Abstract 14264: National Comparison of Hospital Market Share for Out-of-Hospital Cardiac Arrest and Elective Cardiac Surgery

Abstract

Introduction: Competition in the healthcare market is a theoretical driver of innovation, cost-savings, and improved quality. When patients are treated for certain emergent conditions, such as out-of-hospital cardiac arrest (OHCA), individuals have less choice in their treating hospital. For patients undergoing elective cardiac valve replacement surgery (EVRS), hospital choice may reflect distinct referral patterns and preferences. Our objective was to compare hospital market share for different cardiac services, thus allowing for better understanding of the care landscape and target interventions to improve outcomes. Methods: Using age-eligible Medicare fee-for-service institutional claims, an emergency department (ED) treated OHCA cohort was identified via ICD-9/10 diagnosis codes and ED charges. EVRS, an inpatient referral procedure, were identified from in-patient summary claims using procedure codes. Market shares were built for each hospital by sequential addition of ZIP-code areas and calculating the hospital’s cumulative market share. Geographic market share areas were defined for each hospital at 90%, 25% and 10% cut-offs if present. Correlation between corresponding market shares and patient counts were assessed using Pearson’s r. Results: Between 1/2013 and 12/2015, we identified 206,162 EVRS claims and 222,018 OHCA claims. Median age was similar (77 vs 78 yrs), as was percent of female patient (43% vs 44%). Very few beneficiaries (0.38%) appeared in both cohorts. Many more hospitals cared for OHCA than EVRS (4482 vs 1170). More OHCA treating hospitals achieved a 25% market share (68% vs 57%) however, EVRS hospital with a 25% market share covered more population (420,294 vs 66,394) and had a greater client radius (21 vs 15 miles). Among the hospitals providing care to both cohorts, the cumulative market share and patient counts were positively correlated (r = 0.49 and 0.46 respectively, p<0.001 for both). Conclusion: Despite many more hospitals providing care for OHCA, the market share for EVRS and OHCA trend together. This market trend, combined with the association of better outcomes with higher OHCA volume suggests that OHCA should be regionalized within markets to facilities that provide elective cardiac surgical procedures.