Latino children with kidney failure have a surprising survival advantage over white children despite longer waits for transplants, according to a UCSF study that tracked more than 12,000 pediatric patients.
Contrary to several earlier studies of older adults with kidney failure, who are on dialysis, this survival advantage is not shared by African-American children, who have a higher risk of mortality than other racial groups, the UCSF investigators concluded.
Kidney failure in children is usually the result of birth defects, hereditary conditions, acquired kidney disease, or systemic diseases like lupus and high blood pressure. It is treated by transplantation from a living or deceased donor; or dialysis, a procedure that replaces the filtering process of healthy kidneys.
Several observational studies have found that African-American and Latino kidney failure patients over the age of 50 fare better on dialysis than whites, but the reasons for this are not known.
Worse outcomes the norm for minorities
In the study, published Dec. 29, 2016, researchers headed by Elaine Ku, MD, MAS, followed 12,123 patients between the ages of 2 and 19, who had received transplants or were undergoing dialysis. Approximately 25 percent of the children were African American, 26 percent were Latino and the remaining 49 percent were white. Around 13 percent of the patients died during the follow-up period — an average 7.1 years — according to the study, which was published in the Journal of the American Society of Nephrology.
“African-American and Latino patients generally experience worse health outcomes than white patients, but adults with renal failure who are on dialysis have been a notable exception, in that African-American patients treated with dialysis generally do better than white patients,” said first author Ku, of the Division of Pediatric Nephrology at UCSF Benioff Children’s Hospital San Francisco. “We hypothesized that the risk of death would be higher in African-American and Latino children, compared to white children.”
Instead the investigators found that the risk of death was 34 percent lower in Latino children than in white children, whose own risk was 36 lower than in African-American children.
Kidney transplantation is known to result in better survival than dialysis. The investigators found that white children spent 30 percent of the follow-up time on dialysis, compared with 43 percent and 56 percent, respectively, for Latino and African-American patients. When the researchers adjusted for time spent as a dialysis or transplant patient, no difference was found in the mortality rates between African-American and white children, suggesting that ease of access to transplant was a key factor in survival.
Organ allocation a factor in african-american children’s survival
“This paper calls for an evaluation into our organ allocation system to further understand why there are inequities in access to transplant, especially with recent revisions to the national organ allocation system intended to match the best quality organs to those likely to have the longest survival,” Ku said. But the reasons for Latino children’s superior survivorship remain unclear.
“This finding is contrary to our hypothesis, but is consistent with the better survival that has been observed in Latino adults on dialysis and was consistent regardless of patients’ age, body mass index, cause of kidney failure and the type of dialysis.
“I think the lower mortality could be due to something that we could not measure, such as differences in family and social support, or cultural differences in how some Latino families handle chronic illnesses,” Ku said.
Senior author Kirsten Johansen, MD, of the UCSF Division of Nephrology, said the study underscored the need to increase access to transplantation for African-American children, as well as to take a further look at survival in Latino children. “In studying those factors that may be responsible for better survival in Latino pediatric patients, we may be able to improve the outcome for all children with kidney failure,” she said.
The study was supported by grants from the National Institutes of Health. Co-authors are Charles McCulloch, PhD, and Barbara Grimes, PhD, of the UCSF Department of Epidemiology and Biostatistics.
