Imagine you develop a mysterious pain in the side of your neck. After months of trying to ignore the discomfort, you finally make an appointment with your primary care provide, then a specialist who combs through your medical history, your family background, X-ray images and MRI images and comes to a conclusion. She tells you the name of your condition and prescribes the proper therapy regimen.
You leave her office. A tremendous weight has been lifted from your shoulders. Your distress has been legitimized by a medical authority, and you have found that you are not alone.
Unfortunately, this is a rather rose-tinted example, considering that many patients suffering from chronic pain never receive a proper diagnosis. Even with tremendous medical leaps made over the past decades, our understanding of the human body and all of its possible abnormalities is limited. But as we continue to add to our collection of medical knowledge, more diseases and conditions are discovered and classified through the branch of medicine known as nosology, which deals with the classification of disease. While we may take the names of diseases for granted, their classification occurs only after significant research and analysis have been completed and allows for uniform diagnosis and treatment.
Yet while the categorization of disease occurs through authoritative medical committees, nosology is still prone to human bias and ambiguities. Consider myelodysplastic syndrome, formerly known as pre-leukemia, a collection of medical disorders with varying symptoms and severity but always marked by low production of blood cells that originate in the bone marrow or spinal cord.
While MDS can progress to full-blown acute myelogenous leukemia, many cases do not. But because the progression from MDS to AML is not discrete, clinicians have set a fine line between MDS and AML that is supported by data but remains under debate. The controversy has led to two separate and widely used boundary points set by the World Health Organization and the French American British classification. If the overall percentage of bone marrow blasts is over a certain limit 20 percent for the WHO and 30 percent for FAB classification then the patient is said to have progressed from MDS to AML. To confuse the matter even further, scientists and physicians have argued about whether MDS itself can be classified as cancer. While we tend to think of each disease as a distinct entity, many ailments cannot be defined or clearly differentiated.
The classification and diagnosis of disease may also be tainted by special interests, a fact which ought to elicit concern among doctors and patients alike. In the book "Overdiagnosed: Making People Sick in the Pursuit of Health," Geisel Medical School professors and physicians H. Gilbert Welch, Lisa Schwartz and Steve Woloshin describe the conflict of interest between private medical committees and public health.
Take the American Diabetes Association, for example, which recently elected to add "prediabetes" to its canon of diabetic conditions. According to the official ADA website, prediabetes describes "blood glucose levels that are higher than normal but not yet high enough to be diagnosed as diabetes." This new label affixed the stigma of disease upon an estimated 79 million Americans who have suddenly been turned into potential consumers of diabetes drugs. Lest I sound too much like a conspirator, consider that the ADA receives funding from pharmaceutical companies and that the head of the panel that proposed the diabetes cutoff point is a paid consultant to seven major pharmaceutical companies all of which produce drugs for diabetes. Unfortunately, this potential conflict of interest is not an isolated anomaly, leading to valid concerns regarding the independence of the medical committees that set the cutoffs to diagnose conditions.
While practical and necessary for continued diagnosis, treatment and research, nosology is a fallible human attempt to fit our world into an understandable system. Disease classifications are often ambiguous and may fall prey to external interests. Patients themselves should be aware of the limitations of medicine and educate themselves accordingly.
