occurs most commonly in patients with mild to moderate kidney disease due to diabetic nephropathy (such as this patient) or chronic interstitial nephritis (such as in systemic lupus erythematosus or AIDS). It may also be associated with acute glomerulonephritis, specific drugs that impair renin release (NSAIDs and calcineurin inhibitors), tubulointerstitial disease, and drugs that reduce aldosterone production (ACE inhibitors, cyclooxygenase inhibitors, and heparin).