Chronic subdural hematoma rates increasing in the United States

By Will Boggs MD

NEW YORK (Reuters Health) - Researchers from New York University School of Medicine project that 60,000 new cases of chronic subdural hematoma (cSDH) will occur each year in the United States by 2030.

"While of course it is logical to realize that as the U.S. population ages, conditions that are more common in the elderly will increase in incidence, I was still surprised to realize how quickly the increase would affect the daily practices of neurosurgeons," Dr. Uzma Samadani told Reuters Health by email. "Our data suggests that cSDH is going to be a big problem for the health care system."

In the past four decades, the incidence of cSDH has steadily increased around the world, but its epidemiology has not been rigorously studied in the U.S.

Dr. Samadani and colleagues used data from the Veterans Health Information Systems and Technology Architecture (VISTA) network to create a mathematical model to predict the future incidence of cSDH in both VA and civilian populations.

They used two different formulas, one based on a cSDH incidence study in Japan, the other based on a cSDH incidence study in Finland. They adjusted the formulas for different reported levels of alcohol consumption in the three countries (Japan, Finland, and the U.S.). Age-standardized incidences for the VA population were used to predict age-standardized rates of cSDH for the general population.

The incidence of cSDH in the VA population across the 13 years of study was 79.4 cases per 100,000 persons, which translated into average incidences for the general U.S. population of 10.35 (Japan-based formula) and 7.24 (Finland-based formula) cases per 100,000 persons.

Chronic SDH recurred in 11% of the VA patients as late as three years after the initial diagnosis, according to the March 20 Journal of Neurosurgery online report.

Based on the current aging trends, the incidence of cSDH is projected to reach up to 121.4 cases per 100,000 VA patients by 2030 and to reach 8.75 (Finland-based formula) to 17.1 (Japan-based formula) per 100,000 for the general population by 2030.

"Thus," the researchers say, "by 2030, chronic SDH drainage may be the most commonly performed neurological procedure. The length of stay after treatment of chronic SDH might be longer than that after tumor resection, which could result in an increasing number of neurosurgical inpatients."

"The elderly already constitute a large portion of patients receiving medical care," Dr. Samadani said. "Our data is consistent with this problem getting progressively worse. We will need to dedicate more resources to neurosurgery and rehabilitation for cSDH patients. We also need to start thinking about how to reduce brain atrophy as people age, as that seems to be a major component of the root of the problem."

"Research into how to prevent brain atrophy and progressive neurodegenerative diseases - particularly after brain trauma - is critical to containing future medical costs," Dr. Samadani concluded.

Dr. Laurence Marshman, from The Townsville Hospital Department of Neurosurgery, Queensland, Australia, who recently reviewed risk factors for cSDH, told Reuters Health by email, "There are obvious faults in extrapolating data from other non-U.S. populations to model U.S. population behavior. However, the fact that cSDH is a disease of the elderly (i.e., over 70 years) makes it seem inevitable that, with an ever-increasing age of the population, the incidence of cSDH will rise."

"Neurosurgical wards will have to grow, or multiply, to cater for increased cSDH patients," Dr. Marshman said. "However, the same could be said about an increased incidence of malignant primary or metastatic brain tumors, since these are also age-related. An increased aged population puts strain on other areas of medicine and surgery, which may be even more serious: e.g., cardiovascular, peripheral vascular, and cerebrovascular disease."

Dr. Giulio Cecchini, from the Department of Neurology and Neuropsychiatry Sciences, University of Bari, University of Marche, Bari, Italy, told Reuters Health by email, "I was not surprised at the calculated incidence rate. I'm surprised every day at the recurrence rate. We need to know more and more about this pathologic condition and about its pathophysiology."

The Veterans Health Administration supported this research. The authors reported no conflicts of interest.


J Neurosurg 20 March 2015.

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