Independent Weight Loss Maintenance for Communities With Arthritis in North Carolina: the I-CAN Clinical Trial

The study team is currently conducting a pragmatic, community-based assessor-blinded randomized controlled trial (RCT) in overweight and obese adults \> 50 years with knee OA in both urban and rural counties in North Carolina. As the participants randomized to the 18 month diet and exercise group in the WE-CAN study successfully complete the intervention (≥ 5% weight loss), the study team has the unique opportunity to evaluate the effectiveness of a theoretically-based tapered weight maintenance intervention. Eligible participants will be randomized to either the weight-loss maintenance or health education attention control groups.

Results from the Intensive Diet and Exercise for Arthritis (IDEA) trial showed that 10% diet-induced weight loss combined with exercise (D+E) was twice as effective at relieving knee pain and improving function and mobility as previous long-term weight loss and exercise programs in similar cohorts. The treatment effects of D+E on these clinical outcomes were mediated by changes in self-efficacy over the course of the trial. However, most people tend to regain most or all of the lost weight in three to five years. The challenge is maintaining the weight loss and sustaining the efficacy of the intervention.

Our current trial (WE-CAN) is designed to adapt the successful IDEA intervention to real-world clinical and community settings. As WE-CAN participants in the D+E group complete their intervention, the investigators will leverage our organizational infrastructure to maintain weight-loss without supervised intervention by increasing participant confidence to establish and adhere to a routine of good exercise and diet behaviors independently.

Participants will include 212 older adults aged ≥ 51 yrs. with knee osteoarthritis (OA) who achieved a weight loss ≥ 5% in the D+E intervention arm of the WE-CAN trial. All WE-CAN participants meet the ACR clinical criteria for knee OA, which includes knee pain on most days of the week plus at least three of the following six: age ≥ 50 years, stiffness \< 30 min/day, crepitus, bony tenderness, bony enlargement, and/or no palpable warmth. Eligible WE-CAN D+E participants will be randomized to either 6-month facilitated weight-loss maintenance or health education control interventions. The primary aim is to compare the effects of a 6-month weight-loss maintenance intervention grounded in social cognitive theory to a health education intervention on maintaining weight loss subsequent to a 12-month unsupervised follow-up period. Secondary aims will compare the two interventions on WOMAC knee pain and function, health-related quality of life (SF-36), 6-minute walk distance, and weight-loss maintenance self-efficacy following the 12-month unsupervised period. The study team will also establish the cost-effectiveness of a 6-month facilitated weight-loss maintenance intervention for older adults with knee OA by conducting cost-effectiveness and budgetary impact analyses using data from the current trial in a validated computer-simulated model of knee OA.

There have been numerous attempts to prevent weight regain in adults. This study is significant in that it is designed to encourage older adults with knee OA that have experienced significant weight loss to develop strategies that will build self-efficacy for maintaining weight loss on their own long after the active intervention ends.

Eligibility Criteria:
Inclusion Criteria:

* age ≥ 51
* achieved a weight loss ≥ 5% in the D+E intervention arm of the WE-CAN trial

Exclusion Criteria:

* Weight loss \< 5% of baseline body weight
* Significant co-morbid disease that would threaten safety or impair ability to participate in interventions or testing (Blindness; Type 1 diabetes; Severe coronary artery disease)
* Inability to finish 18-month study or unlikely to be compliant (Planning to leave area \> 2 month during the next 18 months)