Association of frailty with body composition among patients on hemodialysis

Although sarcopenia is thought to underlie the manifestations of frailty, association of frailty with measures of body composition is underinvestigated.

Eighty hemodialysis patients were included in the study. Performance-based frailty (PbF) used gait speed over 20 feet and 5 sit-to-stand (1 point each for lowest quintile) for the physical components of the frailty phenotype plus exhaustion (Short Form-36 [SF-36] vitality score <55) and physical activity (lowest quintile of weekly kcal energy expenditure on leisure activity on the Physical Activity Scale for the Elderly questionnaire; 1 point). Function-based frailty (FbF) defined by questionnaire measures of physical functioning (SF-36 Physical Function score <75; 1 point), exhaustion, and physical activity as for PbF. A score of 2 or greater was defined as frail. Outcomes related to muscle size included muscle area of the contractile tissue of the anterior tibialis and quadriceps muscles using magnetic resonance imaging, phase angle using bioimpedance analysis, lean body mass using dual energy X-ray absorptiometry, and body mass index (BMI). Linear regression was used to analyze associations between frailty and muscle size, with and without sex and age covariates.

Fifty-nine percent of individuals met PbF criteria, 63% met FbF criteria, and 55% met both. In univariate analysis, PbF and FbF were associated with smaller muscle area of the quadriceps, smaller phase angle, and higher BMI. Associations remained significant for the quadriceps after adjustment for age and sex. The magnitude of association of PbF with quadriceps muscle area was greater than 10 years of age (-30.3 cm(2)P = .02 vs. -6.6 cm(2)P < .0001) in multivariate analysis. There was no significant association between either measure of frailty and other measures of body composition after adjustment for age and sex.

Frailty was associated with measurements related to muscle size in a population of individuals with chronic kidney disease, a known contributor to muscle wasting.