Malnutrition, Diet and Racial Disparities in Chronic Kidney Disease (CKD)

Overview

In the United States, African Americans are 3.6 time and Hispanics 1.5 times more likely to suffer from chronic kidney disease and need dialysis treatment for life, when compared to the non-Hispanic Whites. Unfortunately many dialysis patients die, so that after 5 years only less than 35% are still alive. Dialysis patients who appear malnourished or who have muscle and fat wasting are even more likely to die. Interestingly, among dialysis patients, minorities (African Americans, Hispanics and Asian Americans) usually survive longer than the non-Hispanic Whites. If the investigators can discover the reasons for these so-called "racial survival disparities" of dialysis patients, the investigators may be able to improve survival for all dialysis patients and maybe even for many other people who suffer from other chronic diseases. During this 5 year study the investigators would like to test if a different nutrition and diet can explain better survival of minority dialysis patients. The investigators will also test if in additional to nutrition there are 2 other reasons for better survival of minority dialysis patients, namely differences in bone and minerals and differences in social and psychological and mental health. The investigators plan to study 450 hemodialysis patients every 6 months in several dialysis clinics in Los Angeles South Bay area. These subjects will include 30% African Americans, 30% Hispanics, 30% non-Hispanic Whites and 10% Asians. Every 6 months the investigators will examine their nutritional conditions, dietary intake, psycho-social conditions and quality of life, and will recruit 75 new subjects to replace those who left our study as a result of kidney transplantation, death or other reasons. Hence, the investigators estimate studying a total of 1,050 hemodialysis patients over 5 years. Clinical events such as hospital admissions and survival will be followed. Blood samples will be obtained every 6 months for measurements of hormones and "biomarkers", and the remainder of the blood will be stored in freezers for future measurements. The investigators plan to design and develop race and ethnicity specific nutritional risk scores and food questionnaires and will test some of these scores in larger national databases of hemodialysis patients. Almost a year after the study starts, the investigators also plan to do additional tests of body composition and dietary intake in a smaller group of these patients at the GCRC.

I. SPECIFIC AIMS \& HYPOTHESES I.1.HYPOTHESES: Despite higher burden of chronic kidney disease (CKD) in minorities, they have greater survival compared to non-Hispanic Whites with CKD. The investigators hypothesize that survival advantages of minority CKD patients (pts) result from biologically plausible mechanisms related to differences in nutritional status \& diet (main hypothesis) or differences in bone-\&-minerals and/or psychosocial \& coping status (2 alternative hypotheses). Differences in these conditions may lead to different degrees of protein-energy wasting, inflammation, oxidative stress, \& platelet activation, leading to thrombo-embolic \& cardiovascular (CV) events. Discovering the biology of CKD racial survival disparities may lead to improving outcomes in both CKD and others chronic diseases. During this 5-year study the principal investigator (Dr. Kalantar-Zadeh) will also help a number of early-career investigators to design and develop additional studies including research in minority populations with chronic diseases using data and resources of this study.