title: Evaluating the Impact of an Accountable Care Organization on Population Health: The Quasi-Experimental Design of the German Gesundes Kinzigtal.
abstract: A central goal of accountable care organizations (ACOs) is to improve the health of their accountable population. No evidence currently links ACO development to improved population health. A major challenge to establishing the evidence base for the impact of ACOs on population health is the absence of a theoretically grounded, robust, operationally feasible, and meaningful research design. The authors present an evaluation study design, provide an empirical example, and discuss considerations for generating the evidence base for ACO implementation. A quasi-experimental study design using propensity score matching in combination with small-scale exact matching is implemented. Outcome indicators based on claims data were constructed and analyzed. Population health is measured by using a range of mortality indicators: mortality ratio, age at time of death, years of potential life lost/gained, and survival time. The application is assessed using longitudinal data from Gesundes Kinzigtal, one of the leading population-based ACOs in Germany. The proposed matching approach resulted in a balanced control of observable differences between the intervention (ACO) and control groups. The mortality indicators used indicate positive results. For example, 635.6 fewer years of potential life lost (2005.8 vs. 2641.4; t-test: sig. P < 0.05*) in the ACO intervention group (n = 5411) attributable to the ACO, also after controlling for a potential (indirect) immortal time bias by excluding the first half year after enrollment from the outcome measurement. This empirical example of the impact of a German ACO on population health can be extended to the evaluation of ACOs and other integrated delivery models of care.
authors: 1 Health Policy and Management, School of Public Health, University of California , Berkeley, Berkeley, California.
authors: Alexander
authors: A
authors: Pimperl
authors: 2 Department of Health, University of Witten/Herdecke , Witten, Germany .|3 OptiMedis AG , Hamburg, Germany .
authors: Timo
authors: T
authors: Schulte
authors: 4 Institute for Health Economics and Health Care Management , Hochschule Neubrandenburg, Neubrandenburg, Germany .
authors: Axel
authors: A
authors: Mühlbacher
authors: 5 Centre for Research in Health Innovation Management, IESE Business School , Barcelona, Spain .
authors: Magdalena
authors: M
authors: Rosenmöller
authors: 6 Department of Health Care Management, Berlin University of Technology , Berlin, Germany .
authors: Reinhard
authors: R
authors: Busse
authors: 3 OptiMedis AG , Hamburg, Germany .|7 Department of Health Services Research and Policy, London School of Hygiene and Tropical Medicine , London, United Kingdom .
authors: Oliver
authors: O
authors: Groene
authors: 1 Health Policy and Management, School of Public Health, University of California , Berkeley, Berkeley, California.
authors: Hector P
authors: HP
authors: Rodriguez
authors: 3 OptiMedis AG , Hamburg, Germany .|8 Gesundes Kinzigtal GmbH , Haslach, Germany .
authors: Helmut
authors: H
authors: Hildebrandt
mesh_terms: D060866:Accountable Care Organizations; D005858:Germany; D006801:Humans; D000075485:Population Health; D057216:Propensity Score; D011787:Quality of Health Care