Comparative safety and effectiveness of cognitive enhancers for Alzheimer's dementia: protocol for a systematic review and individual patient data network meta-analysis

Comparative safety and efficacy of cognitive enhancers for Alzheimer's dementia: a systematic review with individual patient data network meta-analysis

OBJECTIVE

To examine the comparative efficacy and safety of cognitive enhancers by patient characteristics for managing Alzheimer's dementia (AD).

DESIGN

Systematic review and individual patient data (IPD) network meta-analysis (NMA) based on our previously published systematic review and aggregate data NMA.

DATA SOURCES

MEDLINE, Embase, Cochrane Methodology Register, CINAHL, AgeLine and Cochrane Central Register of Controlled Trials up to March 2016.

PARTICIPANTS

80 randomised controlled trials (RCTs) including 21 138 adults with AD, and 12 RCTs with IPD including 6906 patients.

INTERVENTIONS

Cognitive enhancers (donepezil, rivastigmine, galantamine and memantine) alone or in any combination against other cognitive enhancers or placebo.

DATA EXTRACTION AND SYNTHESIS

We requested IPD from authors, sponsors and data sharing platforms. When IPD were not available, we used aggregate data. We appraised study quality with the Cochrane risk-of-bias. We conducted a two-stage random-effects IPD-NMA, and assessed their findings using CINeMA (Confidence in Network Meta-Analysis).

PRIMARY AND SECONDARY OUTCOMES

We included trials assessing cognition with the Mini-Mental State Examination (MMSE), and adverse events.

RESULTS

Our IPD-NMA compared nine treatments (including placebo). Donepezil (mean difference (MD)=1.41, 95% CI: 0.51 to 2.32) and donepezil +memantine (MD=2.57, 95% CI: 0.07 to 5.07) improved MMSE score (56 RCTs, 11 619 participants; CINeMA score: moderate) compared with placebo. According to P-score, oral rivastigmine (OR=1.26, 95% CI: 0.82 to 1.94, P-score=16%) and donepezil (OR=1.08, 95% CI: 0.87 to 1.35, P-score=30%) had the least favourable safety profile, but none of the estimated treatment effects were sufficiently precise when compared with placebo (45 RCTs, 15 649 patients; CINeMA score: moderate to high). For moderate-to-severe impairment, donepezil, memantine and their combination performed best, but for mild-to-moderate impairment donepezil and transdermal rivastigmine ranked best. Adjusting for MMSE baseline differences, oral rivastigmine and galantamine improved MMSE score, whereas when adjusting for comorbidities only oral rivastigmine was effective.

CONCLUSIONS

The choice among the different cognitive enhancers may depend on patient's characteristics. The MDs of all cognitive enhancer regimens except for single-agent oral rivastigmine, galantamine and memantine, against placebo were clinically important for cognition (MD larger than 1.40 MMSE points), but results were quite imprecise. However, two-thirds of the published RCTs were associated with high risk of bias for incomplete outcome data, and IPD were only available for 15% of the included RCTs.

PROSPERO REGISTRATION NUMBER

CRD42015023507.

Comparative effectiveness and safety of antiviral agents for patients with COVID-19: Protocol for a systematic review and individual-patient data network meta-analysis

BACKGROUND

A recent cluster of pneumonia cases in Wuhan, China, has been caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We propose the protocol described below to perform an individual-patient data (IPD) network meta-analysis (NMA) in order to evaluate the efficacies of different antiviral drugs to treat patients with coronavirus disease 2019 (COVID-19).

MATERIALS AND METHODS

We will search the Medline, EMBASE, Cochrane Library, SinoMed, CNKI and VIP databases from their inceptions through July 2020. There will be no restrictions on language, publication year, or publication type. Randomized clinical trials (RCTs) and prospective cohort studies with antiviral treatments for COVID-19 will be considered. Two reviewers will independently select studies and collect data. Risk-of-bias assessments will be completed using the Cochrane risk-of-bias scale. Primary outcome will be the COVID-19 recovery rate. We will combine aggregated data from IPD with the NMA in a single model, compare the effects of different antiviral drugs on patient-relevant efficacy, and rank the results to decide which is the most effective.

TRIAL REGISTRATION

PROSPERO registration number: CRD42020167038.

Statistical analyses and quality of individual participant data network meta-analyses were suboptimal: a cross-sectional study

BACKGROUND

Network meta-analyses using individual participant data (IPD-NMAs) have been increasingly used to compare the effects of multiple interventions. Although there have been many studies on statistical methods for IPD-NMAs, it is unclear whether there are statistical defects in published IPD-NMAs and whether the reporting of statistical analyses has improved. This study aimed to investigate statistical methods used and assess the reporting and methodological quality of IPD-NMAs.

METHODS

We searched four bibliographic databases to identify published IPD-NMAs. The methodological quality was assessed using AMSTAR-2 and reporting quality assessed based on PRISMA-IPD and PRISMA-NMA. We performed stratified analyses and correlation analyses to explore the factors that might affect quality.

RESULTS

We identified 21 IPD-NMAs. Only 23.8% of the included IPD-NMAs reported statistical techniques used for missing participant data, 42.9% assessed the consistency, and none assessed the transitivity. None of the included IPD-NMAs reported sources of funding for trials included, only 9.5% stated pre-registration of protocols, and 28.6% assessed the risk of bias in individual studies. For reporting quality, compliance rates were lower than 50.0% for more than half of the items. Less than 15.0% of the IPD-NMAs reported data integrity, presented the network geometry, or clarified risk of bias across studies. IPD-NMAs with statistical or epidemiological authors often better assessed the inconsistency (P = 0.017). IPD-NMAs with a priori protocol were associated with higher reporting quality in terms of search (P = 0.046), data collection process (P = 0.031), and syntheses of results (P = 0.006).

CONCLUSIONS

The reporting of statistical methods and compliance rates of methodological and reporting items of IPD-NMAs were suboptimal. Authors of future IPD-NMAs should address the identified flaws and strictly adhere to methodological and reporting guidelines.

Comparative Efficacy of Interventions for Aggressive and Agitated Behaviors in Dementia: A Systematic Review and Network Meta-analysis

BACKGROUND

Both pharmacologic and nonpharmacologic interventions are used to treat neuropsychiatric symptoms in persons with dementia.

PURPOSE

To summarize the comparative efficacy of pharmacologic and nonpharmacologic interventions for treating aggression and agitation in adults with dementia.

DATA SOURCES

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, CINAHL, and PsycINFO between inception and 28 May 2019 without language restrictions; gray literature; and reference lists scanned from selected studies and systematic reviews.

STUDY SELECTION

Randomized controlled trials comparing interventions for treating aggression and agitation in adults with dementia.

DATA EXTRACTION

Pairs of reviewers independently screened studies, abstracted data, and appraised risk of bias.

DATA SYNTHESIS

After screening of 19 684 citations, 163 studies (23 143 patients) were included in network meta-analyses. Analysis of interventions targeting aggression and agitation (148 studies [21 686 patients]) showed that multidisciplinary care (standardized mean difference [SMD], -0.5 [95% credible interval {CrI}, -0.99 to -0.01]), massage and touch therapy (SMD, -0.75 [CrI, -1.12 to -0.38]), and music combined with massage and touch therapy (SMD, -0.91 [CrI, -1.75 to -0.07]) were clinically more efficacious than usual care. Recreation therapy (SMD, -0.29 [CrI, -0.57 to -0.01]) was statistically but not clinically more efficacious than usual care.

LIMITATIONS

Forty-six percent of studies were at high risk of bias because of missing outcome data. Harms and costs of therapies were not evaluated.

CONCLUSION

Nonpharmacologic interventions seemed to be more efficacious than pharmacologic interventions for reducing aggression and agitation in adults with dementia.

PRIMARY FUNDING SOURCE

Alberta Health Services Critical Care Strategic Clinical Network. (PROSPERO: CRD42017050130).

Selective reporting bias in randomised controlled trials from two network meta-analyses: comparison of clinical trial registrations and their respective publications

OBJECTIVE

To determine (i) the difference in the frequency of serious adverse events (SAEs) reported in trial registrations and their respective primary publications and (ii) the effect of adding SAE data from registries to a network meta-analysis (NMA) in changing the surface under the cumulative ranking (SUCRA) curve values of interventions.

DESIGN

Secondary analysis of primary publications from two NMAs.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

We included randomised trials published in English after 2005 that were included in two NMAs of pharmacological interventions for Alzheimer's disease and chronic obstructive pulmonary disease.

DATA EXTRACTION

Two reviewers independently searched multiple international trial registries for registration status and abstracted data from the included study publications and ClinicalTrials.gov.

RESULTS

Of the 203 randomised trials included, 140 (69.0%) were registered with a trial registry and 72 (35.5%) posted results in the registry. The proportion of registered trials increased over time (38.5% in 2005 vs 78.6% in 2014). Of the publications with results posted in a trial registry, 14 (19.4%) had inconsistent reporting of overall SAEs; 7 (10.4%) studies did not report SAEs in the publication but did in the registry. In the 134 randomised trials with a prespecified primary outcome in the registry, 19 studies (9.4%) had a change in the primary outcome in the publication. Adding SAEs reported in registries to the NMAs did not affect the ranking of interventions.

CONCLUSION

We identified inconsistent reporting of SAEs in randomised trials that were included in two NMAs. Findings highlight the importance of including trial registries in the grey literature search and verifying safety data before incorporating it into NMAs.

STUDY REGISTRATION

osf.io/mk6dr.

Participants' outcomes gone missing within a network of interventions: Bayesian modeling strategies

Objectives: To investigate the implications of addressing informative missing binary outcome data (MOD) on network meta‐analysis (NMA) estimates while applying the missing at random (MAR) assumption under different prior structures of the missingness parameter.

Methods: In three motivating examples, we compared six different prior structures of the informative missingness odds ratio (IMOR) parameter in logarithmic scale under pattern‐mixture and selection models. Then, we simulated 1000 triangle networks of two‐arm trials assuming informative MOD related to interventions. We extended the Bayesian random‐effects NMA model for binary outcomes and node‐splitting approach to incorporate these 12 models in total. With interval plots, we illustrated the posterior distribution of log OR, common between‐trial variance (τ²), inconsistency factor and probability of being best per intervention under each model.

Results: All models gave similar point estimates for all NMA estimates regardless of simulation scenario. For moderate and large MOD, intervention‐specific prior structure of log IMOR led to larger posterior standard deviation of log ORs compared to trial‐specific and common‐within‐network prior structures. Hierarchical prior structure led to slightly more precise τ² compared to identical prior structure, particularly for moderate inconsistency and large MOD. Pattern‐mixture and selection models agreed for all NMA estimates.

Conclusions: Analyzing informative MOD assuming MAR with different prior structures of log IMOR affected mainly the precision of NMA estimates. Reviewers should decide in advance on the prior structure of log IMOR that best aligns with the condition and interventions investigated.

Comparison of multiple interventions for older adults with Alzheimer disease or mild cognitive impairment: A PRISMA-compliant network meta-analysis

BACKGROUND

The increasing prevalence of Alzheimer disease (AD) emphasizes the need for effective treatments. Both pharmacological therapies such as nutrition therapy (NT) and nonpharmacologic therapies including traditional treatment or personalized treatment (e.g., physical exercise, music therapy, computerized cognitive training) have been approved for the treatment of AD or mild cognitive impairment (MCI) in numerous areas.

METHODS

The aim of this study was to compare 4 types of interventions, physical exercise (PE), music therapy (MT), computerized cognitive training (CCT), and NT, in older adults with mild to moderate AD or MCI and identify the most effective intervention for their cognitive function. We used a system of search strategies to identify relevant studies and include randomized controlled trials (RCTs), placebo-controlled trials evaluating the efficacy and safety of 4 interventions in patients with AD or MCI. We updated the relevant studies which were published before March 2017 as a full-text article. Using Bayesian network meta-analysis (NMA), we ranked cognitive ability based objectively on Mini-Mental State Examination (MMSE), and assessed neuropsychiatric symptoms based on Neuropsychiatric Inventory (NPI). Pairwise and network meta-analyses were sequentially performed for efficacy and safety of intervention compared to control group through RCTs included.

RESULTS

We included 17 RCTs. Fifteen trials (n = 1747) were pooled for cognition and no obvious heterogeneity was found (I = 21.7%, P = .212) in NMA, the mean difference (MD) of PE (MD = 2.1, confidence interval [CI]: 0.44-3.8) revealed that PE was significantly efficacious in the treatment group in terms of MMSE. Five trials (n = 660) assessed neuropsychiatric symptoms with an obvious heterogeneity (I = 61.6%, P = .034), the MD of CCT (MD = -7.7, CI: -14 to -2.4), revealing that CCT was significantly efficacious in NPI.

CONCLUSIONS

As the first NMA comparing different interventions for AD and MCI, our study suggests that PE and CCT might have a significant improvement in cognition and neuropsychiatric symptoms respectively. Moreover, nonpharmacological therapies might be better than pharmacological therapies.

Summarising the Evidence for Drug Safety: A Methodological Discussion of Different Meta-Analysis Approaches

Evidence on drug safety obtained from randomised clinical trials is very limited due to, among other reasons, their relatively small sample size. Hence, combining the results of available studies can prove particularly useful. This paper reviews the different data sources for summarising drug safety outcomes, according to study design, publication of data, and origin of the information. It then discusses the various types of overviews that can be used in the study of treatment harms, focusing on meta-analyses of aggregate data and meta-analyses of individual patient data, with their advantages and drawbacks, such as publication bias and heterogeneity. Although the different approaches available for combining the results are of great utility in assessing treatment harms, none of them is free from limitations. Therefore, it might be appropriate to perform an analysis of sensitivity to assess whether the results are sensitive to the technique that has been used.

The Memory-Enhancing Effects of Liquiritigenin by Activation of NMDA Receptors and the CREB Signaling Pathway in Mice

Liquiritigenin (LQ) is a flavonoid that can be isolated from Glycyrrhiza radix. It is frequently used as a tranditional oriental medicine herbal treatment for swelling and injury and for detoxification. However, the effects of LQ on cognitive function have not been fully explored. In this study, we evaluated the memory-enhancing effects of LQ and the underlying mechanisms with a focus on the N-methyl-D-aspartic acid receptor (NMDAR) in mice. Learning and memory ability were evaluated with the Y-maze and passive avoidance tests following administration of LQ. In addition, the expression of NMDAR subunits 1, 2A, and 2B; postsynaptic density-95 (PSD-95); phosphorylation of Ca²⁺/calmodulin-dependent protein kinase II (CaMKII); phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2); and phosphorylation of cAMP response element binding (CREB) proteins were examined by Western blot. In vivo, we found that treatment with LQ significantly improved memory performance in both behavioral tests. In vitro, LQ significantly increased NMDARs in the hippocampus. Furthermore, LQ significantly increased PSD-95 expression as well as CaMKII, ERK, and CREB phosphorylation in the hippocampus. Taken together, our results suggest that LQ has cognition enhancing activities and that these effects are mediated, in part, by activation of the NMDAR and CREB signaling pathways.

Network meta-analysis of success rate and safety in antibiotic treatments of bronchitis

The purpose of this study was to compare the relative efficacy and safety of different antibiotic drugs and recommend superior regimens in the treatment of bronchitis. With respect to the antibiotic comparisons against quinolones in terms of intention-to-treat patients, we concluded that quinolones had advantages over placebo, β-lactams, sulfonamides, and double β-lactams. Concerning treatment methods for clinically evaluable patients, quinolones demonstrated better performance than β-lactams and sulfonamides. The secondary effects of macrolides, quinolones, and double β-lactams were significantly more adverse than β-lactams with odds ratios (ORs) of 1.5 (95% credible interval [CrI] =1.1–2.0), 1.7 (95% CrI =1.2–2.3), and 2.7 (95% CrI =1.8–4.1), respectively. Significant differences in the prevalence of diarrhea as a secondary effect were only identified among the comparisons of double β-lactams against β-lactams and macrolides (OR =5.0, 95% CrI =2.1–12.0; OR =3.0, 95% CrI =1.7–5.4, respectively). Quinolones can be recommended as the superior treatment for bronchitis, in accordance with our cluster analysis with surface under the cumulative ranking curve. The primary outcomes of network meta-analysis indicated that quinolones showed the best performance among the 8 treatments studied, although β-lactams showed the lowest risk of adverse side effects. Quinolones are recommended as the primary treatment option for bronchitis patients, having taking into account the success rates and safety profiles of the eight drugs studied here.

Contacting authors to retrieve individual patient data: study protocol for a randomized controlled trial

Background

Individual patient data (IPD) meta-analysis is considered the “gold standard” for exploring the effectiveness of interventions in different subgroups of patients. However, obtaining IPD is time-consuming and contact with the researchers responsible for the original trials is usually required. To date, there are no studies evaluating different strategies to optimize the process for retrieval of IPD from such researchers. Our aim is to examine the impact of providing incentives to the researchers responsible for the trials eligible for a meta-analysis to submit their IPD.

Methods/Design

We updated our previously published systematic reviews for type 1 diabetes mellitus comparing long- and intermediate-acting insulin regimens (from January 2013 to June 2015) and for Alzheimer’s dementia comparing cognitive enhancers (from January 2015 to May 2015). Eligible were randomized controlled trials (RCTs) fulfilling the eligibility criteria of the systematic reviews. We will randomly allocate authors of the reports of these RCTs into an intervention or control group. Those allocated to the intervention group will be contacted by email, mail, and phone, and will be asked to provide the IPD from their RCT and will be given a financial incentive. Those allocated to the control group will be contacted by email, mail, and phone, but will not receive a financial incentive. Our primary outcome will be the proportion of authors who provide the IPD. The secondary outcomes will be the time to return the dataset (defined as the period between the information request and the authors’ response with the dataset), and completeness of data. We will compare the response rates in the two groups using the odds ratio and the corresponding 95 % confidence interval. We will also use binary logistic regression and cox regression analyses to examine whether different RCT characteristics, such as study size and sponsor information, influence the probability of providing IPD and the time needed to share the data.

Discussion

This study will determine whether a financial incentive affects response rates when seeking IPD from the original researchers. We will disseminate our findings in an open access scientific journal and present results at national and international conferences.

Trial registration

This trial is registered in Clinical Trials.gov, ID number NCT02569411. Date of registration 5 October 2015.