Chronic kidney disease (CKD) is a progressive loss of kidney function over time, typically defined by a glomerular filtration rate (GFR) below 60 mL/min/1.73 m² or markers of kidney damage (such as proteinuria) lasting more than three months. As kidney function declines, the body’s ability to filter waste, balance electrolytes, and regulate blood pressure is impaired. Symptoms may be minimal early on but can progress to fatigue, swelling, changes in urination, and complications like anemia, bone disease, and cardiovascular issues. CKD is commonly caused by diabetes, hypertension, or glomerulonephritis, and may eventually lead to end-stage renal disease requiring dialysis or transplant. Early detection and management can slow its progression.