Local Poverty Affects Kidney Disease Care

The wealth or poverty of patients’ communities often impacts the care they receive. Researchers recently discovered that this appears to be true for certain aspects of care for end stage renal disease (ESRD)—in particular, the use of an incident arteriovenous fistula (AVF) for hemodialysis vascular access.

Surprisingly, though, the intensity of poverty in the county where a treatment is located was not associated with subsequent AVF use among prevalent patients. The findings suggest that poverty’s effects on AVF use may be mitigated by the Medicare ESRD program, through which Medicare reimburses the costs of ESRD care for all individuals eligible for Social Security benefits regardless of other patient characteristics.

Variability of care

There is substantial geographic variability in the use of AVF for patients with ESRD, despite the knowledge that AVF use for hemodialysis access is safe and is associated with improved survival. The National Kidney Foundation’s Clinical Practice Guidelines for Vascular Access recommends early placement and use of an AVF among patients expected to require hemodialysis.

The reasons why AVF use differs among patient groups and geographic regions are unclear, but investigators suspect that poverty may play a role. Indeed research indicates that treatment centers with low rates of AVF use among incidence patients tend to cluster geographically. These center-to-center and regional variations cannot be accounted for by individual patient characteristics (McClellan WM, et al. J Am Soc Nephrol 2009; 20:1078–1085).

William M. McClellan, MD, MPH, of Emory University’s division of nephrology and Rollins School of Public Health, in Atlanta, and his colleagues designed a study to examine the degree to which incident and prevalent AVF use are associated with the poverty in the county where a treatment center is located. They hypothesized that higher community poverty levels would reduce the proportions of patients using both incident and prevalent AVF.

AVF use and regional poverty

To conduct the analysis, the research team performed a cross-sectional study of 28,135 patients who were treated by 1127 hemodialysis centers in five ESRD networks within 16 states between June 1, 2005, and May 31, 2006. The 2000 U.S. Census was used to categorize county-level poverty, and incident AVF use was ascertained from the Medicare CMS 2728 form. The change in prevalent AVF use over 30 months was calculated from monthly facility reports collected between 2003 and 2005.

An increased concentration of poverty in a treatment center’s county was associated with both lower incident and baseline prevalent AVF rates, the investigators found. In contrast, prevalent AVF rates increased substantially over the 30 months of observation, from 30.9 percent to 38.6 percent. There was no significant association between county poverty concentration and the rate of change in prevalent AVF use. While it was no surprise that centers in poor communities recorded less effective AVF care for incident patients, McClellan and his co-investigators did not expect that the center-specific rate of increase in prevalent AVF use over a 30-month period would be independent of poverty.

“Our research suggests that the community where a treatment center resides may contribute to variations in pre-dialysis care,” McClellan said. “This observation provides support for the development of quality improvement interventions targeted at these poorly performing communities and raises questions as to why poverty plays a role in community-to-community variations in care which are not seen following the start of dialysis.”

That local poverty was not tied to the rate of increase in prevalent AVF use suggests that poverty’s effects on AVF placement are malleable. Programs conducted to promote improved AVF care may help address the low rates of incident AVF use in poor areas. Treatment center-specific improvement in prevalent AVF use was measured during a national systematic effort to improve AVF rates, the authors said. So participation in the Medicare ESRD program may have mitigated the effect of poverty on disparities in ESRD treatment. This mitigation may reflect participation of treatment centers in mandated quality improvement activities.

Why local poverty might affect AVF use

Other experts in the field offered mixed reviews of the study’s findings.

“I’m not sure that the article demonstrates the relationship quite as clearly as claimed,” said Richard Hirth, PhD, professor of health management and policy and associate director of the Kidney Epidemiology and Cost Center at the University of Michigan School of Public Health, in Ann Arbor. “The authors did not control for any patient characteristics, even though they had some patient level data.”

Hirth noted that there clearly is an association of incident AVF use with poverty, although a causal relationship cannot be drawn from this study. “That said, to the extent that the relationship is causal, I would expect that fewer and/or lower quality medical resources both before dialysis and in the dialysis center would contribute,” he said. Clinics in areas with more privately insured patients are likely to have greater resources and that may benefit all patients, he explained.

Allen Nissenson, MD, chief medical officer for DaVita, Inc., one of the largest independent dialysis services providers in the country, noted that underserved communities are more likely to have fewer specialists, including nephrologists, less preventive care and screening, and a higher severity of chronic diseases with attendant higher mortality and morbidity. “This creates a significant disease burden for patients and a cost burden for society,” he said.

McClellan and his team suspect that the knowledge of local primary care physicians might also vary with regional poverty, leading to delays in referrals for AVF placement. In addition, poorer communities might negatively influence opinions, attitudes, and beliefs among individuals with advanced kidney disease about the utility of early AVF surgery. Aggressive screening and educational programs to identify patients with CKD and get them to see a nephrologist early might increase incident AVF use in poor communities, said Nissenson.