Linkage of Medicare Records to the Interagency Registry of Mechanically Assisted Circulatory Support.

Background: The Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) is a United States registry for adults receiving durable United States Food and Drug Administration-approved mechanical circulatory support devices (MCSDs). We merged INTERMACS records with Medicare claims to investigate the uncertainty of penetrance of Medicare beneficiaries within INTERMACS.

Methods: INTERMACS records and Medicare claims (January 1, 2008, through December 31, 2013) from the Centers for Medicare and Medicaid (CMS) were linked using a deterministic matching methodology.

Results: There was annual growth of CMS and INTERMACS centers performing durable MCSD implants among adults from 2008 through 2013 (54% and 87% increase, respectively). The number of CMS centers outnumbered INTERMACS centers throughout all years, with the 68% to 88% of CMS centers being represented in INTERMACS. Although annual patient volume was greatest for INTERMACS, the absolute number of patients significantly increased annually across both data sets from 2008 through 2013 (149% increase in CMS; 268% increase in INTERMACS). As a proportion of all INTERMACS registrants, Medicare beneficiary representation grew from 30% in 2008 to a high of 48% in 2010 and remained stable thereafter. Representation within INTERMACS of MCSDs implanted in Medicare beneficiaries more than doubled, from 36% in 2008 to 77% in 2013.

Conclusions: Using a merged data set of MCSDs implanted between 2008 and 2013, we report that the vast majority of CMS centers and Medicare beneficiaries receiving MCSDs are increasingly captured in INTERMACS. Accordingly, contemporary studies in INTERMACS are relevant and generalizable to the Medicare population.