Evaluation of an exercise treatment strategy in patients with knee osteoarthritis and comorbidity (COOA): Randomized Clinical Trial

Osteoarthritis (OA) is one of the diseases with the highest rate of
comorbidity; rates between 68% to 85% have been reported. Common co-morbidities
in knee OA are cardiac diseases, hypertension, type 2 diabetes, obesity,
chronic obstructive pulmonary diseases (COPD), OA of the foot and hand,
depression, chronic pain, low back pain, visual or hearing impairments and
chronic cystitis. Comorbidity in patients with OA is associated with greater
limitations in daily activities, more pain and a poor functional prognosis. In
patients with OA of the hip and knee comorbidity is associated with greater
limitations in daily activities, more pain and a poor functional prognosis

Physical therapy has been proved to be an effective intervention for patients
with knee and/or hip osteoarthritis in reducing pain
and improving physical functioning. Physical therapy, e.g., exercise therapy,
is recommended in existing guidelines.
As comorbidity is associated with physical and psychological limitations it is
important to adapt exercise therapy to the comorbidity.
In clinical practice these complex patients are often not referred for exercise
therapy, or dropped out in early stage of the treatment and /or are treated
inadequately: Comorbidity may restrict the possibilities for exercise therapy.
Therapists often reduce the intensity of treatment to the level where it is
unlikely that the treatment is effective. In existing guidelines no advice is
given how exercise therapy should be adapted to comorbidity.

In the first phase of the rearch project, the theoretical background of the
treatment strategy was elaborated and described. The comorbidities coronary
diseases, heart failure, diabetes type 2, obesity, COPD, depression, chronic
pain, a specific low back pain, and visual and hearing impairment were
included. For each comorbidity a treatment strategy was developed and described
in a protocol.
In the second phase we tested the developed protocols on case studies (n=14).
The intervention and the measurements of the case studies were approved by the
METC (2010, ABR number 30636).
As a result of the evaluation regarding the process and feasibility of the case
studies the therapists found that the protocol was helpfull in clinical
decision making and tailoring the exercise program to the individual capacity
of the patient. During the pilot study no (serious) adverse events occurred.
The results of the pilot were used to improve the feasibility of the protocol
and to optimize the protocols. The protocols could be reduced to two main
protocols. In protocol (A ) patienst with comorbidities resulting in
physiological impairments are present: coronary diseases, heart failure,
diabetes type 2, obesity and COPD. In protocol (B) patients with comorbidities
resulting in psychological and behavioural impairments are present e.g. chronic
pain, a specific low back pain and depression. The pilot shows also a
statistically significant improvement in physical functioning as measured with
the (WOMAC), the 6 minute walking test, (P<0.05). There was also a
statistically significant decrease in pain, measured with the WOMAC subscale
pain (P<0.05). .

In the third and final phase we aim to evaluate the optimized version of the
protocol on patients with coronary diseases, heart failure, diabetes type 2,
obesity, COPD in a randomized clinical trial. The purpose of the study is
evaluate the effect of the newly developed protocol in knee OA patients and
comorbidity on the outcome physical functioning in comparison to a waiting list
group.

This study is a single-blind randomized controlled trial. Eligible patients
(N=154) will be randomized while using a minimisation procedure. The
experimental group will receive 20-week exercise therapy with the newly
developed treatement strategy, explicitly taking into account the comorbidity.
The control group is a waiting list group. Measurements will be made prior to
the start of therapy (baseline), and at 10 weeks (intermediate), 20 weeks (end
of intervention) and 32 weeks (follow-up).

Patients in the experimental group receive treatment according to the newly
developed treatment strategy, explicitly taking into account the comorbidity.
Prior to treatment, patients relevant goals for the treatment are established.
Examples of frequently established goals are: (1) increasing walking distance
(2) improving stair climbing. The following training modalities are used:
aerobic exercise, strength training, training of coordination and stability,
training of range of motion, training of daily activities such as walking and
stair climbing. The training modalities have been advised in the guideline for
knee an hip osteoarthritis (KNGF).
During the treatment the exercise therapy will be adapted to the comorbidity
in: intensity, duration and content of the therapy. This depends on present
restrictions in exercise therapy, identified by the therapist during anamnesis
and physical examination. The described adaptations in protocol are based on
the decribed approach in the guidelines for the comorbidity. In addition to
exercise therapy, education will be given about the pathology and on how to
cope with it. Therapy sessions will be given once a week, during an hour or
twice a week during half an hour, depending on the complexity of the diseases.
By using the protocol, the therapist is able to tailor the exercise program to
the individual capacity of the patient (on a save way).


Control group
The control group is a waiting list group. If applicable patients can receive
there current medical care related to the knee complaints and/or comorbidity.
The medical care will be registered. After the follow up period of 32 weeks,
the patients can also receive the treatment according to the newly developed
treatment strategy.

This study will provide insight into how exercise therapy treatment can be
adapted in the presence of comorbidity, in patients with
knee osteoarthritis. Patient burden is limited to the time and effort needed to
participate in the therapeutic and measurement
sessions. There are no specific risks associated with participation, as the
patients will be exposed to a treatment that is regularly
provided to osteoarthritis patients within Reade, with adaptations made
specifically for the benefit of patients
with present comorbidity.

The control group is a waiting list group. If applicable patients can receive
there current medical care related to the knee complaints and/or comorbidity.
The medical care will be registered. After the follow up period of 32 weeks,
the patients can also receive the treatment according to the newly developed
treatment strategy.