Weakness and Low Lean Mass in Women With Hip Fracture: Prevalence According to the FNIH Criteria and Association With the Short-Term Functional Recovery.

BACKGROUND AND PURPOSE: People with hip fracture commonly have low muscle mass, reduced muscle strength, limited mobility, and limited ability to function in activities of daily living. Our aim was to assess the role of grip strength and appendicular lean mass (aLM) to predict the short-term functional recovery in women with hip fracture. For both strength and aLM, we focused on the cutoff points recently released by the Foundation for the National Institutes of Health (FNIH).

METHODS: In this short-term prospective observational study, we investigated 138 white women consecutively admitted to a rehabilitation hospital because of their first hip fracture. We measured aLM by dual-energy x-ray absorptiometry, grip strength with a hand dynamometer, and body mass index (BMI) at a median of 18 days after hip fracture occurrence. Functional autonomy was assessed by the Barthel index at the end of the rehabilitation course.

RESULTS: Fifty-five of the 138 women (40%; 95% confidence interval [CI], 32%-48%) had a handgrip strength less than 16 kg, whereas 33 (24%; 95% CI, 17%-31%) had a handgrip strength/BMI less than 0.56. In both cases, the weak women had Barthel index scores significantly lower than the nonweak women (P ≤ .001). One hundred eighteen of the 138 women (86%; 95% CI, 80%-91%) had an aLM less than 15.02 kg, whereas 65 (48%; 95% CI, 39%-56%) had an aLM/BMI less than 0.512. In both cases the Barthel index scores were nonsignificantly different between the women whose aLM indexes were either below or above the cutoff points.

CONCLUSIONS: Categorization according to the FNIH cutoff points for weakness significantly predicted the functional outcome in women with hip fracture, whereas categorization for aLM did not. Adjustments for BMI significantly changed the prevalence of either weakness or low aLM, but did not materially change their predictive roles.