Ethical research guidance and consulting services for PhD candidates since 2008

Cochrane reviews combine the best available evidence from a number of sources and summarise it in a set of systematic reviews, syntheses and meta-analyses. They are an important way to find out what works and what doesn’t when it comes to health care. A Cochrane review looks at all the available research on a topic, taking into account the quality of the studies, the strength of the evidence, and whether or not any biases might have affected the results. The Cochrane Methodology Group develops and publishes guidelines for conducting Cochrane Reviews.

Cochrane Reviews have several advantages over other types of research. They reduce bias by drawing on a large body of evidence that can be compared across different studies. They also give us confidence that we’re getting good information because they are reviewed by experts in the field who prioritise study quality.

What is a systematic review?

A systematic review is a type of meta-analysis that seeks to summarise the results of previous research studies. It can either be narrative or quantitative, depending on how it is conducted. Both types of reviews draw on past studies to determine the strength of evidence (i.e., whether there is enough evidence to support a conclusion). However, they differ in their approach and scope. Narrative reviews take a broader perspective by including all relevant studies, while quantitative reviews focus on one specific outcome.

In general, systematic reviews are more effective than individual studies because they take into account the results of previous research studies. However, they also have some limitations: 1) the review cannot confirm relationships that might exist between two variables; 2) the review cannot identify causal relationships; and 3) it cannot rule out alternative explanations for an observed association. In summary, systematic reviews can provide useful insights about current research topics, but it is important to keep in mind their limitations before drawing conclusions from them.

• Role in Medicine 

A systematic review is a critical tool used in evidence-based medicine. It allows researchers to evaluate the quality of existing research and synthesise the results of multiple studies. Systematic reviews are especially important in the field of health care, where high-quality evidence can guide decisions about treatment options. They aim to improve the decision making process by combining all the available evidence from a given area into one cohesive review.

Common issues that can lead to bias and poor quality include selection bias, contamination, and poor reporting of methods. By minimising these factors, systematic reviewers can produce more accurate and reliable results.

Systematic reviews are especially useful for healthcare professionals who need to make decisions about treatment options for patients or patients with health conditions. For example, someone who wants to prescribe antibiotics to an elderly patient may want to see if there’s a systematic review comparing different treatment regimens with antibiotics.

Steps in Cochrane Review Method

A Cochrane Review is a systematic review of research in health care and health policy that is published in the Cochrane Database of Systematic Reviews. For researchers in the biomedical field conducting a systematic review, the Cochrane method of systematic reviews can be adopted as they are  internationally recognized as the highest standard in evidence-based health care resources. The systematic review can be followed through the rigorous methods outlined in the Cochrane Handbook, this can also be found online at https://training.cochrane.org/handbooks. 

• Types of Cochrane Review

It would be helpful to understand the different types of reviews that Cochrane offers before selecting a specific guide for your research(Chapman, 2022):

• Intervention reviews assess the benefits and harms of interventions used in health care and health policy.
• Diagnostic test accuracy reviews assess how well a diagnostic test performs in diagnosing and detecting a particular disease.
• Methodology reviews address issues relevant to how systematic reviews and clinical trials are conducted and reported.
• Qualitative reviews synthesise qualitative evidence to address questions on aspects of interventions other than effectiveness.
• Prognosis reviews address the probable course or future outcome(s) of people with a health problem.

Resources for systematic review

Cochrane systematic review can be aided by certain software which are available from the Collaboration:

• Review Manager (RevMan) – software for preparing and maintaining Cochrane Reviews: protocols, manuscripts, characteristics of studies, comparison tables, study data, meta-analysis. In addition to reviews of studies of the effects of healthcare interventions, you can use RevMan to write reviews of diagnostic test accuracy studies, reviews of studies of methodology and overviews of reviews.
• Covidence – a primary screening and data extraction tool for Cochrane authors to assess risk-of-bias, and extract data.
• GRADEpro GDT – an online tool to create a Summary of Findings (SoF) table.
  • Summary of Findings Table:A summary of findings table presents the main findings of a review in a transparent and simple tabular format. In particular, the tables provide key information about the quality of evidence, the magnitude of effect of the interventions studied, and the quantity of data on the main outcomes. Most reviews would have just one summary of findings table.
• EPPI-Reviewer – a web-based tool which helps you with all stages of the systematic review process: reference management, screening, risk of bias assessment, data extraction and synthesis. 
• Archie– Cochrane’s database for managing contacts and documents and delivering them for publication. 

Conclusion

Cochrane reviews are used for PhD’s in some universities and medical colleges across India but most universities still require a primary study to explore the outcome of the reviews in a real world setting and to demarcate between practical applications and proposed theories. 

 Reference:

1. Chapman, S. (2022) What are Cochrane Reviews?, Evidently Cochrane. Available at: https://www.evidentlycochrane.net/what-are-cochrane-reviews/ (Accessed: 2022). 
2. Systematic reviews: Cochrane Systematic Reviews (no date) Research Guides. Available at: https://mdanderson.libguides.com/c.php?g=384755&p=7400484 (Accessed: 2022).