Renal impairment refers to a reduction in kidney function, typically measured by decreased glomerular filtration rate or elevated serum creatinine, indicating the kidneys’ diminished ability to filter waste and maintain fluid and electrolyte balance. It matters clinically because impaired renal function affects drug clearance, fluid management, and increases the risk of complications such as electrolyte disturbances. A key association is its frequent coexistence with chronic conditions like diabetes, which can accelerate progression to chronic kidney disease and increase cardiovascular risk.