Clinical Evidence and Intended Use
Framework Position
This chapter establishes the foundation of clinical evaluation.
Before evidence is appraised, it must be clearly defined in relation to:
- the medical device
- its intended purpose
- its intended use
What is clinical evidence?
Clinical evidence refers to data that supports the safety, performance, and clinical benefit of a medical device. (“Regulation (EU) 2017/745 on Medical Devices” 2017).
Sources include:
- clinical investigations
- published literature
- post-market surveillance data
- real-world evidence
The key question is not:
Do we have evidence?
But:
👉 Is this evidence appropriate for this device and its intended use?
Intended purpose vs intended use
Intended purpose
Describes:
- what the device is designed to do
- its medical objective
Intended use
Describes:
- who the device is used on
- under what conditions
- in what setting
This distinction is critical.
Evidence must align with both.
Why intended use matters
Intended use determines:
- relevant population
- appropriate endpoints
- acceptable risk profile
- clinical context
If evidence does not match intended use, it weakens the evaluation.
Evidence–claim alignment
A central principle:
👉 Evidence must be fit for purpose and aligned with intended use
This means:
- aligned with the claim being made
- relevant to the clinical context
- sufficient in scope and quality
Common issues
- Using evidence from different populations
- Ignoring intended use conditions
- Overextending findings beyond study scope
- Mixing endpoints that do not support the claim
A Simple Example: From Data to Clinical Evidence
To make these concepts concrete, consider the following example.
Example: Wearable Blood Pressure Monitor
To understand what clinical evidence means in practice, consider a simple example.
A company develops a wearable blood pressure monitor intended for continuous, non-invasive measurement in adults with hypertension.
Intended Use
The device is intended to:
- measure blood pressure continuously throughout the day
- support monitoring of hypertension trends
- assist clinicians in patient management
- be used in ambulatory, real-world conditions
Clinical Question
Can the wearable device provide measurements that are sufficiently accurate and useful compared to a standard clinical blood pressure cuff?
Data Collected
To answer this, data are collected from:
- patients using the wearable device
- the same patients measured using a validated cuff device (reference standard)
- multiple measurements across different conditions (rest, movement)
Observed Results
Initial findings show:
- measurements from the wearable device closely follow the reference device
- small differences are observed (within a few mmHg in most cases)
- accuracy decreases slightly during movement
From Results to Evidence
At this point, we do not yet make a claim.
Instead, we ask:
- Are the differences clinically acceptable?
- Is the performance consistent under intended conditions?
- Do the limitations affect how the device will be used?
This step — interpreting results in context of intended use — is what turns data into evidence.
Clinical Evidence (Conceptual)
From this evaluation, we may conclude:
- the device performs comparably to the reference under typical conditions
- it provides additional value through continuous monitoring
- limitations (e.g., movement sensitivity) are understood and manageable
Defensible Claim (What we are working toward)
The device provides clinically acceptable blood pressure measurements for continuous monitoring under intended use conditions and supports improved management of hypertension.
This example illustrates how clinical evidence is always evaluated in relation to intended use.
Key takeaway
Clinical evidence is only meaningful when interpreted in relation to intended use.
This chapter defines the foundation on which all further evaluation is built.
What comes next
The next chapter examines how evidence is appraised at the study level.