Sarcopenia Indicators as Predictors of Functional Decline and Need for Care among Older People

Sarcopenia is associated with poor health outcomes. We examined the relative roles of muscle mass, strength, physical performance and obesity as health predictors among older sarcopenic people.

This prospective study examined community-dwelling people aged 75+ (N=262).

Porvoo Sarcopenia and Nutrition Trial.

We collected demographic data and medical history by postal questionnaire including RAND-36 at baseline and at four years and measured BMI, Short Physical Performace Battery (SPPB), hand-grip strength, cognition and two surrogate measures of muscle mass; the Single Frequency Skeletal Muscle Index (SF-SMI) and the Calf Intracellular Resistance Skeletal Muscle Index (CRi-SMI).

Adjusted for age and gender, independent outdoors mobility was predicted positively by baseline physical functioning scores in RAND-36 (p<0.001), the SPPB (p<0.001), the two-minute step test (p<0.001), and grip strength (p=0.023), as well as CRi-SMI (p<0.001). However, the prediction was negative in BMI (p<0.001) and the Charlson co-morbidity Index (p= 0.004). Similar associations were found when the physical component RAND-36 was used as an outcome measure. The use of home care was predicted by high co-morbidity (p=0.057) and low scores in RAND-36 (p<0.001), SPPB (p<0.001) and the two-minute step test (p<0.001), and low CRi-SMI (p<0.001). CRi-SF was a more consistent predictor than SF-SMI, which was partly masked by BMI. Controlled for age, gender and comorbidity, a 10% difference in CRi-SMI was associated with a 4% higher probability (p=0.019) of independently living at home, whereas the respective figures for SF-SMI and BMI were -18% (p=0.098) and -14% (p=0.088).

In contrast to SF-SMI, high CRi-SMI appeared to indicate good prognosis and less need of care, independently of BMI.