Systematic Reviews and Meta-Analyses
Systematic reviews are an umbrella term for a number of different review designs, all with specific goals (e.g., identify scope of available research or gaps, reduce bias, statistically combine and analyze results from multiple studies). They differ from basic literature review articles that qualitatively summarize the literature on a topic and do not necessarily have inclusion or exclusion criteria.
Epidemiological meta-analyses are quantitative types of systematic reviews, in which summary measures of exposure–outcome associations are calculated based on the results of a selection of existing studies. In other words, a meta-analysis statistically combines the results from multiple studies, with the goal of calculating more precise measures, increasing sample size, or reducing bias in the combined results. The goal of meta-analysis is to obtain a more robust understanding of the relationship between an exposure and a health outcome than could be obtained from a single study. While meta-analyses are considered to be strong research designs because of their formal, statistical characteristics, they are not without weakness or critics. For instance, existing studies included in a meta-analysis may have strengths and limitations of their own.
For this Discussion, you examine the validity and strengths and limitations of systematic reviews and meta-analyses in epidemiological research.
Resources
Be sure to review the Learning Resources before completing this activity.
Click the weekly resources link to access the resources.
· Driscoll, A., Grant, M. J., Carroll, D., Dalton, S., Deaton, C., Jones, I., Lehwaldt, D., McKee, G., Munyombwe, T., & Astin, F. (2018).
The effect of nurse-to-patient ratios on nurse-sensitive patient outcomes in acute specialist units: A systematic review and meta-analysisLinks to an external site..
European Journal of Cardiovascular Nursing,
17(1), 6–22.
· Seidler, A. L., Hunter, K. E., Cheyne, S., Berlin, J. A., Ghersi, D., & Askie, L. M. (2020).
Prospective meta-analyses and Cochrane’s role in embracing next-generation methodologiesLinks to an external site..
Cochrane Database of Systematic Reviews,
10, ED000145.
· Page, M. J., McKenzie, J. E., Bossuyt, P. M., Boutron, I., Hoffmann, T. C., Mulrow, C. D., Shamseer, L., Tetzlaff, J. M., Akl, E. A., Brennan, S. E., Chou, R., Glanville, J., Grimshaw, J. M., Hróbjartsson, A., Lalu, M. M., Li, T., Loder, E. W., Mayo-Wilson, E., McDonald, S., McGuinness, L. A., … Moher, D. (2021).
The PRISMA 2020 statement: An updated guideline for reporting systematic reviewsLinks to an external site..
Journal of Clinical Epidemiology,
134, 178–189.
· Haidich, A. B. (2010).
Meta-analysis in medical researchLinks to an external site..
Hippokratia, 14 (Suppl. 1), 29–37.
· Melnyk, B. M., Kelly, S. A., Stephens, J., Dhakal, K., McGovern, C., Tucker, S., Hoying, J., McRae, K., Ault, S., Spurlock, E., & Bird, S. B. (2020).
Interventions to improve mental health, well-being, physical health, and lifestyle behaviors in physicians and nurses: A systematic reviewLinks to an external site..
American Journal of Health Promotion,
34(8), 929–941.
· Siddaway, A. P., Wood, A. M., & Hedges, L. V. (2019).
How to do a systematic review: A best practice guide for conducting and reporting narrative reviews, meta-analyses, and meta-synthesesLinks to an external site..
Annual Review of Psychology,
70, 747–770.
To prepare:
· Review the studies and articles provided in the Learning Resources. Consider the strengths and limitations of systematic reviews and meta-analyses. Make sure you are clear on the difference between the two approaches.
By Day 3 of Week 8
Post a brief summary of your informed opinion regarding the validity of the use of systematic reviews
and meta-analyses in epidemiological research. Include
at least two strengths or limitations of each technique. Provide evidence from
at least one of the articles in the Learning Resources to support and justify your position.
By Day 6 of Week 8
Post substantive responses to
at least two colleagues
on two different days who expressed a differing view to your own in their initial post. Include information from the Learning Resources in your responses as appropriate. You may expand on your peer’s posting with additional insight and resources about meta-analyses, ask a question to further the Discussion, or offer polite disagreement or critique, supported with evidence. You may also make a suggestion or comment that guides or facilitates the Discussion.
RESPOND TO THIS DISCUSSION POST
Simon
Systematic reviews and Meta-analyses
Systematic reviews and meta-analyses are regarded as gold standards in evidence-based epidemiological research due to their structured methodology and comprehensive synthesis of available data. However, other types of literature reviews—such as narrative reviews, scoping reviews, and rapid reviews—also contribute meaningfully to the research landscape, each with distinct strengths and limitations.
Systematic reviews use predefined protocols to identify, appraise, and synthesize all relevant studies on a specific topic. One strength is their rigorous and reproducible approach, which minimizes bias and enhances the credibility of the findings (Page et al., 2021). Another strength is their ability to provide a high level of evidence that can guide clinical practice and policymaking. However, systematic reviews are often time-consuming and resource intensive. They also depend heavily on the quality of the included studies—poor-quality inputs can lead to unreliable conclusions (Haidich, 2010).
Meta-analyses build on systematic reviews by statistically combining data from multiple studies. Their strengths include increased statistical power and the ability to detect small but clinically significant effects (Haidich, 2010). They also help in generalizing findings across diverse populations. Limitations include heterogeneity between studies (differences in populations, interventions, or outcomes), which can complicate interpretation. Additionally, meta-analyses can be skewed by publication bias or inclusion of low-quality studies (Seidler et al., 2020).
The study by Driscoll et al. (2018) exemplifies how a systematic review and meta-analysis can produce compelling evidence—in this case, the association between nurse-to-patient ratios and patient outcomes in acute care settings. The review’s robust methodology and statistical synthesis allowed the authors to conclude that better staffing is associated with improved patient outcomes, which is valuable for healthcare planning and workforce policy.
Besides systematic reviews and meta-analyses,
narrative reviews are another common type. These are more flexible and provide a broad overview of a topic, often including expert opinions. While they are useful for theory development or exploring emerging areas, they are more susceptible to author bias due to the lack of a standardized methodology (Grant & Booth, 2009).
Scoping reviews aim to map the existing literature on a topic and identify key concepts, gaps, and types of evidence available. They are particularly useful in areas with emerging evidence or interdisciplinary research. However, scoping reviews typically do not assess the quality of the included studies or provide detailed synthesis, limiting their utility for evidence-based practice (Munn et al., 2018).
In conclusion, while systematic reviews and meta-analyses offer a high level of evidence and are integral to epidemiological research, other types of reviews also serve valuable purposes depending on the research objective. Each type has its strengths and limitations, and the choice of review should align with the goals, resources, and maturity of the research topic.
References
Driscoll, A., Grant, M. J., Carroll, D., Dalton, S., Deaton, C., Jones, I., Lehwaldt, D., McKee, G., Munyombwe, T., & Astin, F. (2018). The effect of nurse-to-patient ratios on nurse-sensitive patient outcomes in acute specialist units: A systematic review and meta-analysis.
European Journal of Cardiovascular Nursing, 17(1), 6–22.
Links to an external site.
Grant, M. J., & Booth, A. (2009). A typology of reviews: An analysis of 14 review types and associated methodologies.
Health Information & Libraries Journal, 26(2), 91–108.
Haidich, A. B. (2010). Meta-analysis in medical research.
Hippokratia, 14(Suppl. 1), 29–37.
Links to an external site.
Munn, Z., Peters, M. D. J., Stern, C., Tufanaru, C., McArthur, A., & Aromataris, E. (2018). Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach.
BMC Medical Research Methodology, 18, 143.
Page, M. J., McKenzie, J. E., Bossuyt, P. M., Boutron, I., Hoffmann, T. C., Mulrow, C. D., Shamseer, L., Tetzlaff, J. M., Akl, E. A., Brennan, S. E., Chou, R., Glanville, J., Grimshaw, J. M., Hróbjartsson, A., Lalu, M. M., Li, T., Loder, E. W., Mayo-Wilson, E., McDonald, S., McGuinness, L. A., … Moher, D. (2021). The PRISMA 2020 statement: An updated guideline for reporting systematic reviews.
Journal of Clinical Epidemiology, 134, 178–189.
Links to an external site.
Seidler, A. L., Hunter, K. E., Cheyne, S., Berlin, J. A., Ghersi, D., & Askie, L. M. (2020). Prospective meta-analyses and Cochrane’s role in embracing next-generation methodologies.
Cochrane Database of Systematic Reviews, 10, ED000145.
Links to an external site.
