Systematic literature reviews use structured methods to identify, assess and summarise the available evidence on a specific healthcare question.
In HTA, systematic literature reviews help decision-makers understand what evidence exists for a medicine, medical device, diagnostic test, digital health solution or healthcare intervention.
They are often used to support clinical effectiveness assessments, safety reviews, economic models, value dossiers, reimbursement submissions and evidence gap analyses.
Unlike a narrative review, a systematic literature review follows a transparent and reproducible process. It uses predefined research questions, search strategies, eligibility criteria, screening methods and quality assessment.
In simple terms, a systematic literature review helps answer an important question:
What does the total body of evidence show?
Why are systematic literature reviews important?
HTA decisions need to be based on complete and reliable evidence.
A systematic literature review helps ensure that relevant studies are identified and assessed in a structured way. This reduces the risk of selecting evidence selectively or missing important data.
For healthcare companies, systematic literature reviews can help clarify the strength of the evidence base, identify gaps and support the development of value messages.
They can also provide inputs for health economic models, including clinical effectiveness, safety outcomes, quality of life, resource use and epidemiology.
For decision-makers, a well-conducted systematic review helps create confidence that the evidence has been gathered and interpreted transparently.
What is network meta-analysis?
Network meta-analysis is a statistical method used to compare multiple treatments within a connected evidence network.
It is especially useful when direct head-to-head trials are limited or unavailable.
For example, one treatment may have been compared with placebo in one trial, while another treatment has also been compared with placebo in a different trial. Network meta-analysis may help estimate how those treatments compare indirectly.
In HTA, this can be very important because reimbursement bodies often want to know how a new technology compares with existing alternatives or the local standard of care.
Network meta-analysis can support comparative effectiveness, safety evaluation, economic modelling and payer communication.
How do evidence synthesis methods support market access?
Evidence synthesis helps transform scattered scientific evidence into a clear and structured understanding of value.
For market access, this is essential.
A company may need to show how its technology compares with existing treatments, what outcomes are clinically meaningful, what evidence supports its value and where uncertainty remains.
Systematic literature reviews and network meta-analysis can support reimbursement submissions, value dossiers, payer materials, economic models and HTA responses.
They also help identify evidence gaps that may need to be addressed through additional analysis, real-world evidence or local adaptation.
What evidence can be included in a systematic literature review?
The evidence included in a systematic literature review depends on the research question.
In HTA and market access, reviews may include randomised controlled trials, clinical trials, observational studies, real-world evidence, safety studies, economic evaluations, quality of life studies, epidemiological studies and treatment guideline evidence.
The scope should be defined carefully before the review begins.
A clear research question helps determine which databases should be searched, what eligibility criteria should be used and which outcomes should be extracted and analysed.
The quality of the review depends on the transparency and rigour of the process.
Final thoughts
Systematic literature reviews and network meta-analysis are important tools for HTA, reimbursement and market access.
They help organise the available evidence, support comparative assessment and provide inputs for economic models and value communication.
When conducted properly, they make the evidence base clearer, more transparent and more useful for decision-making.
At Clevidence, we support organisations with systematic literature reviews, network meta-analysis, indirect treatment comparisons, evidence synthesis, evidence gap analysis and HTA submission preparation.