Myotonic dystrophy (MD), the most common inherited myopathy, is associated with high cardiovascular mortality 1. A preliminary analysis of the DM1 Heart Registry (URL: ClinicalTrials.gov. Unique identifier: NCT01136330), a comprehensive database that captures information relative to the cardiac management of adults presenting to our center with MD 2 , revealed a high prevalence of venous thromboembolism (VTE). We designed this study to estimate the risk of VTE in MD and its survival consequences. We retrospectively analyzed the data relative to patients referred to our center between January 2000 and January 2015, including 1148 with MD and 1662 with other inherited myopathies (facioscapulohumeral, dystrophinopathy, mitochondrial, glycogen-and lipid-storage diseases, limb-girdle muscular dystrophies, nucleopathies, collagen VI-related disorders, myofibrillar, and congenital). This study was approved by our local Ethics Committee, and all patients granted their written informed consent to participate. We compared patient baseline characteristics using Wilcoxon rank-sum or Fisher exact tests as appropriate. VTE, defined as ≥1 episode of deep vein thrombosis or pulmonary embolism, was analyzed in a competing-risks framework, with death as a competing event. Cumulative incidences (probability of occurrence over follow-up), hazard ratios (HRs), and cumulative hazards of VTE were estimated. We searched for predictors of the hazard of VTE using Cox proportional hazards models for the cause-specific hazards on the time of study scale, with follow-up beginning on the date of inclusion in the study until the occurrence of VTE, death, or last follow-up, whichever occurred first. All patient characteristics described in the results were included in this analysis, including all variables from our database that represent known VTE risk factors. At first presentation, patients with MD, compared with others, were older (40 [29-51] years versus 39 [25-52] years; P=0.029); had a lower proportion of men (556 [48.4%] versus 990 [59.6%]; P<0.0001); had a more frequent personal history of VTE (40 [3.5%] versus 9 [0.5%]; P<0.0001), heart failure (12 [1.0%] versus 128 [7.7%]; P<0.0001), and conduction disease (461 [40.2%] versus 195 [11.7%]; P<0.0001); were treated with vitamin K antagonists (32 [3.0%] versus 25 [1.5%], P=0.009) and estrogen contraceptives (137 [11.9%] versus 140 [8.4%], P=0.002); and had a lower Walton score 3 (1 [0-3] versus 3 [1-6]; P<0.0001) and less frequent ambulation loss (80 [6.9%] versus 405 [24.4%], P<0.0001). A similar prevalence was observed for obesity (123 [10.9%] versus 183 [11.2%]; P=0.85), respiratory failure (133 [13.2%] versus 257 [15.8%]; P=0.071), and cancer (31 [2.8%] versus 33 [1.9%]; P=0.25). VTE