Why One in Five Utah Cities Prescribe More Thyroid Medication Than Anything Else

Nationally, the most prescribed drug in Medicare Part D is almost always a cholesterol medication. Atorvastatin, specifically. It sits at #1 in state after state, which makes sense, cardiovascular disease is the leading cause of death in the U.S., and statins are one of the most commonly prescribed tools to manage it.

Utah is different. In 20 of the 49 cities with meaningful Medicare prescribing data, Levothyroxine, a thyroid medication, knocks Atorvastatin out of the top spot. Sandy, Orem, Provo, Salem, Moab, and a dozen others all show the same pattern.

That's unusual enough to be worth talking about.

What Levothyroxine does

Levothyroxine is a synthetic version of the thyroid hormone your body normally produces. It's prescribed when your thyroid gland isn't producing enough hormone on its own, a condition called hypothyroidism. Most people who have it take one small pill every morning, usually for the rest of their lives.

The symptoms of an underactive thyroid are easy to miss, especially in older adults. Fatigue that seems like normal aging. Weight gain. Feeling cold all the time. Constipation. Brain fog. A lot of people go years without knowing their thyroid is the problem.

That's part of why catching it matters, and why asking about thyroid screening when you turn 65 is worth doing.

The Utah angle

There isn't a single confirmed reason why thyroid prescriptions run higher in Utah than in many other states, but there are a few threads that researchers have pointed to over the years.

One is geography. Utah sits in a region that historically had iodine-poor soil. Iodine is the mineral your thyroid needs to make hormones, and inland areas far from the ocean tend to have less of it in local food and water. Before the widespread use of iodized salt, thyroid disorders were much more common in inland states, a region old textbooks actually called the "goiter belt," which ran from the Great Lakes down through Utah and the Mountain West.

Modern iodized salt has narrowed that gap, but the pattern may have lingered through generations of people who developed thyroid issues earlier in life and are now in the Medicare population.

A second factor is the structure of Utah's healthcare system. Utah has a relatively high rate of primary care physicians per capita in certain areas, and thyroid screening is a standard part of routine bloodwork. More screening means more diagnoses.

What this means if you're turning 65

Thyroid disease is more common in women than men, and it becomes more common with age. By some estimates, up to 20% of women over 60 have some degree of thyroid dysfunction, much of it undiagnosed.

The standard test is a simple blood draw called a TSH (thyroid-stimulating hormone) test. It's included in most routine labs. If you haven't had one recently, it's a reasonable thing to ask your doctor about, especially if you've been feeling more tired or foggy than usual and can't explain why.

If you already take Levothyroxine, a few things are worth knowing as you head into Medicare. First, the drug itself is inexpensive, about $20 per prescription on average, so it won't put much pressure on your Part D plan costs. Second, dosing matters a lot. Too little and you're still symptomatic. Too much and you risk bone loss and heart problems. Regular monitoring is part of managing it well.

One more thing worth knowing

Levothyroxine is one of those medications where generics and brand names actually do matter a little. Most pharmacists and doctors will tell you that switching between different versions, even if they're all technically the same drug, can throw off your levels. If you're stable on what you're taking, try to stay consistent. If you move or switch pharmacies, tell them you're on thyroid medication and want to stay on the same formulation.

It sounds like a small thing. For most medications, it is. For thyroid medication specifically, the margin for variation is tighter than you'd expect.

Source: CMS Medicare Part D Prescribers by Provider and Drug, 2023. Utah city-level data. Cities with 500+ prescriber records included.