Interstate Variation in Receipt of Nephrologist Care in US Patients Approaching ESRD: Race, Age, and State Characteristics

Abstract

Background and objectives: Although multiple factors influence access to nephrologist care in patients with CKD stages 4-5, the geographic determinants within the United States are incompletely understood. In this study, we examined interstate differences in nephrologist care among patients approaching ESRD.

Design, setting, participants, & measurements: This national, population-based analysis included 373,986 adult patients from the US Renal Data System, who initiated maintenance dialysis between 2005 and 2009. Multilevel logistic regression was used to examine interstate variation in nephrologist care (≥12 months before ESRD) for overall and four race-age subpopulations (black or white and older or younger than 65 years).

Results: The average state-level probability of having received nephrologist care in all states combined was 28.8% (95% confidence interval, 25.2% to 32.7%) overall and was lowest (24.3%) in the younger black subpopulation. Even at these lower levels, state-level probabilities varied considerably across states in overall and subpopulations (all P<0.001). Overall, excluding the states in the upper and lower five percentiles, the remaining states had a probability of receiving care that varied from 18.5% to 41.9%. The lower probability of receiving nephrologist care for blacks than whites among younger patients noted in most states was attenuated in older patients. Geographically, all New England states and most Midwest states had higher than average probability, whereas most Middle Atlantic and Southern states had lower than average probability. After controlling for patient factors, three state-characteristic categories, including general healthcare access measured by percentage of uninsured persons and Medicaid program performance scores, preventive care measured by percentage of receiving recommended preventive care, and socioeconomic status, contributed 55%-66% of interstate variation.

Conclusions: Patients living in states with better health service and socioeconomic characteristics were more likely to receive predialysis nephrologist care. The reported national black-white difference in nephrologist care was primarily driven by younger black patients being the least likely to receive care.

Keywords: CKD; US Renal Data System; pre-ESRD care; racial difference; state characteristics.

Figure 1.

Model-based estimates of unadjusted state-level probabilities and 95% confidence intervals of patients who had received nephrologist care at least 12 months before ESRD for all states. The probability estimates were obtained from the null model without covariates (model 1). The horizontal lines represent the 95% confidence intervals. The estimated average state-level probability is indicated by the solid vertical line. The estimated interval range of state-level probabilities for 90% of states is indicated by the left and right dotted lines. The 10 geographic regions were based on the nine US census divisions (50) with two pre hoc modifications to group neighboring states in the same region: Delaware, Maryland, and the District of Columbia were moved from the South Atlantic to the Middle Atlantic region, and a new Southwest Pacific region that consisted of Nevada, California, and Arizona was formed.

Figure 2.

Model-based estimates of unadjusted state-level probabilities of patients who had received nephrologist care at least 12 months before ESRD for black patients (vertical axis) versus white patients (horizontal axis) by age subgroup. (A and B) The probability estimates for younger blacks, younger whites, older blacks, and older whites were obtained separately from the null model without covariates (model 1). Each dot represents an individual state. The diagonal lines are the equality lines. For age ≥65 years, seven small states (Maine, Vermont, North Dakota, South Dakota, Montana, Wyoming, and Idaho) are not shown.