Occurrence of glomerular hyperfiltration in sickle cell anemia by age group. Hyperfiltration is age-dependent, being most prevalent in the 18- to 20-year group. Hyperfiltration is uncommon after the age of 30 years. (A) Hyperfiltration by age using CKD-EPI-2009 with adjustment for race. (B) Hyperfiltration by age using CKD-EPI-2021.