New database provides valuable new resource for improving dialysis outcomes

Mar 4 2009

A nationwide database called the Comprehensive Dialysis Study (CDS) includes detailed information on a wide range of health factors in US dialysis patients and provides a valuable new resource for improving dialysis outcomes, according to a report in an upcoming issue of the Clinical Journal of the American Society of Nephrology (CJASN).

"The primary goal of the CDS is to better understand the interrelations among general health, nutrition, physical function, and health-related quality of life in a representative sample of patients recently starting maintenance hemodialysis," comments Nancy J. Kutner, PhD, Director of the Rehabilitation/ Quality of Life Special Studies Center of the United States Renal Data System (USRDS) at Emory University in Atlanta, GA. "By linking these data with patient-specific information in USRDS files, researchers will be able to examine the predictive significance of early physical and nutritional status for morbidity and mortality outcomes."

The CDS includes 1,646 patients from a random sample of 295 dialysis facilities in 48 states and the District of Columbia. The patients range in age from 19 to 94 years, with an average age of 60. At the time they were enrolled in the CDS, the patients had been on dialysis for an average of four months.

In telephone interviews, patients provided detailed information on a broad range of factors that may affect health, functioning, and long-term outcomes on dialysis. "The CDS includes patient employment status and validated measures of health-related quality of life, physical activity level, sleep disturbance, and depression collected from all participants," says Dr. Kutner. One subgroup of patients gave detailed information on dietary intake; another provided blood samples for assessment of nutrition, inflammation and other key measures.

The CDS provides an unprecedented depth of information on a large group of patients just beginning dialysis. It enables researchers to examine the interrelated factors affecting the health of new dialysis patients. Follow-up of patients enrolled in the CDS will enable researchers to determine which baseline characteristics have the greatest impact on long-term dialysis outcomes.

Because of the relatively low participation rate (less than 20 percent), the CDS falls short of being a nationally representative sample of US dialysis patients. "In addition, while CDS patients were generally similar to the overall population, they were younger on average, had higher educational status, were less likely to have heart failure or stroke, and less likely to be nonambulatory or institutionalized, compared to all incident dialysis patients," according to Dr. Kutner.

Linking the CDS to the USRDS database will help to identify factors associated with survival, hospitalization, use of medical services, and health care costs. "The CDS therefore provides a unique resource to inform the design of interventions addressing several related conditions affecting longevity and health status in patients on dialysis," Dr. Kutner concludes.