3.5 Association between PEs on the outcomes (pain, functional
levels and health related quality of life)
Table 3 shows the association between the PEs and the outcome measures
(pain, functional status and health related quality of life) reported
among the reviewed studies. The results showed that a total of four
trials addressed the association between PEs and pain intensity. Two of
these trials demonstrated a positive association between PEs and pain
intensity, in both the short (7) and long term (26). The other two
trials demonstrated no association between PEs and pain intensity within
the medium term follow-up (6, 27). A total of 6 trials addressed the
outcome of levels of function. Three of the 6 trials demonstrated a
positive significant association between PEs and levels of function, two
trials (5, 6) registered at medium term (> 6 weeks - ≤ 6
months) while the other one (26) at long term (> 6 months).
Three other trials demonstrated no significant associations between PEs
and function levels (24, 25, 27). None of the included trials addressed
the outcome of function levels in the short term (≤ 6 weeks). Neither
short (≤ 6 weeks) nor the long term (> 6 months)
association was reported between PEs and the HRQOL. Only one study (27)
reported the association between PEs and HRQOL over the medium follow-up
term (> 6 weeks - ≤ 6 months), however the association was
not significant.
Discussion
This study investigated the evidence behind the association between PEs
and specific treatment outcomes such as pain intensity, functional level
and HRQOL among people with CLBP. The findings supported evidence on the
association between PEs and the pain and functional levels. Positive PEs
prior to the treatment were shown to be associated with the pain
intensity in both shorter and longer terms among CLBP individuals.
Evidence suggests that PEs have an influence on the pain outcome by
means of a ‘placebo’ effect (28, 29). In addition, several psychological
factors such as individual’s beliefs about their pain; fear avoidance
beliefs; patient’s behaviours; emotions such as anxiety, depression
etc., as well as the regulation of these emotions; lack of support;
coping strategies; faith and religious beliefs; and patient’s recovery
expectations have been discussed in the pain literature as underlying
factors that might influence the pain outcomes (30, 31). However, the
current findings need to be interpreted with caution in acute and
nonspecific low back pain, as the effects might be different because PEs
change over time (32-34). Currently, studies that have examined the
association between PEs and treatment outcomes on acute low back pain
are lacking and hence, the influence of PEs is unknown among people with
acute low back pain. Also, the studies have only measured the PEs at one
point in time, it would be interesting to know if or how they change
throughout a course of treatment
Past studies reported that the positive PEs on an intervention have
positively influenced the functional outcomes (5, 35). However the
current review finding suggests that there is equivocal evidence between
PEs and levels of function. While three studies showed a positive
association between PEs and the levels of function at both medium and
long term (5, 6, 26), three other trials demonstrated no significant
associations between PEs and function levels (24, 25, 27). The
therapist-patient encounter, information provided to the patients during
the encounter, different timings of measuring PEs and use of various
methods to measure PEs might have contributed to this equivocal evidence
(10). While patients with higher expectations for benefiting from joint
replacement surgery had greater gains in HRQOL (36), the findings of the
current review clearly demonstrated no evidence behind PEs and HRQOL
among people with CLBP. Neither short (≤ 6 weeks) nor the long term
(> 6 months) association was reported between PEs and the
HRQOL. Only one study (27) reported the association between PEs and
HRQOL over the medium follow-up term (> 6 weeks - ≤ 6
months), however the association was not significant. Further studies
are warranted to investigate the influence of PEs on HRQOL among people
with CLBP in order to revaluate and reflect on this evidence again in
practice.
The review findings have some implications for policy makers and
clinical managers in the health care sector. The Care Quality Commission
(CQC) ensures the quality of healthcare provided by the majority of
hospital-based care for the National Health Service (NHS) in the UK
(37). PEs of a given care is one of the major determinants for
satisfaction in the quality of health care provided to people (38).
While the CQC’s quality surveillance tool effectively monitors the
quality of care through monitoring care profile indicators such as
mortality rates, timeliness of intervention, waiting times etc. (37),
there is no explicit mention about collecting or documenting PEs on the
care provided. Similarly, NHS collect feedback on the quality of care
provided to the patients, however, it does not collect information on
the PEs of care (39, 40). Perhaps, a lack of sufficient understanding
and evidence behind the influence PEs could have on the treatment
outcomes might be one of the reasons that PEs are not fully represented
in both CQC and NHS audit policies. In the above given context, the
current review might contribute to CQC and NHS policies in future as it
provide preliminary evidence on the impact of PEs on the treatment
outcomes in CLBP care. As patients are ultimately the receivers of
health care provision, understanding and managing their expectations of
care in clinical practice is pivotal (41).
However, PE is often handled as a challenging concept in clinical
practice. Firstly, a huge overlap and differences in the terminologies
used to define PE often cause challenges to practitioners and
researchers to measure and understand the concept of PEs in clinical
practice. Secondly, although many practitioners might sometimes
informally ask the patients about their expectations about treatment,
PEs are not explicitly measured and documented in health care practice.
Thirdly, even if practitioners do inquire about PEs, it might be
generally asked only prior to the initial treatment, however, PEs might
not be followed up in consecutive treatment sessions in practice. The
timing of measuring PEs is relevant in practice especially when PEs were
reported to change over a course of three months among people with CLBP
(32-34). Also, one could argue that monitoring PEs may help clinicians
in the process of decision making (29). However, there is a lack of a
standardized and valid tool in clinical practice to measure PEs (8, 9,
14), hence PEs might be measured differently by different practitioners
in day to day practice. Another challenge in practice includes the
practitioners measuring PEs at different point of time, as the current
review findings supported that the timing of measuring PEs varied
between immediately after treatment to the 1- and 5-year follow-up among
the studies. In the context of the above mentioned challenges in
clinical practice, the findings of the review emphasize to clinicians
and researchers the importance and relevance of considering PEs in the
development and delivery of health care services. Equally, the review
findings identifies a need for a valid tool to measure PEs in practice
and calls the international research community towards the development
of a clinical tool to measure PEs.
Conclusion
In summary, PEs have a positive association on both the short and long
term pain outcomes among individuals with CLBP. The influence of PEs on
the functional outcomes among people with CLBP are inconclusive as the
evidence on the association between PEs and functional outcomes is
equivocal. Limited available studies showed no evidence of an
association between PEs and HRQOL among CLBP patients. Further studies
investigating the influence of PEs with valid tools to measure PE across
standardized time periods and during a treatment programme are warranted
in people with CLBP.