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CHAPTER 6 Recognizing Persons at Risk for Sarcopenia
John E. Morley
Division of Geriatric Medicine, Saint Louis University School of Medicine, St. Louis, MO, USA
Sarcopenia is recognized as a disease with its own International Classification of Disease. However, sarcopenia is rarely recognized or diagnosed by primary care health professionals. The average general practitioner has between 7 and 10 minutes for each patient visit. To make the diagnosis of sarcopenia requires either measuring grip strength or walking speed together with a measure of lean mass. For a primary care clinician to consider making a referral for the diagnosis and treatment for sarcopenia they need to recognize that there is a likelihood that the person may be sarcopenic. This may be particularly difficult in persons with sarcopenic obesity [1]. For this reason there is a need for a rapid screening test for sarcopenia. The need for such a test is particularly important as persons with sarcopenia are at high risk for deleterious outcomes such as falls, hip fractures, disability, hospitalizations, nursing home admissions, and mortality [2, 3]. Lack of knowledge of the average clinician of the existence of sarcopenia as a disease further increases the likelihood of the diagnosis not being considered [4].
SARC‐F
In 2013, SARC‐F was developed by the group at Saint Louis University to provide a rapid screening test to allow the recognition of the possible diagnosis of sarcopenia [5] (Table 6.1). This screener was developed with the recognition that functional deterioration of activities requiring muscle activity is the hallmark of sarcopenia. The screener can either be self‐administered or administered by the person responsible for rooming the patient. It takes less than 30 seconds to complete.
Table 6.1 SARC‐F screen for sarcopenia.
| Component | Question | Scoring |
| Strength | How much difficulty do you have in lifting and carrying 10 pounds? | None = 0 Some = 1 A lot or unable = 2 |
| Assistance in walking | How much difficulty do you have walking across a room? | None = 0 Some = 1 A lot, use aids, or unable = 2 |
| Rise from a chair | How much difficulty do you have transferring from a chair or bed? | None = 0 Some = 1 A lot or unable without help = 2 |
| Climb stairs | How much difficulty do you have climbing a flight of 10 stairs? | None = 0 Some = 1 A lot or unable = 2 |
| Falls | How many times have you fallen in the past year? | None = 0 1–3 falls = 1 ≥4 falls = 2 |
The original validation of SARC‐F was completed in 230 persons in China [6]. SARC‐F was correlated with impaired physical performance and grip strength as well as hospitalizations. Woo et al. [7, 8] compared SARC‐F to working definitions for sarcopenia (Asian, European, and International) in 4000 community dwellers in Hong Kong. SARC‐F had good specificity and poor sensitivity. Equivalent predictive ability of functional measures at four years was compared to working definitions. It also predicted mortality.
Malmstrom et al. [9] evaluated SARC‐F in the St. Louis African American Health Study (AAH), the Baltimore Longitudinal Study of Aging (BLSA) and in the National Health and Nutrition Examination Survey. They found that SARC‐F had internal consistency and good criterion and construct validity. In all three groups it had a good correlation with functional performance and mortality at six years. In the BLSA it predicted mortality.
Tanaka et al. [10] studied a group of patients with cardiovascular disease. They found that an elevated SARC‐F score was associated with lower handgrip and leg strength, respiratory muscle strength, poorer standing balance, slow gait speed and six‐minute walking distance, and lower short physical performance battery (SPPB) score.
A meta‐analysis of seven studies including 12 800 subjects showed that SARC‐F has a high specificity but poor sensitivity, suggesting it is a reasonable screening test for sarcopenia [11]. SARC‐F has been validated in China [6], Hong Kong [7, 8, 12], United States [9, 13], Japan [10, 14–17], Taiwan [18], Mexico [19], Germany [20], France [21], Singapore [22], Korea [23], Austria [24], Turkey [25, 26], Spain [16, 27], and Belgium [28] (Table 6.2).
