Sunday, February 23, 2014

Global Burden of Disease Study (GBD)

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JAMA published a seminal investigation documenting the Health of America compared to other developed countries broken down by disease, risk factors, morbidity and mortality. The massive undertaking involved hundreds of collaborators in thirty-four countries and some highly sophisticated statistics comparing the burden of disease, disability and risk factors. The report here includes the developed countries participating in the Organization for Economic Co-operation and Development.  The State of US Health, 1990-2010, Burden of Disease, Injuries and Risk Factors appears in the August 14 issue of JAMA.[1] If you have any interest in the shortcomings of our health care system or the health of US’s vital human resource, this landmark document is worth the study.

Harvey Fienberg’s editorial on page 585 observes the decline in the US standing among developed nations.  Herein, “results for the United States are presented in detail for the first time.”  The statistics utilized in the study were extremely complex and all inclusive. However, Fienberg points that socioeconomic status relates strongly with mortality[2] and that socioeconomics was not included as a risk factor in this study. The collaborators agreed. The difficulty was in equating socioeconomics across the many cultures in the thirty-four nations that took part in this study.  Fienberg further observes that the assessment for the US as a whole does not account for significant regional differences. However, he does suggest that the framework for assessing the burden of disease is scalable and applicable to states, counties and municipalities.[3]
The statistical terms used in this study include:  Years of Life Lost (YLL) due to premature mortality, Years Lived with Disability (YLD), Disability Adjusted Life Years (DALY), which combines YLL and YLD and, Healthy Life Expectancy (HALE). The article compares these attributes in the thirty-four countries between 1990 and 2010. This monumental study goes beyond all previous reports by including risk factors for disease.

The diseases causing premature mortality, YLL, differed dramatically from those causing morbidity and disability, YLD. In 2010 in the US the big eight YLL were in order: Ischemic heart disease, lung cancer, stroke, COPD, road injury, self-harm, diabetes and cirrhosis. In sharp contrast, the first eight YLD were:  Low back pain, major depression, other musculo-skeletal, neck pain, anxiety disorder, COPD, disorders resulting from drug use, and diabetes.

The risk factors underlying the leading causes for both YLL and YLD diseases were almost the same. The list of risk factors included: Dietary, tobacco, HBP, high BMI, physical inactivity, high serum glucose, ambient particulate pollution, alcohol, drug use and high cholesterol. Dietary risks accounted for over 650 thousand deaths while tobacco use and hypertension accounted for some 450 thousand deaths. Obesity followed closely behind as insurance actuaries have long established. Dietary risks are by far the greatest, but tobacco, obesity, high BP, high blood glucose, sedentary life style, alcohol, cholesterol, drug abuse and air pollution follow in descending parabolic order as causes of disability.

The figure 4 illustration on page 604 in the journal and below reflects the US’s low YLL ranking compared with the thirty three other countries. The cross-index lists countries on one axis and diseases on the other with the ranking for each in the cross-index. The US is 7th from the bottom following the Check Republic and Chile in overall ranking. Our ranking by the raw longevity score, infant mortality and perinatal mortality reported elsewhere[4] are even worse.[5] The US comes in 38th in both longevity and infant mortality. The perinatal mortality rates are even worse.[6]

 Figure 4.

Rank of Age-Standardized YLL Rates Relative to the 34 OECD Countries in 2010
Numbers in cells indicate the ranks of each country for each cause, with 1 representing the best-performing country. Countries are sorted on the basis of age-standardized all-cause years of life lost (YLLs) for 2010. Diseases and injuries contributing to YLLs are ordered by the difference between the US rate and the lowest rate in the Organization for Economic Co-operation and Development (OECD) countries for each cause. Colors indicate whether the age-standardized YLL rate for the country is significantly lower (green), indistinguishable (yellow), or higher (red) from the mean age-standardized YLL rate across the OECD countries. HIV indicates human immunodeficiency virus.[7]

Fienberg writes that setting us on a healthier course will require leadership at all levels of government engaging the profession and the public. Indeed it will, but there has to be more. Fienberg mentions social economic status as a risk factor.  One might add the environmental and behavioral factors and look more closely to the dietary risk that jumps out as, not only the leading risk factor, but by a large margin. Poverty and relative poverty may play as important role as nutrition. The prevalence of ischemic heart disease, diabetes, hypertension and stroke implicate diet and obesity as the underlying cause. These too may reflect poverty as the major risk factor. However, looking at chronic kidney disease(CKD) poisoning, cirrhosis, congenital anomalies, pre-term birth problems, the cancers and the neurological, one wonders if there might not be environmental factors present in the US that are not present in the other countries. Staring at fig 4, one notices a divergence between countries that is hard to attribute to genomics, behavior or health care as outlined.

Studying this somewhat overwhelming research should not be limited to government and public health leaders etc. but may be a lesson in diagnosis itself. A medical history without a social, behavioral, environmental and psychological risk assessment will miss many of the causes of and early diagnosis of disease. One must distinguish between a problem and a diagnosis. Look for a primary underlying cause. “Peal away the layers of the onion.” Fienberg urges inquiry at both the social and biological levels. I love his quote, “Trying to understand the causation of disease using only one of these lines of research is like trying to clap with one hand.” Furthermore, we need to study the burden of disease on a smaller scale. It would be fruitful to analyze the burden of disease on a state, county and municipal level. Risk factors may vary by municipality and indeed by individual. Just as Hippocrates tasted the urine, examined every bodily orifice; he considered the weather the environment and nutrition. We too must consider, social, economic, environmental, behavioral, psychological, dietary and genomic attributes -- critical knowledge for the physician diagnostician. 

One might take exception to vague final diagnoses such as cardiomyopathy, chronic kidney disease, lower respiratory infection, community acquired pneumonia etc. One should  look at the specific cause whether a specific organism or a specific exposure. If disease is by definition a maladaptation to the environment, then one must pay as much attention to the environment as to one’s patient. The same must apply to the social and behavioral factors. Asclepian physicians paid great head to the environment, the air, the winds, the weather, the dampness and the water. Great physicians of the past, like Sherlock Homes saw things in the surroundings that others did not. Look again at figure 4. Some of the US rankings are hard to explain by today’s medical knowledge. Why do we have such excellent medical education and such sad outcomes?  Hippocrates prescribed diets in detail. Perhaps our front line clinics should provide a nutritionist as part of the team.

Food additives in the US have become a poison.  Studies clearly show the deleterious effects of pesticides, sodium, sugars etc. Anything remotely addictive added to packaged food products enhances sales but at the expense of consumer health. The lassie-fair food regulatory policies in the US differ strikingly from those in European countries where fresh foods dominate in the markets over packaged foods. Like grandmother said, eat your vegetables! However, you had better wash them first.
Poverty is an unlisted risk factor and may account for some of the dietary problems. Depletion of living standards for the entire middle class may also lead to dietary and other self-abusive behaviors. The sequestration of wealth --as in the dark ages -- may add to the behavioral risks as well. Herman Boerhaave U. of Lyden and French  Academy of Science 1728 said, “The poor are my best patients because God pays for them.” That sentiment may be hard to find in today’s busy practices. The Affordable Care Act at least establishes a principal of health as a critical infrastructure for us all. The perpetuation of insurance, fee for service and administrative burden may fall short of expectations. The European models of health care are more egalitarian. The medical schools represent our only source for the more equitable distribution of health care. University medical schools have a long history of means testing and free care in support of the poor and the medical community, but they are limited in number and distances between. Today fee for service and insurance mandates silence much of the egality that was once universal in medical schools  It would be naive to think that economics and politics are not risk factors.

We have made great strides in reducing smoking, but one has only to look to see the obesity epidemic. Drug use remains an embarrassment, and environmental pollution is still with us -- perhaps more of a problem here than in Europe.  These factors too may account for some of the discrepancies in outcome between the US and Europe.

Accessibility to care, mal distribution of physicians, the licensing of or exemption of fringe-providers, and continuity of care also play a role in our unfavorable outcomes. We are improving but at a retarded pace and at incredible cost. Diagnosis suffers also from the recent trend – all but eliminating autopsies. In the past, autopsy -- the single one thing historically that propelled us forward in scientific and medical knowledge -- has gone out of style. The CT scan is no substitute. Marie Francois Bichat, 1793, brought pathology to the bedside correlating autopsy with clinical observation. The sign over the door to his autopsy room in Paris read, “Death comes to the aid of the living” and indeed it did for two hundred years. There is no substitute for the Clinical Pathologic Conference (CPC). Even the NEJM today presents cases today without autopsy.
If you don’t do a rectal, you don’t use a head mirror, you don’t feel a pulse and you don’t look at the feet, or take off the shirt to examine the chest, then your diagnosis and your outcome will be as limited as your investment in the patient. These are but some of the shortcuts that characterize today’s “industrialized medicine.” When we practice medicine as a business, it is more profitable to skim the diagnostic caldron for high priced procedures, high patient volume and cover the missed and wrong diagnosis with liability insurance and silence. By industrializing medicine we have opened the door for any and all business ventures to feed at the health care trough no matter how marginal or how harmful.  By denying local medical societies the control over professional privileges and professional behavior, we have left the legislature valorized by lobbyists in control of behavior and the hospital, insurance and drug company free reign.

All the great doctors in history had three things in common: they traveled widely to medical centers all over the world, they translated Hippocrates and they had the Gout. I could do without the gout but would add attendance and participation in CPCs. It is time that we visited the successful healthcare systems in Europe and the East to see what works. Instead of revising curriculum by invention, visit the medical schools in other countries, much older than our own and examine their methods. We were leaders in health care for only a brief span of history, mainly during WWI and WWII while 45 years of Cold War brought both the US and Russia the four horsemen of the Apocalypse.  Perhaps it is time for another Flexner Report -- now a hundred years later.



[1] JAMA,2013;310(6):591-608. Doi:10.1001/jama.2013.13805
[2] National Research Council; Institute of Medicine. US Health in International Perspective: Shorter Lives Poorer Health. National Academies Press; 2013
[3] Katz B. Bradley J. the Metropolitan Revolution. Brookings Institution; 2013
[4]  http://www.enagic.com/enagic_life.php
[5] http://data.worldbank.org/indicator/SP.DYN.IMRT.IN
[6] http://whqlibdoc.who.int/publications/2006/9241563206_eng.pdf
[7] Figure 4 reproduced with permission JAMA RightsLink and Copyright Clearance Center Aug 14 JAMA, Christopher Murray et al; Copyright © 2013, American Medical Association

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