Estimated GFR, Albuminuria, and Physical Function: The Brain in Kidney Disease (BRINK) Cohort StudyPlain-Language Summary

Abstract

Rationale & Objective: Chronic kidney disease (CKD) is associated with impaired physical performance. However, the association between albuminuria, a marker of vascular endothelial dysfunction, and physical performance has not been fully characterized. We hypothesized that estimated glomerular filtration rate (eGFR) and albuminuria would be independently associated with physical performance. Study Design: Cross-sectional analysis. Setting & Participants: A total of 571 adults with and without CKD. Predictors: Creatinine-based eGFR (eGFRCr) and cystatin C-based eGFR (eGFRCysC) and urine albumin to creatinine ratio (UACR). Outcome: Short Physical Performance Battery (SPPB). Analytical Approach: Univariate and multivariable logistic regression models were used to examine associations of eGFR and UACR with impaired physical performance. Results: Of the 571 participants (mean age, 69.3 years), 157 (27.5%) had eGFRCr (mL/min/1.73m2) 300 mg/g vs <30 mg/g), but eGFRCr and eGFRCysC did not. Limitations: Cross-sectional analysis, estimated rather than measured GFR. Conclusions: Only UACR was associated with worse physical performance in the fully adjusted model, suggesting that vascular endothelial function and inflammation may be important mechanisms of decreased physical function. Similar results were found using eGFRCr or eGFRCysC, suggesting that confounding based on muscle mass does not explain the lack of an association between eGFRCr and physical performance.

Keywords

• Albuminuria
• eGFR
• physical performance
• frailty
• CKD