Targeted literature searches are a fundamental part of writing clinical manuscripts that will meet the standards of high-quality journals and contribute meaningfully to evidence-based practice. When physicians write clinical manuscripts, utilizing a targeted literature search can identify high-quality, relevant, and current evidence. While a general literature review is useful, a targeted literature search is specific to the clinical question and should be completed through frameworks established, such as PICO (Population, Intervention, Comparator, Outcome) and PRISMA [1].

How to Conduct a PICO-Based Clinical Literature Review

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How to Conduct a PICO-Based Clinical Literature Review

Table of Content
1. Understanding the PICO Framework
2. Step-by-Step Guide to Conducting a PICO-Based Clinical Literature Review
2.1. Define the Clinical Question
2.2. Search Strategy and Database Selection
2.3. Develop Inclusion and Exclusion Criteria
2.4. Screen and Select Studies
2.5. Data Extraction
2.6. Critical Appraisal
2.7. Data Synthesis and Analysis
2.8. Report Writing and Discussion
3. Tips for Effective PICO-Based Reviews
4. Conclusion
5. References

Clinical literature reviews are integral to evidence-based medicine (EBM), informing clinical and policy decisions. One of the most systematic strategies for developing clinical review questions is the PICO framework, which stands for Population, Intervention, Comparison, and Outcome. This method enhances search precision, improves the relevance of included studies, and supports replicable, systematic inquiry [1].

This article provides a step-by-step guide on conducting a PICO-based clinical literature review that is intended for students, clinicians, and researchers generating high-quality, focused reviews.

1. Understanding the PICO Framework

The PICO framework helps to translate a clinical question into a searchable format. It consists of [2]:

Example:

Category	Description	Example
P (Population)	The patient group or problem	Adults aged ≥65 with type 2 diabetes
I (Intervention)	The treatment or exposure	Metformin therapy
C (Comparison)	A control or alternative intervention	Sulfonylurea (Glipizide)
O (Outcome)	The expected result or effect	Cardiovascular mortality

“In older adults with type 2 diabetes, does metformin compared to sulfonylureas reduce cardiovascular mortality?”

2. Step-by-Step Guide to Conducting a PICO-Based Clinical Literature Review

2.1. Define the Clinical Question

Begin by translating the clinical problem into a clear, structured PICO question.

Example:

In adults with type 2 diabetes (P), does metformin (I), compared to insulin therapy (C), result in better glycaemic control (O)?

Begin by translating the clinical problem into a clear, structured PICO question.

2.2. Search Strategy and Database Selection

Use PICO elements to create a search strategy using Boolean operators and Medical Subject Headings (MeSH).

Databases commonly used:

PubMed/MEDLINE
Cochrane Library
CINAHL
EMBASE
Scopus

Example Search String (PubMed):

(“Type 2 Diabetes Mellitus”[MeSH]) AND (“Metformin”[MeSH] OR metformin) AND (“Insulin”[MeSH] OR insulin therapy) AND (“Glycated Haemoglobin A”[MeSH] OR HbA1c)

2.3. Develop Inclusion and Exclusion Criteria

Criteria should align with the PICO elements to ensure relevant data is captured.

Criteria Type	Inclusion Example	Exclusion Example
Population	ICU patients diagnosed with sepsis	Paediatric populations or outpatients
Intervention	Corticosteroid therapy within 24 hours	Corticosteroids initiated after 72 hours
Comparator	Placebo or no corticosteroid	Comparison to other immune-modulating drugs
Outcome	28-day all-cause mortality	Studies reporting only biochemical markers
Study Design	RCTs, cohort studies	Case reports, editorials, review articles

2.4. Screen and Select Studies

Use the PRISMA 2020 flowchart to document the selection process. Screening typically includes:

Title/Abstract screening
Full-text eligibility check
Duplicate removal

A software tool like Rayyan or Covidence can help manage this process systematically.

2.5. Data Extraction

Use a structured data extraction sheet that maps to the PICO elements.

Data Extraction Table

Study	P (Population)	I (Intervention)	C (Comparison)	O (Outcome)	Key Findings
Smith et al., 2021	Adults with sepsis	Hydrocortisone 200mg/day	Placebo	28-day mortality	Reduced mortality (RR 0.82)
Lee et al., 2022	ICU patients	Early methylprednisolone	Usual care	ICU length of stay	No significant difference

2.6. Critical Appraisal

Use standardized appraisal tools to evaluate the quality and bias of the included studies.

Recommended tools:

Cochrane Risk of Bias Tool (for RCTs)
Newcastle-Ottawa Scale (for cohort and case-control studies)
GRADE approach to rate the strength of evidence

Key aspects to assess:

Randomization method
Blinding
Attrition bias
Outcome assessment
Reporting bias

2.7. Data Synthesis and Analysis

If quantitative synthesis is possible, perform a meta-analysis. If not, conduct a narrative synthesis aligned with the PICO structure.

Meta-analytic Summary Example:

Cardiovascular mortality in the sulfonylurea group was not significantly higher compared with the metformin group (RR 1.47, 95% CI 0.54 to 4.01; I² = 0%) [3].

If heterogeneity is high (I² > 50%), consider subgroup analysis or random-effects models.

2.8. Report Writing and Discussion

Structure the review based on PRISMA or other relevant guidelines.

Sections to include:

Introduction: Rationale and objective
Methods: PICO question, databases, criteria, appraisal
Results: PRISMA flow, study characteristics, findings
Discussion: Clinical relevance, limitations, implications
Conclusion: Summary and recommendation for practice

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3. Tips for Effective PICO-Based Reviews

Ensure conceptual alignment between the PICO question and included studies.
Use MeSH terms and synonyms to capture all relevant articles.
Maintain a transparent audit trail using tools like EndNote or Zotero.
Report limitations, especially in population heterogeneity and outcome variability.
Engage a second reviewer for study selection to minimize bias.

Conclusion

A clinical literature review accomplished through the PICO framework will provide a definitive and reproducible methodological data approach to summarizing evidence. The PICO methodology is especially useful in the area of medical and healthcare research since clarifying intervention-outcome relationships is essential for decision-making.

Need help designing a PICO-based clinical review? Contact Pubrica for expert support in systematic evidence-based reviews.

References

Schardt, C., Adams, M. B., Owens, T., Keitz, S., & Fontelo, P. (2007). Utilization of the PICO framework to improve searching PubMed for clinical questions. BMC medical informatics and decision making, 7, 16. https://doi.org/10.1186/1472-6947-7-16
Hong, J., Zhang, Y., Lai, S., Lv, A., Su, Q., Dong, Y., … & Ning, G. (2013). Effects of metformin versus glipizide on cardiovascular outcomes in patients with type 2 diabetes and coronary artery disease. Diabetes Care, 36(5), 1304–1311. https://doi.org/10.2337/dc12-0719
Hemmingsen, B., Schroll, J. B., Wetterslev, J., Gluud, C., Vaag, A., Sonne, D. P., Lundstrøm, L. H., & Almdal, T. (2014). Sulfonylurea versus metformin monotherapy in patients with type 2 diabetes: a Cochrane systematic review and meta-analysis of randomized clinical trials and trial sequential analysis. CMAJ open, 2(3), E162–E175. https://doi.org/10.9778/cmajo.20130073