Sarcopenia screening in elderly with Alzheimer's disease: performances of the SARC-F-3 and MSRA-5 questionnaires

Background: The 3-item SARC-F (SARC-F-3) and the 5-item Mini Sarcopenia Risk Assessment (MSRA-5) questionnaires have been recently proposed to screen elderly people regarding the risk of sarcopenia. However, no studies have investigated their performances in Alzheimer's disease (AD). Methods: We conducted a single-center observational study, including 130 consecutive AD patients (mean age: 70.71 +/- 8.50 y, 54.6% women) who attended a center for neurodegenerative diseases. Sarcopenia was diagnosed using the European Working Group on Sarcopenia in Older People of 2010 (EWGSOP1) and of 2018 (EWGSOP2) criteria. Sensitivity, specificity, positive and negative likelihood ratio, and the area under the receiver operating characteristic curve (AUC) were used to assess the diagnostic performance of SARC-F-3 and MSRA-5. Results: SARC-F-3 showed a sensitivity of 9.7%, a specificity of 82.8% and an AUC of 0.41 using EWGSOP1, whereas the sensitivity was of 16.7%, specificity of 84.7% and AUC of 0.58 using EWGSOP2. The MSRA-5 displayed a sensitivity of 3.2%, a specificity of 89.9% and an AUC of 0.41 using EWGSOP1, whereas sensitivity was of 0%, specificity of 91.1% and the AUC of 0.55 using EWGSOP2 criteria. The questionnaires showed a moderate agreement (Cohen's k = 0.53). Conclusions: In our sample of AD patients, a sizable number of sarcopenic individuals were misidentified by SARC-F-3 and MSRA-5, making those questionnaires unsuitable for sarcopenia screening. Considering that sarcopenia has a high prevalence in dementia and that its correct and timely identification is paramount for optimal management of patients, the development and validation of an ad-hoc sarcopenia screening tool for AD patients is highly desirable.