Development of a prognostic score in DM1 – Interview with Dr. K. Wahbi

Dr. Karim Wahbi, a cardiologist in the Cardiology Department at the Cochin Hospital and the Institute of Myology, led a study in which medical data from nearly 1,300 myotonic dystrophy type 1 (DM1) patients were analysed over 10 years. This allowed to develop and validate a clinical tool useful for healthcare professionals.
Myotonic dystrophy type 1 (or Steinert’s disease) is one of the most common neuromuscular pathologies in adulthood. It results in multi-systemic involvement including skeletal muscle, the respiratory system, many endocrine glands, with a tendency to diabetes, and polymorphic cardiac involvement.

What is the interest of such a clinical tool?
Steinert’s disease is a life-threatening disease, although multidisciplinary care has greatly improved patient care. The tool that we have developed makes it possible to better predict the risk that a patient will have a vital complication and can help choose the most appropriate care for the evolution of his/her pathology: annual consultation, day hospitalisation or multidisciplinary consultation. This prognostic score approach has already been developed in other chronic diseases, such as cancer. The question that arises is: what is the risk of the patient developing a serious event, such as cardiac arrhythmia, developing severe respiratory failure, or dying, for example. Among the existing tools, the most advanced is the prognostic score, which allows for greater precision concerning the risk for patients.

How is a prognostic score calculated?
To obtain a prognostic score, we identify a number of patient characteristics that are associated with the occurrence of the event in question (for example, death) and through statistical analysis, we study the relationship between different characteristics and the occurrence of the event. We can then develop a mathematical equation that makes it possible to predict the probability of the event as a function of the characteristics measured.
Here, we used the information from the database that I had developed on Steinert’s disease, in relation to cardiac events and prognostic data.

What characteristics did you retain?
We took into account characteristics such as sex, age, mutation size, impact on muscles (walking support, a cane or a wheelchair), respiratory capacity (vital capacity), some cardiac data (PR, QRS, left ventricular ejection fraction), blood pressure and presence of diabetes.
We recorded this information when the patient was seen for the first time at the referral center. In addition, we collected the patient’s vital prognosis and the cause of death, if any.

Should special examinations be performed to calculate a patient’s score?
No, the examinations made for the score are really part of routine patient care, they are always carried out at the time of diagnosis: a clinical examination of the patient, an electrocardiogram and a respiratory functional test. No additional examinations, just these 3 elements are needed to calculate the score, hardly 30 seconds, it’s very simple!


Development and Validation of a New Scoring System to Predict Survival in Patients With Myotonic Dystrophy Type 1.Wahbi K, Porcher R, Laforêt P, Fayssoil A, Bécane HM, Lazarus A, Sochala M, Stojkovic T, Béhin A, Leonard-Louis S, Arnaud P, Furling D, Probst V, Babuty D, Pellieux S, Clementy N, Bassez G, Péréon Y, Eymard B, Duboc D.JAMA Neurol. 2018 Feb 5. doi: 10.1001/jamaneurol.2017.4778. [Epub ahead of print]