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Comparison of Creatinine and Cystatin C to Estimate Renal Function in Geriatric and Frail Patients
Erik Dahlén1, Linda Björkhem-Bergman2
1Jakobsberg Geriatric Clinic, Jakobsberg's Hospital, Järfälla, 177 31 Stockholm, Sweden.
Insights
Estimated glomerular filtration rate (eGFR) using cystatin C (eGFRcys) was lower than creatinine (eGFRcrea) in frail geriatric patients. Frailty, not age, significantly impacted eGFR accuracy.
Area of Science:
- Geriatric Medicine
- Nephrology
- Biomarkers
Background:
- Accurate estimation of glomerular filtration rate (eGFR) is crucial for managing geriatric and frail patients.
- Creatinine-based (eGFRcrea) and cystatin C-based (eGFRcys) equations are commonly used, but their performance in specific populations requires further investigation.
Purpose of the Study:
- To compare the accuracy and consistency of eGFRcrea and eGFRcys in geriatric and frail individuals.
- To assess the influence of frailty and age on the differences between eGFRcrea and eGFRcys.
Main Methods:
- Retrospective, cross-sectional study of 95 geriatric patients.
- Calculated eGFRcrea using the revised Lund−Malmö equation and eGFRcys using the CAPA equation.
- Analyzed absolute mean percentage difference, Lin’s concordance correlation coefficient, and renal failure staging consistency.
Main Results:
- eGFRcys consistently estimated lower GFR than eGFRcrea across all patients and subgroups (p < 0.05).
- The discrepancy between eGFRcrea and eGFRcys increased with higher levels of frailty (r2 = 0.15, p < 0.01).
- Age did not significantly affect the difference between the two eGFR estimates (r2 = 0.004, p = 0.55).
Conclusions:
- eGFRcys provides significantly lower estimates compared to eGFRcrea in geriatric and frail populations.
- Frailty demonstrates a greater impact on eGFR accuracy than chronological age in this cohort.
- Further research is needed to determine the preferred eGFR estimation method for this patient group.
Abstract:
The aim of this study was to compare estimated glomerular filtration rate (eGFR) with creatinine (eGFRcrea) and cystatin C (eGFRcys) in geriatric and frail patients. A retrospective, cross-sectional study was performed at a geriatric clinic in Stockholm (n = 95). The revised Lund−Malmö equation was used to calculate eGFRcrea and the Caucasian-Asian-Pediatric-Adult (CAPA) equation was used for eGFRcys. The absolute mean percentage difference between eGFRcrea and eGFRcys was used as a surrogate measure for accuracy in eGFR. Other outcome measures were consistency expressed in Lin’s concordance correlation coefficient and the proportion of consistent staging of renal failure. Subgroup analyses were performed with regard to frailty (according to Clinical Frailty Scale) and age. eGFRcys estimated lower GFR than eGFRcrea across the entire study population as well as in all subgroups (p < 0.05). Difference between the estimates increased with increasing frailty (r2 = 0.15, p < 0.01), but was not significantly affected by age (r2 = 0.004, p = 0.55). In conclusion, eGFRcys was significantly lower compared to eGFRcrea in geriatric and frail patients. Moreover, frailty had greater impact than age on the accuracy of eGFR. However, this study cannot determine if any of the estimates are preferable over the other in this patient group.
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