Abstract 127: Has DRG 559 Increased Administration of r-tPA In Medicare Beneficiaries With Acute Ischemic Stroke?

Abstract

IV r-tPA has been shown to be an efficacious and cost-effective treatment for acute ischemic stroke (AIS). Lack of adequate reimbursement for treatment of AIS with r-tPA from the CMS may be a barrier for r-tPA use among Medicare beneficiaries. In October 2005, CMS introduced DRG 559- increased reimbursement for iv r-tPA administration. We evaluated the impact of demograhic factors and DRG 559 on use of iv r-tPA for AIS among Medicare beneficiaries. Methods: CMS Medicare claims database from MEDPAR for 2004 and CCW for 2005-07 were accessed. AIS was defined by the presence of a primary diagnosis according to an ICD-9 codes 433 and 434 with a fifth-digit subclassification 1 indicating occlusion with infarction of precerebral and cerebral arteries from DRG 14 and 559. AIS patients receiving iv r-tPA were identified by presence of ICD-9 procedure codes 99.10 and receiving such procedure within one day of admission. r-tPA drip and ship cases were identified and included as r-tPA drip & ship cases in the receiving hospitals. Patients transferred for acute stroke care to another short term general/specialty hospital were excluded as were admissions to hospitals other than short term general/specialty or critical access hospitals and those admissions in the rehab units of the short term general/specialty hospitals. Impact of reimbursement on r-tPA use was assessed using piecewise regression methods in STATA 11. Results: From January 2004 to September 2007 a total of 742,368 AIS admissions were evaluated and estimated use of r-tPA by age, sex, race/ethnicity and geographical region is presented in the table. Trends in use of r-tPA are depicted in the figure . The estimated intercepts and slopes in the figure by pre- and post-DRG 559 and age group depicts the possible effect of increased reimbursement on r-tPA use in this population. A significant increase in r-tPA use with the introduction of DRG 559 in October 2005 (i.e. month = 9 onwards) was noticed by the significant jump (p-value < 0.01) in the intercepts. Conclusion: The results generally suggest the highest use of r-tPA among ages 65-75, men, white race and in the Northeast region.The increase in r-tPA use may be explained by the impact of policy change with introduction of higher reimbursement for r-tPA for AIS among Medicare beneficiaries. Estimates of use of r-tPA by month and age group