Stephen Z. Fadem, MD, FACP, FASN

While diet and exercise are very important components to therapy, several clinical trials have demonstrated the value of medications to help patients prevent the progression of kidney disease. The success of these therapies depends upon what stage of kidney disease the patient is in and the underlying cause of the patient’s kidney disease. For instance, diabetics in the earliest stages do much better with treatment aimed at preventing the disease from getting worse. The Diabetes Control and Complications Trial (DCCT trial) showed aggressive management of diabetes was able to stall not only the progression of proteinuria (large amounts of protein in the urine), but also retinopathy (damage to the eye retina) in early stages.⁽¹⁾

However, the focus should also be on minimizing diseases that sometimes go along with kidney disease. These include cardiovascular disease, blood vessel disease and stroke. Unfortunately, some of the medications which have shown great promise in the oral treatment of type 2 diabetes may increase cardiovascular risks as suggested in two recent trials known as DREAM ⁽²⁾ and ADOPT studies. ⁽³⁾ Large international trials such as the Study of Heart and Renal Protection (SHARP Study) are designed to look at treatments with a class of drugs that lower cholesterol and protect the heart in patients with kidney disease. People who took part in the study also did not have any heart damage and did not have a large amount of fatty molecules in their blood stream. ⁽⁴⁾

Medications are also used to keep the blood pressure within 130/80 mm Hg. For African Americans and people who suffer from proteinuria, targeted blood pressure is lower. ⁽⁵⁾⁽⁶⁾ Other targets include trying to lower the amount of protein abnormally leaked by the kidney using drugs that work on blood vessel tone through a well-known mechanism known as the renin-angiotensin system. These medications are classed as either the angiotensin receptor blockers or converting enzyme inhibitors ⁽⁷⁾. Adding an additional medication that works on the body’s blood and fluid system, aliskaren, may further reduce the small amounts of protein in the urine associated with early kidney disease. ⁽⁸⁾

The use of angiotensin receptor blockers in type 2 diabetics, along with the management and control of blood pressure, has been proven to delay the progression of CKD. This was seen in three trials - RENAAL⁽⁹⁾ , IDNT⁽¹⁰⁾ and IRMA trials. ⁽¹¹⁾ The Collaborative Study Group showed an angiotensin converting enzyme (ACE) inhibitor would delay progression of kidney disease in type
1 diabetes.⁽¹²⁾

A recent study, the ACCOMPLISH Trial⁽¹³⁾ , has shown combining an ACE inhibitor and a calcium channel blocker helps delay progression to cardiovascular endpoints in high risk cardiovascular patients (60 percent of whom are diabetic), many of whom have abnormal kidney function. The final results of this study have yet to be published.

Of course, with respect to disease progression and the other associated diseases that accompany CKD, medications alone do not substitute for continuing to live a healthy lifestyle. Obesity has been shown to be a predictor of CKD⁽¹⁴⁾ , so has smoking⁽¹⁵⁾ – so it is crucial to remain attentive to the lifestyle aspects of therapy. In addition to exercise, watching salt intake, processed foods and keeping your body mass index in control, it might also be advisable to take an aspirin daily, (check with your physician first) and keep your cholesterol in normal range. Taking generic vitamin D in early kidney disease, and switching to a vitamin D analog if the disease progresses might prove to be of therapeutic benefit, but future research is needed to reveal the value of vitamin D therapy in reducing kidney disease endpoints.⁽¹⁶⁾

References
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Stephen Z. Fadem, MD, FACP, FASN, serves as Vice President of the AAKP Board of Directors, member of the AAKP Medical Advisory Board and Co-Medical Editor of Kidney Beginnings: The Magazine. Dr. Fadem is a practicing nephrologist in Houston, Texas.

This article originally appeared in the May 2009 issue of Kidney Beginnings: The Magazine.

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