Incidence and predictors of venous thromboembolism in inherited myopathies: A higher risk in myotonic dystrophy

Background The risk for venous thromboembolism (VTE) in inherited myopathies, which can lead to chronic immobilization, is unknown. Purpose To evaluate incidence of VTE in inherited myopathies, including for patients who lost ambulation, to compare it to incidence of VTE in general population and to identify predictors of VTE events in inherited myopathies. Methods We retrospectively enrolled 2810 adult patients with genetically proven myopathy, admitted to our institutions between January 2000 and November 2014. We collected any information relative to their demographic and genetic characteristics, their muscular functional status including ambulation and the occurrence of VTE. We determined the incidence of venous thromboembolism in this population by using Kaplan–Meier product-limit method, compared it to general population with log-rank test and assessed its predictors with multivariable Cox modeling. Results Over a median follow-up of 8.5 years, 102 patients developed venous thromboembolism, representing a cumulative incidence of 6.2%, higher than in general population matched on age and sex. We identified four independent predictors of VTE: age (hazard-ratio ( HR ) = 1.02, 95%CI = 1.01–1.04, P  = 0.002), a personal history of VTE ( HR  = 5.54, 95%CI = 2.91–10.5, P HR  = 4.63, 95%CI = 2.63–8.18, P HR  = 4.07, 95%CI = 1.14–14.5, P  = 0.030). Loss of ambulation alone was not a significant independent predictor of VTE. Conclusions VTE in inherited myopathies is not a rare condition and is more frequent than in general population. We identified four independent predictors of VTE in these patients. Patients with DM represented the population with the highest risk of VTE.