Patients in our hip fracture, stroke, and joint replacement samples use post-acute care at high rates. In 2002, over 85 percent of hip fracture and joint replacement patients and about 70 percent of stroke patients used some type of Medicare-covered post-acute care. Roughly 22 percent of hip fracture patients and 33 percent of joint replacement patients used inpatient rehabilitation care. Hip fracture patients were much more likely to use skilled nursing care than stroke or joint replacement; stroke patients received home health care at a higher rate than hip fracture patients.
In examining the means of the variables we controlled for in the models, we found some key differences between the populations. The hip fracture sample is older—over half of the hip fracture patients are age 80 or older—and more heavily female, as expected. None of the three groups have a high level of complications, but all three groups have a substantial rate of comorbidities. These results are presented in .
presents the detailed results from our logistic regressions using pooled data for the period January 1996 through June 2003 for each condition. Because the signs and magnitudes of the effects are difficult to interpret from the multinomial logit regression output, we provide corresponding estimates of the changes in the probability of going to each post-acute location and standard errors on these estimates (in parentheses). A negative percentage in these columns indicates that the patient was less likely to go to that post-acute location after the payment system change noted in the row title. The implementation effect rows should be interpreted as the shift due to implementation while the time trend effects show the predicted change in the probability of going to that site in the postimplementation period, evaluated at the quarter following the implementation. The asterisks indicate significance levels, as footnoted on the table. In addition, we constructed , , and displaying case-mix-adjusted probabilities of use that visually display the effects of the payment systems.
Change in Predicted Probability to Site
Predicted Probabilities of Hip Fracture Patients Going to Each PAC Location, 1996–2003
Predicted Probabilities of Stroke Patients Going to Each PAC Location, 1996–2003
Predicted Probabilities of Joint Replacement Patients Going to Each PAC Location, 1996–2003
From the figures, we can see that the probability of patients with a hip fracture being discharged without Medicare-covered post-acute care versus inpatient rehabilitation, skilled nursing, or home health is falling over this time period, while increasing for stroke patients and remaining about the same for joint replacement patients. The probability of going to inpatient rehabilitation increased over time for all three conditions but was especially strongly for joint replacement patients. The probability of going to skilled nursing peaked at the beginning of 1998 for all three conditions, but it fell overall. The probability of using home health care declined for all three conditions, with notable declines associated with the implementation of the home health interim payment system and home health prospective payment.
The predictions from our multinomial logit models show significant changes in where patients went after discharge from acute care and how use was affected by the various post-acute payment systems implemented between 1996 and 2003. When the Balanced Budget Act mandated the implementation of the home health interim payment system in October 1997, the use of home health care went down for all three conditions immediately and continued to decline for stroke patients in the periods following implementation. The interim payment system was associated with an immediate reduction in the probability of hip fracture and joint replacement patients going to home health care of 0.4 and 0.6 percentage points, respectively. The interim payment system reduced the likelihood of a stroke patient going to home health by about 1.4 percent immediately and an additional 0.4 percent in the quarter after the payment system changed. There is evidence of a decrease in the use of skilled nursing on implementation of the home health interim payment system for joint replacement patients and for both stroke and joint replacement patients in the period following implementation.
With the implementation of the prospective payment in SNFs in July 1998 there was an immediate decline in skilled nursing use, which was significant for hip fracture and joint replacement patients. After the implementation, there was an increase in home health use for all three conditions.
The implementation of prospective payment for HHAs in October 2000 was associated with a large decrease in the use of home health care for all three conditions. The likelihood of going to home health after prospective payment decreased by 0.4 percent for hip fracture patients, 1.5 percent for stroke patients, and 1.2 percent for joint replacement patients. It was also associated with a decline in inpatient rehabilitation use for all conditions in the period following implementation and an increase in stroke and joint replacement patients' use of skilled nursing.
The implementation of the inpatient rehabilitation prospective payment system in January 2002 was associated with a decrease in the probability of not receiving post-acute care for all three conditions. The likelihood of going to an SNF increased immediately by 0.8 percent in joint replacement patients. For hip fracture patients, prospective payment was associated with a subsequent increase in the use of inpatient rehabilitation and a decline in use of skilled nursing.
We also ran a model that included interactions for more severely ill patients, with the payment system variables to see if their access was differentially affected by the changes in payment systems. Including these 10 interaction variables across three PAC location choices resulted in only a few weakly significant effects. The changes in the other coefficients, including the payment change variables, when these interactions were included were very small in magnitude and the effects were not qualitatively different. The results from these models are, therefore, not shown in the tables.