Factors Predicting Transitions from Medicare-Only to Medicare-Medicaid Enrollee Status. Results

The analysis indicates that the likelihood that Medicare beneficiaries transition to MME status is associated with the types of services they use, particularly nursing home care (Table 2). For example, among younger Medicare-only beneficiaries with no service utilization--"no ER visit leading to an inpatient admission, no SNF stay, and no non-SNF stay in the past six months"--only 4.9 per thousand (or 0.49 percent) transitioned to MME status. The transition rate increases slightly to 7.1 per thousand when beneficiaries have an "ER visit resulting in an inpatient stay." Thus, an "ER visit resulting in an inpatient stay" is associated with a 2.2 per thousand (7.1 minus 4.9) increase in the chance of transitioning to MME status relative to the base transition rate associated with no service utilization.

Regardless of the age group, a nursing home stay of any kind is associated with increases in the rate of transition to MME status whether or not that stay is preceded by the use of acute care services. Among beneficiaries under 65, a nursing home stay is associated with increases in transition rates ranging from 7.5 per thousand among those who only have a SNF stay to 22.3 per thousand among those who have an "ER visit resulting in an inpatient stay, a SNF stay, and a non-SNF nursing home stay." Similarly, among older beneficiaries, a SNF stay is associated with a 3.1 per thousand increase while an "ER visit resulting in an inpatient stay, a SNF stay, and a non-SNF nursing home stay" is associated with a 10 per thousand increase.

The service combination that is associated with the highest probability of transitioning to MME status is when a beneficiary has an "ER visit resulting in an inpatient stay, a SNF stay, and a non-SNF nursing home stay" all within the past six months: 27.2 per thousand for under 65 and 10.8 per thousand for 65 and above. This combination likely captures the pathway where a beneficiary first suffers an acute medical episode for which they enter the ER and then end up being admitted for an inpatient stay; the beneficiary is then discharged to a Medicare-financed SNF stay for subacute care or rehabilitation, followed by ongoing nursing home care after the Medicare benefit runs out. The data do not tell us if the beneficiary spent down to meet Medicaid resource criteria because of this adverse sequence of events, or would have had sufficiently low resources irrespective of the events, but presumably some do.

Notably, the magnitude of the transition rates, both in levels as well as differences relative to the base rate of no service utilization, are substantially higher among the under 65 than the 65 and above, which is consistent with what Borck et al. (2013) find in their descriptive study of the transitions to MME status.⁹ For example, the pathway "ER visit resulting in an inpatient stay, a SNF stay, and a non-SNF nursing home stay" described earlier is associated with a transition rate of 27.2 per thousand among the under 65, which is more than twice the transition rate of 10.8 per thousand for the same pathway among the 65 and above. Moreover, the respective differences relative to the base rate are 22.3 and 10 per thousand, respectively--again a more substantial transition rate among the under 65.¹⁰

We also find that the other predictor variables are associated with an increased probability of transitioning to MME status (estimates are found in the Appendix, Table A1). We find that a planned inpatient stay is associated with a 4 percent and 2 percent higher odds of entering MME status for the under 65 and the 65 and above, respectively. An outpatient ER visit is associated with a 7 percent and 9 percent higher odds, respectively, of transitioning to MME status, perhaps reflective of a more severe medical episode. A week of home health use is associated with less than a 1 percent increase, though this is not trivial for a long duration of home health use. The model we estimated also included chronic condition indicators, which we will address in a later section.

The results in the previous section highlight that a nursing home stay, particularly a non-SNF stay, is strongly predictive of transition to MME status. The analysis indicates that acute care services and SNF use are associated with having a non-SNF nursing home stay (Table 3). For those under 65 with "no prior ER visit resulting in an inpatient admission or SNF care," the rate of entering a non-Medicare-financed nursing home stay is 0.3 per thousand among those under age 65. The corresponding rate among those age 65 and above is 0.5 per thousand. Having an "ER visit resulting in an inpatient admission" leads to a 0.5 per thousand and 0.7 per thousand increase in this rate, respectively. Having a prior "SNF stay" substantially increases the likelihood of having a non-SNF stay, by 5 per thousand for beneficiaries under 65, and 5.5 per thousand for older beneficiaries. Among those under age 65, having both a prior "ER visit resulting in an inpatient admission and SNF stay" within the past six months is associated with an 8.3 per thousand higher rate of entering a non-SNF nursing home. The same pattern of service utilization among those age 65 and above is associated with a 9.4 per thousand increase. These rates likely reflect a significant acute event that requires discharge to a SNF following an inpatient stay.

Other predictor variables also are associated with a non-SNF nursing home stay. Each planned inpatient stay increases the odds of entering a nursing home by 33 percent and 23 percent, respectively, for the under 65 and the 65 and above (estimates are found in the Appendix, Table A2). Each outpatient ER visit increases the odds of nursing home entry by 5 percent and 12 percent, respectively. Conversely, the amount of home health care is negatively correlated with nursing home entry (odds ratio=0.98 and 0.96 for the under 65 and the 65 and above, respectively), which is consistent with home health care as a potential substitute for nursing home care.

In addition to service utilization, chronic conditions were also associated with the rate of transition to MME status, as well as non-SNF nursing home entry. Younger beneficiaries with Alzheimer's, dementia, and related disorders have 1.8 times the odds of becoming an MME than those without, whereas older beneficiaries with dementia have nearly three times the odds of becoming an MME than those without (estimates are found in the Appendix, Table A1).¹¹ Depression is also a significant factor (odds of 1.5-1.7, depending on the age group). The number of physical chronic conditions is also associated with higher odds of becoming an MME--on average, an 18 percent and 12 percent increase in the odds per condition, for younger and older beneficiaries, respectively.

Chronic conditions are also strong predictors of nursing home entry. Younger and older beneficiaries with dementia are about four times more likely to enter a nursing home than those without dementia (estimates are found in the Appendix, Table A2). The corresponding odds for depression are about 1.7-1.8. Each physical condition is associated with a 12-16 percent higher odds, depending on the age group.