Impact of a commercial accountable care organization on prescription drugs.

OBJECTIVE: To determine the long-run impact of a commercial accountable care organization (ACO) on prescription drug spending, utilization, and related quality of care. DATA SOURCES/STUDY SETTING: California Public Employees' Retirement System (CalPERS) health maintenance organization (HMO) member enrollment data and pharmacy benefit claims, including both retail and mail-order generic and brand-name prescription drugs. STUDY DESIGN: We applied a longitudinal retrospective cohort study design and propensity-weighted difference-in-differences regression models. We examined the relative changes in outcome measures between two ACO cohorts and one non-ACO cohort before and after the ACO implementation in 2010. The ACO directed provider prescribing patterns toward generic substitution for brand-name prescription drugs to maximize shared savings in pharmacy spending. DATA COLLECTION/EXTRACTION METHODS: The study sample included members continuously enrolled in a CalPERS commercial HMO from 2008 through 2014 in the Sacramento area. PRINCIPAL FINDINGS: The cohort differences in baseline characteristics of 40 483 study participants were insignificant after propensity-weighting adjustment. The ACO enrollees had no significant differential changes in either all or most of the five years of the ACO operation for the following measures: (1) average total spending and (2) average total scripts filled and days supplied on either generic or brand-name prescription drugs, or the two combined; (3) average generic shares of total prescription drug spending, scripts filled or days supplied; (4) annual rates of 10 outpatient process quality of care metrics for medication prescribing or adherence. CONCLUSIONS: Participation in the commercial ACO was associated with negligible differential changes in prescription drug spending, utilization, and related quality of care measures. Capped financial risk-sharing and increased generics substitution for brand names are not enough to produce tangible performance improvement in ACOs. Measures to increase provider financial risk-sharing shares and lower brand-name drug prices are needed.

Five-year Impact of a Commercial Accountable Care Organization on Health Care Spending, Utilization, and Quality of Care.

BACKGROUND: Accountable Care Organizations (ACOs) have proliferated after the passage of the Affordable Care Act in 2010. Few longitudinal ACO studies with continuous enrollees exist and most are short term. OBJECTIVE: The objective of this study was to evaluate the long-term impact of a commercial ACO on health care spending, utilization, and quality outcomes among continuously enrolled members. RESEARCH DESIGN: Retrospective cohort study design and propensity-weighted difference-in-differences approach were applied to examine performance changes in 2 ACO cohorts relative to 1 non-ACO cohort during the commercial ACO implementation in 2010-2014. SUBJECTS: A total of 40,483 continuously enrolled members of a commercial health maintenance organization from 2008 to 2014. MEASURES: Cost, use, and quality metrics for various type of services in outpatient and inpatient settings. RESULTS: The ACO cohorts had (1) increased inpatient and outpatient total spending in the first 2 years of ACO operation, but insignificant differential changes for the latter 3 years; (2) decreased outpatient spending in the latter 2 years through reduced primary care visits and lowered spending on specialists, testing, and imaging; (3) no differential changes in inpatient hospital spending, utilization, and quality measures for most of the 5 years; (4) favorable results for several quality measures in preventive and diabetes care domains in at least one of the 5 years. CONCLUSIONS: The commercial ACO improved outpatient process quality measures modestly and slowed outpatient spending growth by the fourth year of operation, but had a negligible impact on inpatient hospital cost, use, and quality measures.