Physical performance measures predict postfracture mortality risk for older men
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Older men with worse grip strength, gait speed and chair stand times within 5 years before a fracture have increased risk for death, according to study findings published in the Journal of Bone and Mineral Research.
“Every 1 standard deviation decrement in grip strength and gait speed and 1 standard deviation increment in chair stand time were associated with 8% to 14% increased mortality risk,” Dima Alajlouni, MScMed, a PhD student in the bone biology division at Garvan Institute of Medical Research in Australia, told Healio. “Greater annual declines in these measurements were also associated with 15% to 38% higher mortality risk, independent of the index values and other covariates, indicating the importance of rehabilitation after fracture to maintain muscle function. Furthermore, inability to perform grip strength, gait speed and chair stands was associated with greater risk of postfracture mortality compared with those who were able to perform all tests.”
Alajlouni and colleagues analyzed data from 830 older men who participated in the Osteoporotic Fractures in Men study. Participants who had at least one low-trauma fracture between enrollment in 2000-2002 and the end of follow-up in 2019 and had grip strength, gait speed and chair stands measured within 5 years of their initial fracture were included. Performance tests were conducted during four clinic visits in 2000-2002, 2005-2006, 2007-2009 and 2014-2016. Researchers contacted the men every 4 months to ask about recent fractures. All fractures were confirmed by radiology reports. High-trauma fractures were not included in the analysis. Mortality was confirmed through death certificates.
Physical performance not linked to subsequent fracture risk
Of the study cohort, 38.8% sustained a proximal fracture, 28.4% had a distal fracture, 20.5% sustained a hip fracture and 12.3% had a clinical vertebral fracture. Median grip strength before initial fracture was 36 kg, median gait speed was 1.14 m/s and median chair stand time was 12 seconds.
During a median follow-up of 3.7 years, 24.2% sustained a subsequent low-trauma fracture, for an incidence rate of 4.7 subsequent fractures per 1,000 person-years. None of the three performance tests was associated with an increase in subsequent fracture risk.
Increased mortality risk with worse physical performance
During a median follow-up of 5.1 years, 64.6% of the cohort died after sustaining a fracture, for a mortality rate of 10.6 per 1,000 person-years. Men who died after a fracture had significantly lower grip strength, slower gait speed and longer chair stand times than those who did not die by the end of the study.
Participants had an increased risk for mortality with each standard deviation (SD) decrease in grip strength (adjusted HR = 1.12; 95% CI, 1.01-1.25) and gait speed (aHR = 1.14; 95% CI, 1.02-1.27) and each SD increase in chair stand time (aHR = 1.08; 95% CI, 0.97-1.21). Men who were unable to perform the grip strength test (aHR = 1.35; 95% CI, 0.83-2.19), gait speed test (aHR = 2.13; 95% CI, 1.51-2.99) or chair stand test (aHR = 1.91; 95% CI, 1.46-2.5) also had an increased risk for mortality, which more than doubled for those unable to perform multiple tests (aHR = 2.13; 95% CI, 1.4-3.24).
Men who died during the study compared with those who survived had a higher median annual rate of decline in grip strength (2.07% vs. 1.88%) and gait speed (2.26% vs. 1.91%), and a higher median annual increase in chair stand time (3.99% vs. 3.06%). Each SD decline in grip strength (aHR = 1.15; 95% CI, 1.01-1.33) and gait speed (aHR = 1.38; 95% CI, 1.13-1.68) and each SD increase in chair stand time (aHR = 1.28; 95% CI, 1.07-1.54) was associated with a greater risk for mortality.
Alajlouni said the findings show the benefit of performing muscle function tests in older men to determine the risk for mortality after a fracture and whether interventions are needed.
“Large studies are needed to assess whether the results we obtained in men are valid in women as well, and to see whether improvement in these modifiable factors can reduce the risk of postfracture mortality,” Alajlouni said.
For more information:
Dima Alajlouni, MScMed, can be reached at d.alajlouni@garvan.org.au.
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