and DCR, respectively) and the odds ratio (OR) for the main adverse events (AEs) using RevMan 5.3 software.

Results

This analysis included 594 patients from three clinical studies. The pooled HRs for PFS and OS were 0.27 (95% confidence interval (CI): 0.22–0.33, P < 0.001) and 0.68 (95% CI: 0.56–0.83, P < 0.001), respectively, indicating that anlotinib administration significantly improved PFS and OS in patients with advanced NSCLC. The pooled RRs for ORR and DCR were 11.62 (95% CI: 2.75–49.14, P < 0.001) and 2.30 (95% CI: 1.91–2.77, P < 0.001), respectively, indicating that anlotinib administration in patients with advanced NSCLC improved ORR and DCR. The pooled OR for AEs of grade 3 or higher was 2.94 (95% CI: 1.99–4.35, P < 0.001), indicating that AEs of grade 3 or higher were more prevalent in the anlotinib group than in the placebo group.

Conclusion

Anlotinib, an effective choice of third- or later line therapy for patients with refractory advanced NSCLC, provides clinical benefits in terms of PFS, OS, ORR, and DCR. AEs associated with anlotinib were tolerable.

Use of Sham Interventions in Randomized Controlled Trials in Neurosurgery

BACKGROUND

 The use of sham interventions in randomized controlled trials (RCTs) is essential to minimize bias. However, their use in surgical RCTs is rare and subject to ethical concerns. To date, no studies have looked at the use of sham interventions in RCTs in neurosurgery.

METHODS

 This study evaluated the frequency, type, and indication of sham interventions in RCTs in neurosurgery. RCTs using sham interventions were also characterized in terms of design and risk of bias.

RESULTS

 From a total of 1,102 identified RCTs in neurosurgery, 82 (7.4%) used sham interventions. The most common indication for the RCT was the treatment of pain (67.1%), followed by the treatment of movement disorders and other clinical problems (18.3%) and brain injuries (12.2%). The most used sham interventions were saline injections into spinal structures (31.7%) and peripheral nerves (10.9%), followed by sham interventions in cranial surgery (26.8%), and spine surgery (15.8%). Insertion of probes or catheters for a sham lesions was performed in 14.6%.In terms of methodology, most RCTs using sham interventions were double blinded (76.5%), 9.9% were single blinded, and 13.6% did not report the type of blinding.

CONCLUSION

 Sham-controlled RCTs in neurosurgery are feasible. Most aim to minimize bias and to evaluate the efficacy of pain management methods, especially in spinal disorders. The greatest proportion of sham-controlled RCTs involves different types of substance administration routes, with sham surgery the less commonly performed.

Salivary biomarkers for diagnosis of systemic diseases and malignant tumors. A systematic review

Background

Saliva evaluation could be a possible alternative to blood and/or tissue analyses, for researching specific molecules associated to the presence of systemic diseases and malignancies. The present systematic review has been designed in order to answer to the question “are there significant associations between specific salivary biomarkers and diagnosis of systemic diseases or malignancies?”.

Material and Methods

The Preferred Reporting Item for Systematic Reviews and Meta-analysis (PRISMA) statement was used to guide the review. The combinations of “saliva” and “systemic diseases” or “diagnosis” or “biomarkers” or “cancers” or “carcinoma” or “tumors”, were used to search Medline, Scopus and Web of Science databases. Endpoint of research has been set at May 2019. Studies were classified into 3 groups according to the type of disease investigated for diagnosis: 1) malignant tumors; 2) neurologic diseases and 3) inflammatory/metabolic/cardiovascular diseases. Assessment of quality has been assigned according to a series of questions proposed by the National Institute of Health. Level of evidence was assessed using the categories proposed in the Oxford Center for Evidence-Based medicine (CEMB) levels for diagnosis (2011).

Results

Seventy-nine studies met the inclusion and exclusion criteria. Fifty-one (64%) investigated malignant tumors, 14 (17.5%) neurologic and 14 (18.5%) inflammatory/cardiovascular/metabolic diseases. Among studies investigating malignant tumors, 12 (23.5%) were scored as “good” and 11 of these reported statistically significant associations between salivary molecules and pathology. Two and 5 studies were found to have a good quality, among those evaluating the association between salivary biomarkers and neurologic and inflammatory/metabolic/cardiovascular diseases, respectively.

Conclusions

The present systematic review confirms the existence of some “good” quality evidence to support the role of peculiar salivary biomarkers for diagnosis of systemic diseases (e.g. lung cancer and EGFR).

Key words:Salivary diagnostics, biomarkers, systemic diseases, malignant tumors, early diagnosis.

Do in vitro solubility studies on endodontic sealers demonstrate a high level of evidence? A systematic review

OBJECTIVE

To systematically review the quality of evidence of available in vitro solubility studies on endodontic sealers according to prespecified evidence criteria.

MATERIAL AND METHODS

This systematic review was based on the PRISMA guidelines and the AMSTAR measurement tool. A systematic duplicate search of the literature on endodontic sealer solubility studies was conducted in PubMed and Embase databases (until 18 October 2017). Mapping terms to subject headings and free text terms were used and combined with hand searching before exclusion of duplicates. Studies specifically dealing with endodontic sealer solubility were selected. The evidence level was graded (low, medium or high) independently by two investigators following systematic data extraction in pilot forms, which was based on prespecified evidence criteria and the modified CONSORT checklist for in vitro studies on dental materials.

RESULTS

The search retrieved 1053 articles, from which 88 were assessed in full. From the 63 articles retained in the final analysis, 11 were classified as having moderate and 52 as low quality of evidence (0 high). The studies graded as low had low sample size (n < 10) and/or insufficient details to allow replicability. Most of the studies did not conform to the modified CONSORT checklist and did not include parameters considered relevant in the prespecified criteria.

CONCLUSIONS

Existing in vitro studies on the solubility of endodontic sealers do not demonstrate a high quality of evidence. Most of these studies do not present systematic reporting nor employ relevant parameters prespecified in our evidence criteria.

Increasing Nonsteroidal Anti-inflammatory Drugs and Reducing Opioids or Paracetamol in the Management of Acute Renal Colic: Based on Three-Stage Study Design of Network Meta-Analysis of Randomized Controlled Trials

Background: Currently, although non-steroidal anti-inflammatory drugs (NSAIDs) were recommended for acute renal colic in the 2018 European Association of Urology guidelines, there are no specific NSAIDs and no specific routes of administration in this guideline. The clinical practice of advocating intravenous opioids as the initial analgesia is still common out of the fear of adverse events from NSAIDs.

Objectives: To comprehensively assess the efficacy and safety of NSAIDs, opioids, paracetamol, and combination therapy for acute renal colic.

Methods: Ovid MEDLINE, Ovid EMbase, the Cochrane Library, Clinical Trials Registry Platform for Clinicaltrials.gov, and WHO International Clinical Trials Registry Platform were searched through February 2, 2018. Two reviewers selected all randomized controlled trails (RCTs) regarding NSAIDs, opioids, paracetamol, combination therapy, and placebo were identified for analysis. We designed a three-stage strategy based on classification and pharmacological mechanisms in the first stage, routes of administration in the second stage, and specific drug branches with different routes in the third stage using network meta-analysis. The pain variance at 30 min was seen as the primary outcome.

Results: 65 RCTs with 8633 participants were involved. Comparing different classification and pharmacological mechanisms, combination therapy with more adverse events was more efficient than NSAIDs for the primary outcomes. Opioids gave rise to more nonspecific adverse events and vomiting events. NSAIDs were superior to opioids, paracetamol, and combination therapy after a full consideration of all outcomes. Comparing different routes of administration, NSAIDs with IV or IM route ranked first from efficacy and safety perspective. Comparing different specific drug branches with different routes, ibuprofen via IV route, ketorolac via IV route and diclofenac via IM route were superior for the management of acute renal colic. The results from diclofenac using IM route were more than those from ibuprofen used with IV route and ketorolac with IV route.

Conclusions: In patients with adequate renal function, diclofenac via the IM route is recommended for patients without risks of cardiovascular events. Ibuprofen and ketorolac with IV route potentially superior to diclofenac via IM route remain to be investigated. Combination therapy is an alternative choice for uncontrolled pain after the use of NSAIDs.