第5节 结果和讨论
对于系统文献综述，撰写研究结果和讨论时的技巧与其他类型的论文类似。具体可参考第2章第4节和第5节，这里仅对需要额外注意的地方进行说明。
与原创性研究有所不同，在撰写综述的结果时，要注意对各个研究结果的整合，尤其是当无法进行meta-analysis时。这里需要达到一个平衡：一方面要保证汇报的全面性；另一方面，又不可对所纳入文献的全部结果进行逐条汇报，否则读者很难抓住论文的重点。
在撰写结果时，可采取以下顺序撰写。首先，介绍文献检索结果，需汇报从初步检索到最终纳入分析的文献数量。结合PRISMA流程图进行介绍，无须重复流程图里介绍的全部内容，仅展示核心内容。其次，介绍纳入文献的基本特点，一般需要对各个研究总的样本量进行汇总。其余的内容，可根据表格中所展示的信息，进行分类汇总。再次，对质量评价结果进行汇报（这个部分，也可以放在前面介绍，注意逻辑性、层次性和流畅性）。最后，介绍主要研究结果。如果采用了meta-analysis，一般多采用森林图的形式展示；如果进行了敏感性分析、亚组分析或评估了发表偏倚，需提供相关结果。
下面以既往发表的一篇文献为例。本研究主要目的是“The aim of this systematic review is to summarize the effect of Mediterranean diet on serum metabolic indices and anthropometric measures among NAFLD patients”，如示例5-24所示，研究结果包含了以下几个方面（这里仅展示了小标题及每个段落的统领句）：文献检索结果，各研究的特点（作者先对各研究的基本特点进行了总结，并在同一段落介绍了各个研究的质量；紧接着，在此小标题下，又通过采用次级标题的形式，对主要结果进行汇报）。
示例5-24 研究结果展示形式
3.1 Database search
The literature search yielded 1142 studies，after removing duplicates（Fig.1）.
3.2 Study characteristics
The included trials were conducted between 2008［29］and 2018［30，31］...The quality of the study was measured by using the Jadad score.
3.2.1 Anthropometric variables
3.2.2 Lipid profile variables...
与原创性研究论文类似，系统文献综述的讨论部分也可以按照以下逻辑书写：概括段；针对主要研究结果分段进行讨论；说明研究的优势或特色（strengths）及局限性（limitations）；研究的启示（对于未来的科研及临床实践有何指导意义）；结论。各个段落的具体撰写要点，参见第2章相关内容，这里仅举例进行说明。同样，以上述论文为例，本研究的主要目的是“The aim of this systematic review is to summarize the effect of Mediterranean diet on serum metabolic indices and anthropometric measures among NAFLD patients”。
讨论包含了以下几个方面：总结概述（示例5-25，这里仅展示了这个段落的核心内容），说明本综述的创新性、主要内容及主要研究发现；此外，还针对主要结果展开了相应的讨论；同时，给出了本综述特色和局限性（示例5-26和示例5-27）；小结。
示例5-25 讨论的总结概述段
To the best of our knowledge，no systematic review has been published to assess the effects of MD on serum metabolic profile and anthropometric measures among NAFLD patients.Therefore，we gathered all the interventional studies，which assessed the effectiveness of MD on NAFLD.The present study included 10 randomized controlled trials，which involved a total of 856 adults with NAFLD.In the present systematic review，it was found that...
示例5-26 综述的特色
This systematic review has some strength；there is no previous systematic review that assessed the effect of a Mediterranean diet on metabolic parameters in patients with nonalcoholic fatty liver disease.Included RCTs were performed in different countries；therefore，differences in lifestyle were considered.There was no limitation for time and language in our systematic review.(https://www.daowen.com)
示例5-27 综述的局限性举例1
There are some limitations to this study that should be taken into account.First，significant heterogeneity was present between the included studies.Heterogeneity may be explained by different and mostly small sample size，different methods for assessment of NAFLD severity，duration of intervention and different ways to encounter control group.Second，there was variability in the control diets；therefore，we could not perform a meta-analysis to quantify the result.The limited number of included studies was also another limitation.Fourth，the effect of sex was not investigated in this review because none of the studies reported its result separately on female and male.
值得注意的是，系统文献综述的局限性这一部分与原始文献有所不同。它不仅需要包含综述层面的局限性，还要考虑所纳入的各个研究所具有的局限性（这也与PRISMA checklist要求的内容一致）。如示例5-27所示，本综述在综述层面的局限性（例如，所纳入各个研究之间的显著异质性及样本量偏小）和各研究本身存在的局限性（例如，未根据性别进行分析）。当然，也有作者着重介绍综述中所纳入各个研究本身存在的局限性，如示例5-28所示：研究多采用了横断面研究设计；研究对象多是学生和亚裔，人群代表性不强；主观测量存在局限性等。
示例5-28 综述的局限性举例2
There are some limitations in this meta-analysis.First，as mentioned earlier，22 of 23 analyzed studies were crosssectional studies，which cannot provide evidence in causality.Second，the majority of the participants were students and Asians，which restricts the present review's generalizability.Third，all the analyzed studies used self-reports in assessing IA or sleep.Therefore，well-known biases such as social desirability and memory recall bias cannot be excluded.Finally，this review cannot draw definitive conclusions concerning the effect of Internet addiction on circadian rhythm and the stability of sleep-wake schedules due to the lack of empirical evidence.
此外，撰写研究的启示一般多从两个方面开展：今后的科学研究以及临床实践（或者卫生政策）。根据期刊要求不同，有些要求作者在讨论中给出启示之后，还会要求使用“要点”的形式，说明本研究的启示。如示例5-29所示，作者从3个方面提出了本综述对临床实践的启示。如示例5-30所示，作者从4个方面提出了本综述对未来研究的启示。
示例5-29 综述对未来临床实践的启示要点
Practice points
1.Internet addiction may result in sleep problems，including lowered sleep quality and reduced sleep duration.
2.Current evidence demonstrates that the association between internet addiction and sleep disturbances exists across different countries，cultures，and ethnicities.
3.Using robust standardized psychometric measures（rather than self-designed measures）in assessing internet addiction and sleep quality is recommended.Standardized measures can ensure the validity and stability in assessing internet addiction and sleep.
示例5-30 综述对未来研究的启示要点
Research agenda
1.Using longitudinal designs and/or randomized controlled trials to assess the causality between internet addiction and sleep can provide healthcare providers direction in treating people with internet addiction problems or those with sleep problems.
2.Most of the studies included in the present metaanalysis comprised students and Asians，Therefore，studies on large samples of Caucasians and those in other age groups are needed to examine whether the association between internet addiction and sleep is consistent across ethnicities and age groups.
3.Studies on reducing or preventing internet addiction are needed to investigate whether the reduced internet addiction can help improve sleep.
4.Impacts of different types of internet addiction are needed to understand which types of internet addiction contribute most to the sleep problems.