Not only are uninsured people with the condition more likely to be diagnosed only after their aorta bursts, but they're also twice as likely as insured patients to die after surgery to fix the problem - even if the operation is done before the aneurysm ruptures.
The findings, published in the current issue of the journal Surgery, represent the first confirmation of a long-suspected effect: that there's a deadly downside to the delay in detection and treatment of abdominal aortic aneurysms that results from uninsured patients' lack of access to regular medical care.
"Although we can't be completely sure that all these patients' aneurysms would have been detected before rupturing if they had insurance, the sizable differences in stage of diagnosis and outcomes between the insured and uninsured strongly suggest that access to care plays a significant role in detecting aneurysms before they rupture," says senior author Gilbert R. Upchurch Jr., M.D., an assistant professor of vascular surgery at the U-M Medical School. "In other words, access is linked directly to death."
Upchurch led the study with former U-M medical student Leslie K. Boxer, M.D., now at Cornell University, using data from the National Inpatient Sample database compiled by the federal Agency for Healthcare Research and Quality.
Doctors call abdominal aortic aneurysms "triple A's", an innocuous-sounding name for a truly deadly condition that kills nearly 16,000 people each year. Starting as a tiny bulge in the wall of the body's largest blood vessel an AAA can stay intact or grow slowly for years, often without symptoms, before suddenly bursting open unpredictably. Or, a tear within the multi-layered wall of the aorta, called an aortic dissection, can grow and eventually lead to an aneurysm at the weakened spot.
Patients whose aneurysms are found while they're still intact can have surgery to correct the problem, using an artificial graft to bypass the weak area. But those whose aneurysms rupture have a 50 percent chance of immediate death.
In the new study, the U-M team looked at a national sample of 5,363 people under age 65 who had either an intact or ruptured AAA between 1995 and 2000. Thirty-six percent of AAA patients with no insurance suffered a rupture in that time, as opposed to 18 percent of those on Medicaid and 13 percent of those with private insurance. "By the time many of the uninsured seek treatment, it's too late," says Upchurch.
The differences between the uninsured and the insured carried over to the operating table, Upchurch and his colleagues found - and those covered by Medicaid didn't fare much better than the uninsured. (The study did not include patients covered by Medicare, because that program offers universal insurance coverage to people aged 65 and older.)
Among AAA patients whose aneurysms were found intact, in time for elective surgery, a small but significant percentage died during the operation or in the hospital after surgery. The rate was 2.6 percent for uninsured patients and 2.7 percent for Medicaid participants, but only 1.2 percent for those with private insurance.
When patients whose aneurysms had ruptured got help fast enough to be brought in for emergency surgery, the odds were stacked high against their survival - but they were stacked much higher against those without insurance. More than 45 percent of the uninsured patients died during or immediately after emergency surgery, as compared with 31.3 percent of Medicaid patients and a relatively low 26 percent of patients with private insurance.
"We know from previous studies that timely access to health care is associated with a lower risk of death during or immediately after AAA surgery," says Upchurch. "These results bear that out by showing worse outcomes among those who are least likely to get early detection and management of their aneurysms."
The authors note that three factors may conspire to keep uninsured people from receiving timely detection and repair of abdominal aortic aneurysms. First, they may delay regular physical exams -- which can sometimes lead to an early detection of a pulsatile abdominal mass -- or which may include a routine abdominal X-ray or ultrasound, on which an AAA can sometimes be detected.
Second, even if their primary care or emergency room physician suspects a problem, uninsured people may not be able to get a referral to a surgeon who can repair an aneurysm electively. Third, hospitals and the health care system may present other barriers to diagnosis and surgery.
Because of all these factors, uninsured people are known to use the emergency department as their health care provider of last resort, in many cases only after severe symptoms arise. AAA is a condition that can persist for years without symptoms, then cause intense pain and other signs upon rupture. Because uninsured people with intact AAAs are less likely to get the regular primary medical care that could lead to a diagnosis, they may only find out they have the condition when they visit an emergency department because of symptoms.
But by then, their odds are worse. In the new study, AAA rupture patients of any insurance status who were admitted to the hospital for surgery from the emergency department had more than twice the death risk than those who were admitted for surgery non-emergently.
The uninsured may even be having an effect on the overall statistics for AAA, Upchurch offers. Despite major advances in diagnostic tools and surgical techniques over the past two decades, there has been little change in the incidence of ruptured AAA and the high death rate for those who have surgery to repair a rupture. During the same time, the economics of medicine and the relationship between patients and insurance carriers has changed.
"It's possible that, at the same time we were making great strides in tools to find and repair AAAs, decreased access to health care has limited the value of these advances," he says.
Besides Upchurch and Boxer, the study's authors are Justin Dimick, M.D., Reid Wainess, B.S., John Cowan, M.D., Peter Henke, M.D., and James Stanley, M.D., all of the Section of Vascular Surgery, Department of Surgery, U-M Medical School, and the U-M Cardiovascular Center.
Reference: Surgery, Vol. 134, No. 2, August, 2003, pp. 142-145.