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Defining and evaluating the Hawthorne effect in primary care, a systematic review and meta-analysis.Frontiers in Medicine 2022In 2015, we conducted a randomized controlled trial (RCT) in primary care to evaluate if posters and pamphlets dispensed in general practice waiting rooms enhanced...
In 2015, we conducted a randomized controlled trial (RCT) in primary care to evaluate if posters and pamphlets dispensed in general practice waiting rooms enhanced vaccination uptake for seasonal influenza. Unexpectedly, vaccination uptake rose in both arms of the RCT whereas public health data indicated a decrease. We wondered if the design of the trial had led to a Hawthorne effect (HE). Searching the literature, we noticed that the definition of the HE was unclear if stated. Our objectives were to refine a definition of the HE for primary care, to evaluate its size, and to draw consequences for primary care research. We designed a Preferred Reporting Items for Systematic reviews and Meta-Analyses review and meta-analysis between January 2012 and March 2022. We included original reports defining the HE and reports measuring it without setting limitations. Definitions of the HE were collected and summarized. Main published outcomes were extracted and measures were analyzed to evaluate odds ratios (ORs) in primary care. The search led to 180 records, reduced on review to 74 for definition and 15 for quantification. Our definition of HE is "an aware or unconscious complex behavior change in a study environment, related to the complex interaction of four biases affecting the study subjects and investigators: selection bias, commitment and congruence bias, conformity and social desirability bias and observation and measurement bias." Its size varies in time and depends on the education and professional position of the investigators and subjects, the study environment, and the outcome. There are overlap areas between the HE, placebo effect, and regression to the mean. In binary outcomes, the overall OR of the HE computed in primary care was 1.41 (95% CI: [1.13; 1.75]; = 97%), but the significance of the HE disappears in well-designed studies. We conclude that the HE results from a complex system of interacting phenomena and appears to some degree in all experimental research, but its size can considerably be reduced by refining study designs.
PubMed: 36425097
DOI: 10.3389/fmed.2022.1033486 -
BMJ Open Science 2022Systematic review and meta-analysis are a gift to the modern researcher, delivering a crystallised understanding of the existing research data in any given space. This...
Systematic review and meta-analysis are a gift to the modern researcher, delivering a crystallised understanding of the existing research data in any given space. This can include whether candidate drugs are likely to work or not and which are better than others, whether our models of disease have predictive value and how this might be improved and also how these all interact with disease pathophysiology. Grappling with the literature needed for such analyses is becoming increasingly difficult as the number of publications grows. However, narrowing the focus of a review to reduce workload runs the risk of diminishing the generalisability of conclusions drawn from such increasingly specific analyses. Moreover, at the same time as we gain greater insight into our topic, we also discover more about the flaws that undermine much scientific research. Systematic review and meta-analysis have also shown that the quality of much preclinical research is inadequate. Systematic review has helped reveal the extent of selection bias, performance bias, detection bias, attrition bias and low statistical power, raising questions about the validity of many preclinical research studies. This is perhaps the greatest virtue of systematic review and meta-analysis, the knowledge generated ultimately helps shed light on the limitations of existing research practice, and in doing so, helps bring reform and rigour to research across the sciences. In this commentary, we explore the lessons that we have identified through the lens of preclinical systematic review and meta-analysis.
PubMed: 35360370
DOI: 10.1136/bmjos-2021-100219 -
Breast (Edinburgh, Scotland) Aug 2016To estimate sensitivity and specificity of CESM for breast cancer diagnosis. (Meta-Analysis)
Meta-Analysis Review
PURPOSE
To estimate sensitivity and specificity of CESM for breast cancer diagnosis.
METHODS
Systematic review and meta-analysis of the accuracy of CESM in finding breast cancer in highly selected women. We estimated summary receiver operating characteristic curves, sensitivity and specificity according to quality criteria with QUADAS-2.
RESULTS
Six hundred four studies were retrieved, 8 of these reporting on 920 patients with 994 lesions, were eligible for inclusion. Estimated sensitivity from all studies was: 0.98 (95% CI: 0.96-1.00). Specificity was estimated from six studies reporting raw data: 0.58 (95% CI: 0.38-0.77). The majority of studies were scored as at high risk of bias due to the very selected populations.
CONCLUSION
CESM has a high sensitivity but very low specificity. The source studies were based on highly selected case series and prone to selection bias. High-quality studies are required to assess the accuracy of CESM in unselected cases.
Topics: Breast Neoplasms; Contrast Media; Female; Humans; Mammography; Sensitivity and Specificity; Tumor Burden
PubMed: 27161411
DOI: 10.1016/j.breast.2016.04.008 -
Journal of Clinical Periodontology May 2015The objective of this study was to assess how authors of systematic reviews (SRs) with meta-analyses published in periodontology and implant dentistry evaluate risk of... (Review)
Review
BACKGROUND/OBJECTIVE
The objective of this study was to assess how authors of systematic reviews (SRs) with meta-analyses published in periodontology and implant dentistry evaluate risk of bias (ROB) in primary studies included in these reviews.
MATERIAL/METHODS
A literature search for SRs with meta-analyses was performed in PubMed and Cochrane library databases up to July 20th 2014. The reference lists of included articles were screened for further reviews. The standards of evaluating ROB in primary studies were evaluated by using a 14-item checklist based on the Cochrane approach for evaluating ROB. Standards in ROB evaluations in Cochrane and paper-based SRs were compared using the Fisher's exact test. All searches, data extraction and evaluations were performed independently and in duplicate.
RESULTS
Seventy SRs were included (45 paper-based and 25 Cochrane SRs, respectively). The median percentage of items addressed was 58% (interquartile range 4-100%). Cochrane SRs more frequently included ROB assessments than paper-based reviews in terms of examiner blinding (p = 0.0026), selective outcome reporting (p = 0.0207) and other bias (p = 0.0241).
CONCLUSIONS
The ROB evaluation in primary studies currently included in SRs with meta-analyses in periodontology and implant dentistry is not sufficiently comprehensive. Cochrane SRs have more comprehensive ROB evaluation than paper-based reviews.
Topics: Bias; Dental Implantation; Humans; Periodontics; Randomized Controlled Trials as Topic; Review Literature as Topic; Selection Bias
PubMed: 25809114
DOI: 10.1111/jcpe.12394 -
European Journal of Preventive... Dec 2016Background Metabolic syndrome is the most important risk factor for developing cardiovascular disease and type 2 diabetes. The aim of this review was to systematically... (Meta-Analysis)
Meta-Analysis Review
Background Metabolic syndrome is the most important risk factor for developing cardiovascular disease and type 2 diabetes. The aim of this review was to systematically assess and perform a meta-analysis of the effects of yoga on the parameters of metabolic syndrome. Methods MEDLINE/PubMed, Scopus, the Cochrane Central Register of Controlled Trials and IndMED were searched and screened from their inception through to 8 March 2016 for randomised controlled trials on yoga for patients with metabolic syndrome. Risk of bias was assessed using the Cochrane risk of bias tool. Results Seven trials with a total of 794 participants were included. No effects of yoga on resolution of metabolic syndrome, diastolic blood pressure, triglycerides, high-density lipoprotein cholesterol and fasting plasma glucose were found, but yoga was superior to usual care for waist circumference (standardised mean difference (SMD) = -0.35; 95% confidence interval (CI) = -0.57 to -0.13; p < 0.01) and systolic blood pressure (SMD = -0.29; 95% CI = -0.51 to -0.07; p = 0.01). However, these effects were not robust against selection bias. No intervention-related adverse events were reported. Conclusion Based on the results of this meta-analysis, no recommendation can be made for or against yoga in order to influence the parameters of metabolic syndrome. Despite methodological drawbacks, and until further research is undertaken, yoga can be preliminarily considered as a safe and effective intervention for reducing waist circumference and systolic blood pressure in individuals with metabolic syndrome who are not adhering to conventional forms of exercise.
Topics: Cardiovascular Diseases; Global Health; Health Status; Humans; Incidence; Metabolic Syndrome; Quality of Life; Risk Factors; Yoga
PubMed: 27550905
DOI: 10.1177/2047487316665729 -
Cancers Feb 2021Fertility-sparing surgery (FSS) is increasingly being offered to women with a gynecological malignancy who wish to preserve fertility. In this systematic review, we... (Review)
Review
Fertility-sparing surgery (FSS) is increasingly being offered to women with a gynecological malignancy who wish to preserve fertility. In this systematic review, we evaluate the best evidence currently available on oncological and reproductive outcome after FSS for early stage cervical cancer, epithelial ovarian cancer, and endometrial cancer. An extensive literature search was conducted using the electronic databases Medline (OVID), Embase, and Cochrane Library to identify eligible studies published up to December 2020. In total, 153 studies were included with 7544, 3944, and 1229 patients who underwent FSS for cervical, ovarian, and endometrial cancer, respectively. We assessed the different FSS techniques that are available to preserve fertility, i.e., omitting removal of the uterine body and preserving at least one ovary. Overall, recurrence rates after FSS are reassuring and therefore, these conservative procedures seem oncologically safe in the current selection of patients with low-stage and low-grade disease. However, generalized conclusions should be made with caution due to the methodology of available studies, i.e., mostly retrospective cohort studies with a heterogeneous patient population, inducing selection bias. Moreover, about half of patients do not pursue pregnancy despite FSS and the reasons for these decisions have not yet been well studied. International collaboration will facilitate the collection of solid evidence on FSS and the related decision-making process to optimize patient selection and counseling.
PubMed: 33670929
DOI: 10.3390/cancers13051008 -
Thyroid : Official Journal of the... Nov 2016Hypothyroidism has been associated with increased pulmonary morbidity and overall mortality. A systematic review was conducted to identify the prevalence and underlying... (Review)
Review
BACKGROUND
Hypothyroidism has been associated with increased pulmonary morbidity and overall mortality. A systematic review was conducted to identify the prevalence and underlying mechanisms of respiratory problems among patients with thyroid insufficiency.
METHODS
PubMed and EMBASE databases were searched for relevant literature from January 1950 through January 2015 with the following study eligibility criteria: English-language publications; adult subclinical or overt hypothyroid patients; intervention, observational, or retrospective studies; and respiratory manifestations. The Preferred Reporting Items for Systematic reviews and Meta-Analyses statement was followed, and Cochrane's risk of bias tool was used.
RESULTS
A total of 1699 papers were screened by two independent authors for relevant titles. Of 109 relevant abstracts, 28 papers underwent full-text analyses, of which 22 were included in the review. Possible mechanisms explaining respiratory problems at multiple physiological levels were identified, such as the ventilator control system, diaphragmatic muscle function, pulmonary gas exchange, goiter caused upper airway obstruction, decreased capacity for energy transduction, and reduced glycolytic activity. Obstructive sleep apnea syndrome was found among 30% of newly diagnosed patients with overt hypothyroidism, and demonstrated reversibility following treatment. The evidence for or against a direct effect on pulmonary function was ambiguous. However, each of the above-mentioned areas was only dealt with in a limited number of studies. Therefore, it is not possible to draw any strong conclusions on any of these themes. Moreover, most studies were hampered by considerable risk of bias due for example to small numbers of patients, lack of control groups, randomization and blinding, and differences in body mass index, sex, and age between subjects and controls.
CONCLUSION
Mechanistic data linking hypothyroidism and respiratory function are at best limited. This area of research is therefore open for retesting hypotheses, using appropriate study designs and methods.
Topics: Airway Obstruction; Animals; Comorbidity; Disease Models, Animal; Evidence-Based Medicine; Goiter; Humans; Hypothyroidism; Prevalence; Pulmonary Ventilation; Reproducibility of Results; Respiratory Insufficiency; Respiratory System; Selection Bias; Sleep Apnea, Obstructive
PubMed: 27673426
DOI: 10.1089/thy.2015.0642 -
Zoonoses and Public Health Jun 2014This is the fifth in a series of six articles describing systematic reviews in animal agriculture and veterinary medicine. The previous articles in this series... (Review)
Review
Conducting systematic reviews of intervention questions II: Relevance screening, data extraction, assessing risk of bias, presenting the results and interpreting the findings.
This is the fifth in a series of six articles describing systematic reviews in animal agriculture and veterinary medicine. The previous articles in this series overviewed the development of a review protocol and the initial steps in conducting a systematic review: identification of a structured question to be answered and conducting a comprehensive literature search to find potentially relevant original research to address the review question. This article describes relevance screening of literature identified in the search to determine which of the original research articles are relevant to the review question, data extraction from primary research studies, the use of standardized procedures to assess the risk of bias in the relevant research studies, presenting the results of the body of research identified and interpreting these results.
Topics: Agriculture; Animals; Data Collection; Databases, Bibliographic; Information Storage and Retrieval; Meta-Analysis as Topic; Research Design; Review Literature as Topic; Selection Bias; Veterinary Medicine
PubMed: 24905995
DOI: 10.1111/zph.12124 -
Journal of Human Nutrition and... Feb 2013Nutrition may be a risk factor for unipolar depression. We aimed to review the association between dietary variables and the risk of depression. (Review)
Review
BACKGROUND
Nutrition may be a risk factor for unipolar depression. We aimed to review the association between dietary variables and the risk of depression.
METHODS
Fifteen databases were searched up to May 2010. Only longitudinal studies for which outcomes were unipolar depression and/or depressive symptoms in adults were eligible for inclusion. Eleven studies were included and critically evaluated. Participants were in the age range 18-97 years and the study sample size was in the range 526-27 111. Follow-up ranged from 2 to 13 years. The diversity of dietary variables and nonlinear associations precluded formal meta-analysis and so a narrative analysis was undertaken.
RESULTS
Variables inversely associated with depression risk were the consumption of nutrients such as folate, omega-3 fatty acids and monounsaturated fatty acids; foods such as olive oil and fish; and a diet rich in fruits, vegetables, nuts and legumes. Some of these associations varied by sex and some showed a nonlinear association.
CONCLUSIONS
At the study level, weaknesses in the assessment of exposure and outcome may have introduced bias. Most studies investigated a cohort subgroup that may have resulted in selection bias. At the review level, there is a risk of publication bias and, in addition, narrative analyses are more prone to subjectivities than meta-analyses. Diet may potentially influence the risk of depression, although the evidence is not yet conclusive. Strengthening healthy-eating patterns at the public health level may have a potential benefit. Robust prospective cohort studies specially designed to study the association between diet and depression risk are needed.
Topics: Depression; Depressive Disorder; Diet; Dietary Fats; Fatty Acids; Female; Folic Acid; Humans; Male; Meta-Analysis as Topic
PubMed: 23078460
DOI: 10.1111/j.1365-277X.2012.01283.x -
BMC Pediatrics Jan 2018An estimated 11% of births occur preterm, and survival is improving. Early studies suggested an association between preterm birth and earlier puberty. Given the adverse... (Review)
Review
BACKGROUND
An estimated 11% of births occur preterm, and survival is improving. Early studies suggested an association between preterm birth and earlier puberty. Given the adverse outcomes associated with early puberty this could have significant public health implications. The objective of this review was to assess the timing of puberty after preterm birth.
METHODS
Pubmed, Embase, Popline, Global Health and Global Health Library were searched using terms relating to "premature birth", "menarche", "puberty" and "follow up studies". Inclusion criteria were a population consisting of pubertal or post-pubertal adolescents and adults; studies which defined preterm delivery in participants and compared outcomes to those after term delivery; and a quantitative assessment of pubertal onset. Assessment of risk of bias was conducted using principles from the Critical Appraisal Study Process.
RESULTS
Our search identified 1051 studies, of which 16 met the inclusion criteria. In females, 8 studies found no association between preterm birth and the timing of menarche. Five studies found earlier onset in preterm infants, 1 found later onset, and 1 showed both earlier and later menarche, depending on birth weight. The range of effect of studies showing earlier menarche was - 0.94 to -0.07 years in the preterm group, with a median of - 0.3 years. In males, 2 studies showed earlier onset of puberty in the preterm group, 5 showed no difference, and 1 showed later onset. Most studies did not present outcomes in the form of a mean with standard deviation, precluding a meta-analysis. There was insufficient data to address potential confounding factors.
CONCLUSIONS
The published evidence does not suggest that being born preterm leads to a significant acceleration in the onset of puberty. This should prove reassuring for public health purposes, and for clinicians counseling parents of infants born preterm.
Topics: Confounding Factors, Epidemiologic; Female; Gestational Age; Humans; Infant, Newborn; Infant, Premature; Menarche; Premature Birth; Sample Size; Selection Bias; Time Factors
PubMed: 29310614
DOI: 10.1186/s12887-017-0976-8