Conducting a Systematic Review

In a nutshell, a systematic review is a secondary study from a collection of primary studies (original research) that pertain to a specific research question. Those primary studies have been analyzed, examined, appraised, and evaluated for the highest level of evidence and quality of methodology, in order to provide the best answer to a research question.

The methods and/or protocol of conducting a systematic review are clear, understandable, rigorous and transparent. In a systematic review, you should see:

• A clearly stated objective.
• Search Methods: The where, and the how. 
• Selection Criteria (inclusion/exclusion): What does the study need to look like to answer your research question.
  • Types of participants, problem, study design
  • Interventions, exposures, outcomes.
• See the example below:

Additional Definitions: 

Systematic reviews are often confused with review articles. This type of publication are often called narrative reviews or literature reviews. 

Literature reviews (or narrative reviews or review articles) are valuable and help to build one's knowledge base on a topic. However, they are quite different from systematic reviews.

• There is no research question.
• It is an overview or BROAD examination of the published literature on a topic.
• There is no critical appraisal of the research. No stated methods as it is not study, but rather a narrative review of the studies. 
• See the example below:

References

1.    Al-Jehani HM, Mousa AH, Alhamid MA, Al-Mufti F. Role of microRNA in the risk stratification of ischemic strokes. Front Neurol. 2025;16:1499493. doi:10.3389/fneur.2025.1499493

2.    Brubaker M, Kapadia S, Maletic V, Chambers JS, Watling CP, Citrome L. Preclinical Evidence for the Use of Brexpiprazole + Antidepressant Treatment for Major Depressive Disorder and Post-Traumatic Stress Disorder: A Systematic Review. Neuropsychiatr Dis Treat. 2025;21:421-436. doi:10.2147/ndt.S501207

3.    Dutta P, Ganduboina R, Muderrisoglu C, et al. Hemoadsorption use in adult cardiac surgery for infective endocarditis: A comprehensive meta-analysis. Asian Cardiovasc Thorac Ann. Mar 28 2025:2184923251328119. doi:10.1177/02184923251328119

4.    Elfil M, Ghaith HS, Elmashad A, et al. Adjunctive middle meningeal artery embolization for chronic subdural hematoma: A systematic review and meta-analysis of clinical trials. J Neurol Sci. Mar 21 2025;472:123469. doi:10.1016/j.jns.2025.123469

5.    Etemadi A, Hosseini M, Rafiee H, et al. Comparative diagnostic accuracy of pre-test clinical probability scores for the risk stratification of patients with suspected pulmonary embolism: a systematic review and Bayesian network meta-analysis. BMC Pulm Med. Apr 8 2025;25(1):162. doi:10.1186/s12890-025-03637-6

6.    Gera P, Frishman WH, Aronow WS. The Use of Statins During Pregnancy in Patients Diagnosed With Preeclampsia: A Systematic Review. Cardiol Rev. Mar 24 2025;doi:10.1097/crd.0000000000000906

7.    Harmouch KM, Hamza M, Kumar N, et al. Revascularization Strategies for Multivessel Disease in Acute Coronary Syndrome: Network Meta-analysis. J Soc Cardiovasc Angiogr Interv. Jan 2025;4(1):102449. doi:10.1016/j.jscai.2024.102449

8.    Naeem A, Kelani H, Salamah HM, et al. Impact of prior antiplatelet therapy on safety and efficacy of alteplase in acute ischemic stroke: a systematic review and meta-analysis. Neurol Sci. Feb 22 2025;doi:10.1007/s10072-025-08024-x

9.    Ojukwu E, Pashaei A, Maia JC, Omobhude OF, Tawfik A, Nguyen Y. Impacts of the COVID-19 Pandemic on the HIV Care Continuum and Associated Factors in High-Income Nations: A Mixed-Methods Systematic Review. AIDS Behav. Apr 2025;29(4):1362-1399. doi:10.1007/s10461-025-04671-5

10.    Stonebraker C, Pein R, Valley ZA, Estes CM, Garber D. Demographics, Management, and Outcomes Associated With Idiopathic Vocal Fold Paralysis: A Systematic Review. Otolaryngol Head Neck Surg. Mar 7 2025;doi:10.1002/ohn.1195
 

• The Campbell Collaboration is an international research network that produces systematic reviews of the effects of social interventions focusing on education, crime and justice, and social welfare.
• The Centre for Reviews and Dissemination (CRD) databases are updated daily and provide decision-makers with access to quality assessed systematic reviews, economic evaluations, summaries of health technology assessments, summaries of all Cochrane reviews and protocols, and summaries of Campbell reviews.
• The Cochrane Database of Systematic Reviews (CDSR) includes the full text of regularly updated systematic reviews of the effects of healthcare prepared by The Cochrane Collaboration.
• The Database of Abstracts of Reviews of Effects (DARE) covers a broad range of health related interventions and complements the CDSR by quality-assessing and summarizing reviews that have not yet been carried out by the Cochrane Collaboration. Each abstract includes a summary of the review together with a critical commentary about the overall quality.
• Both PubMed and PubMed Clinical Queries can be used to locate systematic reviews. The Clinical Queries tool retrieves citations identified as systematic reviews, meta-analyses, reviews of clinical trials, evidence-based medicine, consensus development conferences, guidelines, and citations to articles from journals specializing in review studies of value to clinicians.

NOTE: Linking to the Cochrane Databases and PubMed through the Health Sciences Library ensures that you have access to the full text of systematic reviews and articles when available.