Neuroepidemiology
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Review Comparative Study
The incidence of myasthenia gravis: a systematic literature review.
A systematic review of literature published between 1980 and 2007, on the incidence of myasthenia gravis, was undertaken. ⋯ The most accurate estimate of incidence of myasthenia gravis was around 30/ 1,000,000/year. The incidence in children and adolescents aged 0-19 years was found to be between 1.0 and 5.0/ 1,000,000/year. The rates presented in this review are likely to be an underestimate of the true incidence rates, as mild cases will have been missed and cases in the elderly will have been misdiagnosed.
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Population-based epidemiological studies about headaches, especially migraine, have been carried out in many countries. The aim of this study was to assess the 1-year prevalence of migraine, probable migraine and tension-type headache (TTH) in the Croatian population. ⋯ The prevalence of migraine and probable migraine is similar as in other Western countries. Certain demographic characteristics differ among patients with and without headache.
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Despite declining age-adjusted stroke mortality rates, the disease remains the third most common cause of death in Israel. Based on a national survey, we examined mortality rates during the first 3 years after a first-ever acute ischemic stroke (IS) and the major predictors of short-term (1 month) and long-term (3 years) mortality. ⋯ Approximately one third of patients did not survive 3 years after the first-ever IS. While age and markers of severe stroke were the major predictors of death at 1 month, comorbidities and variables associated with atherosclerotic vascular disease predicted long-term mortality. Improved control of these factors can potentially reduce long-term mortality in stroke victims.
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It is important to establish the validity of diagnostic coding in administrative datasets used in stroke and transient ischemic attack (TIA) research. This study examines the accuracy of emergency department (ED) TIA diagnosis and final diagnostic coding after hospital admission. ⋯ Half of the emergency diagnoses retained a TIA diagnosis after hospital admission. In the setting of neurological admission there were small percentage differences between coded final diagnosis for TIA, stroke and mimic and diagnoses at expert review. Admission of ED TIA cases permitted identification of TIA mimics with serious conditions requiring non-TIA management.
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In the first part of this series, it was highlighted how even though randomised controlled trials can provide robust evidence for therapeutic interventions, for many types of exposure it may not be either practical or ethical to randomise patients to such studies (see part 1). Instrumental variables (IV) analyses have been increasingly employed in recent times in epidemiology to investigate the potential causal effects of an exposure. ⋯ A particular type of IV analysis where a specific genetic variant has been used as the instrument known as 'Mendelian randomisation' has become increasingly common. The aim of the second part of this statistical primer is to outline the approach to Mendelian randomisation and some of the advantages and disadvantages of this approach.