Systems Dynamics modeling for public health: background and oportunities

8/18/2019 Systems Dynamics modeling for public health: background and oportunities

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System Dynamics Modeling forPublic Health: Background and

opportunities

Rafael Arturo Vega Vega

Mauricio Aleandro BuitragoSoto

Systemic !hinking

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ABS!RA&!

!he systems modeling methodology of systemdynamics is 'ell suited to address the dynamiccomple(ity that characteri)es many publichealth issues* !he system dynamics approachin+ol+es the de+elopment of computersimulation models that portray processes of

accumulation and feedback and that may betested systematically to ,nd e-ecti+e policiesfor o+ercoming policy resistance*

System dynamics modeling of chronic disease

pre+ention should seek to incorporate all thebasic elements of a modern ecologicalapproach. including disease outcomes. healthand risk beha+iors. en+ironmental factors. andhealth/related resources and deli+ery systems*System dynamics sho's promise as a means of

modeling multiple interacting diseases andrisks. the interaction of deli+ery systems and


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01!R2D3&!021

Despite remarkable successes in some areas. the health enterprise inAmerica still faces di5cult challenges in meeting its primaryobecti+e of reducing the burden of disease and inury* 6(amplesinclude the gro'th of the underinsured population. epidemics ofobesity and asthma. the rise of drug/resistant infectious diseases.

ine-ecti+e management of chronic illness. long/standing racial andethnic health disparities. and an o+erall decline in the health/related7uality of life* Many of these comple( problems ha+e persisted fordecades. often pro+ing resistant to attempts to sol+e them*

!he term dynamic comple(ity has been used to describe such

e+ol+ing situations* Dynamically comple( problems are oftencharacteri)ed by long delays bet'een causes and e-ects. and bymultiple goals and interests that may in some 'ays con8ict 'ith oneanother* 0n such situations. it is di5cult to kno' ho'. 'here. and'hen to inter+ene. because most inter+entions 'ill ha+e unintendedconse7uences and 'ill tend to be resisted or undermined by

opposing interests or as a result of limited resources or capacities*


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THE SYSTEM DYNAMICS

APPROACH9e belie+e that in many cases thechallenges of dynamic comple(ity inpublic health may be e-ecti+elyaddressed 'ith the systems modelingmethodology of system dynamics* !hemethodology in+ol+es de+elopment ofcausal diagrams and policy/orientedcomputer simulation models that areuni7ue to each problem setting* !heapproach 'as de+eloped by computer

pioneer ay 9* ;orrester in the mid/$


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A system dynamics modelconsists of an interlocking set ofdi-erential and algebraice7uations de+eloped from abroad spectrum of rele+ant

measured and e(periential data*A completed model may containscores or hundreds of suche7uations along 'ith theappropriate numerical inputs*Modeling is an iterati+e process

of scope selection. hypothesisgeneration. causal diagramming.7uanti,cation. reliability testing.and policy analysis*


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System dynamics modeling has been applied to isseso! poplation health since the "#$%s& Topic a'eas ha(e

inclded the !ollo)ing*$* Disease epidemiology including 'ork in

heart disease. diabetes. H0V@A0DS. cer+icalcancer. chlamydia infection. denguefe+er. and drug/resistant pneumococcal

infections"* Substance abuse epidemiology co+ering

heroin addiction. cocaine pre+alence. andtobacco reduction policy

?* Patient 8o's in emergency and e(tendedcare

* Health care capacity and deli+ery in suchareas as population/based healthmaintenance organi)ation planning.dental care. and mental health. and asa-ected by natural disasters or terroristacts

=* 0nteractions bet'een health care or public


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CHRONIC DISEASE

PRE+ENTION !he +alue of system dynamicsmodeling is best e(plained by'ay of illustration* 9e start 'ith

a challenging 7uestion:,hy is it that- despite'epeated calls !o' a g'eate'emphasis on p'ima'yp'e(ention o! ch'onic

disease .inclding ap'ominent 'ecent e/ample0-the (ast ma1o'ity o! healthacti(ities and e/pendit'esin the 2nited States a'emade not !o' sch

p'e(ention bt 'athe' !o'


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MODE4S !o illustrate ho' system dynamics simulation might shedlight on this 7uestion. 'e ha+e built a relati+ely simple modele(ploring ho' a hypothetical chronic disease population may

be a-ected by " types of pre+ention: upstream pre+ention ofdisease onset. and do'nstream pre+ention of diseasecomplications* !he model demonstrates ho' upstreampre+ention may become inad+ertently Cs7uee)ed out bydo'nstream pre+ention and suggests that a focusing of

resources on life/e(tending clinical tools may ultimately hurtmore than it helps*


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;ig $* A simple model of chronic disease pre+ention*


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TO,ARD MORE COMP4ETE MODE4S O5

POP24ATION HEA4TH

System dynamics modeling canand should go further still toincorporate all the basic

elements of a modern ecologicalapproach that can help publichealth agencies achie+e theirgoals of disease pre+ention.health promotion. and assuranceof healthy conditions* Such a

broad approach 'ouldencompass disease. health andrisk beha+iors. en+ironmentalfactors. and resources thatpro+ide health and socialser+ices or are in+ol+ed in

health/related social


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5ig 6& A b'oad (ie) o! poplation health and thespect'm o! possible 'esponses


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5ig 7& O(e'(ie) o! the health ca'e mic'o)o'ld&


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OPPORT2NITIES AND NE,

DIRECTIONSModels combining deli+erysystems and risk and diseaseepidemiology could helppolicymakers and health carepro+iders understand the natureof coordination re7uired to putambitious public health and riskreduction programs in place'ithout o+er'helming deli+ery

capacities* Such models couldreach beyond the health caredeli+ery system per se toe(amine the potential roles ofother deli+ery systems. such as

schools and social ser+iceagencyes. in health risk


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IN CONC42SION8

System dynamics modelingcan help to identify thefeedback loops responsible

for these problems and pointthe 'ay to policies that canmake a lasting di-erence:

aE 3nderinsured population.bE High health care costs.

and

cE !he shortage of nurses*


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By applying a remedy to one sore, you will provoke another;and that which removes the one ill symptom produces others,whereas the strengthening one part of the body weakens therest.

Sir Thomas ore, "topia, #art I $%&%'(


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Systems Dynamics modeling for public health: background and oportunities