Protein loss in the urine harmful for people with high blood pressure

Simple urine test may help identify patients at risk

WASHINGTON, April 30, 2010-Healthy people with high blood pressure who excrete a slight excess of protein in the urine raise their risk of developing kidney and heart complications. According to a study appearing in an upcoming issue of the Clinical Journal of the American Society Nephrology (CJASN), more attention should focus on the potential health effects of urinary protein excretion in individuals with high blood pressure (hypertension).

Kidney dysfunction, common in individuals with hypertension, can increase one's risk of developing heart problems and kidney failure. Therefore, doctors should strive to identify and treat the precursors of kidney dysfunction as a way to maintain hypertensive patients' heart and kidney health.

Research shows that diabetic patients with hypertension who excrete slightly increased amounts of protein in the urine—a condition known as microalbuminuria—have an elevated risk of developing heart and kidney problems. Investigators have wondered whether microalbuminuria (occurring in 10%-30% of individuals, depending on age and clinical conditions) may have similar effects in non-diabetic patients with hypertension.

Over nearly 12 years, Roberto Pontremoli, MD, PhD (University of Genoa, in Italy) and his colleagues followed the health of 917 hypertensive, non-diabetic patients enrolled in the MAGIC (Microalbuminuria: A Genoa Investigation on Complications) study between 1993 and 1997. The investigators found that patients with microalbuminuria at the start of the study were 7.6-times as likely to develop chronic kidney disease and 2.1-times as likely to develop cardiovascular complications (such as heart disease or stroke) compared with individuals without microalbuminuria. Study participants with microalbuminuria also had a 3.2-fold increased risk of developing both kidney and cardiovascular conditions. Even after the researchers considered and adjusted for various patient characteristics that might contribute to health differences (age, body mass index, blood pressure, cholesterol level, and kidney function), individuals with microalbuminuria at the start of the study still had a 2.6-fold increased risk of developing both kidney and cardiovascular problems compared with those without microalbuminuria.

These results demonstrate that microalbuminuria has a profound effect on the health of non-diabetic patients with hypertension. "Our findings emphasize the usefulness of a more widespread evaluation of microalbuminuria in an effort to guide the management of hypertension," said Dr. Pontremoli. Additional research is needed to determine whether specific treatments that are known to improve the health of diabetic patients with microalbuminuria can also help non-diabetic patients.


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Study co-authors include Francesca Viazzi, MD, Giovanna Leoncini, MD, Novella Conti, MD, Cinzia Tomolillo, BS, Giacomo Deferrari, MD (University of Genoa); Giovanna Giachero, PhD (IST-Istituto Nazionale per la Ricerca sul Cancro, in Genoa, Italy); and Marina Vercelli, MD (IST-Istituto Nazionale per la Ricerca sul Cancro and Università di Genova, in Genoa, Italy).

Disclosures: The authors reported no financial disclosures.

The article, entitled "Microalbuminuria Is a Predictor of Chronic Renal Insufficiency in Patients without Diabetes and with Hypertension: The MAGIC Study," will appear online at http://cjasn.asnjournals.org on April 29, 2010, doi 10.2215/CJN.07271009.

The content of this article does not reflect the views or opinions of The American Society of Nephrology (ASN). Responsibility for the information and views expressed therein lies entirely with the author(s). ASN does not offer medical advice. All content in ASN publications is for informational purposes only, and is not intended to cover all possible uses, directions, precautions, drug interactions, or adverse effects. This content should not be used during a medical emergency or for the diagnosis or treatment of any medical condition. Please consult your doctor or other qualified health care provider if you have any questions about a medical condition, or before taking any drug, changing your diet or commencing or discontinuing any course of treatment. Do not ignore or delay obtaining professional medical advice because of information accessed through ASN. Call 911 or your doctor for all medical emergencies.

Founded in 1966, the American Society of Nephrology (ASN) is the world's largest professional society devoted to the study of kidney disease. Comprised of 11,000 physicians and scientists, ASN continues to promote expert patient care, to advance medical research, and to educate the renal community. ASN also informs policymakers about issues of importance to kidney doctors and their patients. ASN funds research, and through its world-renowned meetings and first-class publications, disseminates information and educational tools that empower physicians.

Contact: Shari Leventhal
sleventhal@asn-online.org
202-416-0658
American Society of Nephrology

Posted: April 2010

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