scholarly journals Rate of, and risk factors for, white matter hyperintensity growth: a systematic review and meta-analysis with implications for clinical trial design

2021 ◽  
pp. jnnp-2021-326569
Author(s):  
Robin Brown ◽  
Audrey Low ◽  
Hugh S Markus

BackgroundWhite matter hyperintensities (WMHs) are a highly prevalent MRI marker of cerebral small vessel disease (SVD), which predict stroke and dementia risk, and are being increasingly used as a surrogate marker in clinical trials. However, the influence of study population selection on WMH progression rate has not been studied and the effect of individual patient factors for WMH growth are not fully understood.MethodsWe performed a systematic review and meta-analysis of the literature on progression of WMHs in longitudinal studies to determine rates of WMH growth, and how these varied according to population characteristics and cardiovascular risk factors. We used these data to calculate necessary sample sizes for clinical trials using WMH as an endpoint.ResultsWMH growth rate was highest in SVD (2.50cc/year), intermediate in unselected stroke patients (1.29cc/year) and lower in patients with non-stroke cardiovascular disease, and with cognitive impairment. Age was significantly associated with progression (correlation coefficient 0.15cc/year, 95% CI 0.02 to 0.28cc/year) as was baseline lesion volume (0.6cc/year, 95% CI 0.13 to 1.06 cc/year). Both hypertension (OR 1.72, 95% CI 1.19 to 2.46) and current smoking (OR 1.48, 95% CI 1.02 to 2.16) were associated with WMH growth. Sample sizes for a clinical trial varied greatly with patient population selection and baseline lesion volume; estimates are provided.ConclusionsWMH progression varies markedly according to the characteristics of the population being studied and this will have a major impact on sample sizes required in a clinical trial. Our sample size estimates provide data for planning clinical trials using WMH as an outcome measure.PROSPERO registration numberCRD42020191781.

BMJ ◽  
2018 ◽  
pp. k4738 ◽  
Author(s):  
Joanna C Crocker ◽  
Ignacio Ricci-Cabello ◽  
Adwoa Parker ◽  
Jennifer A Hirst ◽  
Alan Chant ◽  
...  

AbstractObjectiveTo investigate the impact of patient and public involvement (PPI) on rates of enrolment and retention in clinical trials and explore how this varies with the context and nature of PPI.DesignSystematic review and meta-analysis.Data sourcesTen electronic databases, including Medline, INVOLVE Evidence Library, and clinical trial registries.Eligibility criteriaExperimental and observational studies quantitatively evaluating the impact of a PPI intervention, compared with no intervention or non-PPI intervention(s), on participant enrolment and/or retention rates in a clinical trial or trials. PPI interventions could include additional non-PPI components inseparable from the PPI (for example, other stakeholder involvement).Data extraction and analysisTwo independent reviewers extracted data on enrolment and retention rates, as well as on the context and characteristics of PPI intervention, and assessed risk of bias. Random effects meta-analyses were used to determine the average effect of PPI interventions on enrolment and retention in clinical trials: main analysis including randomised studies only, secondary analysis adding non-randomised studies, and several exploratory subgroup and sensitivity analyses.Results26 studies were included in the review; 19 were eligible for enrolment meta-analysis and five for retention meta-analysis. Various PPI interventions were identified with different degrees of involvement, different numbers and types of people involved, and input at different stages of the trial process. On average, PPI interventions modestly but significantly increased the odds of participant enrolment in the main analysis (odds ratio 1.16, 95% confidence interval and prediction interval 1.01 to 1.34). Non-PPI components of interventions may have contributed to this effect. In exploratory subgroup analyses, the involvement of people with lived experience of the condition under study was significantly associated with improved enrolment (odds ratio 3.14v1.07; P=0.02). The findings for retention were inconclusive owing to the paucity of eligible studies (odds ratio 1.16, 95% confidence interval 0.33 to 4.14), for main analysis).ConclusionsThese findings add weight to the case for PPI in clinical trials by indicating that it is likely to improve enrolment of participants, especially if it includes people with lived experience of the health condition under study. Further research is needed to assess which types of PPI work best in particular contexts, the cost effectiveness of PPI, the impact of PPI at earlier stages of trial design, and the impact of PPI interventions specifically targeting retention.Systematic review registrationPROSPERO CRD42016043808.


2018 ◽  
Vol 108 (1) ◽  
pp. 174-187 ◽  
Author(s):  
Marta Guasch-Ferré ◽  
Jun Li ◽  
Frank B Hu ◽  
Jordi Salas-Salvadó ◽  
Deirdre K Tobias

ABSTRACT BACKGROUND Intervention studies suggest that incorporating walnuts into the diet may improve blood lipids without promoting weight gain. OBJECTIVE We conducted a systematic review and meta-analysis of controlled trials evaluating the effects of walnut consumption on blood lipids and other cardiovascular risk factors. Design We conducted a comprehensive search of PubMed and EMBASE databases (from database inception to January 2018) of clinical trials comparing walnut-enriched diets with control diets. We performed random-effects meta-analyses comparing walnut-enriched and control diets for changes in pre-post intervention in blood lipids (mmol/L), apolipoproteins (mg/dL), body weight (kg), and blood pressure (mm Hg). RESULTS Twenty-six clinical trials with a total of 1059 participants were included. The following weighted mean differences (WMDs) in reductions were obtained for walnut-enriched diets compared with control groups: −6.99 mg/dL (95% CI: −9.39, −4.58 mg/dL; P < 0.001) (3.25% greater reduction) for total blood cholesterol (TC) and −5.51 mg/dL (95% CI: −7.72, −3.29 mg/dL; P < 0.001) (3.73% greater reduction) for low-density lipoprotein (LDL) cholesterol. Triglyceride concentrations were also reduced in walnut-enriched diets compared with control [WMD = −4.69 (95% CI: −8.93, −0.45); P = 0.03; 5.52% greater reduction]. More pronounced reductions in blood lipids were observed when walnut interventions were compared with American and Western diets [WMD for TC = −12.30 (95% CI: −23.17, −1.43) and for LDL = −8.28 (95% CI: −13.04, −3.51); P < 0.001]. Apolipoprotein B (mg/dL) was also reduced significantly more on walnut-enriched diets compared with control groups [WMD = −3.74 (95% CI: −6.51, −0.97); P = 0.008] and a trend towards a reduction was observed for apolipoprotein A [WMD = −2.91 (95% CI: −5.98, 0.08); P = 0.057]. Walnut-enriched diets did not lead to significant differences in weight change (kg) compared with control diets [WMD = −0.12 (95% CI: −2.12, 1.88); P = 0.90], systolic blood pressure (mm Hg) [WMD = −0.72 (95% CI: −2.75, 1.30); P = 0.48], or diastolic blood pressure (mm Hg) [WMD = −0.10 (95% CI: −1.49, 1.30); P = 0.88]. Conclusions Incorporating walnuts into the diet improved blood lipid profile without adversely affecting body weight or blood pressure.


2020 ◽  
Vol 5 ◽  
pp. 60 ◽  
Author(s):  
Brittany J. Maguire ◽  
Philippe J. Guérin

Since the coronavirus disease 2019 (COVID-19) outbreak was identified in December 2019 in Wuhan, China, a strong response from the research community has been observed with the proliferation of independent clinical trials assessing diagnostic methods, therapeutic and prophylactic strategies. While there is no intervention for the prevention or treatment of COVID-19 with proven clinical efficacy to date, tools to distil the current research landscape by intervention, level of evidence and those studies likely powered to address future research questions is essential. This living systematic review aims to provide an open, accessible and frequently updated resource summarising the characteristics of COVID-19 clinical trial registrations. Weekly search updates of the WHO International Clinical Trials Registry Platform (ICTRP) and source registries will be conducted. Data extraction by two independent reviewers of trial characteristic variables including categorisation of trial design, geographic location, intervention type and targets, level of evidence and intervention adaptability to low resource settings will be completed. Descriptive and thematic synthesis will be conducted. A searchable and interactive visualisation of the results database will be created, and made openly available online. Weekly results from the continued search updates will be published and made available on the Infectious Diseases Data Observatory (IDDO) website (COVID-19 website). This living systematic review will provide a useful resource of COVID-19 clinical trial registrations for researchers in a rapidly evolving context. In the future, this sustained review will allow prioritisation of research targets for individual patient data meta-analysis.


Author(s):  
Anahita Mansoori ◽  
Zahra Salimi ◽  
Seyyed Ahmad Hosseini ◽  
Razie Hormoznejad ◽  
Maryam Asadi

Background: Several randomized clinical trials (RCTs) has assessed the effect of Anethum graveolens L. (AG) or dill supplementation on lipid profile in adults with cardiovascular risk factors with different results. Therefore, we decided to conduct a systematic review and meta-analysis regarding the available randomized controlled trials to assess AG supplementation's efficacy on lipid profile in adults with cardiovascular risk factors. Methods: PubMed, Embase, Cochrane's database, Ovid, Web of Science, ProQuest, Scopus, and Google Scholar were searched to find relevant articles investigating the effect of AG on the lipid profile of adults with risk factors for cardiovascular disease up to December 2020. Six trials with seven treatment armsmet the inclusion criteria. A random-effects model was used in the meta-analysis. To test heterogeneity, I2 statistics and Cochrane Q test were applied. Results: The results reported a significant improving effect of AG on TG [WMD = -29.20, 95% confidence interval (CI): -34.73,-23.68 mg/dL, p < 0.001], TC (WMD = -16.46, 95%CI: -21.54,-11.39 mg/dL, p < 0.001), LDL-C (WMD = -13.90, 95%CI: -16.08, -11.72 mg/dL, p < 0.001), and HDL-C (WMD = 4.01, 95%CI: 3.48, 4.54 mg/dL, p < 0.001). Conclusion: This meta-analysis of randomized controlled clinical trials revealed that consuming AG extract for more than six weeks might improve lipid profile in adults with cardiovascular risk factors.


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