Dialysis patients fare better when doctors have fewer cases

Study found 2 percent increased risk of death for every 50 additional patients

August 08, 2013
Dr. Kamyar Kalantar-Zadeh, chief, Division of Nephrology and Hypertension, UCI Health School of Medicine

A study led by UCI Health nephrologist Dr. Kamyar Kalantar-Zadeh shows that dialysis patients treated by kidney specialists with a higher patient caseload have a greater risk of dying prematurely than do those who receive care from specialists with a lower caseload.

The study, to appear in the upcoming issue of the Journal of the American Society of Nephrology, is the first of its kind to examine the association between nephrologists’ caseloads and mortality risk in a large urban U.S. setting.

“Our data suggest that patients receiving care from nephrologists with lower caseloads may have greater survival [rates],” Kalantar-Zadeh, chief of the division of nephrology and hypertension at the UCI Health School of Medicine, said in a report from the American Society of Nephrology.

“Such data may help direct health policies and guidelines more effectively,” added Kalantar-Zadeh, MD, Phd, MPH.

With more than 1.5 million people on dialysis worldwide, many kidney specialists oversee the care of large numbers of patients. For the study, Kalantar-Zadeh and his colleagues examined whether hemodialysis patients being treated by nephrologists with higher patient caseloads had a greater risk of dying prematurely than those who received care from nephrologists with fewer cases.

A total of 41 nephrologists, whose caseloads ranged from 50 to 200 dialysis patients in urban areas of California, were retrospectively ranked according to their dialysis patients’ mortality rate between 2001 and 2007.

Major findings include:

  • Nephrologists whose dialysis patients had the best survival rates carried a significantly lower patient caseload than nephrologists whose patients had the worst survival rates.
  • For every additional 50 patients cared for, a nephrologist’s patients had a 2 percent higher risk of dying during the study period, the study found.
  • Patients treated by nephrologists with the lowest patient mortality rates received higher dialysis doses and had longer sessions, and more of them also received kidney transplants.

The authors note that additional studies are needed to confirm findings and to explore the mechanisms by which caseloads influence patient outcomes.

More research also is needed to determine the caseload threshold above which the benefits of increased experience are outweighed by deterioration in quality of care and patient outcomes.

Study co-authors include Kevin T. Harley, MD; Elani Streja, MPH, PhD; Connie M. Rhee, MD, MSc; Csaba P. Kovesdy, MD; and Alpesh N. Amin, MD, MBA.

View the article entitled “Nephrologist Caseload and Hemodialysis Patient Survival in an Urban Cohort” on the journal's website.

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UCI Health media contact:John Murrayjdmurray@uci.edu714-456-7759