TY - CHAP M1 - Book, Section TI - The Kidney & Aging A1 - Dirkx, Tonja C. A1 - Woodell, Tyler B. A2 - Papadakis, Maxine A. A2 - McPhee, Stephen J. A2 - Rabow, Michael W. A2 - McQuaid, Kenneth R. PY - 2023 T2 - Current Medical Diagnosis & Treatment 2023 AB - After 40 years of age, GFR declines annually by an average rate of 0.8 mL/min/1.73 m2 (though some older patients show little or no change) and is accompanied by a decline in renal mass that spares medulla relative to cortex. In an attempt to maintain GFR, renal blood flow decreases, causing a resultant increase in arteriolar resistance and increased filtration fraction. Serum creatinine values may remain relatively constant if muscle mass decreases in parallel with the decrease in GFR; a stable creatinine in the face of significant weight loss suggests progression of kidney disease. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/10/04 UR - accessmedicine.mhmedical.com/content.aspx?aid=1193127776 ER -