Many patients on anti-dementia drugs haven't received recommended thyroid gland tests

TOKYO -- Two thirds of patients using anti-dementia drugs have not received thyroid gland tests which are recommended by medical societies to help diagnose dementia, a study by the Institute for Health Economics and Policy (IHEP) has shown.

Dementia symptoms include deterioration in the function of the thyroid gland, but proper therapies can aid recovery. Thyroid tests, which can detect dementia early and prevent the use of unnecessary medication, are therefore beneficial. The IHEP team that conducted the study pointed out that doctors should examine patients' properly before prescribing drugs.

In Japan, about 4.62 million people were estimated to be suffering from dementia in 2012. Some conditions, such as those related to Alzheimer's disease, are difficult to treat, but overseas data show that the dementia conditions of 10 percent of such patients stem from thyroid gland malfunctions and can be cured.

Multiple medical societies in Japan including the Japan Society of Neurology recommend in their 2017 guidelines on dementia treatment that thyroid hormone levels be tested when a patient is diagnosed with dementia.

However, an examination by the institute of the government's medical receipt database found that only 33 percent of 262,279 patients aged 65 or older who were diagnosed as having cognitive problems and were given anti-dementia drugs in fiscal 2015 had received thyroid gland tests a year or more before they were prescribed the medication.

The ratio of such patients was as low as 25.8 percent at clinics, and remained at 57.1 percent even at medical institutions designated as specialized centers for dementia treatment. The study found that the older patients were the less likely they were to receive thyroid gland tests.

Anti-dementia drugs are administered to patients with Alzheimer's disease or Lewy body dementia (a disease associated with abnormal deposits of a protein), to slow down the progress of the symptoms. However, they are not effective in treating deterioration of thyroid gland functions.

Nobuo Sakata, senior researcher at the IHEP and a medical doctor, says failure to test the thyroid gland, leading to curable dementia conditions being overlooked, is "a big problem." He warned that the use of inappropriate drugs might not bring recovery and could result in disadvantages such as a loss of appetite or dizziness.

(Japanese original by Toshiyasu Kawachi, Medical Welfare News Department)