Review articles are a means of summarizing the potentially vast volume of research on a topic. However, the methodological quality of review articles varies, and reviews on the same topic may reach different conclusions. We evaluated 65 review articles published between 2000 and 2005 that addressed the effectiveness of microbial food safety interventions, using criteria for methodological soundness developed in the medical field. Overall, the methodological quality of the review articles was poor, with none of the reviews providing information on the method of locating primary research studies or the inclusion/exclusion criteria for selecting primary studies. None of the reviews included a critical appraisal of the methodological quality of the primary studies. Less than half of the reviews stated a focused research question, explored possible reasons for differences in the results of primary studies, discussed the generalizability of results, or proposed directions for future research. There is a need to improve the methodological quality of review articles on microbial food safety interventions if they are to be of use in policy and decision making.
"The reporting of multiple outcomes is common in controlled trials in veterinary medicine (Sargeant et al., 2006, 2009a,b, 2010b). Often, different outcomes measure different aspects of potential intervention effects, such as outcomes related to morbidity or mortality and outcomes related to quality of life or production/performance. "
[Show abstract][Hide abstract] ABSTRACT: This article is the third of six articles addressing systematic reviews in animal agriculture and veterinary medicine. This article provides an overview of clinical trials, both randomized controlled trials (RCTs) and challenge trials, where the disease outcome is deliberately induced by the investigator. RCTs are not the only study design used in systematic reviews, but are preferred when available as the gold standard for evaluating interventions under real-world conditions. RCTs are planned experiments, which involve diseased or at-risk study subjects and are designed to evaluate interventions (therapeutic treatments or preventive strategies, including antibiotics, vaccines, management practices, dietary changes, management changes or lifestyle changes). Key components of the RCT are the use of one or more comparison (control) groups and investigator control over intervention allocation. Important design features in RCTs include as follows: how the population is selected, approach to allocation of intervention and control group subjects, how allocation is concealed prior to enrolment of study subjects, how outcomes are defined, how allocation to group is concealed (blinding) and how withdrawals from the study are managed. Guidelines for reporting important features of RCTs have been published and are useful tools for writing, reviewing and reading reports of RCTs.
Zoonoses and Public Health 06/2014; 61 Suppl S1:18-27. DOI:10.1111/zph.12126 · 2.37 Impact Factor
"Some of the disadvantages to using reviews are that they are sometimes not easy to adapt to individual cases, they become outdated as new research is published, the quality of the review itself needs to be addressed, and one can often find conflicting results between reviews (Barnes and Bero, 1998; Hoving et al., 2001). Evaluations of traditional narrative reviews in the medical literature (Mulrow, 1987; McAlister et al., 1999) and on-farm food safety literature (Sargeant et al., 2006b) illustrate that these reviews do not report the use of scientific methods to identify, assess and synthesize the literature available on the review topic, potentially resulting in invalid conclusions. "
[Show abstract][Hide abstract] ABSTRACT: This article is the first in a series of six articles related to systematic reviews in animal agriculture and veterinary medicine. In this article, we overview the methodology of systematic reviews and provide a discussion of their use. Systematic reviews differ qualitatively from traditional reviews by explicitly defining a specific review question, employing methods to reduce bias in the selection and inclusion of studies that address the review question (including a systematic and specified search strategy, and selection of studies based on explicit eligibility criteria), an assessment of the risk of bias for included studies and objectively summarizing the results qualitatively or quantitatively (i.e. via meta-analysis). Systematic reviews have been widely used to address human healthcare questions and are increasingly being used in veterinary medicine. Systematic reviews can provide veterinarians and other decision-makers with a scientifically defensible summary of the current state of knowledge on a topic without the need for the end-user to read the vast amount of primary research related to that topic.
Zoonoses and Public Health 06/2014; 61 Suppl S1(S1):3-9. DOI:10.1111/zph.12128 · 2.37 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Literature reviews are important information sources for multiple stakeholders in zoonotic public health with limited time to keep up with the rapid increase in primary research in this field. However, their validity depends on their methodological soundness. The study purpose was to evaluate the methodological soundness of literature reviews in zoonotic public health. Relevant reviews (n = 132) published between January 2000 and August 2006 were identified on three issues: Mycobacterium avium ssp paratuberculosis as a potential cause of Crohn's disease in humans (30 reviews); antimicrobial use in animals as a risk factor for antimicrobial resistance in human pathogens (36); and the zoonotic potential of transmissible spongiform encephalopathies (66). The zoonotic aspect of the issue was the focus of 59 reviews and a subsection of 73 reviews. Two independent reviewers evaluated reviews using 13 criteria: 10 previously validated in the medical field, and three applicable to aetiology research. No review met more than eight of 13 criteria for methodological soundness; two articles met only one criterion. Two reviews described methods for identifying relevant primary research. In only two and four reviews respectively, authors conducted quantitative syntheses of research evidence or reported summarized measures of effect for the zoonotic risk to humans. Recommendations for future research and economic impact were provided in 64 and 10 reviews respectively. In 14 reviews, conclusions exceeded evidence presented. The various review authors' position on the evidence for the zoonotic association and the zoonotic risk to public health were inconsistent for all three issues. Reviews addressing potential zoonotic public health issues lack structured and transparent methodology preventing the end user from assessing the review's validity. These reviews should adhere to structured scientific principles similar to what is used for primary research articles.
Zoonoses and Public Health 02/2009; 56(9-10):477-89. DOI:10.1111/j.1863-2378.2008.01194.x · 2.37 Impact Factor
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