FSGS may also be secondary to another process, including hyperfiltration injury to the glomerulus as may occur in chronic hypertension, diabetes mellitus, and conditions in which kidney mass is reduced (progressive kidney disease, obesity, sickle cell disease, reflux nephropathy, or after nephrectomy). Direct injury to podocytes may also cause FSGS as seen with certain drugs (pamidronate, interferon) and infections, including HIV.