Occupational rehabilitation for musculoskeletal and mental disorders
reduced after all the programmes in our study, but the
reductions were smaller than the suggested minimal
detectable change (18). This was surprising, as the
inpatient programmes included physical activity desig-
ned to reduce fear of movement. Fear-avoidance beliefs
about work were targeted by work-related problem
solving through group discussions and creating an
individual RTW plan. It is possible that graded work
exposure at the workplace could have been more effec-
tive. However, the participants had been sick-listed for
approximately 7 months on average; hence changing
their fear-avoidance beliefs could be difficult. Another
possible explanation is the use of ACT as the cognitive
behavioural therapy. A key component in ACT is ac-
ceptance, meaning that participants are encouraged to
acknowledge and accept their symptoms rather than
try to control them. This could result in participants
accepting, and thus reporting, more fear-avoidance
beliefs after participating in the programme than they
otherwise would, which might explain the small re-
ductions observed (20). This might explain why one
of the inpatient programmes was successful in terms of
RTW despite small changes in fear-avoidance beliefs.
Conversely, previous studies have suggested that the
responsiveness of the FABQ might be low (18, 21),
which should be evaluated further in future research.
The results of the current study indicate that using
a cut-off between low-risk and medium/high-risk pa-
tients could be useful to predict whether patients will
RTW. The cut-offs recommended by Wertli et al. (7)
were used. These cut-offs are widely used in Norway,
as they are included in the Norwegian neck and pain
registry, used at back- and neck-pain clinics at all uni-
versity hospitals. We are not aware of previous studies
assessing the association between FABQ and future
work participation using these cut-offs. Our findings
are in line with a study by Staal et al. (22) reporting that
participants with high fear-avoidance beliefs (median-
based cut-offs: work 26; physical activity 16) returned
to work more slowly than those with low scores. Due to
the limited number of participants, it was not possible
to differentiate between medium- and high-risk patients
in the present study, and this should be done in future
studies. As FABQ-work measures fear-avoidance be-
liefs about work specifically, it is not surprising that
this subscale had a stronger association with future
work participation than the physical activity subscale.
Øyeflaten et al. (6) found FABQ-work to be a strong
predictor for RTW in a group of participants with
mixed diagnoses (musculoskeletal, psychological and
unspecific diagnoses). However, we are not aware of
studies evaluating the FABQ separately for diagnoses
other than musculoskeletal complaints. The reduction
in fear-avoidance beliefs was quite similar for the 2
181
diagnosis groups during follow-up, despite participants
with psychological diagnoses having lower baseline
values. The results also suggest that the work subscale
is associated with future work participation for parti-
cipants with psychological disorders. The association
was, in fact, somewhat stronger for this diagnosis
group than for the musculoskeletal group. Avoidance
behaviour is seen in many psychological disorders.
However, the FABQ could measure different charac-
teristics for the 2 diagnosis groups. In psychological
disorders, it might be measuring a more central part of
the disorder itself, and not just a prognostic factor. This
could also explain why the physical activity subscale
showed a stronger association with future work partici-
pation for participants with a psychological diagnosis,
compared with those with a musculoskeletal diagnosis.
The main strengths of this study were the randomized
design and the use of registry data to assess sickness
absence. The latter ensured no recall bias or missing
data. Some limitations of this study should be addres-
sed. Firstly, the response rate was low on follow-up
questionnaires, gradually decreasing, from approx-
imately 100% for the first questionnaire to 40–47% at
12 months’ follow-up. At the start and the end of the
programme there were more missing questionnaires for
the outpatient programmes, which we assume is due to
organizational differences, as the inpatient participants
answered the questionnaire at the centre, while the out-
patient participants had to answer them at home. For
the rest of the time-points, the response rate was similar
between the programmes. To compare between-group
changes over time, linear mixed models were used,
which are less sensitive to missing values in outcome
data. However, these models rely on the assumption of
“missing at random”, and the possibility of bias due to
differential loss to follow-up cannot be disregarded. The
observed association between FABQ and future work
had low precision, due to the low number of participants
answering questionnaires at both the start and end of
the programmes. However, other than the loss of sta-
tistical power, we do not expect missing questionnaires
to affect these results significantly. We do not expect
that those replying would differ from those not reply-
ing, in the association between the change on FABQ
and work-participation days. Finally, in order to make
the FABQ questionnaire usable for participants with
conditions other than back pain, some of the wording
was changed. Hence, the questionnaire was an adapted
version of the previous validated version.
Conclusion
This study did not find any evidence to show that inpa-
tient occupational rehabilitation reduced FABQ scores
more than outpatient cognitive behavioural therapy. An
J Rehabil Med 51, 2019