diffusion of abandonment decisions...three models of diffusion 2) social influence 1 • peer...

Diffusion of Abandonment Decisions:

What happens after comparative effectiveness research?

By Julie Berez

Mentors: Guy David, PhD Mark Neuman, MD, MSc

Presentation Outline • Overview of Comparative Effectiveness

Research and Diffusion • Project Aims & Objectives • Case Study: Abandonment of PA

Catheters for CABG in Florida • Future Steps • Debrief

What is comparative effectiveness research?

Overview Aims Case Study Future Steps Debrief

• Research that analyzes the effectiveness, benefits, and harms of treatments and technologies as compared to their counterparts in order to inform health care decisions.

• Can be original research such as clinical trials or systematic reviews of existing research to draw more definitive conclusions.

Why is CER controversial? • Seen as healthcare “rationing”. • Potentially infringes on doctors’ autonomy.


Why is CER important? • New treatments and technology are often rushed to

market without formalized evaluation of the effectiveness compared to existing treatments.

• Many treatments and technologies are currently used with harmful side-effects and few benefits.

• Overutilization needs to be addressed in light of soaring healthcare costs.


Do doctors change practice patterns because of CER?

• Doctors are hesitant to change practice styles even when evidence shows that an alternative is superior.1

• A group of doctors or hospitals will often react quickly while others hold out for years.

• After the 2007 COURAGE trial, doctors in hospitals with large volumes of cardiac patients abandoned PCI for angina rapidly while other doctors held out.2

• Diffusion models are a good way to conceptualize this gradual decision to abandon.

1Lanfant, C. (2003). ”Clinical Research to Clinical Practice—Lost in Translation.” New England Journal of Medicine 349(9): 868-874. 2Howard, D. H., C. Shen, et al. (2011). ”Comparative Effectiveness Research, COURAGE, and Technological Abandonment." NBER Working Papers Series.


Three Models of Diffusion

1) Contagion1 • Innovations spread like epidemics—a doctor abandons a

procedure upon coming in contact with a doctor who has already abandoned the procedure.

1Young, H. P. (2009). ”Innovation Diffusion of Heterogeneous Populations: Contagion, Social Influence, and Social Learning.” The American Economic Review 99(5): 1899-1924.

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2) Social Influence1 • Peer pressure—a doctor abandons when a certain

proportion of his colleagues have abandoned.


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3) Social Learning1 • Cost-Benefit Analysis—a doctor abandons after forming

an educated decision based on peers’ experiences with abandonment.


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Aims & Objectives • To develop an economic theory on the diffusion of

the abandonment decision following comparative effectiveness research.

• To incorporate multiple empirical studies on the abandonment of different procedures into a comprehensive understanding of the diffusion process.


Case Study: Abandonment of PA Catheter use during CABGs in Florida


• Example of a procedure that has been abandoned overtime after a negative CER finding.

• Hypothesis: “Entrant” physicians act as messengers, spreading practices learned at previous hospital to new hospital.

• Contagion vs. Social Learning Theory?

What is a PA Catheter?

• Used during various types of heart surgery to measure hemodynamic data.

• Many physicians believe that this information will help reduce mortality among patients. 1


Tabima, D.M. Free Radical Biology and Medicine. 2008.

1Weiner, R. S., G. Welch (2007). ”Trends in the Use of Pulmonary Artery Catheter in the United States, 1993-2004.” JAMA 298(4): 423-429.

Nationwide Use of PA Catheters: 1989-20031


1996: Connors et. al. demonstrate increased mortality with PA catheters through multicenter observational study (Presented in 1994) 2

1Weiner, R. S., G. Welch (2007). ”Trends in the Use of Pulmonary Artery Catheter in the United States, 1993-2004.” JAMA 298(4): 423-429.

2Connors, A. F., Jr. T. Speroff, et al. (1996). ”The Effectiveness of Right Heart Catheterization in the Initial Care of Critically Ill Patients: SUPPORT Investigators” JAMA 276(1): 889-897.

Hypothesis Overview Aims Case Study Future Steps Debrief

• “Entrant” physicians act as messengers, spreading practices learned at previous hospital to new hospital.

Methods • Longitudinal data set of Florida inpatient discharges

from 1992-2008.

• Isolate “entrants” among cardiothoracic surgeons for each year, link back to fellowship or previous hospital, and characterize PA catheter use trends for CABG in previous hospital.

• Analyze data for shifts in PA catheter use corresponding with entrant physician.


0

10

20

30

40

50

60

1992 1994 1996 1998 2000 2002 2004 2006 2008

% PACs during CABG


Hypothetical Example

• John Smith is a fellow in thoracic surgery at Hospital A from 1995-1997.

• Hospital A is a high-tech teaching hospital that abandoned PAC for CABG after hearing about Connors’ study in 1994.

Hospital A

1997


Hospital B


• Hospital B used PACs during 80% of CABGs in 1996.

• John Smith continues the practice of CABG without PAC learned in residency, and explains to colleagues the rationale for abandoning PACs.

Hospital A

1997


Hospital A Hospital B

0102030405060708090

1992 1996 2000 2004 2008

Hospital AHospital B

% PACs during CABG


Future Steps • Look for hypothesized trends in newly obtained

1992-2008 Florida inpatient data.

• Learn to use econometric models to analyze time series data.

• Work towards a grant to carry out a broader study using national data and a series of empirical examples.


Lessons Learned • Data, data, data ($$, rights, and ownership).

• The difference between theoretical and empirical studies.

• The benefits of collaborative work between disciplines.


Thank You! • Dr. Mark Neuman and Dr. Guy David • Joanne Levy • Lissy Madden • LDI Staff • SUMR Scholars • My Family


diffusion of abandonment decisions...three models of diffusion 2) social influence 1 • peer...

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