Decomposing Differences in Risk-Adjusted Rates of Emergency Department Visits Between Micropolitan and Urban Nursing Homes.

OBJECTIVES: Nursing homes (NHs) in micropolitan areas are reported to have different facility and market factors than urban NHs, but how these factors contribute to differences in emergency department (ED) visits remains unknown. This study examined and quantified sources of micropolitan-urban differences in NH risk-adjusted rates of any ED visit, ED without hospitalization or observation stay (outpatient ED), and potentially avoidable ED (PAED) visits of long-stay residents. DESIGN: The 2011-2013 national Medicare claims and NH Minimum Data Set (MDS) 3.0 were analyzed. We implemented generalized estimating equation models to examine micropolitan-urban differences in ED rates and Blinder-Oaxaca decompositions to quantify the contributions of NH and market factors. SETTING AND PARTICIPANTS: The study cohort included 12,883 unique privately owned, freestanding NHs from urban and micropolitan areas. MEASURES: Quarterly risk-adjusted rates of any ED visits, outpatient ED visits, and PAED visits were calculated from Medicare claims and MDS. NH and market characteristics were extracted from the Certification And Survey Provider Enhanced Reporting and Area Health Resources File. RESULTS: Over the study period, risk-adjusted rates averaged 10.2%, 3.4%, and 3.3% for any ED, outpatient ED, and PAED visits, respectively. Compared with urban NHs, micropolitan NHs reported similar rates of any ED, but significantly higher rates of outpatient ED and PAED (ß = 0.20% and 0.27%; both P < .05). Observable differences in NH characteristics (eg, number of beds, percentage Medicare or Medicaid residents, and employment of nurse practitioners and physician assistants) explained more than 20% of the micropolitan-urban differences in rates of outpatient ED and PAED visits; market factors (mainly Medicare Advantage penetration) explained about 46% of the differences in rates of outpatient ED visits. CONCLUSIONS AND IMPLICATIONS: Compared with urban NHs, micropolitan NHs tend to utilize more avoidable emergency care that can be partially explained by facility size, payer mix, use of nurse practitioners and physician assistants, and market structure.