What is Systematic Review and How to Conduct a Good Systematic Review of Randomized Controlled Trials

What is Systematic Review ? I Steps in Writing Systematic Review I Systematic Review Methodology 

Introduction

The amount of studies published in the biomedical literature has increased strikingly over the last few decades. This enormous abundance of published literature makes clinical medicine and decision making increasingly complex, and knowledge from various high quality researches is often needed to inform a particular clinical decision. However, available studies are often heterogeneous with regard to their design, quality, and studies subjects and may handle the research question in a different way.  

Systematic review has a high level of substantiation as represented by the evidence-based pyramid. Therefore, a well-conducted systematic review is considered a feasible solution in keeping health clinicians ahead regarding contemporary evidence-based medicine.

The role of evidence-based medicine in biomedical research is quickly mounting. Systematic reviews have gradually replaced expert commentaries and traditional narrative reviews as a way of summarising research evidence.   

A systematic review is a review of the evidence on a clearly formulated question that uses systematic methods to identify, collect and analyse data from the included studies in the review and critically appraise all relevant research. The methods used in the systematic review must be reproducible and transparent.

A systematic review can be of two types.

·       Quantitative systematic review: this will include studies that have numerical data

·   Qualitative systematic review: this will derive data from observation, interviews, or verbal   interactions and focuses on the meanings and interpretations of the participants. 

Check List for Conducting Systematic Review

Systematic Review Sections in a Published Literature  

1. Background

·         Brief contextual literature review

·         Research question or study aim

2. Methodology

·         Search procedures

·         Eligibility criteria: inclusion and exclusion criteria

·         Data extraction

·         Quality criteria and assessment

·         Data synthesis

·         Ethical considerations

3. Results/Findings

·         Study flow

·         Characteristics of included studies

·         Quality of included studies

·         Synthesis of data

4. Discussion

·         Revisiting the research question

·         Discussion in relation to previous research

·         Limitations of the review

·         Future research

·         Implications/recommendations

5. Conclusion

Stages in Conducting Systematic Review

1.        Formulate the review question

2.        Develop and register your protocol

3.        Define inclusion and exclusion criteria

4.        Develop search strategy and search databases

5.        Select and critically appraise the studies

6.        Extract relevant data

7.        Assess study quality

8.        Analyze and interpret results

Following Worldwide Databases can be used for Conducting Systematic Review 

·         PubMed https://pubmed.ncbi.nlm.nih.gov/

·         Cochrane https://www.cochranelibrary.com/

·         Clinical trials.gov https://clinicaltrials.gov/

·         EMBASE https://www.embase.com/

·         Scopus https://www.scopus.com/home.uri

·         Web of Science https://mjl.clarivate.com/search-results

·         Google Scholar https://scholar.google.com/

PRISMA Flow Diagram

PRISMA Flow Diagram helps in identification and screening of relevant studies.  

How to Assess the Quality of Randomized Controlled Trials/Studies

The quality of a randomized controlled trial to be assessed by finding out the answers to the following questions:  

1.         Was the treatment assigned to the groups random?

2.        Was the treatment allocation concealed?

3.        Were the treatment groups similar at baseline?

4.        Were the eligibility criteria specified?

5.        Were the investigator and the patient blinded?

6.   Was the measure of variability and point estimates presented for the primary outcome measure?   

7.        Were the analyses include intention‑to‑treat analysis?

Where to Register Systematic Review Protocol?

PROSPERO is an international database of prospectively registered systematic reviews.

Advantages of Systematic Reviews

·   Explicit methods limit bias in recognizing and eliminating studies
·   More reliable and accurate conclusions because of methods used
·   Large amounts of information can be accumulated quickly by healthcare providers,
     researchers, and policymakers 
·   Results of different studies can be formally compared to establish generalisability of
     findings and consistency of results
·   Systematic reviews increase the accuracy of the overall result

Limitations of Systematic Reviews

1.  Systematic reviews with narrowly defined review questions provide specific answers to
     specific questions
2.  Alternative questions that have not been answered usually need to be reconstructed by      the reader

Conclusions

In conclusion a systematic review is a method of critically appraising, summarising, and attempting to reconcile the evidence.

 

References

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2. Curtin University. https://libguides.library.curtin.edu.au/systematic-reviews.
3. Greenhalgh T. How to read a paper: Papers that summarise other papers (systematic reviews and metaanalyses). BMJ 1997;315:672.
4. Tawfik, G.M., Dila, K.A.S., Mohamed, M.Y.F. et al. A step by step guide for conducting a systematic review and meta-analysis with simulation data. Trop Med Health 47, 46 (2019). https://doi.org/10.1186/s41182-019-0165-6.
5. Terry Hanley & Laura Cutts. What is a systematic review? Counselling Psychology Review. 28(4). 2013.
6. Uman LS. Systematic reviews and meta-analyses. J Can Acad Child Adolesc Psychiatry. 2011;20(1):57-59.