Author(s): MURA, M., BACKES, A., MALISOUX, L., Institution: LUXEMBOURG INSTITUTE OF HEALTH, Country: LUXEMBOURG, Abstract-ID: 1539

INTRODUCTION:
Osteoarthritis is one of the most prevalent musculoskeletal disorders, often leading to pain and reduced physical function. Physical activity is recommended by international organizations as an effective non-pharmaceutical strategy to improve function and reduce disease-related pain in osteoarthritis patients. However, patients frequently do not meet the physical activity levels recommended (i.e. 6000 steps/day for patients with osteoarthritis), highlighting the need for targeted support strategies. The PIANISSIMO study aims to evaluate adherence and retention of patients in a 6-month intervention designed to promote physical activity in patients with osteoarthritis. Additionally, the study seeks to explore the relationship between daily step counts and pain.
METHODS:
PIANISSIMO is an innovative intervention based on the “Capability, Opportunity, Motivation Behaviour” (COM-B) framework. The intervention included several behaviour change techniques such as feedback on daily steps, weekly personal goal setting, and population-tailored daily notifications about practice opportunities, benefits of physical activity for osteoarthritis and general health. The intervention is delivered through a dedicated mobile app, which also collects demographic data, connection logs, daily step count and weekly pain questionnaires (Likert scale, from 0 to 10). Adherence is assessed by the change in mean weekly connection rate between the first and last month, as well as questionnaires response rates. Retention rate is reported as percentage of participants who continued to log into the app through the full 6 month intervention. The relationship between physical activity and pain is examined using a linear mixed effects model.
RESULTS:
Sixty-nine participants were included (59.9±7.6 years, BMI 27.3±5.5 kg.m-2). Adherence decreases by 33% over the 6-month period, from 6.9±3.2 logs/week in the first month to 4.6±4.3 logs/week in the last month (p=0.01). In total, participants completed 76% of the pain questionnaires, 56% of the WOMAC questionnaires and 28% of the weekly questionnaire on daily step goals. Retention rate was 52.5%. On average, participants performed 6878±3701 steps/day during the 6 months and they answered 20 pain questionnaires, with mean pain score = 2.7±2.4 (a.u. from 0 to 10). There was no significant association between pain and mean daily steps recorded over 1, 3 and 7 days before or after the reported pain score.
CONCLUSION:
This 6 month mobile app–based intervention demonstrated high adherence and moderate retention rate. These rates are within the range expected in our hypothesis (both ≥33%), indicating that digital support tools are feasible for promoting physical activity in individuals with osteoarthritis. Despite good completion of pain questionnaires, participants set relatively few weekly step goals. Overall, PIANISSIMO underscores both the potential and the limitations of app based interventions for long term physical activity promotion among people with osteoarthritis.