Epidemiology of myasthenia gravis in Austria: rising prevalence in an ageing society

The purpose of this study was to investigate recent epidemiological trends of myasthenia gravis (MG) in Austria. We used the national hospital discharge register, which records the discharge diagnoses of all inpatient stays in Austria to calculate the yearly inpatient prevalence of MG from 1992 to 2009 (main or secondary diagnosis of MG). The population prevalence was indirectly estimated. The temporal and geographical variability of the inpatient prevalence was correlated with the number of practicing neurologists. The inpatient prevalence of 2009 was calculated as 8.0 and the population prevalence as 15.69 (95 % CI 13.16-19.42) per 100,000. We observed a 2.2 fold increase in the inpatient prevalence between 1992 and 2009, which was mainly due to a rise in the number of older patients (A(3)aEuro parts per thousand 50 years). Partly this could be accounted for by an ageing of the population as a whole and a rise in the age of hospitalised patients. However, after adjusting for demographic factors an unexplained average yearly rise of 3.7-3.9 % remained. We found a significant spatial and temporal correlation of MG inpatient prevalence rates with the number of practicing neurologists, which increased over the same period. The results from this study support the notion that the prevalence rate of MG in Austria is rising and near the higher end of the wide range discussed in the literature. Our data argue for the importance of specialist neurological care for the diagnosis of this disease.