The prognostic and discriminatory utility of the Clinical Frailty Scale and modified frailty Index compared to age

Ben Carter, Victoria Keevil, Atul Anand, Christopher Osuafor, Robert Goudie, Jacobus Preller, Matthew Lowry, Sarah Clunie, Susan Deborah Shenkin, Kathryn McCarthy, Jonathan Hewitt, Terry Quinn

Research output: Contribution to journalArticlepeer-review


Background: There is no consensus on the optimal method for the assessment of frailty. We compared the prognostic utility of two approaches (modified Frailty Index [mFI], Clinical Frailty Scale [CFS]) in older adults (≥65 years) hospitalised with COVID-19 versus age. Methods: We used a test and validation cohort that enrolled participants hospitalised with COVID-19 between 27 February and 30 June 2020. Multivariable mixed-effects logistic modelling was undertaken, with 28-day mortality as the primary outcome. Nested models were compared between a base model, age and frailty assessments using likelihood ratio testing (LRT) and an area under the receiver operating curves (AUROC). Results: The primary cohort enrolled 998 participants from 13 centres. The median age was 80 (range:65–101), 453 (45%) were female, and 377 (37.8%) died within 28 days. The sample was replicated in a validation cohort of two additional centres (n = 672) with similar characteristics. In the primary cohort, both mFI and CFS were associated with mortality in the base models. There was improved precision when fitting CFS to the base model +mFI (LRT = 25.87, p < 0.001); however, there was no improvement when fitting mFI to the base model +CFS (LRT = 1.99, p = 0.16). AUROC suggested increased discrimination when fitting CFS compared to age (p = 0.02) and age +mFI (p = 0.03). In contrast, the mFI offered no improved discrimination in any comparison (p > 0.05). Similar findings were seen in the validation cohort. Conclusions: These observations suggest the CFS has superior prognostic value to mFI in predicting mortality following COVID-19. Our data do not support the use of the mFI as a tool to aid clinical decision-making and prognosis.

Original languageEnglish
Article number87
Issue number5
Publication statusPublished - 24 Aug 2022


  • COVID-19
  • clinical frailty scale
  • frailty
  • modified frailty index
  • older people
  • prognosis


Dive into the research topics of 'The prognostic and discriminatory utility of the Clinical Frailty Scale and modified frailty Index compared to age'. Together they form a unique fingerprint.

Cite this