Associations of Social Deprivation and Oncology Physician Network Vulnerability With Acute Care Utilization in the SEER-Medicare Population.

[OBJECTIVE] The objectives of this study were to evaluate associations of social deprivation with acute care utilization among patients with cancer, and to examine potential effect modification by physician network vulnerability.

[STUDY SETTING AND DESIGN] For this retrospective cohort study, the primary exposure variable was neighborhood-level socioeconomic disadvantage, operationalized through the social deprivation index (SDI). We assembled physician patient-sharing networks and calculated a measure of network vulnerability for each referral region to capture specialist scarcity. The two outcomes of interest were counts of emergency department (ED) visits and non-elective hospitalizations during the 12 months following cancer diagnosis. We conducted hurdle regressions, with logistic and negative binomial mixed-effects models for the zero and positive, non-zero parts of the outcome distribution, respectively, and stratified by physician network vulnerability.

[DATA SOURCES AND ANALYTIC SAMPLE] We analyzed 2016-2020 Surveillance, Epidemiology, and End Results (SEER)-Medicare linked data for Medicare beneficiaries diagnosed with breast, colorectal, or lung cancer.

[PRINCIPAL FINDINGS] The study cohort comprised 47,756 patients with breast, colorectal or lung cancer. Patients in high SDI neighborhoods (vs. low) had a higher probability of at least one ED visit across all physician network vulnerability strata (low network vulnerability-average marginal effect (AME) [95% CI]: 0.03 [0.01-0.05]; medium network vulnerability-AME [95% CI]: 0.03 [0.01-0.04]; high network vulnerability-AME [95% CI]: 0.05 [0.02-0.08]). Conditional on at least one ED visit, patients in high SDI neighborhoods (vs. low) had a greater relative risk of additional ED visits when their region was characterized by low physician network vulnerability (RR [95% CI]: 1.25 [1.09-1.43]).

[CONCLUSIONS] Our findings suggest that SDI and physician network vulnerability interact to increase the probability and likelihood of ED visits, but the interaction was minimal for non-elective hospitalizations. More research is needed to better understand how social drivers of health and oncology workforce scarcity affect care utilization and outcomes in patients with cancer.