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M. Rivano Fischer et al.
quently repeated observations, following each person,
allows for some conclusions to be drawn regarding the
changes observed.
One way to make comparisons between time periods
is to find appropriate control subjects or a reference
group (not subjected to the studied intervention) (9).
However, there are problems inherent in the identifi-
cation of adequate controls, the main one being the
assumption that patients referred to MMR or other
treatments are alike. Referral sources, usually physici-
ans, make judgements before deciding whether to send
patients to pain rehabilitation, judgement weighting
several aspects. Therefore, important variables that
should be controlled for in any matching procedure,
such as functioning, activity levels, and motivation
for change, cannot be controlled for by matching the
usual variables, diagnoses, age and sex. Furthermore,
patients with pain who are not referred to a specific
rehabilitation may seek healthcare in other places,
which may often not have been controlled for. A study
reported by Post Sennehed found ”limited feasibility
in identifying 2 comparable groups for evaluation of
the multimodal rehabilitation programme” (30). Our
study, therefore, approached the problem by using a
large sample and repeated measures over an extended
period of time, in order to obtain answers as to whether
MMR has an impact on sick-leave benefits.
Future research
The possibility of linking SQRP data to the SSIA data-
base opens up several avenues for future research. One
such area is that of identifying subgroups of patients
participating in MMR in relation to changes in their
patterns of sick leave. Other areas refer to possible as-
sociations between patterns of physical, psychological
or activity-related limitations reported by patients and
patterns of sick leave, the prediction value that patients’
self-descriptions might have on patterns of sick leave,
and how work conditions interact with outcomes of
MMR at long-term follow-up after interventions.
Conclusion
Since the extent of sick-leave benefits seems to increase
during the year prior to participating in MMR and de-
crease during 2 years after rehabilitation, the results of
this study highlight the importance of offering MMR to
patients with chronic pain. The results, based on data
from 2 large national databases, indicate that MMR
has an impact on sick-leave benefits regardless of sex
or policy changes in the sick-leave benefit system.
The authors have no conflicts of interest to declare.
www.medicaljournals.se/jrm
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