Unwarranted variation (or geographic variation) in health care service delivery, first so termed by Dr. John Wennberg, refers to differences that cannot be explained by illness, medical need, or the dictates of evidence-based medicine. It can be caused by shortfalls in three areas:
- Effective care and patient safety, which includes services of proven clinical effectiveness, such as using lipid-lowering agents in patients with coronary artery disease.
- Preference-sensitive care, treatment for conditions that have significant trade-offs in terms of risks and benefits for the patient. But the choice of care is, or should be, driven by the patient’s own preferences.
- Supply-sensitive care, care which is strongly correlated with healthcare system resource capacity and is generally provided in the absence of medical evidence and clinical theory.
In 1967, while working in the Regional Medical Program[clarification needed] created with a $350,000 grant from President Lyndon B. Johnson, Dr. Wennberg was analyzing Medicare data to determine how well hospitals and doctors were serving their communities. He found 4 types of variation: 1) the underuse of effective care; 2) variations in outcomes attributable to the quality of care; 3) the misuse of preference-sensitive treatments; and 4) the overuse of supply-sensitive services.
According to Health Dialog, a privately held, for-profit disease-management company that was established to address unwarranted variation:
If you live in northern Idaho, and you develop back pain, chances are good that you’ll undergo surgery to treat your pain. Move to the southern tip of Texas, however, and the chances that you’ll undergo that same surgery will drop by a factor of 6. The surgery is no more effective in Idaho than it is in Texas. It’s just that doctors in the northwest are more likely than those in southern Texas to recommend surgery. This phenomenon, in which doctors practice medicine differently depending on where they’re from, is called practice pattern variation. And it isn’t limited to treating back pain, or even surgical decisions. There is also variation in treatment for chronic conditions, such as use of beta blockers for individuals with Congestive Heart Failure (CHF) or lipid testing for those with diabetes.
Dr. Wennberg and his colleagues at the Dartmouth Center for Evaluative Clinical Sciences have documented these wide variations in how healthcare is practiced around the country. They have also asserted that most of this variation is, in fact, unwarranted. Health Dialog was built to directly address unwarranted variation in healthcare: the overuse, underuse and misuse of medical care. Wennberg and his colleagues further concluded that if unwarranted variation in the healthcare system could be reduced, the quality of care would go up and healthcare costs would go down. Studies have shown that if unwarranted variation could be reduced in the Medicare population, quality of care would rise dramatically and costs could be lowered by as much as 30%.
Unwarranted variation in medical practice, as noted by Martin Sipkoff in 9 Ways To Reduce Unwarranted Variation, is costly — and deadly. Analysis of Medicare data reveals that per-capita spending per enrollee in Miami is almost 2.5× as great as in Minneapolis, even after adjusting data for age, sex, and race. Worse, 57,000 lives are lost annually because physicians aren't using evidence-based medicine to guide their care, according to a recent report from the National Committee for Quality Assurance.
"We're literally dying, waiting for the practice of medicine to catch up with medical knowledge," says Margaret O'Kane, president of NCQA. The report, "The State of Health Care Quality 2003," says these deaths "should not be confused with those attributable to medical errors or lack of access to health care. This report shows that a thousand Americans die each week because the care they get is not consistent with the care that medical science tells us they should get."
"Practice variation is one of the greatest problems we face in controlling costs, but we believe that it is something we can do something about." Dwayne Davis, MD, medical director of Geisinger Health Care
- Studies show that individuals with diabetes should have blood lipids monitored regularly, yet patients in Chicago are 50% less likely to receive these tests than patients in Fort Lauderdale.
- A patient with heart disease in Bloomington, Indiana, is three times more likely to have bypass surgery than a similar patient in Albuquerque.
- In Miami, where medical services are abundant, Medicare pays more than twice as much per person per year as it does in Minneapolis, with no discernible difference in overall health or life expectancy.
The English NHS
Inspired by the work of Jack Wennberg, the first NHS Atlas of Variation in Healthcare was published in November 2010 by the Department of Health QIPP Right Care programme. Thirty four topics, selected by clinicians as being important to their speciality, were mapped by Primary Care Trust area (the healthcare commissioning body at the time). The Atlas was published as a challenge to commissioners to consider the opportunities to maximise health outcome and minimise inequalities by addressing unwarranted variation.
"Awareness is the first important step in identifying and addressing unwarranted variation; if the existence of variation is unknown, the debate about whether it is unwarranted cannot take place":15
The 2010 Atlas revealed widespread variations in outcome, quality, cost and activity, including:
- A two-fold variation among strategic health authorities in the incidence of major amputations per 1000 patients with registered Type 2 diabetes and a five-fold variation in the percentage of people with diabetes receiving the NICE recommended nine key care processes
- A four-fold variation in directly standardised rate of elective admissions in persons diagnosed with epilepsy per 100,000 population
- A threefold variation in the percentage of patients admitted to hospital who spend 90% of their time on a Stroke Unit
- A four-fold variation in emergency asthma admissions for children and young adults
- A six-fold variation in provision of Hip replacement per 1,000 people in need
- A two-fold variation in cancer inpatient expenditure per 1,000 population
A further extended Atlas was published in November 2011, mapping variation across 71 indicators and a follow-on series of Atlases focussing on specific themes in more depth like Children and Young People, Diabetes, Kidney Disease and Respiratory Disease. A forthcoming atlas will be about Liver Disease, Diagnostics, Organ Donation and Transplantation. Publication of the Atlases has been well received within the NHS and by patient groups and clinical societies.
In 2012, the British Department of Health published a Mandate for the new NHS Commissioning Board. The Mandate to the NHS Commissioning Board set out the objectives for the NHS and highlights the areas of health and care where the Government expects to see improvements. On variation in healthcare, the Mandate charged the Board with the responsibility to "shine a light on variation" and "to make significant progress... in reducing unjustified variation", and further, "Success will be measured not only by the average level of improvement but also by progress in reducing health inequalities and unjustified variation.":7,13,27
- Medical Guesswork Businessweek.com Archived November 5, 2007 at the Wayback Machine
- Unwarranted Variation Health Dialog, healthdialog.com Archived December 11, 2007 at the Wayback Machine
- Michael T. McCue Clamping down on variation - Managed Healthcare Executive, February 01, 2003
- The Dartmouth Atlas of Healthcare, 1999.
- Fisher E.S., Wennberg D.E., Stukel T.A., et al. The implications of regional variations in Medicare spending. Part 1. Ann Intern Med. 2003; 138: 273-287.
- 9 Ways To Reduce Unwarranted Variation Managed Care Magazine, November 2003
- The NHS Atlas of Variation in Healthcare NHS, 2010
- The Mandate: A mandate from the Government to the NHS Commissioning Board April 2013 to March 2015, Department of Health, November 2012
- A presentation on Unwarranted Variation from Dr. John Wennberg
- The complete Right Care Atlas series is available as PDF downloads and as interactive InstantAtlas(tm) version on Right Care
- Phil DaSilva, Joint National Lead for Right Care, in conversation with Jack Wennberg on the NHS Atlas
- Right Care Essential Reading List: Unwarranted variation in health care - with an introduction by Sir Muir Gray September 2011
- The High Cost of Health Care, The New York Times Editorial, Nov. 25, 2007
- State of the Nation’s Health, Maggie Mahar, Dartmouth Atlas, Spring 2007
- Medical Guesswork: From heart surgery to prostate care, the medical industry knows little about which treatments really work, John Carey, Business Week, May 29, 2006
- Care Varies Widely At Top Medical Centers: Study Finds NYU, UCLA Used More Services Vs. Mayo, UC-San Francisco for Similar Patients, RON WINSLOW, Wall Street Journal, May 16, 2006
- Less care could help chronically ill, study says, Mary Jo Feldstein, St. Louis Post Dispatch, May 16, 2006
- Spending won’t get N.J. better end-of-life care, Philadelphia Inquirer, July 26, 2006
- Heart Procedure Is Off the Charts in an Ohio City, REED ABELSON, New York Times, August 18, 2006
- Back pain is behind a debate, USA Today, October 17, 2006
- High prices don’t translate into better healthcare in South Florida, Miami Herald, John Dorschner, December 17, 2006
- Clamping down on variation, Michael T. McCue, Managed Healthcare Executive, Feb 1, 2003
- Fisher, E.S. et al., Variations in the Longitudinal Efficiency of AcademicMedical Centers, Health Affairs, 7 October 2004
- Modifying Unwarranted Variations In Health Care: Shared Decision Making Using Patient Decision Aids: A review of the evidence base for shared decision making, O’Connor, AM et al., Health Affairs, 7 October 2004
- Wennberg, JE et al., Use Of Medicare Claims Data To Monitor Provider-Specific Performance Among Patients With Severe Chronic Illness: Analyses of seventy-seven of America’s "best hospitals" document extensive variation in the amount of care provided to patients with three common chronic conditions, Health Affairs, Oct. 7, 2004.
- Fisher, ES et al., The Implications of Regional Variations in Medicare Spending. Part 1: The Content, Quality, and Accessibility of Care, The Annals of Internal Medicine, 2003; 138: 273-287.
- Fisher, ES et al., The Implications of Regional Variations in Medicare Spending. Part 2: Health Outcomes and Satisfaction with Care, The Annals of Internal Medicine, 2003; 138: 288-298.
- Wennberg, JE et al., Unwarranted variations in healthcare delivery: implications for academic medical centres, BMJ. 2002 October 26; 325(7370): 961–964.
- Wennberg, JE, Geography and the Debate overMedicare Reform, J.E.Wennberg, E.S. Fisher, and J.S. Skinner, HealthAffairs, 13 February 2002.
- Wennberg, JE et al., Hospital use and mortality among Medicare beneficiaries in Boston and New Haven. N Engl J Med 1989;321:116873.
- Wennberg, JE at al., Are hospital services rationed in New Haven or overutilized in Boston?, Lancet 1987;i:11858.