Background/Purpose: In this pilot and feasibility study, we evaluated whether a behaviorally-designed intervention utilizing gamification and social support could improve both physical activity and reduce symptoms in veterans with osteoarthritis of the knee (KOA). We hypothesized that the weekly average of daily steps over 32 weeks of follow-up would be greater in participants randomized into the intervention arm compared to the control arm and that symptoms of KOA would be reduced over time.

Methods: Veterans with a diagnosis of KOA, 40-80 years old, and who did not use assistive devices for ambulation were enrolled. Participants received a Fitbit^TM and completed an initial 2-4 week observation period. A web-based platform administered surveys on a biweekly basis and tracked physical activity through linkage to the Fitbit^TM application. All participants selected a daily step goal that was either 33%, 40%, or 50% above their baseline. The intervention arm received points and advanced through levels based on performance. They also selected a social support partner that received updates on their progress to help motivate participants to meet their step goals. Controls received only daily texts with their step counts from the prior day. Participants were also randomized to receive corticosteroid injections vs. lidocaine only in a factorial design (not shown here). The primary outcome was the change in average daily steps over 32 weeks. Step counts were averaged over 2-week periods and analyzed over all time-points using mixed effects regression and adjusting for baseline (days with < 1000 steps were considered missing). Secondary outcomes included the total Knee Osteoarthritis Outcome Score (KOOS) assessed over all time points. We determined differences in slope of change in KOOS between the intervention and control arms.

Results: Of the 36 consented participants, 33 were randomized and 31 were included in the final analysis. Two patients were withdrawn due to lack of participation. Most participants were male (90.3%) and Black (70.96%). The mean (SD) age and BMI of the study population were 60 (13) years old and 33.7 (5.9) kg/m², respectively. Diabetes (42%), hypertension (42%), and sleep apnea (45%), were the most common comorbidities and were comparably distributed between the trial arms. Over all observations, participants that received the intervention walked a total of 1119 (95% CI: -562, 2799) more steps per day compared with the control arm (P=0.19) (Figure 1). The effect was greatest in the first 6-months (180 days) [1491 (-272, 3254) p=0.10]. Greater improvement in total KOOS and several sub-scales was observed in participants that received the intervention (Table 1).

Conclusion: This remote behaviorally-designed intervention might help patients achieve improvements in both steps per day and symptoms over 32 weeks. A larger, multi-site study is underway and will provide greater precision with regard to the degree to which this intervention is effective in promoting exercise and reducing symptoms of KOA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/a-remote-behaviorally-designed-intervention-to-promote-physical-activity-in-patients-with-knee-osteoarthritis-results-of-a-pilot-randomized-clinical-trial/