Volume 46 | Number 3 | June 2011

Abstract List

Yi Zhang Ph.D., Dennis J. Cotter, Mae Thamer Ph.D.


To examine the association between dialysis facility chain affiliation and patient mortality.

Study Setting

Medicare dialysis population.

Study Design

Data from the United States Renal Data System (USRDS) were used to identify 3,601 free‐standing dialysis facilities and 34,914 Medicare patients' incidence to end‐stage renal disease (ESRD) in 2004. Mixed‐effect regression models were used to estimate patient mortality by dialysis facility chain and profit status during the 2‐year follow‐up.

Data Collection

USRDS data were matched with facility, cost, and census data.

Principle Findings

Of the five largest dialysis chains, the lowest mortality risk was observed among patients dialyzed at nonprofit (NP) Chain 5 facilities. Compared with Chain 5, hazard ratios were 19 percent higher (95 percent CI 1.06–1.34) and 24 percent higher (95 percent CI 1.10–1.40) for patients dialyzed at for‐profit (FP) Chain 1 and Chain 2 facilities, respectively. In addition, patients at FP facilities had a 13 percent higher risk of mortality than those in NP facilities (95 percent CI 1.06–1.22).


Large chain affiliation is an independent risk factor for ESRD mortality in the United States. Given the movement toward further consolidation of large FP chains, reasons behind the increase in mortality require scrutiny.