He states that:
...in recent years UK specialists have suggested the treatment of subclinical hypothyroidism in patients only with clear symptoms. In the United States they go further: the endocrinologists' and thyroidologists' consensus statement "favors routine screening" and "early detection and early treatment," with some even suggested lowering the current threshold for diagnosis."He claims that because thyroid symptoms are not specific, that patients "hang a lot of life's problems" on a thyroid condition, and therefore pressure doctors to be treated.
He then goes on to claim that while the epidemiology has not been well studied, "subclinical hypothyroidism spontaneously corrects in 80% of patients in two years." He backs this up by citing one study of a very small population, published in the Journal of Clinical Endocrinology and Metabolism. That study found that among 40 patients who had subclinical hypothyroidism -- defined as a TSH above 5, with "normal" Free T4 -- all of them "reverted" to "normal" TSH levels...within four to five years.
Dr. Spence then goes on to state that "thyroxine prescribing has doubled in the past decade, which cannot reflect a true rise in incidence of hypothyroidism." The only conclusion is that we are overdiagnosing and overtreating thyroid disease. Again, through overdiagnosis, doctors are systematically failing in our duty to protect the well, which is the worst medicine of all."
How can Dr. Spence conclude that there is no rise in the incidence of hypothyroidism? With increasing amounts of endocrine-disrupting chemicals in our water and food supplies, a population that now has decades of cumulative radiation exposure, and unexplained increases in the rates of autoimmune diseases, to dismiss the rise in prescriptions as solely due to overdiagnosing and overtreating is unscientific.
And going back to his contention that hypothyroidism is overdiagnosed because of 40 study participants who "reverted" to normal levels within five years...first, he ignores the controversy over what TSH range is considered to be "normal." Only four of the patients reverted to TSH values less than 2.0, while 65% reverted to levels above 3.0, and 30% "normalized" at levels above 4.12. That means that most of the patients had TSH levels above 3.0 -- a level that many physicians -- at least in the U.S. believe warrants treatment. Many endocrinologists in the United States believe that a TSH level above 3.0 is not "normal" and that controversy has been going on for more than a decade.
Next, Dr. Spence fails to mention, that in that study he cited, among the 40 people studied, three had a goiter, and 24 were positive for thyroid peroxidase autoantibodies (TPOAbs), which is suggestive of Hashimoto's disease. Five patients had diabetes, 11 had high blood pressure, and 13 had hyperlipidemia (elevated blood fats/cholesterol.)
How many of those patients with a goiter saw that goiter grow during the years they went without treatment, waiting for their TSH to "normalize?" How many of them experienced neck discomfort, interference with swallowing or breathing, or developed a cosmetically unsightly goiter, when thyroid treatment may have slowed or halted growth of the goiter, or even reduced the size of the goiter?
How many of those 24 patients who have elevated TPO antibodies and Hashimoto's disease continued to experience symptoms of a failing thyroid, despite fluctuations in their TSH? And how many of those patients will eventually go on to develop overt hypothyroidism? Studies have shown that treatment of patients with "euthyroid" (normal thyroid levels) in Hashimoto's patients may prevent elevation of TSH levels to overt hypothyroidism (TSH above 10), alleviate symptoms, and even reduce thyroid antibodies. (Duygu Yazgan Aksoy, et. al. "Effects of Prophylactic Thyroid Hormone Replacement in Euthyroid Hashimoto's Thyroiditis" Endocr J (Japan) Vol. 52: 337-343, (2005).)
How many of those 24 patients who have elevated TPO antibodies and Hashimoto's disease will go on to develop thyroid cancer? Subclinically hypothyroid TSH levels in Hashimoto's patients increases the risk of developing thyroid cancer. (The association between serum TSH concentration and thyroid cancer).
How many of those who had elevated cholesterol would have seen their cholesterol levels normalize if they had been treated for hypothyroidism? According to the American Association of Clinical Endocrinologists, after diet, thyroid disease is the most common secondary cause of high cholesterol. Prescribing instructions for all cholesterol-lowering medications such as statin drugs, recommend testing for hypothyroidism prior to a physician prescribing them. (You'll find all of these drugs have prescribing information that states: "Prior to initiating therapy with ____, secondary causes for hypercholesterolemia (e.g., poorly controlled diabetes mellitus, hypothyroidism, nephrotic syndrome, dysproteinemias, obstructive liver disease, other drug therapy, alcoholism) should be excluded...")
How many of the diabetics might have had better control of their diabetes and lower Hemoglobin A1C levels with appropriate thyroid treatment? According to endocrinologist, Patricia Wu, MD, FACE, FRCP, writing in the journal, Clinical Diabetes, "The presence of thyroid dysfunction may affect diabetes control."
Given that we know that even subclinical thyroid disease is a risk for heart disease, how many of the patients with high blood pressure might have protected their heart health with thyroid treatment? Just recently, a study in the Journal of the American Medical Association pointed out that "subclinical hypothyroidism is associated with an increased risk of coronary heart disease events and coronary heart disease."
As a patient advocate, I think the real "bad medicine" is Dr. Spence's effort to extrapolate life- and health-changing thyroid diagnosis and treatment advice out of one study of 40 people, while ignoring all the peripheral issues -- heart health, cholesterol, blood pressure, diabetic control, thyroid cancer risk, and progression to overt hypothyroidism -- that can result from the failure to treat subclinical hypothyroidism.
Note on 12/10/12: The British Medical Journal has published my response to Dr. Spence's article at their site. Please "like" the post there, and if you feel inclined, I urge patients and practitioners to write your own responses as well! You can submit them here.