Evaluating whether changes in utilization of hospital outpatient services contributed to lower Medicare readmission rate.

OBJECTIVE: Descriptive analysis comparing changes in hospital inpatient readmissions to emergency department visits and observation stays that occurred within 30 days of an inpatient stay. POPULATION: Medicare fee-for-service (FFS) beneficiaries that had at least one acute hospital inpatient stay. DATA SOURCE: Using 100 percent of claims in the Chronic Condition Data Warehouse, we compare growth in annual readmission stays to post-hospitalization emergency department visits and observation stays that were not accompanied by an inpatient stay. Comparisons are performed at the national level and within the Dartmouth Hospital Referral Regions (HRRs).
RESULTS: In calendar year 2012, the national, all-cause, 30-day hospital readmission rate among Medicare FFS beneficiaries was 18.5 percent, a significant decline from 19 percent in 2011, which was also the average rate over the previous five years. The number of index admission stays per-1,000 Medicare beneficiaries declined by 4.3 percent, from 283.4 in 2011 to 271.3 in 2012. On a per-1,000 beneficiary basis, the number of readmission stays declined by 6.8 percent, from 53.8 in 2011 to 50.1 in 2012. On the same per-beneficiary basis, the rate of outpatient visits to an emergency department occurring within 30 days of an index hospitalization remained similar at 23.5 in 2011 and 23.4 in 2012. Per-1,000 beneficiaries, the number of observation stays within 30 days of an index hospitalization increased by 0.3 percent, from 3.4 in 2011 to 3.7 in 2012. DISCUSSION: The reasons behind the decline in the Medicare readmission rate in 2012 are not yet clear. When looking at utilization changes in absolute terms, our findings suggest that the reduction in the nation-wide readmission rate observed in 2012 was not primarily the result of increases in either post-index ED visits or post-index observation stays.