Dialysis patients may live longer if their kidney specialist sees fewer patients

Dialysis patients receiving treatment from kidney specialists with a higher patient caseload have a greater risk of dying prematurely than those receiving care from specialists with a lower caseload, according to a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN). The study is the first of its kind to examine the association between nephrologist caseload and mortality risk in a large urban US setting.

How many patients a physician sees may affect patients' health outcomes. To see if this is true for kidney specialists, many of whom take care of a large number of dialysis patients, Kamyar Kalantar-Zadeh, MD, MPH, PhD (University of California Irvine Medical Center) and his colleagues examined whether hemodialysis patients cared for by nephrologists with a higher patient caseload had a greater risk of dying prematurely than those receiving care from nephrologists with a lower caseload. A total of 41 nephrologists with a caseload of 50 to 200 dialysis patients from an urban California region were retrospectively ranked according to their dialysis patients' mortality rate between 2001 and 2007.

Among the major findings:

• Nephrologists whose dialysis patients had the best survival had a significantly lower patient caseload than nephrologists whose patients had the worst survival.
• For every additional 50 patients cared for by a nephrologist, patients had a 2% higher risk of dying during the study period.

"Our data suggest that patients receiving care from nephrologists with lower caseloads may have greater survival," said Dr. Kalantar-Zadeh. "Such data may help direct health policies and guidelines more effectively."

The authors noted that additional studies are needed to confirm findings and to explore mechanisms by which caseload influences patients' outcomes. More research is also needed to determine the caseload threshold above which the benefits of increased experience are outweighed by a deterioration in quality of care and patient outcomes.