ACO leakage among gynecologic cancer patients: Incidence, predictors, and impact on annual Medicare expenditure.

Objective: To examine patterns of Accountable Care Organizations (ACO) leakage, the receipt of healthcare by ACO-assigned patients from institutions outside assigned ACO network, among patients with gynecologic cancer. ACO leakage was estimated as rates of patients seeking care external to their ACO assignment. Factors associated with ACO leakage were identified and cost differences within the first year of cancer diagnosis described.
Methods: Medicare 5% data (2013-2017) was used to quantify rates of leakage among gynecologic cancer patients with stable ACO assignment. Crude and multivariable adjusted risk ratios of ACO leakage risk factors were estimated using log-binomial regression models. Overall and cancer-specific spending differences by ACO leakage status were compared using Wilcoxon rank-sum test.
Results: Overall incidence of ACO leakage was 28.1% with highest leakage for outpatient care and uterine cancer patients. ACO leakage risk was 56% higher among Black relative to White patients, and 77% more for those in higher relative to lowest quintiles of median household income. Leakage decreased by 3% and 8% with each unit increase in ACO size and number of subspecialists, respectively. Healthcare costs were 19.5% higher for leakage patients.
Conclusions: ACO leakage rates among gynecologic cancer patients was overall modest, with some regional and temporal variation, higher leakage for certain subgroups and substantially higher Medicare spending in inpatient and outpatient settings for patients with ACO leakage. These findings identify targets for further investigations and strategies to encourage oncologists to participate in ACOs and prevent increased health care costs associated with use of non-ACO providers.
Competing Interests: Declaration of competing interest The authors report no conflicts of interest.
(Published by Elsevier Inc.)