The CDC’s Diabetes Systems Modeling Project: Developing a New Tool for Chronic Disease Prevention and Control Jack Homer, Andrew Jones, Don Seville Homer Consulting & Sustainability Institute Joyce Essien Rollins School of Public Health, Emory University Bobby Milstein Dara Murphy Centers for Disease Control and Prevention International SD Conference Oxford, U.K. July 27, 2004

Client and Issue SAFER HEALTHIER PEOPLE ™ Client: CDC’s Division of Diabetes Translation –Policy and Epidemiology Branches Issue: What are the pros and cons of “upstream” (prevention) and “downstream” (control) efforts?

Upstream Prevention and Protection Total  3% Downstream Care and Management Total  97% Public Health Efforts Today

Growth of Obesity and Diabetes in the U.S. Diagnosed & with Diagnosed Diabetes Dx diabetes TIME Magazine Cover Story, 8 December 2003.

Model Structure BMI/Obesity Clinical Management of Diagnosed PreD & Diabetes Downstream Upstream

Base Run Obesity Prevalence Time (Year) Diabetes Prevalence Time (Year) Deaths per Complicated Time (Year) Deaths per Population Time (Year)

Deaths per Population Time (Year) Downstream-Only Intervention Blue: Base run; Red: Clinical mgmt of diagnosed up from 66% to 90% Base Downstream

Deaths per Population Time (Year) Upstream-Only Intervention Blue: Base run; Red: Clinical mgmt up from 66% to 90%; Green: Caloric intake down 4% (99 Kcal/day) Downstream Upstream Base

Deaths per Population Time (Year) Mixed Intervention Blue: Base run; Red: Clinical mgmt up from 66% to 90%; Green: Caloric intake down 4% (99 Kcal/day); Black: Clin mgmt up to 80% & Intake down 2.5% (62 Kcal/day) Base Downstream Upstream Mixed

Linking Insights to Action 1.Cross-stakeholder model-based learning laboratories 2.Analyzing the effectiveness of goal- setting

Diagnosed Prevalence Fraction Relative to 2000 Value Time (Year) No progress +24% +14% Meet onset goal (-29%) Goals, Actual Performance, and Model Runs 2010 prevalence goal -38% 2000 prevalence goal -11% +33% “It felt like we flunked”

Prevalence * Deaths Small outflow, people can live for decades with the disease Chronic Disease Level rises until the inflow is less than the outflow Onset * Large inflow, double the outflow * Diagnosed

“It is expected that if you do a good job, things ought to go down.” – Diabetes Branch Leader

Prevalence Acute Infectious Disease Onset Large inflow, but usually fast to reduce Level falls as inflow quickly drops below outflow Large outflow via recovery or death Recovery Deaths Think measles, flu or SARS

Three of the Resulting Actions Head of the division amended the 38% goal for prevalence to say that they are not aiming for a decline Clients now broadcasting an improved mental model for chronic disease Epidemiology and Policy leaders co- writing their first paper on using SD to improve internal consistency of goals

Bridging the SD/Audience Divide Sometimes a stock/flow-dominated model is what client needs Help client to identify and communicate the shortcomings of old mental models and benefits of the new

Supplementary Materials

Possible Areas for Intervention BMI/Obesity Clinical Management of Diagnosed PreD & Diabetes

Now CDC is Exploring More “Upstream” Interventions Deaths from complications Diabetes onset Complications onset Caloric Intake Mean body weight/BMI Basal metabolic rate Caloric balance Physical Activity Obese Fraction of Population

Past Focus of Interventions into the Diabetes System Has Been “Downstream” Deaths from complications Diabetes onset Complications onset

Bridging the Divide 1.Learn client’s analytic needs and turn-ons 2.“Go Native” in language and form 3.Help client to identify and communicate shortcomings of old mental models

Missing Goals Was Attributed as Failure “The current epidemiology of type 2 diabetes could be used to argue that the [National Diabetes Prevention and Control Program] has been a monumental failure… [One] hypothesis, that this is a little known government bureaucracy spending large sums of money without achieving the desired goals, cannot be refuted based on the information at hand.” Anonymous reviewer of paper by client

What We Did Used model to check realism of objectives We “Went Native” in language and form –Fit to their variable names –Results in table format, not graphs

We’ll Focus On the Two Stocks that, Together, are “Diagnosed Prevalence” Deaths from complications Diabetes onset Complications onset Caloric Intake Mean body weight/BMI Basal metabolic rate Caloric balance Physical Activity Obese Fraction of Population

The Public Health Challenge of Chronic Disease Leading cause of illness, disability, and death in developed countries –70-80% of U.S. health care claims –Over 50% of U.S. adult population have at least one chronic disease; 25% have two or more A systems approach is needed –Dynamic complexity: Long delays of disease progression –Need SD for better goal-setting, priorities, coordination –Need to understand over-time impacts of “upstream” and “downstream” interventions

SAFER HEALTHIER PEOPLE ™ Chronic Disease Interventions, and the CDC’s Stated Mission “CDC: Enhancing Health Protection!” – Dr. Julie Gerberding, Director “UPSTREAM” “DOWNSTREAM”

Diabetes Stocks & Flows Deaths from complications Diabetes onset Complications onset Caloric Intake Mean body weight/BMI Basal metabolic rate Caloric balance Physical Activity Obese Fraction of Population

In 2000, They Set HP 2010 Goals Baseline ~2000 HP 2010 Target Percent Change Reduce Prevalence of Diagnosed Diabetes (5-3) 40 per 1, % Reduce Diabetes–related Deaths Among Diagnosed (5-6) 8.8 per 1, % Increase Diabetes Diagnosis (5-4) 68%80% +12 Percent points “It is expected that if you do a good job, things ought to go down.”

We Looked at the Stock/Flow Internal Consistency of the Objectives It is physically impossible for the diagnosed prevalence to fall at all, much less 38% If the diagnosis flow rises sufficient to boost the fraction diagnosed by 12 points And if the deaths flow drops 11% People with Normal Glycemic Levels People with Undiagnosed Diabetes onset People with Diagnosed Diabetes Diagnosis rate Deaths from complications

We Looked at the Stock/Flow Internal Consistency of the Objectives It is physically impossible for the diagnosed prevalence to fall at all, much less 38% If the diagnosis flow rises sufficient to boost the fraction diagnosed by 12 points And if the deaths flow drops 11%

Unexpected Behavior from the Model No continued progress Meet prevalence goal -38% +24% +13% Meet onset goal “It is expected that if you do a good job, things ought to go down.” – Diabetes Branch Leader

Exploring the Existing Mental Model: Infectious Disease “Even here in chronic disease, we are still living with the model that you find the patients, you give them a shot, and they recover.” People with Normal Health People with Undiagnosed Infectious Disease People with Diagnosed Infectious Disease Onset Diagnosis rate Deaths from complications Interventions in infectious diseases boost an important outflow: recovery Recovery

Diagnosed Prevalence Fraction Relative to 2000 Value Time (Year) No progress +24% Meet detection goal +42% +13% Meet onset goal (-29%) Unexpected Behavior from the Model Meet prevalence goal -38% “It is expected that if you do a good job, things ought to go down.” – Diabetes Branch Leader

Then 2000, they set goals for 2010, including Diagnosed Prevalence Yet another aimed for the deaths flow to drop 11% Another aimed for a 29% reduction in the onset rate One goal aimed to boost the fraction diagnosed by 12 points Can they meet the goal of a 38% drop in diagnosed prevalence?

Exploring the Existing Mental Model: Acute Infectious Disease People with Normal Health People with Undiagnosed Infectious Disease People with Diagnosed Infectious Disease Onset Diagnosis rate Deaths from complications 2. Those who don’t die, recover naturally and quickly Recovery Think measles, flu or SARS 1. People who die, die soon 3. Quarantines and vaccinations can cut onset significantly When you cut the inflow to a bathtub with two big drains, the water level falls quickly

In 2000, They Set HP 2010 Goals In 2000, they set a goal of 38% reduction in diagnosed prevalence by 2010 At same time, other goals for diagnosis and care –Fraction diagnosed up 12 percentage points –Reduce diabetes–related deaths among diagnosed by 11% “It is expected that if you do a good job, things ought to go down.” – Diabetes Branch Leader

History of Healthy People 2000 In 1990, stakeholders set “Healthy People 2000” objectives Goal for diagnosed prevalence was an 11% reduction between 1990 and 2000 During 90s, significant advances Combined effect by 2000 was 33% increase in diagnosed prevalence fraction “It felt like we flunked” –Program person -11% +33%

Drivers Calibrated Using National Survey Data BMI/Obesity 20% 81% 85% 84% 86% 60% 480 Kcal/day 2,465 Kcal/day 66% (Values shown are estimates for 2004.) 66% Clinical Management of Diagnosed PreD & Diabetes