Oral Virtual Presentation (Virtual only) ESA-SRB-ANZBMS 2021

Muscle strength and physical performance are associated with risk of post fracture mortality but not subsequent fracture (#18)

Dima Alajlouni 1 2 , Dana Bliuc 1 2 , Thach Tran 1 2 , Robert D Blank 2 , Peggy M Cawthon 3 4 , Kristine E Ensrud 5 6 7 , Nancy E Lane 8 , Jackie R Center 1 2
  1. Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
  2. Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
  3. California Pacific Medical Center, Research Institute, San Francisco, California, USA
  4. Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA
  5. Center for Care Delivery and Outcomes Research, Minneapolis VA Healthcare System, Minneapolis, MN, USA
  6. Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN, USA
  7. Department of Medicine, University of Minnesota, Minneapolis, MN, USA
  8. Department of Medicine, University of California at Davis Medical Center, Sacramento, CA, USA

Background: Muscle strength and physical performance measurements are associated with incident fractures and mortality. However, their impact on post fracture outcomes is not clear.

Objective: To assess the association between muscle strength and performance with subsequent fracture and mortality after a fracture.

Methods: The study included 830 MrOS USA participants with low-trauma index fracture who had muscle strength and physical performance assessments within 5 years prior to the index fracture. Mixed effects models were used to estimate the annual change in muscle strength and performance following index fracture. Index value and decline of each test were examined as predictors of subsequent fracture and mortality using Cox proportional hazards models adjusted for age, FNBMD, prior fractures, falls, BMI, index fracture type, lifestyle factors, and comorbidities.

Results: Median follow-up from index fracture to mortality was 5.1(IQR: 1.8-9.6) years and to subsequent clinical fracture was 3.7 years (1.3-8.1). During follow-up, 536 (65%) men died and 201 (24%) men had a subsequent fracture. Index strength and performance were independently associated with mortality risk; HRs per SD change for lower grip strength, lower gait speed, and greater sit-to-stand time were 1.12(95%CI: 1.01-1.25), 1.14(1.02-1.27), and 1.08(0.97-1.21), respectively. The annual decline in these tests was also associated with increased mortality risk, independent of the baseline value and other confounding effects (HR per SD of the change: 1.15(95% CI: 1.01-1.33), 1.38(1.13-1.68), 1.28(1.07-1.54), respectively). Men who were unable to complete one or multiple tests had even greater risk of mortality. However, muscle strength and performance were not associated with subsequent fractures.

Conclusion: Both lower muscle strength and physical performance measured prior to index fracture as well as their decline were associated with post-fracture mortality but not subsequent fracture risk. However, it remains to be seen whether improvement in these parameters can reduce mortality risk after incident fracture.