Kidney Week

Abstract: PO2331

Muscle Mass and Estimates of Renal Function: A Longitudinal Cohort Study

Session Information

• Reassessing Race in Predicting Progression
  November 04, 2021 | Location: On-Demand, Virtual Only
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 2101 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Authors

• Groothof, Dion, Universitair Medisch Centrum Groningen, Groningen, Groningen, Netherlands

Dion Groothof,

• Post, Adrian, Universitair Medisch Centrum Groningen, Groningen, Groningen, Netherlands

Adrian Post,

• Polinder-Bos, Harmke A., Erasmus MC, Rotterdam, Zuid-Holland, Netherlands

Harmke A. Polinder-Bos,

• Erler, Nicole, Erasmus MC, Rotterdam, Zuid-Holland, Netherlands

Nicole Erler,

• Flores-Guerrero, Jose L., Universitair Medisch Centrum Groningen, Groningen, Groningen, Netherlands

Jose L. Flores-Guerrero,

• Kootstra-Ros, Jenny E., Universitair Medisch Centrum Groningen, Groningen, Groningen, Netherlands

Jenny E. Kootstra-Ros,

• Pol, Robert, Universitair Medisch Centrum Groningen, Groningen, Groningen, Netherlands

Robert Pol,

• De Borst, Martin H., Universitair Medisch Centrum Groningen, Groningen, Groningen, Netherlands

Martin H. De Borst,

• Gansevoort, Ron T., Universitair Medisch Centrum Groningen, Groningen, Groningen, Netherlands

Ron T. Gansevoort,

• Gans, Reinold O.B., Universitair Medisch Centrum Groningen, Groningen, Groningen, Netherlands

Reinold O.B. Gans,

• Kremer, Daan, Universitair Medisch Centrum Groningen, Groningen, Groningen, Netherlands

Daan Kremer,

• Kieneker, Lyanne M., Universitair Medisch Centrum Groningen, Groningen, Groningen, Netherlands

Lyanne M. Kieneker,

• Bano, Arjola, Universitat Bern Institut fur Sozial- und Praventivmedizin, Bern, BE, Switzerland

Arjola Bano,

• Muka, Taulant, Universitat Bern Institut fur Sozial- und Praventivmedizin, Bern, BE, Switzerland

Taulant Muka,

• Franco, Oscar, Universitat Bern Institut fur Sozial- und Praventivmedizin, Bern, BE, Switzerland

Oscar Franco,

• Bakker, Stephan J.L., Universitair Medisch Centrum Groningen, Groningen, Groningen, Netherlands

Stephan J.L. Bakker,

Background

Current guidelines suggest using creatinine-based estimated glomerular filtration rate (eGFR_Cr) as measurement of renal function, but muscle mass as key determinant of creatinine after renal function may lead to imprecise estimates. We explored effects of 24-hour height-indexed creatinine excretion rate (CER index) – as accurate marker of muscle mass – on eGFR_Cr and muscle mass-independent cystatin C-based eGFR (eGFR_Cys) and predicted probabilities of misclassification given age, sex, and CER index.

Methods

We included 8,076 community-dwelling individuals enrolled in the PREVEND study. Misclassification was defined as eGFR_Cr ≥60 ml/min/1.73 m² when eGFR_Cys was <60 ml/min/1.73 m². Cross-sectional associations were quantified with quantile regression and logistic regression and longitudinal associations with linear mixed-effects models.

Results

In a simulated 70-year-old male with low muscle mass (CER index of 4 mmol/24 hour/m), predicted baseline eGFR_Cr and eGFR_Cys were 87.5 and 60.5 (difference: 27.0) ml/min/1.73 m², respectively (Figure). Percentages (95% CI) of misclassification in males and females older than 60 years with low muscle mass were 18.5% (14.8% to 22.1%) and 15.2% (11.6% to 18.8%), respectively. Over time, for that same 70-year-old male, eGFR_Cr and eGFR_Cys disagreed with 2.3, 4.9, 7.7, and 10.7 ml/min/1.73 m² at baseline, 5 years, 10 years, and 15 years of follow-up, respectively.

Conclusion

Low muscle mass may cause considerable overestimation of single measurements of eGFR_Cr. Muscle wasting may cause spurious overestimation of repeatedly measured eGFR_Cr. Implementing muscle mass-independent markers for estimating renal function, like cystatin C as superior alternative to creatinine, is crucial to accurately assess renal function in settings of low muscle mass or muscle wasting.