Journal of Rehabilitation Medicine 51-1CompleteIssue | Page 66

Effects of multimodal back exercise
Table II. Cost areas of direct and indirect medical/back disorder costs
(ICD = international classification of diseases, ATC-Codes = Anatomical
Therapeutic Chemical/Defined Daily Dose Classification)
Cost areas
Direct medical costs
Hospital charges
Rehabilitation charges
Sick pay
Outpatient charges
Outpatient charges Cure/
Rehabilitation/outpatient
surgery
Exercise charges
Therapeutic aid charges
Drug charges
Medical costs Back disorder costs
ICD:
ICD:
ICD:
ICD:
ICD: ICD: M40–54
ICD: M40–54
ICD: M40–54
-
-
all
all
all
all
all
Exercise costs per exercise -
session (2008: 14.09
EUR, 2009: 13.64 EUR)*
number of training sessions
all
Hydrotherapy/Med. baths,
Traction therapy, movement
exercises, electrotherapy,
physiotherapy, machine-
aided medical gymnastics,
complex services D1-KG,
non-specific massages,
non-specific packs
ATC-Codes: all
ATC-Codes: H02, M01A,
M01B, M02, M03, N01B,
N02A, N02B, N03AX12,
N06AA
Indirect medical costs
Lost productivity costs
ICDs: all sick leave days*
lost productivity costs
per day
ICDs: M40-54 sick leave
days* lost productivity
costs per day
(TS) spanning 24 weeks. The core of the exercise programme
consists of dynamic strength/mobility training. During the
first 12 weeks, 2 exercise sessions take place per week (basic
exercises in 4 stages, see Table III); in the second 12 weeks
(maintenance training), this reduces to 1 session per week. Each
exercise session lasts 1 h, during which the strength and mobil-
ity of the trunk stabilizers and the neck muscles are exercised
on 5 machines (19): the DAVID ® F110, 120, 130, 140, and 150
(DAVID ® Health Solutions, Helsinki, Finland).
In the basic training stage, the exercising follows the 1-set
principle, i.e. 1 exercise set is completed on each machine.
During maintenance training, 2 sets are performed per exercise
machine. The intensity is calculated and set on the machine to
achieve maximal strength results (maximum voluntary contrac-
tion; MVC). The muscle group just trained is stretched before
moving on to the next machine.
The exercises aim to reduce muscular imbalance, improve
circulation in muscle/joint structures, and increase the strength
and mobility of trunk stabilizers and neck muscles. Prior to
starting BE and after the basic and maintenance exercises, bio-
mechanical function analysis of the spine is performed. Mobility
and maximal strength measurements are taken from the exercise
machines and related to standard values for age and sex (20).
The resulting strengths/weaknesses profile is incorporated into
Table III. Back exercise program stages
Phase
Orientation
Adjustment
Strength
Optimization
Maintenance
program
the training plan: the weakest muscle group is exercised
first and, in case of pronounced muscular imbalance, the
weaker side (left/right) or the weaker antagonists (exten-
sors/flexors) are worked more intensively.
In the ergonomic exercises, proper spinal seating pos-
ture (frequent change of position, keep moving) as well
as spine-friendly work and lifting techniques are taught
and practiced (approximately 5 min per exercise session,
for a total of 3 h).
Starting with the 13 th session, an exercise programme is
taught for transferring the functional gymnastic exercises
to the home for daily use. It is supported by a training ma-
nual (or DVD) designed to teach back-friendly behaviour
in daily life and the workplace. The home exercises must
be continued independently following the formal training
in order to sustain the improvements achieved.
Statistical analyses
The study is based on the intention-to-treat (ITT) prin-
ciple. Similar to an ITT evaluation in an RCT, the study
participants remain in their initial groups and are consi-
dered in the analyses regardless of whether they actually
participated in the intervention.
Disparities among the studied groups in the differences
between means of the indirect and direct medical costs
were checked with univariate analyses of variance (ANO-
VA). For the 3-fold interactions time*treatment*GCPS
and time*treatment*direct medical costs, repeated measu-
rement ANOVAs were used to determine whether the back
exercise has a significant effect on the changes in back pain and
the direct medical costs. Binary data (sex) were checked with
the χ 2 test. The cost-effectiveness of different back pain severity
grades (GCPS) was arrived at by calculating the individual net
monetary benefit (NMB). For this, the maximum willingness to
pay (MWTP=λ) for a reduction of 1 GCPS grade λ is multiplied
by the individual effectiveness (ΔE: pre- minus post-GCPS
value) and the changes in direct medical costs (ΔC: post- minus
pre-direct medical costs) are subtracted from this product:
NMB i =λ * ∆E i – ∆C i .
The difference between means of BE and ST for different
MWTPs were then tested with ANOVA. By iteration, the
MWTP values that resulted in significant differences between
means were determined. The NMB represents the individual
monetary benefit at a specified maximum willingness to pay λ.
It exhibits all the stochastic properties of a normally distributed
random variable (21–23). Unlike in the case of the incremental
cost-effectiveness ratio (ICER), for the NMB the maximum
willingness to pay is also considered. The statistical processing
of the data is facilitated, since costs and effects are brought into
linear form by a quotient (24). All analyses were performed
with propensity score weights. The analyses were run using
IBM SPSS release 22, including the SPSS propensity score
matching extension by Thoemmes (12).
Training intensity
Week TS per week (MVC), %
Repetitions
1–4
5–6
7–9
10–12
13–24
2
2
2
2
1
< 30
40–60
70–80
80–90/40–60*
1 st set: 30–40
2 nd set: 80–90
*weekly change of training intensity. TS: training sessions.
35
25
15
12/30
30
12
63
RESULTS
Study participants
Of 2,444 intervention subjects contacted in writing
from 2008 and 2010, 1,942 agreed to take part in the
J Rehabil Med 50, 2018