Using Medicare Enrollment Data to Identify Beneficiaries in Assisted Living

Abstract

Objectives: Develop an approach for identifying Medicare beneficiaries residing in US assisted living (AL) communities in calendar year 2018.

Design: We used the following data sources: national directory of licensed ALs, file of US addresses and their associated 9-digit ZIP codes (ZIP+4), Medicare Enrollment Database (EDB), Master Beneficiary Summary File (MBSF), and the Minimum Data Set (MDS).

Setting and participants: A total of 412,723 Medicare beneficiaries who lived in ZIP+4 codes associated with an AL were identified as residents. Approximately 28% of the 16,682 ALs in which these beneficiaries resided were smaller communities (<25 beds).

Methods: For each AL, we identified ZIP+4 codes associated with its address. Using this ZIP+4 file, we searched through the Medicare EDB to identify beneficiaries who lived in each ZIP+4 code. The MBSF and MDS were used to exclude beneficiaries who died before 2018 and those whose AL and nursing home stays overlapped. We identified 3 cohorts of Medicare beneficiaries: (1) residents of a specific AL (one AL address per ZIP+4), (2) most likely AL residents, and (3) not likely AL residents. Comparisons across these cohorts were used to examine construct validity of our approach. Additional comparisons were made to AL residents based on the National Survey of Long-Term Care Providers (NSLTCP) and to fee-for-service (FFS) Medicare community-dwelling and long-stay nursing home residents.

Results: The cohorts of beneficiaries identified as AL residents exhibited good construct validity. AL residents also showed similarity in demographic characteristics to the 2018 sample from the NSLTCP, and as expected were different from FFS community and nursing home beneficiaries.

Conclusion and implications: We developed a methodology for identifying Medicare beneficiaries who reside in ALs. As this residential setting continues to grow, future studies will need effective approaches for identifying AL residents in order to evaluate the quality of care they receive.

Keywords: Assisted living; Medicare; ZIP+4 codes; methodology.

Figure 1:

Flow Chart for Identifying AL Communities and Their Medicare Beneficiary Residents Note: “Cohort A: 1 address per ZIP+4” = ZIP+4 code cover only one physical address known to be AL. This cohort includes Medicare beneficiaries who are definitely residents of a specific AL community. “Cohort B: >1 address per ZIP+4” = ZIP+4 code covers more than 1 physical address, with some known to be AL address and others not. This cohort includes Medicare beneficiaries who very likely to be AL residents as well as those who are not. “Cohort C: ZIP+4 with N addresses <=N beneficiaries” = subset of Cohort B, in which more than one AL shares ZIP+4 codes and the number of Medicare beneficiaries exceeds the number of associated addresses. This cohort includes beneficiaries who very likely reside in ALs, but it is not possible to identify their specific AL of residence. “Cohort D: ZIP+4 with N addresses > N beneficiaries” = subset of Cohort B, in which the number of addresses exceeds the number of Medicare beneficiaries. For these beneficiaries, it is not possible to distinguish between those who are residents of AL versus their Medicare eligible neighbors.

Figure 2:

Comparison of Identified CY2018 Assisted Living Residents in Cohorts A+C to Residents in the 2018 National Survey of Long-Term Care Providers (NSLTCP) Note: A+C= CY2018 Cohort of AL and their residents; NSLTCP=National Study of Long-term Care Providers. Data sources: The AL population data (Cohorts A+C) were based on all ALs with identified Medicare beneficiary residents in CY2018, based on the methodology reported by the authors. The NSLTCP estimates were derived from the 2018 biennial survey, reported in Caffrey, Sengupta, and Melekin, NCHS Data Brief, No. 404, September 2021 (reference no.14)