How to Synthesize Evidence as a Medical Student: Reflections From a Latin American Medical Student
"Students should limit themselves to studying medicine through books and only begin research once they are physicians." Students who propose research ideas often hear this response from teachers.
This perspective piece is written for those who, despite the obstacles, have a burning passion to immerse themselves in research. Primary investigation is limited now more than ever before. Despite this limitation, students interested in research should not give up and must continue in order to discover what lies on the other side of research. In this article I will discuss the importance of systematic reviews from a medical student's point of view.
Systematic reviews are secondary studies to answer a question, usually using the PICO style (population-intervention-control-outcome), but can be adapted to PECO (population-exposure-control-outcome) or PO (population-outcome) styles. For example:
- PICO: what is the efficacy and safety of SGLT2 inhibitors compared to placebo in heart failure patients?
- PECO: does being hypertensive, compared to not being hypertensive, increase mortality in COVID-19 pneumonia?
- PO: what are the clinical characteristics, diagnosis and management (outcomes) of patients with intracranial complications due to rhinosinusitis?
I recommend using different databases and having an appropriate knowledge of search strategies. The latter is the most important step because if there is an error, the whole review will be inadequate. Once you have exported the references from each database, it is necessary to remove duplicates using a reference manager. For selection, it is necessary that at least three people are involved since it should be carried out independently by two reviewers to reduce errors and report the Kappa coefficient for transparency, and a moderator to resolve study conflicts between reviewers.
Personally, I have learned that quantitative synthesis (i.e. meta-analysis, meta-regression) is not the goal of your review, but qualitative synthesis. You should write and organize your tables not for you to read, but for others to read in the most logical way possible. Always think of the readers.
So far, we have just described the theory and from this point forward you will read my reflections and recommendations.
Lack of mentors
In mid-2018, I had partially read the concept of systematic reviews, but did not understand its methodology, and without a mentor I did not have the opportunity to vocalize my ideas. At the end of that year, I was selected to join a rotation in a local public health institution, where the authorities provided me the methodological material and integrated me into a review. Before this rotation, I was limited by the lack of mentoring programs, and my mistake was not pursuing the accomplishment of my research project. For this reason, I recommend that you read the Cochrane's Handbook or another practical manual before venturing into a systematic review. These manuals will give you a deeper understanding of the methodology and meta-analyses.
Not everyone knows how to conduct a systematic review
Many people do not understand how to conduct systematic reviews. What should you do when you are a part of a complex study with other people who are inexperienced in conducting systematic reviews? The answer is easy: become a popularizer of science! Initially, my research group did not know the methodology, so I proposed to schedule dedicated time to teach the theory/practice. Now, more than five of my colleagues know the methodology and are now conducting their own reviews.
Money for paid databases
Fortunately, my study center gives me access to some paid databases, however, not all students have the same opportunity. It is not the end of the world if you do not have access to paid databases. Doing a search using few databases is not the most appropriate, thus the editor or reviewers of the journal may reject your study. You could mention that you did a manual search using Google Scholar or references of other related reviews. Another option is to conduct the study with a mentor or students who have access to a paid database. You can even apply for funding and invest it in resources such as databases.
Search strategy is based on trial and error
Formulating a search strategy is a complex and time-consuming issue. I learned through these three procedures: 1) reviewing the search strategy of several published systematic reviews; 2) reviewing methodological papers; 3) observing experienced people. I recommend taking at least a month to practice with non-real PICO questions. Trial and error are the basis for acquiring not only speed, but precision.
A medical student can be very skilled in the methodology of systematic reviews, but objectively specialists have a greater understanding of the subject. Your paper should be reviewed by a specialist. Then, you have to be attentive about how you write, since it has to be direct and pleasant for your readers. Remember that you could help save a life through publishing quality information in the form of well-conducted reviews that are read by health professionals.
With determination and curiosity, medical students can conduct research. Evidence synthesis is necessary to evaluate new interventions to improve the lives of patients, and this methodology should not be limited to postgraduates. It is necessary for Latin America to invest more in education that integrates the student into research, since without science, there is no future.
- Chambergo-Michilot D, Tauma-Arrué A, Loli-Guevara S. Effects and safety of SGLT2 inhibitors compared to placebo in patients with heart failure: A systematic review and meta-analysis. IJC Heart & Vasculature. 2021;32:100690.
- Pranata R, Lim MA, Huang I, Raharjo SB, Lukito AA. Hypertension is associated with increased mortality and severity of disease in COVID-19 pneumonia: A systematic review, meta-analysis and meta-regression. J Renin Angiotensin Aldosterone Syst. 2020;21(2).
- Patel NA, Garber D, Hu S, Kamat A. Systematic review and case report: Intracranial complications of pediatric sinusitis. Int J Pediatr Otorhinolaryngol. 2016;86:200–12.
This article was authored by Diego Chambergo-Michilot, medical student at the Universidad Científica del Sur in Lima, Peru. Twitter: @DiegoMichilot