June 20, 2022

Journal of Cachexia, Sarcopenia, and Muscle – 2022 Feb;13(1):264-275. doi: 10.1002/jcsm.12871.

Sarcopenia is a progressive loss of muscle function and mass that is mostly related to aging [1]. Due to sarcopenia’s adverse outcomes in several conditions, diagnosis and integration into treatment plans is highly recommended [1]. In the care of older adults, cognitive impairment, functional decline, or acute life-threatening medical conditions, such as severe pneumonia, myocardial infarctions, or highly proliferative hematological conditions can preclude patients from self-reported assessment. In addition, a severe acute condition can lead to a massive functional decline within a short time-frame. Thus, physical resilience can be underestimated if a superior premorbid condition is not known to the treating physician. To overcome these barriers, the authors aimed to validate the SARC-F questionnaire, a broadly used screening questionnaire for severe sarcopenia-related functional impairments [2], for the use of proxy-reported information of the patients’ current and premorbid status.

In this validation trial [3], 104 patients from a rheumatology/hematology outpatient service and a geriatric in-patient rehabilitation as well as their 135 proxies (partners, children, siblings, etc.) participated. Patients performed the Short Physical Performance Battery (SPPB) on day 0 and answered the SARC-F questionnaire. Proxies were divided into two groups: Proxies in group A answered the SARC-F questionnaire with regard to the patient twice, once on day 0, and secondly after 3 months. At this point in time, proxies were asked to answer the SARC-F retrospectively recalling the functional status of day 0. Proxies in group B answered the SARC-F only once after three months, recalling the functional status of day 0.

Group B was generated to exclude a recall bias given the probability that proxies remember their answers from day 0 rather than recalling the patient’s functional status of day 0. A SPPB score below 9 points was set as reference for severe sarcopenia-related functional impairments. When proxy-reported SARC-F was compared with the patient-reported version, non-inferiority was demonstrated for both groups (group A/ad-hoc screening: p<0.001, group A/retrospective screening: p=0.007), group B/retrospective screening: p=0.026).

Furthermore, ad-hoc SARC-F in group A and retrospective SARC-F in both groups showed areas under the ROC curves of ≥0.9. In conclusion, proxy-reported SARC-F is a valid tool to assess the risk of severe functional impairments in older adults. In addition, it can be used to assess the premorbid status.

Over- and under-treatment remains a major problem in the care of older patients with highly proliferative malignancies. Assessment of the premorbid status could potentially give valuable information on the physical reserve of a patient, thereby, guiding treatment intensity. Integrating evaluation of the premorbid condition in future clinical trials should be considered in this patient population.


  1. Cruz-Jentoft, A.J., et al., Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing, 2019. 48(1): p. 16-31.
  2. Malmstrom, T.K., et al., SARC-F: a symptom score to predict persons with sarcopenia at risk for poor functional outcomes. J Cachexia Sarcopenia Muscle, 2016. 7(1): p. 28-36.
  3. Maurus, J., et al., Validation of a proxy-reported SARC-F questionnaire for current and retrospective screening of sarcopenia-related functional impairments. J Cachexia Sarcopenia Muscle, 2022. 13(1): p. 264-275.