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).
Table 6.2 Validations of SARC‐F.
| Author | Country | n | Outcomes |
| Cao et al. [6] | China | 230 | Predicts poor function, grip strength, and hospitalization |
| Woo et al. [7, 8] | Hong Kong | 4000 | Good specificity compared with Asian and European working definitions – predictive of function (gait speed, grip strength, and repeated chair stand) at 4 years and mortality at 10 years |
| Malmstrom [9] | United States: St. Louis United States: Baltimore United States: NHANES | 998 1053 3288 | Instrumental activities of daily living (IADL) deficits, slower chair stands, lower grip strength, lower short physical performance battery scores (cross‐sectionally) and predicted poor IADL deficits, poor physical performance and 6‐year hospitalization IADL deficits, lower grip strength at baseline, and mortality at two‐month follow‐up Slower walk speed, knee extensor strength at baseline, and mortality at 27‐month follow‐up |
| Tanaka [10] | Japan | 235 | Lower grip, leg and respiratory muscle strength, poorer gait speed and walking distance, and poorer balance and SPPB |
| Wu [18] | Taiwan | 670 | Low grip strength and lean mass, poor quality of life, and hospitalization and mortality |
| Parra‐Rodriguez [19] | Mexico | 487 | Reliability. ADL deficits, low gait speed, poor grip strength, lower SPPB |
| Ida [14] | Japan | 207 | Specificity (85.8% men and 72.4% women); sensitivity (14.8 and 33.3%) to EWGOS |
| Kemmler [20] | Germany | 74 | Diagnostic overlap equivalent for SARC‐F to EWGSOP, FNIH, IWGS |
| Rolland [21] | France | 504 | Specificity 85% versus FNIH; lower physical performance |
| Tan [22] | Singapore | 115 | More than two hospitalization in a year; higher rate of falls |
| Kotiarczyk [13] | United States | 141 | Specificity versus EWGSOP 78.7% and versus FNIH 81.1%, low sensitivity |
| Kim [23] | Korea | 1222 | High specificity versus Asian sarcopenia. Poor grip strength, slow walking speed, lower quality of life, poor cognitive performance |
| Ida [15] | Japan | 140 | High specificity (90.89–95.5%) and predictive value (81.5%) in chronic liver disease |
| Peball [24] | Austria | 434 |
High prevalence in Parkinson disease compared
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