Rev Bras Fisiol Exerc 2020;19(4):267-69
doi: 10.33233/rbfex.v19i4.4235
OPINION
Types
of outcomes in research: what is their importance?
José Francisco dos
Santos1, Renata Sena dos Santos1, Antônio Marcos Andrade
da Costa1,2
1Faculdade do Centro Oeste Paulista, Bauru, SP, Brazil
2Centro Universitário Social da Bahia, Salvador, BA, Brazil
Received:
May 23, 2020; Accepted: June 25, 2020.
Corresponding
author: Antônio Marcos Andrade da Costa, Av. Oceânica, 2717 Ondina
40170-010 Salvador BA
José Francisco dos
Santos: jfdossantos64@hotmail.com
Renata Sena dos Santos:
re.sena@gmail.com
Antônio Marcos Andrade
da Costa: antoniomarcoshand@gmail.com
Currently, in the field of sports science, we are increasingly
experiencing the transition from a decision-making model based on isolated
expert opinions to an evidence-based decision model. This process demands that
professionals have the skills and competence to carry out a systematic critical
assessment of the available scientific information, before applying an intervention.
Evidence-based practice is a strategy aimed at improving the quality of care
for clients or patients. This approach involves the definition of a problem,
the search and critical evaluation of the available scientific evidence, the
application of that evidence in clinical practice and finally the quantitative
and or qualitative evaluation of the results [1].
The cornerstone for building a good evidence-based practice lies in
formulating an appropriate research question, as it enhances the recovery of
evidence and directs the scope of research, avoiding unnecessary search
efforts. According to Richardson and Murphy [2], the acronym called P.I.C.O,
the search strategy should be incorporated as a way to facilitate the
construction of a clear and objective question, where the (P) is the
characteristics of the participants, (I) is an intervention or indicator from
which the evidence is wanted, (C) the usual control or condition to be compared
and (O) is the outcome or outcome expected as a result. Within this process, an
obstacle to the elaboration of a good investigation question is precisely the
definition of that last item, the outcome. The choice of the outcome should
always be aligned with the research question, and the hypothesis to be tested.
The outcomes or endpoints are variables that must be monitored during
the execution of a scientific experiment, in order to assess the impact of an
intervention or exposure on a given population [3]. In general, outcomes can be
presented in different ways:
•
Dichotomous (eg male or female);
•
Continuous (eg triglyceride values);
•
Ordinal (eg functional classification of heart
failure);
•
Temporal (eg survival curve)
Given the variety of types of outcomes and their remarkable relevance
for obtaining an adequate answer to the research question, it is necessary to
know their classifications, applications and limitations in the context of
decision-making.
The outcomes can be classified according to their relevance within the
research as primary and secondary. Primary outcomes should be designed with the
main condition of interest being to obtain a direct benefit to the client or
patient (for example, improved quality of life, reduced mortality, increased
strength). Secondary outcomes, on the other hand, are additional results that
should only serve to strengthen the interpretation of the results found in
primary outcomes or may also serve as generators of hypotheses.
The outcomes can also be categorized as to their subjectivity of
measurement as "subjective outcomes" or soft endpoints, which are
those where the interpretation of the result is dependent on the expertise of
the evaluator, and therefore more subject to verification bias (for example,
examination resonance imaging). End the outcomes we call objectives or hard
endpoints, as is the case of “death from all causes”, which has little or no
scope for subjectivity in its measurement, so that, its interpretation is less
susceptible to distortions due to measurements misleading. Thus, whenever
possible we should use them in our praxis [4].
Some outcomes can also be differentiated as to the relevance of their
application in the population, such as clinical outcomes that are the result of
variables whose value translates into immediate benefit to the client or
patient (for example, reduction in the number of infarctions or mortality),
which should be privileged whenever possible. And what we call surrogate
endpoints, which are usually continuous variables, such as laboratory tests,
tests of physiological variables or results of biomechanical analyzes, which
occur before the clinical outcome [4]. Therefore, its use should be limited, in
most cases, to raising mechanistic hypotheses regarding the clinical outcome,
which should be tested in a pragmatic way in the future.
The Surrogate endpoints have fundamental value in phases I and II of
studies involving human beings, especially when the potential benefits and
safety of a new intervention are being considered [4]. However, we suggest
caution when considering this type of result as evidence for decision-making to
replace the clinical result, since the human organism is complex, composed of
multiple systems that interact with each other, at all times, often causing us
to establish a direct association between the surrogate result and the clinical
one in a hasty manner, which can lead us to a false interpretation of the
effectiveness.
In synthesis, whenever possible, we should prefer objective outcomes
that assess clinical benefits focused on the client or patient, such as maximum
strength gain, mortality, and fatal events such as heart attacks, rather than
outcomes that assess laboratory changes such as elevated blood glucose,
cholesterol, or electroneuromyographic activation. Of
course, this is just an initial provocation on the topic, but it allows us to
open a discussion that can, with the maturation of ideas, provide subsidies to
improve the quality of care in our interventions.
Academic
links
This study resulted in the conclusion work of José Francisco dos Santos
and Renata Sena dos Santos for the Specialization in
Exercise Physiology Applied to Rehabilitation at the Faculty of Centro Oeste Paulista, Bauru, SP, Brazil, guided by Professor Ms.
Antônio Marcos Andrade da Costa.