Other complications include hypertensive retinopathy and hypertensive nephropathy. Dihydropyridine calcium channel blockers can worsen proteinuria in patients with nephropathy. Examples are diabetic kidney disease, glomerulonephritis, and IgA nephropathy. Other abnormalities that are found include glomerulosclerosis, IgA nephropathy and interstitial nephritis. Angiotensin II receptor antagonists are drugs indicated for hypertension, diabetic nephropathy and congestive heart failure. Benfotiamine has been studied in laboratory models of diabetic retinopathy, neuropathy, and nephropathy. Preservation of kidney function in diabetic nephropathy. A definitive diagnosis of membranous nephropathy requires a kidney biopsy. It has been recognized that the incidence of hypertensive nephropathy varies with ethnicity. Urinary retention can lead to bladder diverticula, kidney stones, and reflux nephropathy. It may also delay progression of diabetic nephropathy. The incidence of hypertensive nephropathy varies around the world. Not all patients with diabetes go on to develop diabetic nephropathy. Iodinated contrast agents may cause allergic reactions, contrast-induced nephropathy, hyperthyroidism and possibly metformin accumulation. A history of smoking encourages the progression of diabetic nephropathy.