Has inpatient hospital treatment before and after age 65 changed as the difference between private and Medicare payment rates has widened?

The past decade witnessed a dramatic increase in inpatient hospital payment rates for patients with private insurance relative to payment rates for those covered by Medicare. A natural question is whether the widening private-Medicare payment rate difference had implications for the hospital care received by patients just before and after turning 65-the age at which there is a substantial shift from private to Medicare coverage. Using a large discharge dataset covering the period 2001-2011, we tracked changes at age 65 in the following dimensions of hospital care: overall hospitalization rates, case mix, referral-sensitive surgeries, length of stay, full established charges, number of procedures, mortality, and composite measures of inpatient quality and patient safety. In all cases we found either no change or a change that was small and inconsistent with payment rate changes during the study period.