E382: Association of Hospital Market Concentration with Outcomes of Complex Cancer Surgery

The association of hospital market concentration, financial costs, and quality of oncologic care has not been well-defined. We sought to evaluate variations in patient outcomes and financial expenditure following complex cancer surgery across high and low concentration markets.

Methods:

Medicare 100% Standard Analytic Files were used to identify patients with lung, esophageal, gastric, hepatopancreaticobiliary, or colorectal cancer who underwent surgical resection between 2018 and 2021. The hospital market Herfindahl-Hirschman index was used to categorize hospitals into low- and high-concentration markets. Multi-level, multivariable regression models adjusting for patient characteristics (i.e., age, sex, comorbidities, and social vulnerability), year of procedure, and hospital factors (i.e., case volume, nurse-bed ratio and teaching status) were used to assess the association between hospital market concentration and outcomes.

Results:

Among 159,236 beneficiaries, mean (SD) age was 74.3 (6.5) years, and roughly one-half the cohort was male (n=75,528, 47.4%). Overall, 36.3% (n=57,831) of hospitals were within a high-concentration market; of note, there was marked geographic variation relative to market concentration (Figure). Low- versus high- market concentration hospitals were more likely to be located in high social vulnerability areas (36.3% vs 28.0%; p< 0.001), as well as care for racial/ethnic minority individuals (14.9% vs 8.4%; p< 0.001), and patients with more comorbidities (≥2 Elixhauser comorbidities, 71.6% vs 70.1%; p< 0.001). On multivariable analysis, treatment at hospitals in high-concentration markets was associated with lower odds of perioperative complications (OR 0.93, 95%CI 0.89-0.97), extended length-of-stay (OR 0.93, 95%CI 0.89-0.97), and readmission within 30-days (OR 0.96, 95%CI 0.92-0.99) versus low-concentration hospital markets (all p< 0.05). In contrast, there was no difference in median Medicare expenditures for the index surgical admission (low-concentration: $16,305, IQR: $12,855-$24,724 vs high-concentration: $16,088, IQR: $12,713-$23,328; OR 1.00, 95%CI 0.98-1.02) (both p >0.05).

Conclusions:

Hospital market concentration impacted odds of peri-operative complications, length-of-stay, and readmission yet were not associated with expenditures related to complex cancer surgery. Hospital market consolidation may provide a good value proposition for complex, highly specialized procedures as these hospitals achieved higher quality care at equivalent costs.