Age and causes of death in adult-onset myotonic dystrophy

Abstract

Myotonic dystrophy is a relatively common type of muscular dystrophy, associated with a variety of systemic complications. Long term follow-up is difficult because of the slow progression. The objective of this study was to determine survival, age at death and causes of death in patients with the adult-onset type of myotonic dystrophy. A register of myotonic dystrophy patients was set up in Southern Limburg (the Netherlands), using data longitudinally collected over a 47-year period (1950-97). Survival for 180 patients (from the register) with adult-onset type myotonic dystrophy was established by the Kaplan-Meier method. The median survival was 60 years for males and 59 years for females. Survival of the patients was also estimated from the age of 15 years to the ages of 25, 45 and 65 years and compared with the expected survival of age- and sex-matched birth cohorts from the normal Dutch population. The observed survival to the ages of 25, 45 and 65 years was 99%, 88% and 18% compared with an expected survival of 99%, 95% and 78%, respectively. Thus, survival to the age of 65 in patients with adult-onset myotonic dystrophy is markedly reduced. A weak positive correlation between the CTG repeat length and younger age at death was found in the 13 patients studied (r = 0.50, P = 0.08). The cause of death could be determined in 70 of the 83 deceased patients. Pneumonia and cardiac arrhythmias were the most frequent primary causes of death, each occurring in approximately 30%, which was far more than expected for the general Dutch population. In addition, we assessed mobility in the years before death in a subgroup of 18 patients, as a reflection of the long-term physical handicap in myotonic dystrophy patients. Half of the patients studied were either partially or totally wheelchair-bound shortly before their death.

Usefulness of clinical and electrocardiographic data for predicting adverse cardiac events in patients with myotonic dystrophy

“…This was slightly higher than a previously reported rate of 0.1% to 0.2% per year for the general population (24), especially considering that the mean age in the present cohort was only 33 years. However, this rate remains quite low compared with the rates of 0.4% to 2% per year that can be extracted from other series (11,15,19,25). This can be explained by the fact that our cohort was derived from a systematic ascertainment and follow-up program among family members of patients diagnosed with DM1.…”

“…CONCLUSIONS : Dans une vaste cohorte non sélectionnée de 428 patients atteints de DM1, l'incidence cumulative de mort subite était relativement faible et la conduction retardée à l'électrocardiogramme de surface pouvait être utile pour repérer les patients vulnérables à une mort subite ou à l'installation d'un stimulateur cardiaque. the general population (10,11). Sudden death in DM1 patients has traditionally been associated with conduction defects and heart block, but malignant ventricular arrhythmias have been identified and may contribute significantly to those deaths, complicating the task of developing a strategy to prevent sudden death in patients with DM1 (12)(13)(14).…”

Management of Cardiac Involvement Associated With Neuromuscular Diseases: A Scientific Statement From the American Heart Association

“…92 Respiratory complications and cardiac arrhythmias are the most frequent primary causes of death in DM1. 93,94 In patients with DM2, cardiac problems appear to be less severe or frequent (10%-20%). Conduction defects are normally limited to first-degree atrioventricular and bundle-branch block; however, sudden death and severe cardiac arrhythmias have been described in a small number of patients.…”

Nuclear RNA Foci in the Heart in Myotonic Dystrophy

“…3 Sudden cardiac death ranks second after respiratory failure as a cause of death among patients with DM1. 4 The genetic basis for this multisystem, dominantly inherited disorder is an unstable expansion of CTG repeats in the 3Ј untranslated region of the dystrophia myotonica protein kinase (DMPK) gene. 5 Variability of the DM1 phenotype is explained partly, but not entirely, by variation in length of the expanded repeat.…”