Ischemic Stroke Subtypes and Risk Factors: The Probable Bias Arisen From the Classification Style Across Studies

Response:We thank Dr Tuttolomondo et al1 for their interest regarding our recent article.2 In their comments, they address the issue of selecting a precise ischemic stroke classification system to evaluate the relationship between ischemic stroke subtype and diabetes mellitus. An attempt to classify ischemic stroke had been initiated to serve different purposes, including therapeutic decision-making in day-to-day clinical practice, accounting for patients' characteristics in clinical trials, phenotyping of patients in genetic studies, or classifying patients in epidemiological studies. The method of classification depended on the extent of information available for the stroke events, and this itself is highly dependent on the purpose of the study. Clinical trials or hospital-based clinical case series will generally have extensive information available for the stroke events. Apart from these types of studies, community-based surveillance studies for stroke also have been initiated for the purpose of disease detection, assessment of trends, identification of service needs for program and policy development, or research in specific populations. These studies use existing administrative health service data for their purposes, and thus detailed information on the stroke events in these circumstances are often somewhat limited. For our study, which is based on continuous stroke surveillance in an entire community population over a prolonged period of time, we …