Table 1 Studies conducted in the MOBILIZE project to identify knowledge gaps in the design and conduct of exercise therapy and self-management trial in people with multimorbidity

Bricca et al. 2019, 2020, 2021 (Systematic review protocol, systematic review, and infographic) [27, 36, 37]

To investigate the benefits and harms of exercise therapy for people with multimorbidity.

Exercise therapy appears to be safe and to have a beneficial effect on physical and psychosocial health in people with multimorbidity. Although the evidence supporting this was of low quality, it highlights the potential of exercise therapy in the management and care of this population.

Exercise therapy was deemed as a potentially beneficial intervention for people with multimorbidity supporting its use as part of an intervention to improve health in people with multimorbidity. Given that no superior type of exercise therapy type was found to improve health, we discussed with stakeholders and patient partners the optimal type, dose, and intensity of the programme, considering patient preferences and the fact that it was easy to deliver and implement in clinical practice. The intervention details are reported in the TIDieR checklist incorporating the CERT items (Table 4), and Toigo & Boutellier checklist (S2 Table).

Harris et al. 2020 (systematic review) [40]

To quantify recruitment, retention and differential retention rates and associated trial, participant, and intervention characteristics in randomised controlled trials (RCTs) evaluating the effect of exercise therapy in people with multimorbidity.

Three in four eligible people with multimorbidity were randomised to RCTs using exercise therapy, of which nine out of 10 provided end of treatment outcomes with no difference seen between the intervention and comparison groups. However, the results must be interpreted with caution due to large differences between the included studies.

When planning the recruitment and retention phase, we used this knowledge to identify how many people were needed to be screened to reach the target number of people included in the feasibility study.

Pihl et al. 2021 (registry based) [42]

To investigate if comorbidities are associated with change in health outcomes following an 8-week exercise and education programme in knee and hip osteoarthritis.

Health outcomes improved regardless of coexisting comorbidities. This means that comorbidities are not associated with worse nor better health outcomes following an 8-week exercise and education programme in individuals with osteoarthritis, suggesting exercise as a viable treatment option for individuals with osteoarthritis, irrespective of comorbidities.

This knowledge supported the assumption that exercise therapy may be beneficial across people with several combinations of conditions, and no specific adaptation needs to be made for the subgroup of patients with OA and another condition.

Pihl et al. 2021 (registry based) [41]

To identify prognostic factors for health outcomes following an 8-week supervised exercise therapy and education programme for individuals with knee and hip osteoarthritis alone or with concomitant hypertension, heart or respiratory disease, diabetes, or depression.

Age, self-efficacy, self-rated health, and pain intensity may be prognostic of change in health outcomes following an 8-week exercise therapy and patient education programme for individuals with OA, irrespective of comorbidities.

We focused our self-management support programme on providing tools to improve self-efficacy, self-rated health and pain. The themes for the 24 self-management sessions are reported in Table 2.

Bricca et al. 2022 (systematic review) [39]

To assess the quality of health Apps and their potential for behaviour change.

Apps for people with a chronic condition or multimorbidity appear to be of acceptable quality but have low to moderate potential for promoting behaviour change.

We selected the highest (free) quality health Apps, and those with the highest potential for behaviour change, available for people in Denmark and provide practical support for downloading or using such Apps during one of the self-management sessions.

Jäger et al. 2022 (scoping review) (under review) [35]

To map the literature on patient-centred interventions for people living with multimorbidity that

supports self-management.

The results pointed to an extensive use of cognitive behavioural therapy as a basis for interventions, as well as behaviour change theories and chronic disease management frameworks. The most coded Behaviour Change Techniques (BCTs) stemmed from the categories Social Support, Feedback and Monitoring, and Goals and Planning.

We considered which of the several BCTs used in RCTs were the most effective to promote behaviour change and which ones could be implemented in the clinical setting in which the intervention would be tested.

Bricca et al. 2022

(Systematic review) [38]

To investigate the effect of behavioural interventions in people with multimorbidity and to identify Behaviour Change Techniques (BCTs) associated with better outcomes.

Behavioural interventions targeting lifestyle behaviours may improve health-related quality of life and physical function, and reduce depression symptoms, whereas little to no effect was achieved on physical activity and weight loss in people with multimorbidity. However, the evidence for physical activity and weight loss was of low quality and the end-treatment benefits diminished over time. Yet, studies using the BCTs ‘action planning’ and ‘social support (practical)’ reported greater physical activity and weight loss.

These findings guided the developed of the the self-management sessions related to the importance of physical activity and how to implement it in daily routines (Table 3).

Zangger et al. 2022 (systematic review) (under review)

To assess the effect of digital health solutions promoting physical activity among people with one or more chronic conditions

Overall, using a digital health solution shows a small improvement in physical activity, physical function, quality of life, and a small reduction in depressive symptoms, but no change in anxiety symptoms compared to usual care.

We found low quality of evidence for the effect of digital solutions in promoting physical activity and improving health in people with multimorbidity. This knowledge guided the development of the self-management sessions related to self-monitoring (Table 3).