Systematic reviews are a valuable tool to inform healthcare decision-making.1 2 While a single randomised controlled trial (RCT) is insufficient to definitively guide healthcare decisions, a systematic review synthesising multiple RCTs can overcome this limitation. The results of rigorous systematic reviews possess wide-ranging applicability to numerous stakeholders within the evidence-based medicine ‘ecosystem’. Clinicians consult systematic reviews to inform their clinical decisions.3 Researchers rely on systematic reviews to identify knowledge gaps in existing literature.4 Health policymakers use systematic review evidence to inform practice guidelines and legislation.5 6 Journal editors often prioritise systematic reviews for their impact on readership attention and journal metrics.7 Finally, patients are empowered by systematic reviews that assess the beneficial and harmful patient-important outcomes of available management strategies.8 Evidently, systematic review authors have an important responsibility to ensure their findings provide the most accurate results possible. The biomedical literature expands by 22 systematic reviews daily,9 with no evidence that production is waning. More systematic reviews are desirable if they identify and inform important research questions that improve patient care.10 However, production of this magnitude is problematic when systematic reviews offer ‘extensive redundancy, little value, misleading claims and/or vested interests’.11 As we outlined in part 1, bias is a systematic deviation from the truth in the results of a research study due to limitations in study design, conduct, or analysis.2 Deviations may either overestimate or underestimate a study’s true findings depending of the type and magnitude of bias. As the results of a systematic review are only as valid as the studies it includes, pooling biased results from different studies can compromise the credibility of systematic review findings when no assessment, or a poor assessment, of risk of bias is performed.3 12 Inadequate study design, conduct, or analysis …

中文翻译：

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鉴定“不可思议”！第 2 部分：找出差异 - 严格的偏倚风险评估可能会改变系统评价的主要发现

系统评价是为医疗保健决策提供信息的宝贵工具。1 2 虽然单个随机对照试验 (RCT) 不足以明确指导医疗保健决策，但综合多个 RCT 的系统评价可以克服这一限制。严格系统评价的结果对循证医学“生态系统”内的众多利益相关者具有广泛的适用性。临床医生咨询系统评价以告知他们的临床决策。3 研究人员依靠系统评价来确定现有文献中的知识差距。4 卫生政策制定者使用系统评价证据来为实践指南和立法提供信息。5 6 期刊编辑通常优先考虑系统评价对它们的影响读者关注度和期刊指标。7 最后，系统评价赋予患者权力，系统评价评估现有管理策略对患者的有益和有害结果。8 显然，系统评价作者有重要责任确保他们的发现提供尽可能准确的结果。生物医学文献每天增加 22 篇系统评价，9 没有证据表明产量正在下降。如果系统评价能够识别并告知改善患者护理的重要研究问题，则需要更系统的评价。10 然而，当系统评价提供“大量冗余、价值不大、误导性主张和/或既得利益”时，这种规模的生产是有问题的。 11 正如我们在第 1 部分中概述，偏差是由于研究设计、实施或分析的限制而导致研究结果与真相的系统性偏差。2 偏差可能高估或低估研究的真实结果，具体取决于偏差的类型和程度。由于系统评价的结果仅与其所包含的研究一样有效，因此在未对偏倚风险进行评估或评估不佳的情况下，将来自不同研究的偏倚结果汇总可能会损害系统评价结果的可信度。 3 12 不充分研究设计、实施或分析……