A systematic review of pregnancy exposure registries: examination of protocol-specified pregnancy outcomes, target sample size, and comparator selection

2016 ◽  
Vol 26 (2) ◽  
pp. 208-214 ◽  
Author(s):  
Kate Gelperin ◽  
Hoda Hammad ◽  
Kira Leishear ◽  
Steven T. Bird ◽  
Lockwood Taylor ◽  
...  
Keyword(s):  
Systematic Review ◽  
Sample Size ◽  
Pregnancy Outcomes ◽  
Target Sample Size ◽  
Target Sample

scholarly journals A systematic review of the “promising zone” design

Trials ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Julia M. Edwards ◽  
Stephen J. Walters ◽  
Cornelia Kunz ◽  
Steven A. Julious
Keyword(s):  
Systematic Review ◽  
Sample Size ◽  
Interim Analysis ◽  
Practical Implementation ◽  
Ethical Concerns ◽  
Target Sample Size ◽  
Maximum Sample Size ◽  
Sample Size Calculations ◽  
Original Target ◽  
Design Simplicity

Abstract Introduction Sample size calculations require assumptions regarding treatment response and variability. Incorrect assumptions can result in under- or overpowered trials, posing ethical concerns. Sample size re-estimation (SSR) methods investigate the validity of these assumptions and increase the sample size if necessary. The “promising zone” (Mehta and Pocock, Stat Med 30:3267–3284, 2011) concept is appealing to researchers for its design simplicity. However, it is still relatively new in the application and has been a source of controversy. Objectives This research aims to synthesise current approaches and practical implementation of the promising zone design. Methods This systematic review comprehensively identifies the reporting of methodological research and of clinical trials using promising zone. Databases were searched according to a pre-specified search strategy, and pearl growing techniques implemented. Results The combined search methods resulted in 270 unique records identified; 171 were included in the review, of which 30 were trials. The median time to the interim analysis was 60% of the original target sample size (IQR 41–73%). Of the 15 completed trials, 7 increased their sample size. Only 21 studies reported the maximum sample size that would be considered, for which the median increase was 50% (IQR 35–100%). Conclusions Promising zone is being implemented in a range of trials worldwide, albeit in low numbers. Identifying trials using promising zone was difficult due to the lack of reporting of SSR methodology. Even when SSR methodology was reported, some had key interim analysis details missing, and only eight papers provided promising zone ranges.

scholarly journals Target and actual sample sizes for studies from two trial registries from 1999 to 2020: an observational study

BMJ Open ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. e053377
Author(s):  
Adrian Gerard Barnett ◽  
Paul Glasziou
Keyword(s):  
Observational Study ◽  
Sample Size ◽  
Outcome Measures ◽  
Large Trial ◽  
Sample Sizes ◽  
Actual Sample ◽  
Target Sample Size ◽  
Target Sample ◽  
Study Characteristics ◽  
Over Time

ObjectivesTo investigate differences between target and actual sample sizes, and what study characteristics were associated with sample sizes.DesignObservational study.SettingThe large trial registries of clinicaltrials.gov (starting in 1999) and ANZCTR (starting in 2005) through to 2021.ParticipantsOver 280 000 interventional studies excluding studies that were withheld, terminated for safety reasons or were expanded access.Main outcome measuresThe actual and target sample sizes, and the within-study ratio of the actual to target sample size.ResultsMost studies were small: the median actual sample sizes in the two databases were 60 and 52. There was a decrease over time in the target sample size of 9%–10% per 5 years, and a larger decrease of 18%–21% per 5 years for the actual sample size. The actual-to-target sample size ratio was 4.1% lower per 5 years, meaning more studies (on average) failed to hit their target sample size.ConclusionRegistered studies are more often under-recruited than over-recruited and worryingly both target and actual sample sizes appear to have decreased over time, as has the within-study gap between the target and actual sample size. Declining sample sizes and ongoing concerns about underpowered studies mean more research is needed into barriers and facilitators for improving recruitment and accessing data.

scholarly journals Using Facebook and LinkedIn to Recruit Nurses for an Online Survey

2017 ◽  
Vol 41 (1) ◽  
pp. 96-110 ◽  
Author(s):  
Yehudis Stokes ◽  
Amanda Vandyk ◽  
Janet Squires ◽  
Jean-Daniel Jacob ◽  
Wendy Gifford
Keyword(s):  
Social Media ◽  
Sample Size ◽  
Cost Efficiency ◽  
Online Survey ◽  
Limited Information ◽  
Participant Recruitment ◽  
Level Of Education ◽  
Target Sample Size ◽  
Target Sample ◽  
English Speaking

Social media is an emerging tool used by researchers; however, limited information is available on its use for participant recruitment specifically. The purpose of this article is to describe the use of Facebook and LinkedIn social media sites in the recruitment of nurses for an online survey, using a 5-week modified online Dillman approach. Within 3 weeks, we exceeded our target sample size ( n = 170) and within 5 weeks recruited 267 English-speaking nurses ( n = 172, Facebook; n = 95, LinkedIn). Advantages included speed of recruitment, cost-efficiency, snowballing effects, and accessibility of the researcher to potential participants. However, an analysis of the recruited participants revealed significant differences when comparing the sociodemographics of participants recruited through Facebook and LinkedIn, specifically relating to the characteristics of sex, age, and level of education. Differences between Facebook and LinkedIn as recruitment platforms should be considered when incorporating these strategies.

scholarly journals Persepsi Mahasiswa Akuntansi Terhadap Independensi Akuntan Publik: Studi Empirik pada Mahasiswa Akuntansi di Bandung

2021 ◽  
Vol 13 (2) ◽  
pp. 378-387
Author(s):  
Trimanto Setyo Wardoyo ◽  
Tatik Budiningsih ◽  
Herman Kambono ◽  
Elvira Veronica
Keyword(s):  
Sample Size ◽  
Accounting Students ◽  
Accounting Profession ◽  
Proper Place ◽  
Target Sample Size ◽  
Perceptions Of Students ◽  
Target Sample ◽  
Public Accountants ◽  
The City ◽  
Public Accountant

Abstract This study aims to determine the perceptions of accounting students towards the independence of public accountants in the city of Bandung. Positive perceptions indicate that the accounting profession, especially public accountants, has a proper place in accounting students. Through a questionnaire distributed with a sample of accounting students in the city of Bandung, with a target sample size of 60 students. From 137 respondents gathered, it can be seen based on the results of the analysis that students majoring in accounting in Bandung perceive that public accountants in Indonesia are not independent. In addition, the results of this study are expected to be inference for accounting students in Indonesia. The results of this study also show that there are differences in the perceptions of students majoring in accounting in Bandung who have never and who have taken auditing courses on the independence of public accountants in Indonesia. Keywords: Perception, Independence, Accounting Profession, and Public Accountant

scholarly journals Levothyroxine and the risk of adverse pregnancy outcomes in women with subclinical hypothyroidism: a systematic review and meta-analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Magnus Bein ◽  
Oriana Hoi Yun Yu ◽  
Sonia Marzia Grandi ◽  
Francesca Y. E. Frati ◽  
Ihab Kandil ◽  
...  
Keyword(s):  
Systematic Review ◽  
Subclinical Hypothyroidism ◽  
Pregnancy Outcomes ◽  
Neonatal Death ◽  
Observational Studies ◽  
Pregnancy Loss ◽  
Meta Analysis ◽  
Adverse Pregnancy Outcomes ◽  
Adverse Pregnancy ◽  
Levothyroxine Treatment

Abstract Background Levothyroxine replacement therapy may decrease the risk of adverse pregnancy outcomes among women with subclinical hypothyroidism (SCH). The aim of this study is to conduct a systematic review and meta-analysis to examine the risk of adverse pregnancy, perinatal, and early childhood outcomes among women with SCH treated with levothyroxine. Methods A systematic literature search was conducted using Ovid-Medline, Ovid-EMBASE, Pubmed (non-Medline), Ebsco-CINAHL Plus with full text and Cochrane Library databases. Randomized controlled studies (RCTs) and observational studies examining the association between treatment of SCH during pregnancy and our outcomes of interest were included. Studies that compared levothyroxine treatment versus no treatment were eligible for inclusion. Data from included studies were extracted and quality assessment was performed by two independent reviewers. Results Seven RCTs and six observational studies met our inclusion criteria. A total of 7342 individuals were included in these studies. RCTs demonstrated several sources of bias, with lack of blinding of the participants or research personnel; only one study was fully blinded. In the observational studies, there was moderate to serious risk of bias due to lack of adjustment for certain confounding variables, participant selection, and selective reporting of results. Pooled analyses showed decreased risk of pregnancy loss (RR: 0.79; 95% CI: 0.67 to 0.93) and neonatal death (RR: 0.35; 95% CI: 0.17 to 0.72) associated with levothyroxine treatment during pregnancy among women with SCH. There were no associations between levothyroxine treatment and outcomes during labour and delivery, or cognitive status in children at 3 or 5 years of age. Conclusion Treatment of SCH with levothyroxine during pregnancy is associated with decreased risks of pregnancy loss and neonatal death. Given the paucity of available data and heterogeneity of included studies, additional studies are needed to address the benefits of levothyroxine use among pregnant women with SCH.

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