Abstract
BACKGROUND: It is uncertain whether consolidation in health care markets affects the quality of care provided and health outcomes. OBJECTIVES: To examine whether changes in market competition resulting from acquisitions by two large national for-profit dialysis chains were associated with patient mortality. METHODS: We identified patients initiating in-center hemodialysis between 2001 and 2009 from a registry of patients with end-stage renal disease in the United States. We considered two scenarios when evaluating consolidation from dialysis facility acquisitions: one in which we considered only those patients receiving dialysis in markets that became substantially more concentrated to have been affected by consolidation, and the other in which all patients living in hospital service areas where a facility was acquired were potentially affected. We used a difference-in-differences study design to examine the associations between market consolidation and changes in mortality rates. RESULTS: When we considered the 12,065 patients living in areas that became substantially more consolidated to have been affected by consolidation, we found a nominally significant (8%; 95% confidence interval 0%-17%) increase in likelihood of death after consolidation. Nevertheless, when we considered all 186,158 patients living in areas where an acquisition occurred to have been affected by consolidation, there was no observable effect of market consolidation on mortality. CONCLUSIONS: Decreased market competition may have led to increased mortality among a relatively small subset of patients initiating in-center hemodialysis in areas that became substantially more concentrated after two large dialysis acquisitions, but not for most of the patients living in affected areas.