Nephrologist Caseload and Hemodialysis Patient Survival in an Urban Cohort

Abstract

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.

Hemodialysis Patient Outcomes: Provider Characteristics

“…This finding differs from findings of Harley et al [9], who studied prevalent patients undergoing dialysis in an urban Southern California area and reported higher mortality among those cared for by nephrologists with larger case loads. This difference likely reflects differences in patient populations and geographic distribution.…”

“…This difference likely reflects differences in patient populations and geographic distribution. The Harley et al [9] study included only 41 nephrologists who practice in the greater Los Angeles area, and our study included all nephrologists who provided dialysis care to Medicare patients in the United States in 2006. The association between provider case load and patient outcomes might differ by geographic region.…”

“…The few studies that have reported an association between provider characteristics and patient clinical outcomes such as hospitalizations and mortality have focused on mortality after acute myocardial infarction [4–7] or on surgical outcomes [8]. Larger nephrologist case load was associated with higher dialysis patient mortality in an urban cohort of prevalent dialysis patients [9]. Whether other characteristics of physicians who care for hemodialysis patients are associated with patient morbidity and mortality is unknown.…”

Blood Pressure of Maintenance Hemodialysis Patients in the Dalmatian Region of Croatia: Differences between Hospital and Out-of-Hospital Dialysis Centers

“…Age, sex and socioeconomic circumstances also have an impact [47], as well as the number of patients under a physician's care [48]. …”

Early Dialysis Initiation, a Look from the Rearview Mirror to What’s Ahead

“…Ericksen et al, pointed out that rural dialysis patients have less nephrologist follow-up (18). Harley et al reported that a higher dialysis patient caseload in urban areas was associated with higher mortality, a relationship that may well hold for rural areas (19). Lichter and Parsi reported that "rural blacks are even more 'ghettoized' than blacks living in metro areas" (20).…”