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International Journal of Clinical... Jun 2016Observational studies have been recognised to be essential for investigating the safety profile of medications. Numerous observational studies have been conducted on the... (Review)
Review
Observational studies have been recognised to be essential for investigating the safety profile of medications. Numerous observational studies have been conducted on the platform of large population databases, which provide adequate sample size and follow-up length to detect infrequent and/or delayed clinical outcomes. Cohort and case-control are well-accepted traditional methodologies for hypothesis testing, while within-individual study designs are developing and evolving, addressing previous known methodological limitations to reduce confounding and bias. Respective examples of observational studies of different study designs using medical databases are shown. Methodology characteristics, study assumptions, strengths and weaknesses of each method are discussed in this review.
Topics: Databases, Pharmaceutical; Humans; Observational Studies as Topic; Pharmacoepidemiology; Research Design
PubMed: 27003827
DOI: 10.1007/s11096-016-0285-6 -
Contraception Aug 2022Systematically review the existing evidence about couples-based interventions and postpartum contraceptive uptake and generate recommendations for future research. (Review)
Review
OBJECTIVE
Systematically review the existing evidence about couples-based interventions and postpartum contraceptive uptake and generate recommendations for future research.
DATA SOURCES
PubMed, Web of Science, PsycINFO, Embase, and CINAHL through June 7, 2021.
STUDY SELECTION AND DATA EXTRACTION
Studies with a couples-based intervention assessing postpartum contraceptive uptake. Two independent reviewers screened studies, extracted data, and assessed risk of bias with RoB-2 (Cochrane Risk of Bias 2) for randomized and ROBINS-I (Risk of Bias in Non-Randomized Studies - Interventions) for observational studies. Data were synthesized in tables, figures, and a narrative review.
RESULTS
A total of 925 papers were identified, 66 underwent full text review, and 17 articles, which included 18 studies - 16 randomized, 2 observational - were included. The lack of intervention and outcome homogeneity precluded meta-analysis and isolating the effect of partner involvement. Four studies were partner-required, where partner involvement was a required component of the intervention, and 14 were partner-optional. Unadjusted risk differences ranged from 0.01 to 0.51 in favor of couples-based interventions increasing postpartum contraceptive uptake versus standard of care. Bias assessment of the 16 randomized studies classified 8, 3, and 5 studies as at a high, some concern, and low risk of bias. Common sources of bias included intervention non-adherence and missing outcome data. One observational study was at a high and the other at a low risk of bias.
CONCLUSIONS
Future studies that assess couples-based interventions must clearly define and measure how partners are involved in the intervention and assess how intervention adherence impacts postpartum contraceptive uptake.
Topics: Contraceptive Agents; Contraceptive Devices; Female; Humans; Observational Studies as Topic; Postpartum Period; Text Messaging
PubMed: 35577147
DOI: 10.1016/j.contraception.2022.05.001 -
Methods in Molecular Biology (Clifton,... 2021Longitudinal or observational study designs are important methodologies to investigate potential associations that may not be amenable to randomized controlled trials....
Longitudinal or observational study designs are important methodologies to investigate potential associations that may not be amenable to randomized controlled trials. In many cases, they may be performed using existing data and are often cost-effective ways of addressing important questions. The major disadvantage of observational studies is the potential for bias. The absence of randomization means that one can never be certain that unknown confounders are present, and specific studies designs have their own inherent forms of bias. Careful study design may minimize bias. Establishing casual association based on observational methods requires due consideration of the quality of the individual study and knowledge of their limitations.
Topics: Bias; Humans; Longitudinal Studies; Observational Studies as Topic; Research Design; Risk Factors; Sample Size
PubMed: 33871840
DOI: 10.1007/978-1-0716-1138-8_6 -
Annales Pharmaceutiques Francaises Nov 2018The new use of medico-administrative databases is a major change in the medical assessment field. Given the limits of the randomized clinical trials when it comes to... (Review)
Review
The new use of medico-administrative databases is a major change in the medical assessment field. Given the limits of the randomized clinical trials when it comes to accurately represent the heterogeneity and complexity of medical care in a real-world context, an increasing demand of observational studies comes from healthcare systems as decision tools. The lack of intervention generates real-world data and assesses both the care and the outcomes of patients in routine practice. Despite this external validity, the bias and confounding factors are a challenge to the internal validity of observational studies. An appropriate study design and statistical methods are necessary to neutralize them and consider a causal relationship between a treatment and a clinical outcome.
Topics: Biomedical Research; Databases, Factual; Delivery of Health Care; Humans; Observational Studies as Topic; Research Design; Treatment Outcome
PubMed: 30103940
DOI: 10.1016/j.pharma.2018.07.003 -
Drug and Therapeutics Bulletin Sep 2016The development of evidence-based medicine has encouraged clinicians to consider the best available evidence when making clinical decisions, individualised for the...
The development of evidence-based medicine has encouraged clinicians to consider the best available evidence when making clinical decisions, individualised for the patient.(1,2) A hierarchy of levels of evidence about therapy is described, with the highest being meta-analyses and large, well-designed randomised controlled trials.(3-5) Lower down the hierarchy are observational studies, a group that includes cohort, case-control and cross-sectional studies. Here we describe the benefits and limitations of observational studies, and how to assess their quality.
Topics: Evidence-Based Medicine; Humans; Observational Studies as Topic
PubMed: 27609426
DOI: 10.1136/dtb.2016.9.0426 -
PLoS Medicine Aug 2014The PLOS Medicine Editors endorse four measures to ensure transparency in the analysis and reporting of observational studies. Please see later in the article for the...
The PLOS Medicine Editors endorse four measures to ensure transparency in the analysis and reporting of observational studies. Please see later in the article for the Editors' Summary.
Topics: Editorial Policies; Guidelines as Topic; Observational Studies as Topic; Periodicals as Topic
PubMed: 25158064
DOI: 10.1371/journal.pmed.1001711 -
The Journal of Hand Surgery Aug 2018Observational studies are common research strategies in hand surgery. The case-cohort design offers an efficient and resource-friendly method for risk assessment and... (Review)
Review
Observational studies are common research strategies in hand surgery. The case-cohort design offers an efficient and resource-friendly method for risk assessment and outcomes analysis. Case-cohorts remain underrepresented in upper extremity research despite several practical and economic advantages over case-control studies. This report outlines the purpose, utility, and structure of the case-cohort design and offers a sample research question to demonstrate its value to risk estimation for adverse surgical outcomes. The application of well-designed case-cohort studies is advocated in an effort to improve the quality and quantity of observational research evidence in hand and upper extremity surgery.
Topics: Epidemiologic Studies; Humans; Observational Studies as Topic; Orthopedics; Research Design; Upper Extremity
PubMed: 29703682
DOI: 10.1016/j.jhsa.2018.03.013 -
The Journal of Thoracic and... Feb 2022
Topics: Humans; Observational Studies as Topic; Randomized Controlled Trials as Topic; Reproducibility of Results; Research Design; Thoracic Surgery
PubMed: 33277031
DOI: 10.1016/j.jtcvs.2020.10.120 -
International Endodontic Journal Sep 2021To record the prevalence of a priori power calculations in manuscripts published in three endodontic journals between 2018 and 2020 and detect further associations with... (Review)
Review
AIM
To record the prevalence of a priori power calculations in manuscripts published in three endodontic journals between 2018 and 2020 and detect further associations with a number of study characteristics including journal, publication year, study design, geographic region, number of centres and authors, whether the primary outcome pertained to a statistically significant effect and whether confidence intervals (CIs) were reported.
METHODOLOGY
The contents of the three leading endodontic journals with the highest impact factor (International Endodontic Journal, IEJ; Journal of Endodontics, JOE; and Australian Endodontic Journal, AEJ) were assessed from January 2018 to December 2020. The proportion of articles reporting a priori power calculations were recorded, and relevant associations as described above were assessed. Univariable and multivariable logistic regression were used to identify significant predictors, whilst interaction and linear trend effects were also considered.
RESULTS
A total of 716 original research articles were included. The vast majority were published in the JOE (417/716; 58.2%), followed by the IEJ (225/716; 31.4%) and the AEJ (74/716; 10.4%). Overall, a priori power considerations were reported in 243 out of 716 articles (33.9%). The IEJ presented 1.61 times higher odds for including a priori power considerations compared to JOE (adjusted odds ratio, OR = 1.61; 95%CI: 1.11, 2.34), whilst for the AEJ, the corresponding odds were 41% lower in comparison to JOE (adjusted OR = 0.59; 95%CI: 0.31, 1.14). For each additional year indicating more recent publication, the odds for adopting appropriate reporting practices for power considerations were increased by 64% (adjusted OR = 1.64; 95%CIs: 1.32, 2.04). There was strong evidence that interventional research was associated with 10.54 times higher odds for a priori considerations compared to observational study design (adjusted OR = 10.54; 95%CIs: 5.50, 20.19).
CONCLUSIONS
The high prevalence of failure to include a priori power considerations was indicative of suboptimal reporting in endodontic research, in the three endodontic journals analysed. Although the condition improved over time, efforts to incorporate a correct determination of the required sample size at the design stage for any future study should be endorsed by journal editors, authors and the scientific community.
Topics: Australia; Endodontics; Humans; Observational Studies as Topic; Research Design
PubMed: 33872405
DOI: 10.1111/iej.13531 -
Nephrology (Carlton, Vic.) Oct 2020In evidence-based medicine, clinical research questions may be addressed by different study designs. This article describes when randomized controlled trials (RCT) are... (Review)
Review
In evidence-based medicine, clinical research questions may be addressed by different study designs. This article describes when randomized controlled trials (RCT) are needed and when observational studies are more suitable. According to the Centre for Evidence-Based Medicine, study designs can be divided into analytic and non-analytic (descriptive) study designs. Analytic studies aim to quantify the association of an intervention (eg, treatment) or a naturally occurring exposure with an outcome. They can be subdivided into experimental (ie, RCT) and observational studies. The RCT is the best study design to evaluate the intended effect of an intervention, because the randomization procedure breaks the link between the allocation of the intervention and patient prognosis. If the randomization of the intervention or exposure is not possible, one needs to depend on observational analytic studies, but these studies usually suffer from bias and confounding. If the study focuses on unintended effects of interventions (ie, effects of an intervention that are not intended or foreseen), observational analytic studies are the most suitable study designs, provided that there is no link between the allocation of the intervention and the unintended effect. Furthermore, non-analytic studies (ie, descriptive studies) also rely on observational study designs. In summary, RCTs and observational study designs are inherently different, and depending on the study aim, they each have their own strengths and weaknesses.
Topics: Confounding Factors, Epidemiologic; Evidence-Based Medicine; Humans; Observational Studies as Topic; Randomized Controlled Trials as Topic; Research Design
PubMed: 32542836
DOI: 10.1111/nep.13742