Impact of baseline fatigue on a physical ability intervention to prevent mobility disability

Authors: GLYNN, NANCY - University Of Pittsburgh; GMELIN, THERESA - University Of Pittsburgh; SANTANASTO, ADAM - University Of Pittsburgh; LOVATO, LAURA - Wake Forest University; LANGE-MAIA, BRITTNEY - Rush University Medical Center; NICKLAS, BARBARA - Wake Forest University; FIELDING, ROGER - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; MANINI, TODD - University Of Florida; MYERS, VALERIE - Klein Buendel, Inc; DE REKENEIRE, NATHALIE - Centre Muraz Organisation De Cooperation Et De Coordination Pour La Lutte Contre Les Grandes Endemi; SPRING, BONNIE - Northwestern University; PAHOR, MARCO - University Of Florida; KING, ABBY - Stanford University; REJESKI, W. JACK - Wake Forest University; NEWMAN, ANNE - University Of Pittsburgh

Submitted to: Journal of the American Geriatrics Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2019
Publication Date: 12/22/2019
Citation: Glynn, N.W., Gmelin, T., Santanasto, A.J., Lovato, L.C., Lange-Maia, B.S., Nicklas, B.J., Fielding, R.A., Manini, T.M., Myers, V.H., De Rekeneire, N., Spring, B.J., Pahor, M., King, A.C., Rejeski, W., Newman, A.B. 2019. Impact of baseline fatigue on a physical ability intervention to prevent mobility disability. Journal of the American Geriatrics Society. https://doi.org/10.1111/jgs.16274.
DOI: https://doi.org/10.1111/jgs.16274

Interpretive Summary: The purpose of this study was to examine the impact of baseline measures of "fatigue" (self-reported tiredness or reduced energy level) on the effectiveness of a group-based physical activity (PA) intervention to prevent major mobility disability (MMD: inability to walk 400 M) in participants from the Lifestyle Interventions and Independence for Elders (LIFE) study. We used data from the LIFE study which was a randomized trial of men and women aged 65 years or older who underwent a structured PA intervention or health education (HE) over an average time of 2.6 years. LIFE was a multicenter eight-site (including USDA-HNRCA at Tufts Boston) randomized trial that compared the efficacy of a structured PA exercise training intervention with an HE intervention on reducing the incidence of major mobility disability. For this analysis, study participants (N = 1591) at baseline were 78.9 +/- 5.2 years of age. Self-reported fatigue was assessed using a six-question scale rating energy levels in the past week. Participants performed a usual-paced 400-m walk every 6 months to assess major mobility disability defined as the inability to walk 400-m at a follow-up visit. Among those with higher baseline fatigue, PA participants had a 29% lower risk of MMD. For those with lower baseline fatigue, there was no effect on the development of MMD in the PA participants. These results suggest that a long-term moderate intensity PA exercise program was particularly effective at preserving mobility in older adults with higher baseline levels of fatigue.

Technical Abstract: OBJECTIVES: Our aim was to examine the impacts of baseline fatigue on the effectiveness of a physical activity (PA) intervention to prevent major mobility disability (MMD) and persistent major mobility disability (PMMD) in participants from the Lifestyle Interventions and Independence for Elders (LIFE) study. DESIGN: Prospective cohort of individuals aged 65 years or older undergoing structured PA intervention or health education (HE) for a mean of 2.6 years. SETTING: LIFE was a multicenter eight-site randomized trial that compared the efficacy of a structured PA intervention with an HE program in reducing the incidence of MMD. PARTICIPANTS: Study participants (N=1591) at baseline were 78.9+/-5.2 years of age, with low PA and at risk for mobility impairment. MEASUREMENTS: Self- reported fatigue was assessed using the modified trait version of the Exercise-Induced Feelings Inventory, a six- question scale rating energy levels in the past week. Responses ranged from 0 (none of the time) to 5 (all of the time). Total score was calculated by averaging across questions; baseline fatigue was based on the median split: 2 or higher = more fatigue (N=856) and lower than 2=less fatigue (N=735). Participants performed a usual-paced 400m walk every 6 months. We defined incident MMD as the inability to walk 400m at follow-up visits; PMMD was defined as two consecutive walk failures. Cox proportional hazard models quantified the risk of MMD and PMMD in PA vs HE stratified by baseline fatigue adjusted for covariates. RESULTS: Among those with higher baseline fatigue, PA participants had a 29% and 40% lower risk of MMD and PMMD, respectively, over the trial compared with HE (hazard ratio [HR] for MMD=.71; 95% confidence interval [CI] =.57-.90; P=.004) and PMMD (HR=.60; 95% CI=.44-.82; P=.001). For those with lower baseline fatigue, no group differences in MMD (P=.36) or PMMD (P=.82) were found. Results of baseline fatigue by intervention interaction was MMD (P=.18) and PMMD (P=.05). CONCLUSION: A long-term moderate intensity PA intervention was particularly effective at preserving mobility in older adults with higher levels of baseline fatigue.