Measures of Physical Performance and Muscle Strength as Predictors of Fracture Risk
For some reason, when I think of fracture risk, I immediately think of bone density. My thoughts are being challenged with this recent study.
The FRAX seems to be the predictive tool of choice for predicting 10 year risk of osteoporetic fracture. The self-report tool focuses on familial history of hip fracture and patient previous history of hip fracture. It considers glucocorticoids, smoking and alcohol consumption. It also considers secondary osteoporosis and bone mineral density. When you think the aspects of this predictive tool, the focus is very targeted toward bones.
I have been seeing more and more studies looking at physical performance and the ability to predict various adverse events. I'm seeing a pattern of physical performance tests that seem to have value in predicting adverse events: the timed chair stands test, gait speed and grip strength. For older adults, it seems that these 3 physical function measures have quite a bit of value and insight into the direction the patient's health is heading.
Often times, our evaluations are laser focused a the specific condition being treated. It seems the above three tests provide important insight into the patient's health. This is another study that highlights the predictive value of physical performance tests: this particular study focuses on fractures.
You'll find the abstract to the recent study below.
Measures of physical performance and muscle strength as predictors of fracture risk independent of FRAX, falls and BMD: A meta-analysis of the Osteoporotic Fractures in Men (MrOS) Study.
Measures of muscle mass, strength and function predict risk of incident fractures, but it is not known whether this risk information is additive to that from FRAX® probability.
We investigated, in the Osteoporotic Fractures in Men (MrOS) Study cohorts (Sweden, Hong Kong, USA), whether measures of physical performance/ appendicular lean mass by DXA predicted incident fractures in older men, independently of FRAX probability.
Baseline information included falls history, clinical risk factors for falls and fractures, femoral neck BMD, and calculated FRAX probabilities. An extension of Poisson regression was used to investigate the relationship between time for 5 chair stands, walking speed over 6m, grip strength, appendicular lean mass (ALM) adjusted for body size (ALM/height2), FRAX probability [major osteoporotic fracture (MOF) with or without femoral neck BMD, available in a subset of n = 7531], and incident MOF (hip, clinical vertebral, wrist or proximal humerus). Associations were adjusted for age, time since baseline, and are reported as hazard ratio (HR) for first incident fracture per SD increment in predictor, using meta-analysis.
5660 men in USA (mean age 73.5 years); 2764 in Sweden (75.4 years); and 1987 in Hong Kong (72.4 years) were studied. Mean follow-up time was 8.7-10.9 years.
Greater time for 5 chair stands was associated with greater risk of MOF [HR:1.26(95%CI:1.19,1.34)], whereas greater walking speed [HR:0.85(95%CI:0.79,0.90), grip strength [HR:0.77(95%CI:0.72,0.82)] and ALM/height2[HR:0.85(95%CI:0.80,0.90)] were associated with lower risk of incident MOF. Associations remained largely similar after adjustment for FRAX, but that between ALM/height2and MOF was weakened [HR:0.92(95%CI:0.85,0.99]. Inclusion of femoral neck BMD markedly attenuated the association between ALM/height2and MOF [HR:1.02(95%CI:0.96,1.10)].
Measures of physical performance predict incident fractures independently of FRAX probability. Whilst the predictive value of ALM/height2being substantially reduced by inclusion of BMD requires further study, these findings support the consideration of physical performance in fracture risk assessment.