A population-based study of severe, less common comorbidities in Duchenne muscular dystrophy

Since the increasing longevity and the advent of new therapeutic modalities in Duchenne muscular dystrophy (DMD), comprehensive clinical surveillance is of paramount importance. Our study aimed to examine the occurrence of severe, less common comorbidities among patients with DMD and their impact on life expectancy and overall disease burden.

This was a retrospective, nationwide study of all male patients with DMD who were followed at a medical clinic in Sweden, born and deceased during the period 1970-2019. Data regarding cause-of-death and comorbidities were retrieved by the medical records and the Cause of death Registry. The assessed variables were defined as 'severe' when depicting comorbidities with potentially serious, life-threatening outcomes.

Of the 129 included patients, approximately 56% presented with at least one severe complication or event, the most common being gastrointestinal complications and life-threatening arrhythmias, with incidence rates of 56.8 and 48.3/10,000 person-years, respectively. Acute kidney injury with an incidence of 16.6/10,000 person-years, was primarily seen within the months preceding death. Vascular events occurred in 10.7% of the patients, mainly cerebrovascular events and venous thromboembolism -including fatal post-traumatic pulmonary embolism-, each with an incidence of 23.5/10,000 person-years. Fracture occurrence, predominantly seen among non-ambulatory patients, had an incidence of 310/10,000 person-years. We further studied cumulative incidences and associations with loss of ambulation and glucocorticoids.

Our study provides new insights into severe comorbidities in DMD, emphasizing the need for lifelong disease monitoring, especially considering that many complications are subject to prevention and, if detected early, to successful treatment.