J. T. Adler1, D. C. Chang1, H. Yeh1 1Massachusetts General Hospital,Boston, MA, USA
Background: In kidney transplantation, practice patterns and utilization vary across the 58 Donor Service Areas (DSAs) in the United States. However, most patients would assume that his or her treatment is based on unique patient factors, and not on any economic or healthcare market factors. Nevertheless, market competition has been shown to contribute significantly to variability in both patient and graft outcomes after kidney transplantation. Relatively little is known about how competition affects access to transplantation (ATT) after the initiation of dialysis. Understanding how competition relates to ATT may improve outcomes and access in kidney transplantation.
Methods: The United States Renal Data System, which contains all new registrations for dialysis, was queried for adult incident dialysis registrations in 2008; final follow-up was through June 2013. Cox proportional hazards models were used to estimate the time from onset of dialysis to ATT, which was defined as enrolling on the kidney waitlist or receiving a living donor kidney transplant. To measure market competition, the Herfindahl-Hirschman Index (HHI) was calculated for each DSA and categorized as no (HHI 1), low (HHI 0.52-0.97), medium (HHI 0.33-0.51), or high (HHI 0.09-0.32) competition.
Results: 104,789 adults began dialysis in 2008. After adjusting for age and comorbidities (Table), increasing competition was strongly associated with increased ATT (HR 1.57, P < 0.001, high vs. no competition). Additional factors associated with increased ATT were male sex (HR 1.16, P < 0.001) and being under the care of a nephrologist at time of dialysis initiation (HR 1.70, P < 0.001). Compared to Whites, Asian patients had increased ATT (HR 1.38, P <0.001), while Black patients had decreased ATT (HR 0.77, P < 0.001).
Conclusion: Even after adjusting for comorbidities and other known patient factors, market competition plays a strong role in ATT. Understanding the interplay between competition and the conduct of kidney transplantation may improve ATT, and it deserves further investigation.
