Nephrologist caseload and hemodialysis patient survival in an urban cohort.
Physician caseload may be a predictor of patient outcomes associated with various medical conditions and procedures, but the association between patient-physician ratio and mortality among patients undergoing hemodialysis has not been determined. We examined whether a higher patient-nephrologist ratio affects patient mortality risk using de-identified data from DaVita dialysis clinics and the U.S. Renal Data System. A total of 41 nephrologists with a caseload of 50-200 hemodialysis patients from an urban California region were retrospectively ranked according to their hemodialysis patient mortality rate during a 6-year period between 2001 and 2007. We calculated all-cause mortality hazard ratios for each nephrologist and compared patient- and provider-level characteristics between the 10 nephrologists with the highest patient mortality rates and the 10 nephrologists with the lowest patient mortality rates. Nephrologists with the lowest patient mortality rates had significantly lower patient caseloads than nephrologists with the highest mortality rates (median [interquartile range], 65 [55-76] versus 103 [78-144] patients per nephrologist, respectively; P<0.001). Additionally, patients treated by nephrologists with the lowest patient mortality rates received higher dialysis doses, had longer sessions, and received more kidney transplants. In demographic characteristic-adjusted analyses, each 50-patient increase in caseload was associated with a 2% increase in patient mortality risk (hazard ratio, 1.02; 95% confidence interval, 1.00 to 1.04; P<0.001). Hence, these results suggest that nephrologist caseload influences hemodialysis patient outcomes, and future research should focus on identifying the factors underlying this association.
Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California Irvine Medical Center, Orange, California;
Kevin T
KT
Harley
Elani
E
Streja
Connie M
CM
Rhee
Miklos Z
MZ
Molnar
Csaba P
CP
Kovesdy
Alpesh N
AN
Amin
Kamyar
K
Kalantar-Zadeh
D000328:Adult; D000368:Aged; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000401:mortality* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009398:Nephrology / Q000706:statistics & numerical data; D006435:Renal Dialysis / Q000401:mortality*; D014505:Urban Population / Q000706:statistics & numerical data; D000078329:Workforce; D016526:Workload / Q000706:statistics & numerical data