ARTICLE IN BRIEF
A large-scale analysis of hospital data confirms that tPA use is very low for acute ischemic stroke, particularly in hospitals that are smaller, in rural locations, and in the Midwest and South.
Nearly two-thirds of US hospitals did not administer recombinant tPA to patients with ischemic stroke over a recent two-year period, an analysis of the Medicare database suggests.
DR. DAWN KLEINDORFER: “There is a wide variation in rates of recombinant tPA administration by hospital. How small a hospital is by far the biggest factor [associated with low rates of tPA use].”
Smaller hospitals, those in rural locations, and those in the Midwest and South were least likely to treat patients with tPA, said Dawn Kleindorfer, MD, associate professor and director of the Stroke Prevention Research Program in the department of neurology at the University of Cincinnati College of Medicine.
“There is a wide variation in rates of recombinant tPA administration by hospital. How small a hospital is by far the biggest factor [associated with low rates of tPA use],” she said here at the American Stroke Association International Stroke Conference 2009.
Dr. Kleindorfer said her team has previously estimated that tPA use in the US was administered at a rate of 1.8 percent to 3.0 percent of all ischemic stroke events. “However, we hypothesized that the rate of tPA use may vary widely depending on regional variation, with some hospitals providing this therapy to patients often, while others not at all.
“We also hypothesized that a large percentage of the U.S. population likely does not have access to hospitals using tPA regularly,” she said.
STUDY PROTOCOLS
To obtain what she termed a big picture snapshot of tPA use nationwide, Dr. Kleindorfer and colleagues combed the MEDPAR database, a claims-based dataset that contains every fee-for-service Medicare-eligible hospital discharge in the U.S. The study interval was July 1, 2005, to June 30, 2007.
The 4,750 hospitals within the MEDPAR database reported 495,186 ischemic stroke admissions over the two-year study period. Overall, patients were administered tPA during 11,884 (2.4 percent) of these admissions, Dr. Kleindorfer reported. Individual hospital treatment rates ranged from 0 to 23 percent.
“We found, unfortunately, that 62 percent of US hospitals did not give tPA to Medicare patients within the two-year study period,” said Dr. Kleindorfer. The study is the first description of tPA treatment rates by US hospitals using a comprehensive administrative dataset, Dr. Kleindorfer said.
Based on county populations, approximately 162 million Americans, or 60 percent of the US population, lived in counties that had a hospital with a treatment rate greater than the 2.4-percent national average, the study showed. Dr. Kleindorfer noted that areas served by hospitals often cross county lines, but said this provides an overall estimate of public access to tPA-treating hospitals.
Limitations of the CDC-funded study are that coding data were used to count ischemic stroke admissions and only data on Medicare patients were analyzed, the researchers said.
WHY THE DISPARITIES?
“A lot has to do with volume,” Dr. Kleindorfer told Neurology Today. “Many hospitals just use carotid endarterectomy to treat ischemic stroke. If you only see one stroke patient every other year, it's hard to keep the system up and revised.” tPA was approved in the mid-1990s, while carotid endarterectomy has been around since the mid-1950s.
The rates of tPA use “are distressingly low. We need to do better,” commented Harold P. Adams Jr., MD, professor and director of the Division of Cerebrovascular Disorders in the department of neurology at the University of Iowa Hospitals and Clinics in Iowa City. Dr. Adams was not involved with the research.
The primary reason for low rates of tPA use is the short three-hour treatment window during which the drug must be administered in the US, Dr. Adams said.
The third European Cooperative Acute Stroke Study recently showed that tPA is safe and results in modest but significant improvement in clinical outcomes when given up until 4.5 hours after symptom onset, according to a study by Werner Hacke, MD, and colleagues last year in the New England Journal of Medicine, he noted. “European and Canadian guidelines have been changed to reflect the longer window, and this will probably happen in the U.S. as well. This will hopefully allow more patients to be treated,” Dr. Adams said.
Nevertheless, treatment as early as possible after symptom onset is still the goal and even 4.5 hours isn't very much time.
HURDLES TO OVERCOME
“There are several hurdles to overcome,” he said. “Getting patients to recognize stroke symptoms and to call 911 — not their doctor's office — immediately is the single biggest problem,” he said.
Next, emergency medical services and hospitals need to be mobilized, Dr. Adams said. “Set up a protocol whereby EMS rapidly assesses the patient and calls ahead. This allows the hospital to have a radiologist ready to take a CT scan of the brain and a physician ready to give acute treatment.
“Once the patient arrives at the hospital, lab workers, clinicians, and radiologists should move as quickly as possible with the goal of treating the patient within an hour of arrival,” he said.
Dr. Adams said his institution has developed a stroke toolkit that outlines “exactly what has to be done and exclusion and inclusion criteria for tPA so everything can be done quickly.”
Another major hurdle is that many small institutions do not have neurology coverage, Dr. Adams said. “Although tPA has been approved for almost 13 years and we have guidelines for safe and effective use, there's still a certain amount of uncertainty. Many [non-neurologists] have reservations about using tPA because of the risk of bleeding, which is not small,” he explained.
Among the approaches that can improve rapid access to acute stroke care in small and rural communities are telemedicine, helicopter transport, stroke networks, and telephone consults, Dr. Adams said.
“In Iowa, we're already using phone consults and helicopter transport,” he said. “Drip and ship: Get the patient started [on tPA] at the community hospital and then transfer him to a stroke center,” he said.
tPA Use: The Statistics
- The mean tPA treatment rates for hospitals with fewer than 50 beds was 0.18 percent. This was significantly less than the 0.83 percent treatment rate for hospitals with 50 to 200 beds and the 2.33 percent treatment rate for hospitals with more than 200 beds.
- The mean tPA treatment rates for counties whose population density is fewer than 50 people per square mile was 0.37 percent. This was significantly less than the 1.06 percent treatment rate for counties with 50 to 500 persons per square mile and the 2.78 percent treatment rate for counties with more than 500 people per square mile.
- The mean tPA treatment rates for hospitals in the Southern and Midwest regions of the U.S. were 0.86 and 0.91 percent, respectively. This was significantly less than the 1.45 percent and 1.74 percent treatment rates for hospitals in the West and Northeast, respectively.
