5PSQ-096 Abstract withdrawn

<h3>Background and Importance</h3> Accurate assessment of glomerular filtration rate (GFR) is essential for diagnosing kidney disease and determining the appropriate dosing of medications eliminated via the kidneys. In clinical practice, serum creatinine is the standard biomarker used to estimate kidney function, but non-GFR factors, such as age, muscle mass, and nutritional status, can compromise its accuracy. The combination of creatinine and cystatin C has been shown to enhance the performance of GFR estimates across diverse patient populations. However, given the additional costs associated with cystatin C measurement, it is crucial to determine which patients would benefit most from its use. <h3>Aim and Objectives</h3> This study compares the clinically significant differences between creatinine- and cystatin C-based equations in older patients, age-matched healthy older adults, and younger individuals. <h3>Material and Methods</h3> Data from older medical patients (30-day follow-up), older healthy participants matched by age and sex to the older patients, and younger healthy participants were adapted from the FAM-CPH study. Exclusion criteria included cognitive cooperation difficulties, terminal illness, autoimmune diseases, a current cancer diagnosis, and the use of immunosuppressive or anti-inflammatory medication. GFR was estimated using CKD-EPI equations based on the 2009 creatinine (CKD-EPIcrea), 2012 cystatin C (CKD-EPIcysC), and the 2012 combination of creatinine and cystatin C (CKD-EPIcomb). The primary outcome was a comparison of the proportion of participants with a ≥15% difference between CKD-EPIcrea and CKD-EPIcomb. <h3>Results</h3> Of the 128 older patients in the FAM-CPH cohort, 54 were eligible for this study. Fifty-two of the 54 participants (48% female; median age 75 years) were matched with older healthy participants, while the younger control group comprised 59 participants (49% female; median age 26 years). Older individuals had significantly lower eGFR values across all equations than younger controls. Overall, 36% of older patients had an eGFRcomb that differed by more than 15% from eGFRcrea. This discrepancy was observed in 8% of older controls and 4% of younger controls (p ≤ 0.0004). <h3>Conclusion and Relevance</h3> Approximately one-third of older medical patients had a difference of ≥15% between CKD-EPIcrea and CKD-EPIcomb, significantly higher than among older and younger controls. These results suggest that older patients may gain the most significant performance-related benefit from the implementation of cystatin C. <h3>References and/or Acknowledgements</h3> <h3>Conflict of Interest</h3> No conflict of interest