Purpose of review: Chronic kidney disease (CKD) has generally been characterized functionally as a glomerular filtration rate (GFR) less than 60 ml/min/1.73 m2, without accounting for cause, signs of structural damage, or relative risk of sequelae. Recently released guidelines define CKD as abnormalities of kidney structure or function, present for more than 3 months. We review the recent literature about CKD and its implications for renal surgery.
Recent findings: Most estimates of GFR are based on serum creatinine, after adjusting for age, race, sex, and/or body mass. Recent research indicates that many individuals have GFR values less than 60 ml/min/1.73 m2 without other manifestations of CKD. Nephron loss due to normal aging or renal surgery (CKD-S) may have lower likelihood of CKD progression, and may infer better survival, compared to individuals with the same degree of CKD due to medical causes. Patients with mild and moderate CKD due to surgical nephron loss may benefit from an alternative measurement method of renal function such as cystatin-C-derived or directly measured GFR.
Summary: CKD includes a diverse group of individuals with reduced GFR from a variety of causes. Classification of CKD according to GFR, albuminuria, and cause, may improve the management of patients with reduced GFR, as some causes (e.g., nephrectomy and aging) appear to be associated with a relatively low risk of progression.