Evaluating Patient-Based Outcome Measures - NIHR Health ...

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What are patient-based outcome measures?
specific needs to be addressed (Frankel, 1991).
There is therefore little evidence in the literature of
patient-based outcome measures adding to existing
sources of health status in informing populationlevel
decision-making.
Individual patient care
It has been argued that patient-based outcome
measures offer an important adjunct to clinicians
in the care of their patients (Tarlov et al., 1989;
Anonymous, 1991b). Self-completed questionnaires,
if proved reliable and valid, offer a quick
and reliable way for patients to provide evidence
of how they view their health that complements
what the clinician collects from clinical and other
evidence (Nelson and Berwick, 1989). The value
of this additional information is partly because
time pressures increasingly constrain health professionals
and limit the amount of direct contact.
The primary purposes of inviting patients to complete
health status questionnaires are to enable
health professionals to screen for health problems
that may not otherwise become apparent and to
monitor the progress of problems identified in
the patient and the outcomes of any treatments.
Patient-based outcome measures can provide
prognostic information about the cause of illness
independent of diagnosis (Mauskopf et al., 1995).
It is also been argued that such measures can be
used to select patients for treatment, for example
identifying patients able to undergo surgery
(O’Boyle, 1992). Reports have appeared arguing
that it is feasible to incorporate shorter measures
into the routines of clinical practice (Nelson et al.,
1990; Wolfe and Pincus, 1991). When patients are
asked about the value of such requests, the majority
are positive and consider the information conveyed
by questionnaires important for health professionals
to know about them (Nelson et al., 1990;
Street et al., 1994). Doctors also find the information
of value (Young and Chamberlain, 1987;
Williams, 1988). However, clinicians report that
whilst they regard the issues raised by such instruments
as very important, they are not able to make
systematic and regular use of information about
the QoL of their patients as provided by questionnaires
(Taylor et al., 1996). In some fields of
medicine, more systematic trials to evaluate the
impact of providing clinicians with information
from patients in this way have found little evidence
that clinical decisions are changed because of the
additional data about their patients and health
status is not improved (Rubenstein et al., 1989;
Kazis et al., 1990). One likely explanation for the
apparent lack of impact of patient-based outcome
measures on clinical practice is that it is still not
clear how to present the data in useful forms and
how clinicians should make use of the evidence
(Deyo and Patrick, 1989).
From a more formal perspective, the precision of
the score from an individual (as in the context of
clinical care) is less than that obtained for a group
of patients. There is considerable measurement
error in the numerical value of an individual
respondent’s report. This has the consequence
that usefulness in the context of individual
patient care will be more difficult.
In summary, there is little evidence to date to
support the use of patient-based outcome measures
in routine practice and more trials are needed to
examine their usefulness in this context (Long
and Dixon, 1996). It may be that the existence
of ‘normative’ data from representative samples
of the general population will facilitate the
interpretation of some instruments (Jenkinson
et al., 1996).