The current status of medical care for myotonic dystrophy type 1 in the national registry of Japan.

INTRODUCTION/AIMS: Myotonic dystrophy (DM) is a systemic disease with multiple organ complications, making the standardization of medical care a challenge. To clarify the current treatment patterns and demographic features of Japanese DM patients, we analyzed data from Japan's national registry.

METHODS: Using the Japanese National Registry of Muscular Dystrophy (Remudy), we analyzed medical care practice for the multisystemic issues associated with adult DM type 1 patients, excluding congenital DM.

RESULTS: We included 809 patients with a median age of 44.2 years. Among them, 15.8% used ventilators; 31.7% met the index considered at risk for sudden death due to cardiac conduction defects (PR interval > 240 ms or QRS duration > 120 ms), and 2.8% had implanted cardiac devices. Medication for heart failure was prescribed to 9.6% of the patients. Overall, 21.2% of the patients had abnormal glucose metabolism, of which 42.9% were treated with oral medications. Among the oral medications, dipeptidyl peptidase-4 inhibitors were the most common. Cancers were observed in 3.7% of the patients, and endometrial and breast cancers were dominant. Mexiletine was prescribed for myotonia in 1.9% of the patients, and only 1% of the patients received medication for daytime sleepiness.

DISCUSSION: This study shows difference in treatment patterns for DM1 in Japan compared to other countries, such as lower rates of use of implantable cardiac devices and higher rates of ventilator use. This data may be useful in discussions aimed at standardizing medical care for patients with DM.