Fit & Strong! Plus Trial Outcomes for Obese Older Adults with Osteoarthritis

Abstract

Background and objectives: We compared the effectiveness of standard Fit & Strong! (F&S!; targets physical activity [PA]) to Fit & Strong! Plus (F&S! Plus; targets PA and dietary weight loss) on weight, diet quality, and PA outcomes.

Research design and methods: We randomly assigned 413 overweight older adults with OA to the F&S! or F&S! Plus programs and assessed outcomes at 2 and 6 months.

Results: The F&S! Plus group lost -2.0 ± 0.2 kg (mean ± SE, 2% of starting weight) at 2 months that was maintained at 6 months. Two- and 6-month BMI and waist circumference improved significantly in the F&S! Plus group (p < .001). Diet quality at 2 months showed greater improvement in the F&S! Plus group: 4.6 ± 0.7 versus 2.0 ± 0.7, p = .006, with no significant difference between groups at 6 months. The F&S! Plus group differentially improved on PA engagement at 2 months and at 2 and 6 months in joint pain (6-month mean ± SE: -1.5 ± 0.3 vs -0.6 ± 0.3, p = .02), function (-4.7 ± 0.9 vs -1.5 ± 0.9, p = .01), and 6-min walk test (29.5 ± 5.1 m vs 14.1 ± 5.2 m, p = .04).

Discussion and implications: Adding a dietary weight loss component to F&S! achieved weight and waist circumference benefits that were maintained at 6 months. Importantly, the weight loss was accompanied by clinically meaningful improvements in OA symptoms and mobility. Future work should investigate minimum thresholds for weight reduction that improve long-term function in this population.

Keywords: Arthritis; Comparative effectiveness trial; Physical activity; Weight management.