Acute Kidney Injury Linked to Increased Risk of High Blood Pressure

Hospitalized patients with acute kidney injury (AKI) were 22 percent more likely to develop high blood pressure within two years than patients who did not experience AKI, according to a study by UC San Francisco and Kaiser Permanente researchers.

The research team analyzed the medical records of 43,611 adult members of the Kaiser Permanente Northern California integrated healthcare delivery system who were hospitalized between 2008 and 2011. After accounting for other known risk factors, they found that the 2,451 patients who had experienced AKI were 22 percent more likely to develop high blood pressure (greater than 140/90 mmHg) during the two-year follow-up period than those who had not.

As reported in the July 1 online issue of the Journal of the American Society of Nephrology, the scientists also found that the more severe the AKI – formerly known as acute renal failure – the greater the likelihood of developing high blood pressure.

Lead author Chi-yuan Hsu, MD, MSc, a UCSF professor of medicine, described AKI as “an abrupt decline in kidney function” that can occur during hospitalization as a result of major surgery or from septic shock. Other causes include dye contrast agents used for certain imaging tests and some chemotherapy agents. Excessive use of non-steroidal anti-inflammatory drugs such as ibuprofen can also cause AKI, he said.

“To our knowledge, this is the first study in adults to show that an episode of AKI can lead to elevated blood pressure during the months after they leave the hospital,” said Alan Go, MD, senior author and chief of cardiovascular and metabolic conditions research at the Kaiser Permanente Division of Research. “High blood pressure is one of the most important and common causes of stroke, heart disease and kidney failure, so preventing AKI may also help to reduce the population burden of hypertension.”

Hsu said that two potentially effective ways to reduce the risk of AKI are to give adequate hydration before administering contrast dye and to perform “off-pump” or “beating heart” cardiac bypass surgery rather than using a heart-lung machine to stop the heart during surgery. “In addition, one very recent study reported that a technique called ischemic preconditioning – basically, inflating and then deflating the blood pressure cuff – reduced the risk of AKI after cardiac surgery,” said Hsu.

The research team is currently investigating other adverse consequences of AKI and ways to reduce AKI in hospitalized patients.

Co-authors of the study are Raymond K. Hsu, MD, MAS, of UCSF, and Jinrong Jang, MA; Juan D. Ordonez, MD, MPH; and Sijie Zheng, MD, PhD, of Kaiser Permanente.

The study was supported by funds from the National Institutes of Health.

UC San Francisco is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes top-ranked graduate schools of dentistry, medicine, nursing and pharmacy, a graduate division with nationally renowned programs in basic, biomedical, translational and population sciences, as well as a preeminent biomedical research enterprise and two top-ranked hospitals, UCSF Medical Center and UCSF Benioff Children’s Hospital San Francisco.