In the July/August â€™05 issue of Endocrine Practice, an influential journal read by endocrinologists throughout the United States, researchers again tackled the question of whether treating hypothyroidism (underactive thyroid) with a combination of conventional t4 therapy (Synthroid, Levoxyl, levothyroxine) along with t3 (Cytomel) was superior to using t4 alone. In my opinion this study was a fumble. It failed to show that the addition of t3 to conventional t4 improved the level of fatigue or depression of the hypothyroid patients studied.
What could have gone wrong, I asked myself? Having recently reviewed a previous study that failed to show improvement with combination therapy, I was sure the next set of researchers were going to get it right. Why do I feel so confident of a positive effect of t3 on patients with hypothyroidism? It is because so many patients of mine and my colleagues who are still suffering with symptoms of hypothyroidism on t4 treatment alone, have shown impressive improvement when t3 was added. How could this benefit have been missed by dedicated researchers again?
As I mentioned, in a previous review of a study of combination therapy that showed negative results I pointed out the deficiencies in the research that resulted in that misstep for science. Could the same research errors have occurred in the new study, I wondered? Sadly, the answer is probably yes.
What exactly went wrong here? First and I think most importantly, the researchers studied patients with hypothyroidism regardless of whether they had complaints of fatigue or depression. How, I ask, is it possible to measure improvements in fatigue and depression in people who donâ€™t have those complaints? If I studied the effect of an acne cream on those who didn’t have acne doesnâ€™t it make sense that the study would show that the cream didnâ€™t cause an improvement in pimples. So it is with this study. If it ainâ€™t broke, how are you going to fix it? What is most aggravating is that this was the same approach of studying patients without symptoms taken by the previous study.
Another big problem was that when the researchers in this study added t3 to the t4 they unintentionally made these patients more hypothyroid by failing to give enough of the thyroid medication. If you ask me this should have disqualified the study right then and there. How can you study the benefits of thyroid hormone therapy of any type if you make the patients worse then when they started? I rest my case.
I suppose we just have to wait for our research scientists to discover what they are doing wrong in their studies of hypothyroidism, before they can get it right. Hopefully doctors treating hypothyroidism will maintain an open mind about the subject until then.
Note: t3, brand name Cytomel, is a prescription drug. Only a patient and their physician can decide if using t3 is an advisable choice.