This thesis addresses health-policy relevant questions regarding quantity and quality of service delivery in primary healthcare using health administrative data from the province of Ontario. It is comprised of four chapters that explore the following questions: (1) What is the impact of switching from an enhanced fee-for-service (EFFS) payment model to a blended capitation payment model on the specialist referral rates of primary care physicians? (2) What are the rates of inappropriate laboratory testing in the province of Ontario? (3) What are the costs and determinants (physician and practice characteristics) of these inappropriate tests? (4) What is the impact of primary care payment structure on the quantity (number and cost) and the quality (appropriateness) of clinical laboratory testing? Fee-for-service (FFS) payment systems give physicians an incentive to treat patients on the margin of being referred, whereas in capitation systems physicians do not have a financial incentive to treat such marginal patients. Chapter 1 empirically examines how these two payment systems affect referral rates. The results show an increase in specialist visits upon a switch from an EFFS model to a blended capitation model when the physician is listed as the referring physician in the data, but no change in total specialist visits for these physicians’ patients. This change is not observed immediately upon switching payment models. Physicians paid by blended capitation who practice in an interdisciplinary health team have fewer specialist visits per rostered patient compared to EFFS physicians, despite an increase in their patients’ specialist visits after joining the interdisciplinary team. Using a definition of inappropriateness that quantifies ordering clinical laboratory tests too often or too soon following a previous test, Chapter 2 examines the rates of inappropriate laboratory testing for nine selected analytes in Ontario. The chapter finds that the percentage of inappropriate tests ranges from 6% to 20%. Moreover, between 60% and 85% of the time, the physician ordering an inappropriate test is the same physician who ordered the previous test. The findings also show that specialists are more likely than primary care physicians to order repeat tests too soon. Chapter 3 examines the costs and determinants associated with the rates of inappropriate laboratory utilization. The associated costs of inappropriate/redundant laboratory testing for the selected analytes ranges between 6 – 20% of the total cost of each test. Statistical analyses of the association of physician and practice characteristics with inappropriate testing are done using a logit model. Conditional upon the variables within the model, male physicians, physicians trained outside of Canada, older physicians, and a younger patient population are all shown to be associated with less inappropriate testing. Primary care physicians in group practices and in payment models with pay-for-performance (P4P) incentives are less likely to order inappropriate tests and specialist physicians are twice as likely to order inappropriately compared to FFS primary care physicians. Differences in physician, practice and patient characteristics, however, explain only a small amount of the variation in inappropriate utilization. Chapter 4 examines how physicians’ laboratory test ordering patterns change following a switch from an FFS payment model enhanced with P4P to a blended capitation payment model, and the differences in ordering patterns between traditional staffing and interdisciplinary teams within the blended capitation model. Using a propensity score weighted fixed-effects specification to address selection, the chapter estimates that a mandatory switch to capitation would lead to an average of 3% fewer laboratory requisitions per patient. Patients’ laboratory utilization also becomes more concentrated with the rostering physician. More importantly, using diabetes-related laboratory tests as a case study, physicians order 3% fewer inappropriate/redundant tests after joining the blended model and 9% fewer if they joined an interdisciplinary care team within the blended model. / Thesis / Doctor of Philosophy (PhD)

Background: The United States health care system faces two fundamental challenges: a high growth rate of health care spending and deficiencies in quality of care. The growth rate of health care spending is the dominant driver of our nation’s long-term federal debt, while the inconsistent quality of care hinders the ability of the health care system to maximize value for patients. To address both of these challenges, public and private payers are increasingly changing the way they pay providers—moving away from fee-for-service towards global payment contracts for groups of providers coming together as accountable care organizations. This thesis evaluates the change in health care spending and in quality of care associated with moving to global payment for accountable care organizations in Massachusetts in the first 4 years. This thesis studies the Blue Cross Blue Shield of Massachusetts Alternative Quality Contract (AQC), a global payment contract that provider organizations in Massachusetts began to enter in 2009. The AQC pays provider organizations a risk-adjusted global budget for the entire continuum of care for a defined population of enrollees insured by Blue Cross Blue Shield of Massachusetts. It also awards substantial pay-for-performance incentives for organizations meeting performance thresholds on quality measures. This work assesses its effect on spending and quality through the first 4 years of the contract. Methods: Enrollee-level claims data from 2006-2012 were used with a difference-in-differences design to evaluate the changes in spending and quality associated with the Alternative Quality Contract over the first 4 years. The study population consisted of enrollees in Blue Cross Blue Shield of Massachusetts plans (intervention group) and enrollees in commercial employer-sponsored plans across 5 comparison states (control group). Unadjusted and adjusted results are reported for each comparison between intervention and control. Changes in spending for all 4 AQC cohorts relative to control were evaluated. In adjusted analyses of spending, I used a multivariate linear model at the enrollee-quarter level, controlling for age, sex, risk score, indicators for intervention, quarters of the study period, the post-intervention period, and the appropriate interactions. For analyses of quality, an analogous model at the enrollee-year level was used. Process and outcome quality were evaluated. Results: Seven provider organizations joined the AQC in 2009, with a total of 490,167 individuals who were enrolled for at least 1 calendar year in the study period. The control group had 966,813 unique individuals enrolled for at least 1 year during the study period. Average age, sex, and risk scores before and after the AQC were similar between the two groups. In the 2009 cohort, claims spending grew on average $62.21 per enrollee per quarter less than control over 4 years (p<0.001), a 6.8% savings. Analogously, the 2010, 2011, and 2012 cohorts had average savings of 8.8% (p<0.001), 9.1% (p<0.001), and 5.8% (p=0.04), respectively, by the end of 2012. Savings on claims were concentrated in the outpatient facility setting, specifically procedures, imaging, and tests (8.7%, 10.9%, and 9.7%, respectively, p<0.001). Organizations with and without risk-contracting experience saw similar average savings of 6.3% and 7.7%, respectively, over 4 years (p<0.001). About 40% of savings were explained by lower volume. Pre-intervention trends were not statistically different between intervention and control (-$4.57, p=0.86), suggesting savings were not driven by inherently different trajectories of spending. No differences in coding intensity were found. In sensitivity analyses, estimates were robust to alterations in the model, variables, and sample. Notably, claims savings were exceeded by incentive payments to providers (shared savings and quality bonuses) in 2009-2011, but exceeded incentives payments in 2012, generating net savings. Improvements in quality among intervention cohorts generally exceeded New England and national comparisons. Quality performance on chronic care measures increased from 79.6% pre-intervention to 84.5% post-intervention in the 2009 cohort, compared to 79.8% to 80.8% for the HEDIS national average, a 3.9 percentage-point relative increase over the 4 years. Analogously, preventive care and pediatric care measures increased 2.7 and 2.4 percentage points relative to control, respectively. On outcome measures, achievement of hemoglobin A1c, LDL cholesterol, and blood pressure control grew by 2.1 percentage points per year in the 2009 cohort after the AQC, while HEDIS averages remained largely unchanged (Figure). Conclusion: After 4 years, physician organizations in the AQC had lower spending growth relative to control and generally outperformed national averages on quality measures. Shared savings coupled with quality bonuses can exceed savings on claims in initial years, but over time, savings on claims may outgrow incentive payments. Incentive payments themselves may serve meaningful purposes, as quality measures may protect against stinting and shared savings may help ease providers into risk contracts. Changes in utilization suggest that this payment model can help modify underlying care patterns, a likely prerequisite for sustainable reform. The AQC experience may be useful to policymakers, insurers, and providers embarking on payment reform. Combining global budgets with pay-for- performance may encourage organizations to embark on the delivery system reforms necessary to slow spending and improve quality.