What is PRO?
PRO or Patient-reported
outcome is a relatively novel method to evaluate the
outcome of any treatment by clinician or researcher (in clinical
trial) purely based on the inputs got from the patient
alone.
Ask the doctor, why ask the patient?
Objective data regarding outcome can be given by the
treating physician (cure/survival/disability limitation), by investigations
(return of deranged biochemistry to normal) and by the caregiver (return to
functional normality). These are Observer-reported outcomes (OROs) and medicine
has long relied on these for evidence-based management.
Any illness followed by its treatment weighs
physically, mentally, emotionally, economically on the patient. Patients
perceive the outcome of the treatment in comparison to their expectations based
on prior knowledge. Patient response and compliance to treatment are
intricately linked to the ultimate treatment outcome.
What information do I want from the patient? – The
PRO instrument:
The outcome of interest
that we want to study is the PRO Concept, while the PRO instrument is the means
to collect the data related to the PRO concept, in the form of questionnaire
and the information and documentation that supports its use.
In other words, PRO instrument is a questionnaire that compiles data related to the PRO
concept of interest which can be summarized as a score.
Content validity is the extent to which an instrument
measures the concept of interest that is desired from both the developer’s and
user’s perspective.
Stepsinvolved are: -
1. Defining the concept – concept should be clearly defined
based on review and literature
gap analysisof existing PRO
instruments as well as taking inputs from scientific research
services, domain specialists, developers
and most importantly the patients or the users and should focus on the core
characteristics.
2.
Conceptual Framework – Breakdown
the concept to sub-concepts and finally to items or the questions that will be
included in the questionnaire. Each item should be crisp and clear with focus
on only one aspect. It should not unnecessarily cause strain to the patient in
recalling.
3. End-point Model– Endpoint
is the final measured outcome of the treatment that will be compared, and an
endpoint model summarises all the endpoint based on OROs and PROs.
4.
Review of Preliminary Instrument –
Literacy review is done to understand
the proportion of people who may or may not have the literacy level to take the
questionnaire.
Translation review is done to ensure conceptual equivalence when
translated to another language.
Cognitive interview is the process where the user is made
to take the questionnaire by thinking aloud to understand the approach of the
user to the questions and that it follows the intention of the item. This is
done until saturation is reached on the information received for reviewing the
instrument.
5.
Reliability Testing – Measure
to estimate reproducibility and consistent true estimation of outcomes under
consideration. It is further described below.
6.
Validation –
It is an ongoing never-ending
process of improving the instrument by repeated feedback mechanism.
Evaluating PRO instrument:
As clinical validation data
accumulates, a PRO instrument undergoes review and revision to make them
robust. It includes the evaluating for the following: -
1.
Validity– is
the extent to which the scores and their interpretations, supported by theoretical
evidence, correlate with the proposed use of the instrument.
2. Reliability-
a.
Reproducibility or test-retest reliability-It
is assessed under same conditions in same user in a close span of time to
assess any variations in recording results that can be attributed to the
instrument. It is calculated by intra-class correlation coefficient (ICC).
b.
Internal consistency- The
items should deliver same scores in similar situations consistently. It is
determined by Cronbach’s alpha or coefficient of reliability.
c.
Floor and ceiling effect–
i.e. the instrument’s ability to measure extremes of construct helps choose the
proper instrument for the study.
d.
Inter-interviewer reliability-there
should not be significant difference in scores when interviewed by two different
interviewers.
e.
Variability – Instrument
should have ability to detect changes when outcomes are different, else it is
no good.
Why pubrica?
When you order our services, we promise you the
following – Plagiarism free, always on Time, outstanding customer support,
written to Standard, Unlimited Revisions support and High-quality Subject
Matter Experts.
Comments
Post a Comment