Effect of Risk of Bias on the Effect Size of Meta-Analytic Estimates in Randomized Controlled Trials in Periodontology and Implant Dentistry

Education and learning: potential methodological and ethical issues in systematic reviews containing a meta-analysis: some critical reading suggestions for junior doctors

Junior doctors make clinical decisions regularly; therefore, they need to adequately interpret the evidence supporting these decisions. Patients can be harmed if clinical treatments are supported by biased or unreliable evidence. Systematic reviews that contain meta-analyses of randomized controlled trials are a relatively low-biased type of evidence to support clinical interventions. Therefore, it is reasonable to think that doctors will likely select this type of study to answer clinical questions. In this article, doctors are informed about potential methodological and ethical issues in systematic reviews that contain a meta-analysis that are sometimes not easily identified or even overlooked by the current tools developed to assess their methodological quality or risk of bias. The article presents a discussion of topics related to data extraction, accuracy in reporting, reproducibility, heterogeneity, quality assessment of primary studies included in the systematic review, sponsorship, and conflict of interest. It is expected that the information reported will be useful for junior doctors when they are reading and interpreting evidence from systematic reviews containing meta-analyses of therapeutic interventions, mainly those doctors unfamiliar with methodological principles.

Frequency of Neurologic Manifestations in COVID-19: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

One year after the onset of the coronavirus disease 2019 (COVID-19) pandemic, we aimed to summarize the frequency of neurologic manifestations reported in patients with COVID-19 and to investigate the association of these manifestations with disease severity and mortality.

METHODS

We searched PubMed, Medline, Cochrane library, ClinicalTrials.gov, and EMBASE for studies from December 31, 2019, to December 15, 2020, enrolling consecutive patients with COVID-19 presenting with neurologic manifestations. Risk of bias was examined with the Joanna Briggs Institute scale. A random-effects meta-analysis was performed, and pooled prevalence and 95% confidence intervals (CIs) were calculated for neurologic manifestations. Odds ratio (ORs) and 95% CIs were calculated to determine the association of neurologic manifestations with disease severity and mortality. Presence of heterogeneity was assessed with I 2, meta-regression, and subgroup analyses. Statistical analyses were conducted in R version 3.6.2.

RESULTS

Of 2,455 citations, 350 studies were included in this review, providing data on 145,721 patients with COVID-19, 89% of whom were hospitalized. Forty-one neurologic manifestations (24 symptoms and 17 diagnoses) were identified. Pooled prevalence of the most common neurologic symptoms included fatigue (32%), myalgia (20%), taste impairment (21%), smell impairment (19%), and headache (13%). A low risk of bias was observed in 85% of studies; studies with higher risk of bias yielded higher prevalence estimates. Stroke was the most common neurologic diagnosis (pooled prevalence 2%). In patients with COVID-19 ≥60 years of age, the pooled prevalence of acute confusion/delirium was 34%, and the presence of any neurologic manifestations in this age group was associated with mortality (OR 1.80, 95% CI 1.11-2.91).

DISCUSSION

Up to one-third of patients with COVID-19 analyzed in this review experienced at least 1 neurologic manifestation. One in 50 patients experienced stroke. In those >60 years of age, more than one-third had acute confusion/delirium; the presence of neurologic manifestations in this group was associated with nearly a doubling of mortality. Results must be interpreted with the limitations of observational studies and associated bias in mind.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020181867.

The adjunctive use of host modulators in non-surgical periodontal therapy. A systematic review of randomized, placebo-controlled clinical studies

BACKGROUND

Considering the role of the inflammatory host response in the pathogenesis of periodontitis, different host modulators have been proposed to enhance the outcomes of non-surgical periodontal therapy (NSPT), but their efficacy has not been fully clarified.

OBJECTIVES

This systematic review investigated the efficacy of host modulators combined with NSPT in reducing probing pocket depth (PPD) in periodontitis patients.

MATERIALS AND METHODS

Placebo-controlled RCTs with ≥6 months follow-up were searched. Meta-analysis was conducted when ≥5 studies using the same host modulator were identified.

RESULTS

Fifty eight studies met the inclusion criteria. After 6 months, local administration of 1.2% statin gels as adjuncts to NSPT significantly improved PPD reduction (1.83 mm) in infrabony defects and systemic administration of sub-antimicrobial dose doxycycline (SDD) in addition to NSPT improved PPD reduction of deep pockets. Administration of probiotics conferred limited clinical benefits. Local bisphosphonate and metformin gels showed potential for clinical use in infrabony defects, which needs to be confirmed.

CONCLUSIONS

Local delivery of statins in infrabony defects and systemic SDD for deep pockets may confer additional clinical benefits to NSPT. Their long-term effectiveness and safety need to be confirmed in independent multi-centred studies. Further studies are needed to confirm the benefit of other host modulators.

Degree of Risk of Bias in Randomized Controlled Trials: Does It Have an Impact on Root Coverage Outcomes?

OBJECTIVE

Improvement over time in mean (MRC) and complete root coverage (CRC) reported in randomized controlled trials (RCTs) has been documented. Our objective was to assess the effect that the ROB has on relevant outcomes reported in RCTs evaluating the efficacy of a commonly performed root coverage procedure.

METHODS

RCTs that involved the use of a bilaminar technique of coronally advanced flap with connective tissue graft were selected. The following data were extracted: MRC, CRC, whether conflict of interest was addressed (yes/no), adequacy of random sequence generation, allocation concealment, and blinding of outcome assessment. Trials were categorized into four groups as per different time periods: before Consolidated Standards of Reporting Trials (CONSORT) (before 1996), CONSORT (1997 to 2001), CONSORT 2001 (2002 to 2010), and CONSORT 2010 (2011 to 2019). Differences between group means were assessed using statistical analyses.

RESULTS

The search yielded a total of 47 RCTs published between 1993 and 2019 that met the inclusion criteria. A trend toward lower ROB over time in the selected RCTs was observed. However, differences in MRC and CRC with respect to the degree ROB of included trials were not significant.

CONCLUSIONS

Degree of ROB did not influence MRC and CRC reported in the RCTs included in this investigation. This finding suggests that the observed improvement of clinical outcomes over time should be attributed to other factors, such as refinement of surgical techniques.

Dose-response-relationship of stabilisation exercises in patients with chronic non-specific low back pain: a systematic review with meta-regression

Stabilization exercise (SE) is evident for the management of chronic non-specific low back pain (LBP). The optimal dose-response-relationship for the utmost treatment success is, thus, still unknown. The purpose is to systematically review the dose-response-relationship of stabilisation exercises on pain and disability in patients with chronic non-specific LBP. A systematic review with meta-regression was conducted (Pubmed, Web of Knowledge, Cochrane). Eligibility criteria were RCTs on patients with chronic non-specific LBP, written in English/German and adopting a longitudinal core-specific/stabilising/motor control exercise intervention with at least one outcome for pain intensity and/or disability. Meta-regressions (dependent variable = effect sizes (Cohens d) of the interventions (for pain and for disability), independent variable = training characteristics (duration, frequency, time per session)), and controlled for (low) study quality (PEDro) and (low) sample sizes (n) were conducted to reveal the optimal dose required for therapy success. From the 3,415 studies initially selected, 50 studies (n = 2,786 LBP patients) were included. N = 1,239 patients received SE. Training duration was 7.0 ± 3.3 weeks, training frequency was 3.1 ± 1.8 sessions per week with a mean training time of 44.6 ± 18.0 min per session. The meta-regressions' mean effect size was d = 1.80 (pain) and d = 1.70 (disability). Total R² was 0.445 and 0.17. Moderate quality evidence (R² = 0.231) revealed that a training duration of 20 to 30 min elicited the largest effect (both in pain and disability, logarithmic association). Low quality evidence (R² = 0.125) revealed that training 3 to 5 times per week led to the largest effect of SE in patients with chronic non-specific LBP (inverted U-shaped association). In patients with non-specific chronic LBP, stabilization exercise with a training frequency of 3 to 5 times per week (Grade C) and a training time of 20 to 30 min per session (Grade A) elicited the largest effect on pain and disability.

Psychological interventions in reducing stress, depression and anxiety among parents of children and adolescents with developmental disabilities: A systematic review and meta-analysis

AIMS

To evaluate the effectiveness of psychological interventions in reducing stress, depression and anxiety among parents of children and adolescents with developmental disabilities.

DESIGN

A systematic review and a meta-analysis.

DATA SOURCES

Seven electronic databases (CINAHL, CENTRAL, EMBASE, ProQuest Dissertation and Theses, PsycINFO, PubMed and Scopus) were searched from each database's point of inception to December 2018.

REVIEW METHODS

Quality appraisal was conducted using the Cochrane Risk of Bias Tool. Data were analysed using Review Manager 5.3. The overall quality of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation system.

RESULTS

A total of 18 studies were included in this review. Eleven studies were involved in a meta-analysis and the remaining seven studies were summarized narratively. The meta-analysis found that psychological interventions significantly reduced parental stress at postintervention but not at 3-6 months' postintervention. Inconclusive evidence was found for the effectiveness of psychological interventions in reducing parental depression and anxiety.

CONCLUSION

Psychological interventions appeared to reduce parental stress temporarily. Healthcare professionals can offer varied psychological interventions for parents to choose from. Policymakers can ease accessibility and affordability for parents to attend interventions.

IMPACT

Psychological interventions were found to have short-term effects in reducing parental stress. Inconclusive evidence was found for the effectiveness of psychological interventions in reducing parental depression and anxiety. Healthcare professionals should ensure that knowledge is transmitted to parents when delivering their interventions. Policymakers worldwide should ensure that parents of children and adolescents with developmental disabilities can attend interventions by making them accessible and affordable.

The Effect of Sphenopalatine Block on the Postoperative Pain of Endoscopic Sinus Surgery: A Meta-analysis

Objectives

The use of sphenopalatine ganglion block (SPGB) with a local anesthetic to decrease postoperative pain after endoscopic sinus surgery (ESS) is controversial. We investigated the role of a perioperative SPB to minimize postoperative pain related to ESS in patients with chronic sinusitis through a systematic review of the relevant literature.

Data Sources

PubMed, SCOPUS, Google Scholar, Embase, and the Cochrane Register of Controlled Trials.

Review Methods

We screened the relevant literature published before June 2018. Eight articles that compared perioperative SPGB (treatment group) with a placebo or no treatment (control group) were included for this analysis of the outcomes, which included perioperative morbidities in ESS. For quantitative variables, the standardized mean difference was applied to standardize and summate the results of the studies, and the odds ratio was used in outcome of incidence analysis.

Results

Intraoperative bleeding ( P < .0001), postoperative pain ( P = .0001), nausea and vomiting ( P = .0117), and recovery from sedation ( P < .0001) in the treatment group were significantly reduced compared with the control group. No significant adverse effects were reported in the enrolled studies. In subgroup analyses according to the SPGB approach (transoral or transnasal), the transnasal approach showed higher positive effects on intraoperative bleeding and postoperative pain compared to the transoral approach.

Conclusion

In our study, SPGB combined with a local anesthetic for ESS effectively reduced intra-and postoperative morbidities. This procedure showed no significant adverse effects. Given the ease and effectiveness of this procedure, the transnasal approach should be highly recommended as a routine procedure compared to the transoral approach.

Impact of Selection Bias on Treatment Effect Size Estimates in Randomized Trials of Oral Health Interventions: A Meta-epidemiological Study

Emerging evidence suggests that design flaws of randomized controlled trials can result in over- or underestimation of the treatment effect size (ES). The objective of this study was to examine associations between treatment ES estimates and adequacy of sequence generation, allocation concealment, and baseline comparability among a sample of oral health randomized controlled trials. For our analysis, we selected all meta-analyses that included a minimum of 5 oral health randomized controlled trials and used continuous outcomes. We extracted data, in duplicate, related to items of selection bias (sequence generation, allocation concealment, and baseline comparability) in the Cochrane Risk of Bias tool. Using a 2-level meta-meta-analytic approach with a random effects model to allow for intra- and inter-meta-analysis heterogeneity, we quantified the impact of selection bias on the magnitude of ES estimates. We identified 64 meta-analyses, including 540 randomized controlled trials analyzing 137,957 patients. Sequence generation was judged to be adequate (at low risk of bias) in 32% ( n = 173) of trials, and baseline comparability was judged to be adequate in 77.8% of trials. Allocation concealment was unclear in the majority of trials ( n = 458, 84.8%). We identified significantly larger treatment ES estimates in trials that had inadequate/unknown sequence generation (difference in ES = 0.13; 95% CI: 0.01 to 0.25) and inadequate/unknown allocation concealment (difference in ES = 0.15; 95% CI: 0.02 to 0.27). In contrast, baseline imbalance (difference in ES = 0.01, 95% CI: –0.09 to 0.12) was not associated with inflated or underestimated ES. In conclusion, treatment ES estimates were 0.13 and 0.15 larger in trials with inadequate/unknown sequence generation and inadequate/unknown allocation concealment, respectively. Therefore, authors of systematic reviews using oral health randomized controlled trials should perform sensitivity analyses based on the adequacy of sequence generation and allocation concealment.