Kidney disease is a global health problem, affecting more than 10% of the world's population and more than half of adults over 70 years of age in the United States. Persons with kidney disease are at higher risk for cardiovascular disease, heart failure, physical function decline, and mortality. Kidney scarring is a dominant factor in the development of kidney disease. Our group has evaluated several tests to determine the severity of scarring without requiring kidney biopsies, using MRI imaging scans and evaluating markers of scarring that we can measure in the urine. In this study we will use these measures to evaluate pirfenidone as a promising potential new treatment for patients with kidney disease.