Oral Virtual Presentation (Virtual only) ESA-SRB-ANZBMS 2021

Creatinine to cystatin C ratio: A novel biomarker of sarcopenia measures and falls risk in community-dwelling older women? (#6)

Marc Sim 1 2 , Jack Dalla Via 2 , David Scott 3 4 , Wai H Lim 1 5 , Jonathan M Hodgson 1 2 , Kun Zhu 1 6 , Robin M Daly 3 , Gustavo Duque 4 7 , Richard L Prince 1 6 , Joshua R Lewis 1 2 8
  1. Medical School, The University Western Australia, Perth, Western Australia, Australia
  2. School of Medical & Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
  3. Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia
  4. Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, Melbourne, Victoria, Australia
  5. Department of Renal Medicine, Sir Charles Gairdner Hospital, Perth, WA, Australia
  6. Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
  7. Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
  8. Centre for Kidney Research, Children's Hospital at Westmead, The University of Sydney, Sydney, New South Wales, Australia

Background: The contribution of age-related muscle impairment to falls and associated injury (e.g. fracture) is well recognised. The ratio of creatinine to cystatin C (Cr:Cyc) has been proposed as a biomarker of muscle mass, but its relationship to adverse outcomes, including falls, remain unclear. We examined the relationship between Cr:Cyc with sarcopenia measures (muscle mass and function), 5-y self-reported falls and 14.5-y fall-related hospitalizations in a prospective cohort study of 1,118 community-dwelling older women (mean±SD, age 75.2±2.7 y).

Methods: Serum Cr:Cyc, hand grip strength and timed-up-and-go (TUG) performance were assessed at baseline (1998), while dual-energy X-ray absorptiometry (DXA) derived ALM/Height (m)2 was obtained in a subset of women at baseline (n=334). Incident 5-y self-reported falls and 14.5-year fall-related hospitalizations from linked health records were examined.

Results: In a multivariable-adjusted model, each SD decrease in Cr:Cyc was associated with reduced grip strength (β=-0.11, p<0.001) and ALM/Height2 (β=-0.13, p=0.002), but not TUG (β=0.01, p=0.086). Women with the lowest Cr:Cyc (Quartile [Q] 1) had 6.6% (1.4 kg) weaker grip strength and 3.3% (0.2 kg/m2) lower ALM/Height2 compared to women in Q4 (both p<0.05). Overall, 329 women reported an incident fall over 5 years, and 439 fall-related hospitalizations were recorded over 14.5 years. Women in Q1 of Cr:Cyc had a greater relative hazard for falls (HR 1.50 95%CI 1.11-2.01) and fall-related hospitalizations (HR 1.48 95%CI 1.14-1.91) compared to Q4 in the multivariable-adjusted model (Figure 1). Results remained unchanged when grip strength was included in the multivariable-adjusted model.

Conclusion: The use of Cr:Cyc may represent a viable muscle biomarker to help clinicians identify individuals at risk of falls who may benefit from primary prevention programs (e.g. diet and exercise). Future work should seek to confirm the utility and cut-points of Cr:Cyc as a biomarker contributing to sarcopenia diagnosis and management.

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