Abstract: TH-PO661
The Difference Between eGFR by Cystatin C vs. Creatinine Provides Clinical Information About Frailty in SPRINT
Session Information
- Geriatric Nephrology
November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Geriatric Nephrology
- 1100 Geriatric Nephrology
Authors
- Potok, O. Alison, UCSD, San Diego, California, United States
- Ix, Joachim H., UCSD, San Diego, California, United States
- Shlipak, Michael, San Francisco VA Medical Center, San Francisco, California, United States
- Katz, Ronit, University of Washington, Seattle, Washington, United States
- Hawfield, Amret T., Wake Forest School of Medicine, Winston-Salem, NC, North Carolina, United States
- Rocco, Michael V., Wake Forest School of Medicine, Winston-Salem, NC, North Carolina, United States
- Ambrosius, Walter T., Wake Forest School of Medicine, Winston-Salem, NC, North Carolina, United States
- Cho, Monique E., University of Utah, Salt Lake City, Utah, United States
- Pajewski, Nicholas M., Wake Forest School of Medicine, Winston-Salem, NC, North Carolina, United States
- Rastogi, Anjay, Division of Nephrology, Los Angeles, California, United States
- Rifkin, Dena E., UCSD, San Diego, California, United States
Background
In prior studies, the discrepancy between the glomerular filtration rate (eGFR) estimated using either creatinine [eGFRCr] or cystatin C [eGFRCys] has been treated as measurement error related to kidney function. We propose instead that clinical information about frailty and muscle strength is contained in these differences. We examined the difference between eGFR by cystatin C and creatinine and its relationship to frailty, in cross-sectional and longitudinal analyses.
Methods
9092 SPRINT participants had baseline measures of serum creatinine and cystatin C. eGFRCr and eGFRCys were calculated using CKD-EPI equations, and eGFRDiff was defined as eGFRCys - eGFRCr. A 37-item frailty index (FI) included questionnaires, past medical history, cognitive tests and laboratory data (excluding albuminuria and eGFR). As defined in prior studies, frailty was FI > 0.21.
Results
Average (SD) was 68 (±9) years for age and was 73 (±23) for eGFRCys, 72 (±20) for eGFRCr, and 0.45 (±15) mL/min/1.73m2 for eGFRDiff. Compared to participants with minimal difference in eGFR, those with a substantially positive difference eGFRDiff (≥20 mL/min/1.73m2) were younger (64 vs. 68 years) and more likely to be male (77% vs. 64%). Those with a substantially negative eGFRDiff (≤ -20 mL/min/1.73m2) were more likely to be frail (OR=1.34 95%CI [1.11; 1.61], p<0.01 in fully adjusted model, Table 1), and were at higher risk for death (HR=1.64 95%CI [1.14;2.36] p=0.008).
Conclusion
In SPRINT, an eGFRCys estimate that was substantially less than an eGFRCr estimate was associated with underlying frailty. The difference between eGFRCys and eGFRCr may provide important information on functional status and prognosis that should be incorporated into clinical reasoning when evaluating these measures.
Association of eGFRDiff groups with frailty at baseline
Outcome: Frailty | Negative eGFRDiff (< - 20 mL/min/1.73m2) (n=226) | eGFRDiff Reference (-20 to +20 mL/min/1.73m2) (n=1796) | Positive eGFRDiff (≥ 20 mL/min/1.73m2) (n=103) | |||
OR (95%CI) | p value | OR (95%CI) | p value | OR (95%CI) | p value | |
Unadjusted | 1.43 (1.20; 1.70) | <0.001 | 0 (ref) | 0.54 (0.43; 0.67) | <0.001 | |
Fully adjusted * | 1.40 (1.15; 1.72) | 0.001 | 0 (ref) | 0.76 (0.60; 0.97) | 0.028 |
*adjusted for age, gender, race, education, body mass index, randomization arm, albuminuria, cardiovascular risk factors, chronic kidney disease stage
Funding
- Other NIH Support