Statement of Michael Hillman, M.D., MBA, Medical Director,
Business and Community Health Services, Marshfield Clinic, Marshfield, Wisconsin

Testimony Before the Subcommittee on Health
of the House Committee on Ways and Means

Hearing on Promoting Disease Management in Medicare

April 16, 2002

On behalf of the physicians and staff of Marshfield Clinic, I want to thank you for conducting this hearing and for the opportunity to comment on Disease State Management in the Medicare program.

This document will summarize the following: (1) why it is important to view ‘disease management’ as a carve-out of ‘population health management’; (2) Marshfield Clinic’s approach to disease management, particularly as it relates to the Medicare population;  (3) how the current reimbursement system influences (or may influence) population health strategies to reduce the cost of health care, while improving the health, of the Medicare population.

Marshfield Clinic is the largest private group medical practice in Wisconsin and one of the largest in the United States, with 678 physicians, 5158 additional staff, and 1.6 million annual patient encounters.  The Marshfield Clinic system includes a major diagnostic treatment center, a research facility, a reference laboratory and 39 regional centers located in northern, central and western Wisconsin. The largest concentration of physicians is in the city of Marshfield (population ~19,000).  The facility houses almost half of the physicians at the Clinic.  The facility is attached to a 534-bed hospital, St. Josephs, which is owned by a separate company, Ministry Health Care. Marshfield Clinic serves a disproportionately large socio-economically challenged population.  As a 501(c)(3) non-profit organization, Marshfield Clinic is a public trust, and thus obligated to serve all who seek care, regardless of their ability to pay. The Clinic serves several federally designated Health Provider Shortage Areas (HPSAs).  These communities are typically geographically remote, older, and educationally-challenged. Logging, mining, and agriculture are the economic mainstays. The Clinic also provides services in partnership with a federally funded Community Health Center at 13 locations in Wisconsin providing comprehensive integrated care to un- and under-insured residents of the community with incomes at or below 200% of the federal poverty level.   Security Health Plan of Wisconsin, a tax-exempt health maintenance organization, is a wholly owned subsidiary of Marshfield Clinic and provides financing for health care services for almost 120,000 members throughout northern, central and western Wisconsin.

Marshfield Clinic has developed and acquired sophisticated tools, technology, and other resources that complement and support the population health management strategy of the Clinic.  These include an electronic medical record, a data warehouse, an immunization registry, and an epidemiological database that enable enhanced definitions of disease states, diagnoses or conditions, and activity-based cost analysis of CPT level interventions.  These tools have enormous scientific, clinical and social policy potential that has only been partially tapped. 

During the last three decades, Marshfield Clinic funded and installed, and fully implemented a sophisticated electronic medical record (EMR) which now contains years of historical data, including diagnoses, procedures, test results, medications, immunizations, alert events, outcome measurements, and demographics.  Marshfield Clinic’s 39 regional centers are linked by common information systems. The EMR provides instant portability across our system facilitating communication between providers in different departments and at different centers.  For instance, easy access to previous diagnostic test results avoids duplicate ordering of lab and radiology tests.   We presently put 2.5% of revenue into the operation and maintenance of the Clinic’s information system, a cost for FY 2001 that amounted to $22,073 per physician.

Marshfield Enhanced Charting & Code Acquisition (MECCA) is an integral part of the EMR.  It allows us to collect high quality data for health care, research and education. It is a point-of-care application, acting as an electronic medical assistant that requires providers to document and/or review data from lists of items, such as visit types, providers, vital signs, diagnoses, procedures, medications, and alerts.  MECCA plays an important role in patient safety because it tracks drug allergies and other diagnoses including past medical history, family history, food alerts, latex allergies, and allergic reactions. Because MECCA is required for all scheduled patient encounters in Marshfield Clinic (including ambulatory surgery, unscheduled encounters, and hospital procedures), it helps us track the resources needed for medical care and is the foundation of an order-entry system for providers. MECCA will also be used to capture data from Hospital Discharge Summaries.   Patient identifying information is only available to providers who have previously taken care of the patient.

Marshfield Clinic has developed innovative preventative health care measures such as an immunization registry (Regional Early Childhood Immunization Network or “RECIN”).  RECIN is a computer program that allows the sharing of immunization information between and among providers and public health departments.  RECIN allows providers to have electronic access to a child’s immunization history, including any alerts or reactions to immunizations.  Such access minimizes the possibility of over-immunization and potentially severe allergic reactions.  Equally important, access to this information allows public health personnel to target children who have not been immunized.  As a consequence of this program, Marshfield Clinic and concerned public agencies have been able to increase childhood immunization rates from 67% to 92% in Wood County alone. The RECIN platform can be applied to many other population health care problems affecting Medicare.  Examples include  anticoagulation, lipid, and diabetes management, as well as  preventive services including flu and pneumovax vaccinations for vulnerable populations.

Marshfield Clinic has also developed a very unique resource known as MESA (Marshfield Epidemiologic Study Area) for clinical research in population health management.

MESAImage showing MESA Zip Code Boundaries

In the 24 zip code areas shown in map of Wisconsin, virtually all of the 88,000 residents get almost all of their medical care from a Marshfield Clinic facility.  This population is very stable.  The Clinic has medical records of this population dating back to the early 1900s.

MESA captures nearly all the health care information of those residing in the 24 zip codes above.  Consequently, population-based health research can be done that includes all of the populations that comprise these geographic communities.  Unlike most other research facilities, MESA researchers can monitor the residency of individuals on a daily basis by using updates of births, deaths, new patients, and name and address changes to Clinic databases. This allows researchers to monitor the health of a community over time by linking this residency information with the extensive health care information available in Clinic databases and medical records[i].

The research opportunities afforded by MESA contrast starkly to the studies performed by payers(HMOs and other insurers).  Payer research is largely based on claims data and is restricted to narrow populations circumscribed by a common disease from multiple communities, receiving their healthcare from multiple provider organizations.  Likewise, MESA affords a very important perspective not provided by the research of traditional academic medical centers.  Typical academic medical research is accomplished through randomized clinical trials.  In these studies populations are studied across multiple sites in very disparate geographic communities.  Typically, the populations are medically homogenous except for the single hypothetical factor that is being tested.  This type of research has limited value because it is so severely restricted.  It is widely accepted that multiple, often un-anticipated variables, are important determinants to individual's and populations' health.  Yet, there are very few tools to study multiple variables simultaneously.  MESA is a platform that enables analysis of multiple variables simultaneously.

‘DISEASE MANAGEMENT’ AS A PART OF ‘POPULATION HEALTH MANAGEMENT’

Medicare is defined by a predominantly aged population, many members of which have chronic diseases or conditions.  Hence, the need for ‘disease management’. Patients with chronic conditions typically enter a health care delivery system seeking acute care services traditionally covered under insurance, but they also may need services related to counseling and behavior change, support groups, communication between visits, continuous coordination with other health professionals, and medical supplies.  Unfortunately, traditional fee-for-service payment approaches offer a chronically ill patient face-to-face office visits as the primary mechanism for receiving care and rarely encompass the range of services needed across the continuum of care. There is a misalignment among what the patient needs, how the services are provided, and how needed services are reimbursed.

The explosive growth in the size of the Medicare population is one of three drivers that will completely transform health care in the next 10-15 years.  The other two drivers are human genomics and a revolution in healthcare consumerism.  It is essential to consider these drivers, as well as the health factors that drive chronic disease, so that we minimize the possibility that changes in the Medicare health system cause unintended, more expensive, consequences.

People use physicians primarily when they are, or perceive they are, ill. Their use of physicians is defined primarily by encounters.  Most traditional fee-for-service reimbursement occurs on a ‘per encounter’ basis.  Therefore, physicians compete with each other for per-encounter business.  They compete more vigorously for those encounters that reimburse at higher rates.  The corollary is also true.  It is not in the best business interest of physicians to compete for those patient encounters that are reimbursed at lower rates (i.e. Medicare).  This situation poses a significant access problem for the Medicare population.  Especially, when because of their age and chronic diseases, they require so much non-reimbursed care (care that does not have to be physician-encounter-driven). Therefore, it becomes in our enlightened self-interest to manage patients in the most cost-effective manner possible.  Hence, our strategy to use population health management principles.

Population health management  The sine qua non of population healthcare management is the improvement of the health status of a selected population by focusing on the needs of that population.  There are multiple determinants of the healthcare needs of any population.

Multiple determinants of health model.[ii]

Image showing multiple determinants of a health model

In the context of the multiple determinants of health model, population health management can be defined as “the technical field of endeavor which utilizes a variety of individual, organizational and cultural interventions to help improve the morbidity patterns (i.e., the illness and injury burden) and the health care use behavior of defined populations.”[iii] 

The generally accepted objectives for population health management include: (1) reduction in volume of services utilized, (2) shift of utilization to lower cost settings, (3) achievement of clinical improvement by focusing on the health status of the population, (4) integration of health care services, (5) organization of providers into networks, and (6) evaluation and documentation of quality.[iv]  Within each of these objectives, there is great number of considerations from both philosophical and operational perspectives, especially as they relate to the performance of the access system for a horizontally integrated health system like Marshfield Clinic. 

To simultaneously accomplish the first 3 goals of population health, mechanisms must be in place to assist patients in becoming active, empowered participants in their own health care decisions, while reducing the need and use of unnecessary or ineffective medical services - enhancing the overall health status of a defined population.[v]

The increase in patient responsibility inevitably results in a fundamental change in the patient-physician relationship. Patients, and the information with which they make decisions, are no longer solely dependent on their physicians.  Patients, in the above model, are partners.  They are customers.  They are consumers.   The consumerism that has already reshaped other large parts of the American economy (retail, information, automotive, and manufacturing) is carrying over to healthcare.[vi]  Much of this consumerism is driven by the increased information available on the Internet.

Physicians at Marshfield Clinic are not unique in their resistance to the demands of a changing healthcare delivery system.  The value of specialty practice culturally persists at the Clinic today.  The desire to develop this core competency of specialty care drove the formation of the Clinic.  Implicit in subspecialty training is the emphasis on "sickness-care".  Specialists are not needed to prevent illness.  They are needed to perform extraordinarily technical deeds to stave off mortality and reduce morbidity.  However, even the most ardent advocates of specialty practice will now admit that it is not efficient use, for example, of a heart surgeon's time to manage a post-operative valve replacement patient's anticoagulation medicine.  It is also not good patient care, because it not something that heart surgeons are expert at doing. 

Likewise, it is not the best use of a cardiologist's time to manage Type II diabetes in patients that have a stable myocardial status.  Again, it is also not good patient care.  It is not something that cardiologists are expert at doing.  Then, whose job is it to manage these patients with these problems?  At Marshfield Clinic, like many physician-oriented multi-specialty clinics, it falls to the primary care physicians- internists and family practitioners, and their physician extenders (Nurse Practitioners and Physician Assistants).   For the last 6 years, the Marshfield Clinic has purposefully re-directed patients under the care of procedural specialists to the primary care departments.

We believe that the business case to be made for this approach is sound, even considering the internal conflict attendant Medicare fee-for-service reimbursement.  Primary care is the entry point from which subspecialty care demand is generated.  Dysfunctional access to primary care limits the growth of subspecialty care.   Dysfunctional access to primary care makes it virtually impossible to develop a consistent, system-wide collaborative effort to maximize customer satisfaction and consumer health outcomes at the lowest cost per life. 

To further improve access to primary care, we are redefining the scope of practice for the different members of the health care team.  For example: primary care physicians see new patients, provide hospital care, do complex follow-up exams, and perform procedures.  Nurse Practitioners and Physician Assistants do most follow-up care and screening (as opposed to diagnostic) exams.  Registered Nurses triage acute patient symptoms, provide case management, educate, and coach behavioral change- all integral elements of disease management.

Disease Management.  Disease Management is a further refinement and application of population health principles that we now utilize in the Marshfield Clinic.  There are four basic steps.[vii]  One, define the population.  Two, determine what care processes will most effectively and efficiently meet the needs of that population.  Three, measure the effectiveness of those care processes.  Four, improve the care processes further.  The vision for  Marshfield Clinic using population health as a core strategy is to develop consistent, continually improving, system-wide collaboration to maximize customer satisfaction and consumer health outcomes at the lowest cost per life, and as a result, deliver care that is of superior value and liking to the members of its communities.

DISEASE/POPULATION HEALTH MANAGEMENT AT MARSHFIELD CLINIC

In 1995, Marshfield Clinic performed an “outside-in” assessment of its primary care system.  From the patient-as-a-customer perspective, we found that our system could improve greatly by addressing the following needs:  providing symptom-based advice with respect to whether patients needed to see a provider; if they don’t, how they can self-manage their symptoms; if they do, when do they need to be seen, and with what type of provider.

The needs of the providers-as-a-customer were different.  Our providers wanted to provide continuity of care 24-7-365 (although they were not willing/able to work 24-7-365) and increase their access (by reducing unnecessary patient encounters). 

Marshfield Clinic found that the respective needs of the patients and the providers could be met, and exceeded, by a 24-7-365 Registered Nurse (RN) call center that systematically answered patients symptom-based concerns, and, using Marshfield Clinic’s electronic medical record in combination with the physicians on-call, provide true continuity of care.  Strictly speaking, we developed a population health management/disease management intervention on healthcare resource utilization.

This RN call center department was named ProActive Health. This department provided these interventions on behalf of both Marshfield Clinic and Security Health Plan (the Clinic’s wholly owned insurance product).  The interventions that this department developed in collaboration with its customers include the following:  symptom-based triage, prenatal health, asthma, secondary cardiac prevention, diabetes, and anticoagulation management. The basic principles underlying all of these interventions are as follows:

Marshfield Clinic has a number of disease management programs in various states of maturity.  These programs include: Diabetes, Prenatal Health, Congestive Heart Failure, Asthma, Lifestyle Management, Secondary Cardiac Prevention, and Anticoagulation Management.  In addition, a number of programs are on the “drawing board”.  Those programs include Hypertension, Hyperlipidemia, Obesity, Post-natal care, and Low Back Pain.  Many members of the Medicare population suffer from several of these conditions concurrently.  To give you a more complete picture of how a mature disease management program should work, we will describe our Anticoagulation Service Disease Management program in more depth.

The Anticoagulation Service is particularly germane for the following reasons.  One, it demonstrates how all the essential components of a disease management program work together.  Two, it is the program of ours that is most fully developed with respect to clinical and economic outcomes measurement.  Three, it demonstrates the power of connecting a disease management program directly to physician practices.

Anticoagulation is the process of making the blood less likely to clot (form a scab) inside the body.  When a clot forms inside the body (within the blood vessels), it causes either a stroke or heart attack.  There are a number of very common conditions in the Medicare problem that predispose the formation of these internal clots.  These conditions include atrial fibrillation (2-3% of the population over 65 years of age), congestive heart failure, deep vein thrombosis (especially after orthopedic procedures and during cancer chemotherapy), and mechanical heart valve replacement.  Almost all of these conditions are caused by age and chronic disease.

The most common outpatient drug used for anticoagulation is warfarin.  While the risk/benefit ratio of using warfarin in this patient population is indisputable, the window of therapeutic benefit is narrow.  That is, under-anticoagulation with this drug doesn’t prevent stroke and heart attack.  Over-anticoagulation can cause dangerous internal bleeding.  Furthermore, the metabolism of this drug (the way that it is broken down by the body) is very sensitive to changes in diet, exercise, and many other common medications taken by this population (e.g. antibiotics).  Therefore, the administration of this drug has to be done very carefully.  A monthly blood test is required to adequately monitor the effects of this medication.

When this drug is administered in the standard way, the incidence of hospitalizations or death is 7-10% per year (the risk of stroke or heart attack without this drug is substantially higher).  However, with our disease management approach to patients taking this medication, that risk is reduced to less than 2% per year. 

All five of the ‘ProActive Health’ dot points described above were used in this program.  The patients are introduced to the program by their physicians (to reassure the patient that it is an extension of their physician’s practice) or are referred immediately upon discharge from the hospital.  The patients are entered into a special tracking database that prevents them from falling through the ‘cracks’ due to the complicated monitoring schedule and telephonic follow-up routine.  Our nurses case manage the patients through guidelines developed by Marshfield Clinic.  They adjust the patients’ warfarin doses according to protocol.  They educate and coach the patients about recognizing on their own the many pitfalls that influence anticoagulation (diet, activity, other medications, other illness).  The RN case managers have access to the Medical Director of the program and the patient’s personal physician for the 5-10% of time when the protocols don’t cover a patient’s situation.  All of the interactions are documented in both database and the Clinic’s electronic medical record.  The RN’s EMR note is  signed by the patient’s personal physician (so they always know what is going on with their patient).  In addition to the RN case manager, the patients have access to the 24-7-365 RN ProActive Health Nurseline for acute symptom-based advice.  This entire program is done telephonically without any reimbursement from CMS.

We recently conducted a study that was funded by the Agency for Healthcare Research and Quality under its new Integrated Delivery System Research Network initiative.  It assessed the impact of Marshfield Clinic's Anticoagulation Service on health care utilization measures, including urgent care, emergency department and inpatient events.  In the study, we compared these measures in two study groups of individuals receiving warfarin therapy.  One group consisted of individuals that were enrolled and managed in the Anticoagulation Service; the other group consisted of individuals who received standard care for their warfarin management needs.  All study subjects were under the care of Marshfield Clinic cardiologists for at least some of their health conditions.  The study included a total of 408 study subjects and 359 years of study observation time.

In the course of providing this intervention, we noted that two-thirds of the phone calls were not directly related to warfarin dosing.  Rather, they resulted from the patients calling in about other health concerns that they correctly thought would influence their state of anticoagulation.  Therefore, in the study funded by AHRQ, we looked at all hospital events, not just the events directly related to warfarin.  Hospital events occurred at a much lower rate in the Anticoagulation Service group compared to the standard care group.  Based on our analyses, the expected difference in hospitalizations per 100 person years was approximately 28.7 hospitalizations.  This difference was not only large but also statistically significant (P<.014).

For the 86% of the study population that are Medicare beneficiaries, total Medicare costs avoided per hospital event were estimated at $9,443 in constant year (2000) dollars.  Hospital facility costs represented about 76% of these costs.  Non-hospital costs, primarily physician and laboratory costs for both inpatient and outpatient care, represented the remaining 24% of costs.  Estimated avoided CMS costs were $8,221 per hospitalization.  The difference between total Medicare costs per hospitalization and CMS avoided costs, which was $1,222 per hospitalization, is represented by expected Medicare beneficiary co-payments and deductible: $446 per hospitalization and annual Part B deductible of $776.

Total avoided Medicare hospitalization-related costs per 100 person years of Anticoagulation Service enrollment compared to standard care was estimated at approximately $271,014 based on a differential hospitalization rate of 28.7 events and an average total Medicare-related cost of $9,443 per hospitalization.  CMS total avoided costs per 100 person years were estimated at $235,943.  Reduced Medicare beneficiary co-payments and deductibles were estimated at $35,071.  In developing estimates of avoided costs, a conservative approach was utilized; it is believed a greater savings are likely available than those estimated.

Using the Marshfield Enhanced Charting & Code Acquisition (MECCA), we know that our system has 12,477 unique patients on warfarin anticoagulation.  95% of those patients are Medicare-eligible.  If we generalized the Anticoagulation Service to the entire population receiving warfarin under the care of Marshfield Clinic, CMS would avoid over $28,000,000.  It will cost Marshfield Clinic about $3,000,000 to do so, none of which is currently reimbursed. 

We are certain that near-equally compelling savings can be achieved with our congestive heart failure, diabetes, and other population health initiatives.  The anti-coagulation example provides clear evidence that better health can be achieved at significantly less cost.  These results can be greatly expedited if Medicare reimbursement policy influences the healthcare market to rely less on patient-physician encounters, and more on integrated systems of care that extend the benefits of patient-physician relationships.

THE RELATIONSHIP OF MEDICARE REIMBURSEMENT TO THE HEALTHCARE MARKETPLACE AND POPULATION HEALTH MANAGEMENT

The health care system that we presently live with is not well designed to meet the needs of the chronically ill.  The current delivery system responds primarily to acute and urgent health problems emphasizing diagnosis, ruling out serious conditions, and relieving symptoms. Patients with chronic conditions are better served by a systematic approach that emphasizes self-management, care planning with a multidisciplinary team, and ongoing assessment and follow-up.  This systematic approach requires a large front-end investment in information systems and process change.  Marshfield Clinic is making that investment.  Yet the health care marketplace, largely shaped by CMS reimbursement policy, works against developing this type of approach. 

Even without any financial incentive or reimbursement for this front-end investment required for population health, clinics like Marshfield in the Wisconsin Medicare payment locality, are already under-reimbursed by CMS.  Marshfield Clinic recently conducted an internal analysis to determine to what extent the Medicare program covers the cost of providing services to Medicare beneficiaries.  Our analysis demonstrates that the Clinic presently recovers only about 70% of its costs in providing Medicare Part B services.  We do not believe that we are unique, but suspect that the shortfalls in Medicare revenue are common for physicians providing Medicare Part B services.  We urge you to take steps to remedy this inequity as soon as possible.

To calculate the percent of its Medicare allowed costs for which Medicare reimbursement is received, Marshfield accountants eliminated all expenses and revenues received that might potentially be questioned by the Medicare program.  Our methodology for FY 2000 follows principles applied in our annual FQHC cost report that was audited by external auditors and submitted to the state.  (Marshfield Clinic in conjunction with Family Health Center Inc. functions as a federally qualified health center (FQHC) under the Medicaid Program.)  For the purposes of this analysis, all expenses and revenues from activities such as the outreach lab, veterinary lab, research and education, rental property and optical and cosmetic surgery departments were removed.  Our accountants also removed all non-Medicare “Allowed” costs related to our bad debt, interest expenses, marketing programs, government affairs activities, National Advisory Council, goodwill amortization and other miscellaneous costs.

For FY 2000, Marshfield Clinic’s Medicare revenue was 71.52% of costs for fee-for-service Medicare.  For FY 2001 Medicare revenue (un-audited) as a percent of costs goes down to 70.59%.  For FY 2002 we project that Medicare revenue will decrease as a percent of costs to approximately 68.5%.

Reimbursement shortfalls of this magnitude interfere with the Clinic’s capacity to further implement disease management programs in the many departments where we believe efficiencies can be captured.   The declines in Medicare reimbursement that Marshfield Clinic experienced in FY 2000 and 2001, and has projected for FY 2002 are due in part due to payment updates lowered by CMS in anticipation of volume offsets.  CMS has assumed that increasing volume in response to tightening reimbursement takes place uniformly across the country.  We believe that this simplistic point of view and the pursuant regulatory response by CMS are a constant source of frustration and a major obstacle to the coordination of care for beneficiaries by organizations whose mission is to provide better patient care. 

Marshfield Clinic has demonstrated that by reducing both the volume and intensity of services provided to Medicare beneficiaries, savings are accruing to Medicare Part A, Medicare Part B, and the beneficiaries we serve.  Unfortunately, from the point of view of promoting the financial viability, disease management activities that serve the welfare of beneficiaries and the interest of the Medicare program can be potentially self-defeating if not reimbursed.  It will be difficult to promote the long-term view that disease management strategies are a rational response to the current economic incentives of the Medicare fee-for-service program. 

Organizations that stake their future to the currency of patient-physician encounters as the basic unit of medical care value are at risk in the present fee-for-service reimbursement environment.  At the same time, we believe that patients who stake their future to the healthcare system that devalues the benefit of patient-physician relationships are equally at risk.

CONCLUSIONS

In summary, we believe that there are significant quality-of-care concerns as well as the business case to be made that population/disease management holds significant promise for the Medicare program.    However, Congress must take several steps to address the misalignment of incentives in the Medicare reimbursement market. 

The Institute of Medicine suggests that fee-for-service payment can be adapted to provide incentives for quality improvement by encouraging cooperation and providing reimbursement for care outside of the traditional office visit, which is not always optimal for meeting patients’ needs. This approach involves developing relative values for the elements of work performed over time by physicians and other health professionals.[viii]

That may be a reasonable suggestion, but probably not realistic. It still relies on encounters (although not face-to-face), rather than care as the unit of value from which reimbursement occurs.   And that is the reason that capitation, as it has been thus far administered, also doesn’t work.  It also relies on encounters.  Although in a capitated system, encounters have negative value instead of a positive value.

We need to develop a reimbursement system that is somewhere in between: a system that reimburses for continually improving value (quality +quantity ¸ unit cost) in care.  Marshfield Clinic looks forward to the opportunity to work with you on this.         

Thank you for considering our views.


[i] DeStefano F, Eaker ED, Broste SK, Nordstrom DL, Peissig PL, Vierkant RA, Konitzer KA, Gruber RL, Layde PM. (1996). Epidemiologic Research in an Integrated Regional Medical Care System: The Marshfield Epidemiologic Study Area. J Clin Epidemiol; 49: 643-652.

[ii] Evans, R., M. Barer, and T. Marmor. (1994) Why are Some People Healthy and Others Not?  The Determinants of Health of Populations.Aldine de Gruyter. New York.

[iii] Chapman, LS. (1997). HEALTH MANAGEMENT: Optimal Approaches for Managing the Health of Defined Populations. Summex Corporation. Seattle, WA.

[iv] Fos, PJ, DJ Fine, and PJ Foss. (2000).  Designing Health Care for Population:  Applied Epidemiology in Health Care Administration.  Jossey-Bass.  San Francisco

[v] Montrose, G. (1995).  The Art & Science of Demand Management. Group Health Association of America

[vi] Herzlinger, R. (1997). Market-Driven Health Care. Perseus  Books, New York.

[vii] Runde, D. (1999). Weaving Disease Management Into the Fabric of Patient Care.  Health Care Horizons Institute for the Future.  Menlo Park, CA

[viii] Institute of Medicine(U.S.). Committee on Quality of Health Care in America. (2001). Crossing the Quality Chasm: A new Health System for the 21st Century.  Washington, D.C.  National Academy Press.