NEW ORLEANS – The incidence of hospitalizations for status epilepticus rose nearly fourfold during 1980-2009, according to researchers who analyzed the National Center for Health Statistics’ National Hospital Database Survey.
The population-adjusted incidence increased from 3.7/100,000 to 14.2/100,000, although the median hospital length of stay for status epilepticus (SE) remained relatively stable at a median of 4-5 days. Hospitalizations for SE also tended to follow a bimodal distribution with the greatest incidence in the first decade of life and between the 5th and 6th decades.
The data on the epidemiology of SE are "quite limited" and come mainly from small, population-based studies, which often do not have findings that are generalizable to the U.S. population and do not provide temporal trends, said Dr. Bhavpreet Dham of the University of Medicine and Dentistry of New Jersey, Camden.
Dr. Dham also noted that it is estimated that $4 billion is spent each year in the United States on status epilepticus hospitalizations, which is even more than is spent on myocardial infarctions or heart failure (Seizure 2005;14:46-51).
He and his colleagues analyzed 699,690 patient discharges in the study’s 30-year time span. These hospitalizations accounted for just 0.07% of about 1 billion hospitalizations in the database. The database covers hospitals in all 50 states and the District of Columbia and uses abstracted ICD-9 codes for diagnoses.
"We believe that this is one of the largest epidemiological studies of SE," Dr. Dham said.
In most of the years, the incidence of SE was about 10% higher in men than in women, and nonwhite patients also had a higher incidence than did whites.
In-hospital mortality (about 8.4% overall) did not differ between the sexes. Although mortality was lowest among patients aged 10 years or younger (2.7%) and highest among those older than 80 years (19%), the incidence of hospitalizations was lowest for patients in the first decade of life and highest in those older than 80 years.
These changes may be the result of a temporal shift in population age distribution during the past 30 years because of more adults living to an older age than there were 30 years ago. In recent years more people have been diagnosed with SE, Dr. Dham noted.
He said that the study is limited by the investigators’ inability to audit the database to review patient charts and the lack of morbidity and mortality data for patients once they left the hospital. Furthermore, the investigators could not differentiate between convulsive, nonconvulsive, and refractory SE because the ICD-9 coding does not allow it.
Dr. Dham said that he had no relevant financial disclosures.