Estimation of incidence, prevalence, and age-at-diagnosis of myasthenia gravis among adults by hospital discharge records.

Background: The Hungarian Health Insurance Fund, using appropriate information technology, covers all of the secondary care of the country and maintains a database of Hospital Discharge Records (HDR). Our study aimed to determine the incidence, average age-at-diagnosis (AaD), and prevalence of myasthenia gravis (MG) among adults and the regional heterogeneity of these measures to assess the potential usefulness of HDRs for monitoring.

Methods: The nationwide database of 336,679 HDRs from 2004 to 2009 was analyzed. The incidence and prevalence were determined for adults in 2007. Patients with MG code in 2007, 2008, and 2009 but without that in 2004-2006 were defined as incident. Distribution of AaD was described for these cases. Patients with an MG code in 2007, 2008, and 2009 were defined as prevalent in 2007. The heterogeneity of regional age-standardized indices was tested.

Results: The observed incidence and prevalence was 2.76/100,000 (men: 2.37/100,000; women: 3.11/100,000) and 17.42/100,000 (male: 13.08/100,000; female: 21.28/100,000), respectively. These estimates were within published ranges. The mean AaD was significantly higher for men than for women (63.60 vs. 51.92; p < 0.001). Significant regional heterogeneity was observed for all measures.

Conclusions: HDRs seem to be useful for developing MG indicators because they adequately estimate epidemiological parameters of MG occurrence.