Patients with end-stage renal disease (ESRD) who initiate dialysis within the Veterans Affairs (VA) health system are more likely to do so at lower levels of renal function compared with those who initiate dialysis outside the system, according to new study.

The study, led by Margaret K. Yu, MD, of Veterans Affairs Puget Sound Health Care System in Seattle, compared veterans who initiated dialysis within the VA system (16,761 patients) with 3 groups who initiated dialysis outside the VA: veterans whose dialysis was paid for by the VA (4,013 patients); veterans whose dialysis was not paid for by the VA (99,436 patients); and non-veterans (851,333 patients). For the study, Dr. Yu and her colleagues linked data from the VA, Medicare, and the U.S. Renal Data System.

All 4 groups exhibited a temporal trend toward starting dialysis at higher levels of estimated glomerular filtration rate (eGFR) from 2000 to 2009, but those initiating dialysis within the VA system were significantly less likely than the other groups to start dialysis at an eGFR of 10 mL/min/1.73 m² or higher, the researchers reported online ahead of print in the Clinical Journal of the American Society of Nephrology.

The adjusted probability of initiating dialysis at an eGFR of 10 mL/min/1.73 m² or higher was 31% for veterans starting dialysis within the VA compared with 36%, 40%, and 39% for veterans whose dialysis was started outside the VA but paid for by the VA, those whose dialysis was not paid for by the VA, and non-veterans, respectively.

“The finding of an upward trend in eGFR at initiation among veterans who started dialysis within the VA, where physicians are salaried and cannot bill insurance for dialysis services, seems to suggest that temporal trends in eGFR at initiation are unlikely to be explained entirely by provider-level financial incentives,” the authors wrote.

Additionally, the study showed that differences in eGFR at initiation within versus outside the VA were most pronounced among older patients and patients with a higher risk of 1-year mortality, the investigators reported.

“Collectively these findings suggest that health system factors may play a significant role in shaping decisions about dialysis initiation, especially in medically complex patients and those with limited life expectancy,” they concluded.

In an editorial accompanying the new report, Venkat Ramanathan, MD, of the VA Medical Center in Houston, and Wolfgang C. Winkelmayer, MD, of Baylor College of Medicine in Houston, observed that the findings of the study by Dr. Yu's team “support the possibility of provider-induced demand, in that veterans approaching ESRD experienced differential timing of dialysis initiation depending on their providers' financial incentives, with salaried physicians in the VA system initiating patients relatively later than nephrologists outside the VA who received incrementally higher monthly payments for each additional patient.”

Drs. Ramanathan and Winkelmayer pointed to other possible explanations for the findings. “The most important and obvious one is residual confounding,” they wrote. “The data presented already showed considerable differences in demographics and observed clinical characteristics among these groups of veterans.”

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