Department of Research & Evaluation News

PASADENA, Calif. – Black, Hispanic, and Asian patients have higher rates of end-stage renal disease than white patients due in part to faster kidney function decline and in part because they were more likely to survive, according to a Kaiser Permanente Southern California study published today in the print edition of the American Journal of Kidney Disease. 

Patients with end-stage renal disease – also known as kidney failure – require dialysis or kidney transplants to survive.  The disparate rates of kidney failure were influenced by faster kidney function decline among blacks, Hispanics, and Asians patients, and more frequent deaths among white patients during chronic kidney disease.

The authors studied 1,119,816 Kaiser Permanente patients in Southern California with chronic kidney disease, or ongoing loss of kidney function. Clinicians measured kidney function by using creatinine levels in the blood to estimate the rate at which kidneys filter fluid, or estimated Glomerular Filtration Rate (eGFR).  After taking into account the age and sex of the patients, the rate of kidney failure was 2.5 times higher in black patients, 2.2 times higher in Hispanic patients, and 2.0 times higher in Asian patients compared to white patients.  The researchers identified a subgroup of patients whose kidneys were projected to fail during the study period.  By examining mortality in this subgroup, the researchers hoped to clarify if survival influenced rates of kidney failure among racial groups in the study.

Blacks in this country historically have the highest rates of end-stage kidney disease. Racial grounds for this disparity aren’t well understood because kidney disease progresses at widely variable rates and death before kidney failure is common, frequently from cardiovascular causes, said Stephen F. Derose, MD, MHSH, Department of Research & Evaluation, Kaiser Permanente Southern California. With this study we aimed to untangle the rate of kidney function decline from the rate of survival and explore the forces that drive high kidney failure rates among certain groups. 

Among patients with chronic kidney disease, black patients had 54 percent increased odds of projected kidney failure compared to white patients; Hispanic and Asian patients had 49 and 41 percent increased odds compared to white patients, respectively.  The odds of mortality among  patients whose kidneys were projected to fail during the study period was 18 percent lower among black patients, 33 percent lower among Hispanic patients, and 42 percent lower among Asian patients compared to whites.  The authors also found no evidence of a healthy survivor effect in which higher mortality among black, Hispanic, and Asian patients prior to or during the earlier stages of kidney disease led to lower mortality during the later stages of kidney disease. 

To improve chronic kidney disease outcomes, it may be important to closely monitor for signs of accelerated kidney decline in black, Hispanic, and Asian patients and increase attention to indicators of cardiovascular health in white patients. The same types of therapies, such as blood pressure and cholesterol control, are likely to help, regardless of race, Derose said. .  We can use these results to better target interventions to improve outcomes in patients with chronic kidney disease. 

Kaiser Permanente can conduct transformational health research in part because it has the largest private patient-centered electronic health system in the world. The organization’s electronic health record system, Kaiser Permanente HealthConnect®, securely connects 9.1 million patients to 1,700 physicians in 611 medical offices and 37 hospitals. It also connects Kaiser Permanente’s research scientists to one of the most extensive collections of longitudinal medical data available, facilitating studies and important medical discoveries that shape the future of health and care delivery for patients and the medical community. 

This study was funded by the National Institutes for Health.

Kaiser Permanente is committed to using its highly diverse and representative member population as a laboratory for studying the epidemiological sources of disparities in health care.  Earlier this month, Kaiser Permanente released a study that found younger patients and black men did not experience significant declines in hospital stays for heart failure during the study period, despite drops in national rates.  And a study last year found rates of diagnosed diabetes are much higher among some Asian subgroups as compared to Asians as a whole.

Other study authors included: Mark P. Rutkowski, MD; Peter W. Crooks, MD, Renal Business Group; Jiaxiao M. Shi, PhD, Jean Q. Wang, MS, and Steven J. Jacobsen, MD, PhD, Kaiser Permanente Southern California Department of Research & Evaluation; Kamyar Kalantar-Zadeh, MD, MPH, PhD, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, & David Geffen School of Medicine at UCLA; Csaba P. Kovesdy, MD, Salem Veterans Affairs Medical Center & University of Virginia; Nathan W. Levin, MD, Renal Research Institute.

About the Kaiser Permanente Department of Research & Evaluation
The Department of Research & Evaluation conducts high-quality, innovative research into disease etiology, prevention, treatment and care delivery. Investigators conduct epidemiology, health sciences and behavioral research as well as clinical trials. Areas of interest include diabetes and obesity, cancer, HIV/AIDS, cardiovascular disease, aging and cognition, pregnancy outcomes, women’s and children’s health, quality and safety, and pharmacoepidemiology. Located in Pasadena, Calif., the department focuses on translating research to practice quickly to benefit the health and lives of Kaiser Permanente Southern California members and the general population. Visit kp.org/research.

About Kaiser Permanente
Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, our mission is to provide high-quality, affordable health care services to improve the health of our members and the communities we serve. We currently serve more than 9 million members in nine states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to www.kp.org/newscenter.