The Difference Between Cystatin C– and Creatinine-Based Estimated GFR and Associations With Frailty and Adverse Outcomes: A Cohort Analysis of the Systolic Blood Pressure Intervention Trial (SPRINT)

The Difference Between Cystatin C– and Creatinine-Based Estimated GFR and Incident Frailty: An Analysis of the Cardiovascular Health Study (CHS)

“…We demonstrate that lower eGFR Diff is strongly associated with prevalent and incident frailty and all-cause mortality, in fully adjusted models. These findings, along with those from SPRINT, 4 support the idea that eGFR Diff is an indicator of frailty, poor outcomes, and mortality. Several studies [5][6][7] found that lower eGFR cys is associated with higher risk for frailty, whereas lower eGFR cr is not.…”

“…Maintenance monotherapy with niraparib (Zejula; Tesaro), an inhibitor of poly(ADP-ribose) polymerase, improves progression-free survival in patients with relapsed high-grade serous epithelial ovarian cancers that are platinum sensitive, with or without germline mutations in BRCA1 and BRCA2. [1][2][3][4][5] Clinical trials and the summary of product characteristics suggest that niraparib may not have adverse effects on the kidney. 2,4,6,7 The purpose of this study is to describe kidney function parameters of patients followed up at our center for up to 12 months after initiation of niraparib therapy.…”

Assessment of kidney function: clinical indications for measured GFR

“…Particularly when creatinine-based eGFR presents an implausibly high value in contrast to the cystatin C–based eGFR, we recommend to interpret the creatinine-based result with caution [ 64 ]. Potok et al [ 65 , 66 ] hypothesize that prognostic information about frailty and mortality is embedded in the difference between cystatin C and creatinine, i.e that frailty would be less prevalent in older adults with a higher value of cystatin C–based eGFR as compared with creatinine-based eGFR.…”

Differences Between Cystatin C– and Creatinine-Based Estimated GFR—Early Evidence of a Clinical Marker for Frailty

“…In this issue of AJKD, Potok et al evaluate the utility of measuring the differences between cystatin C-and creatinine-based estimated glomerular filtration rate (eGFR) as a proxy for frailty by examining associations with FI (in participants from the Systolic Blood Pressure Intervention Trial [SPRINT]) 11 and PFP (in participants in the Cardiovascular Health Study [CHS]). 12 Because creatinine-based equations overestimate GFR in frail patients (given lower serum creatinine levels in the context of sarcopenia) while cystatin C level is less affected by sarcopenia, the authors hypothesize that a high creatininebased eGFR relative to a cystatin C-based eGFR may reflect the influence of muscle mass and diet, and as such, capture important clinical information.…”

“…In SPRINT (n = 9,092), the difference in GFR estimated by cystatin C and creatinine levels was associated with the validated 35-item FI. 11 Participants who had a difference between GFR estimates (eGFR based on cystatin C − eGFR based on creatinine) less than −15 mL/min/1.73 m 2 had 1.41-fold increased odds of being frail by FI criteria; those with differences ≥ 15 mL/min/1.73 m 2 had lower odds of being frail (odds ratio [OR], 0.61). The association between difference in GFR estimates and prevalent frailty was significant regardless of the patient's eGFR category (based on creatinine level).…”