Screening for Stroke, Peripheral Artery Disease and Abdominal Aortic Aneurysm
Posted by medconsumers on June 1, 2007
Perhaps you got a mailing from Life Line, or noticed its mobile clinic at your synagogue, church or workplace. Life Line is in the business of selling vascular screening, primarily tests for stroke, peripheral artery disease and abdominal aortic aneurysm. The prices are low—$45 each test—because most insurance companies and Medicare will not pay for the tests (with one exception).
Life Line has a presence in nearly all states, and according to its Web site, has already screened 4,715,306 people. Often the company sets up shop at local hospitals, but its promotional literature offers this qualification, “We are in no way trying to replace the services provided by these local hospitals. Rather, we want to work in conjunction with them to identify asymptomatic individuals with significant disease.”
It’s unlikely that local hospitals would see Life Line as encroaching on their turf. On the contrary, screening symptomless people creates customers who can be funneled right to the hospital, where more tests and, often, surgery can be done.
Screening by definition involves testing people without symptoms. “Don’t wait for a medical problem” is Life Line’s seductive sales pitch. Screening sometimes can extend life or result in less drastic surgery than would be necessary had the disease been discovered after symptoms appeared. However, all screening tests have their risks that are rarely mentioned to the public. They find abnormalities that may be better off left undetected. In the case of abdominal aortic aneurysm—not all will rupture and, in certain circumstances, an operation on one that is symptomless can be riskier than leaving it alone.
Mass screening for vascular disease is a relatively new idea. Before plunking down your money, the question to be answered is this: Have any studies proven that detecting and treating this symptomless problem will either prolong my life or improve its quality?
An objective source of screening information is the U.S. Preventive Services Task Force, which appoints an independent panel of experts to review all relevant studies and issue screening guidelines for doctors and consumers based on the findings.
The USPSTF has taken an in-depth look at the three screening tests promoted by Life Line and advises against ultrasound screening for peripheral artery disease (hardening of arteries in the leg), ultrasound screening of the carotid artery in the neck (purportedly to prevent strok) and abdominal aortic aneurysm (AAA) in women. In all cases the potential harm of false-alarm test results and unnecessary surgery outweigh any life-prolonging benefit.
The one exception is AAA screening for men between the ages of 65 and 75 years who have ever smoked—the only people who will benefit and the only ones to receive Medicare reimbursement.
An aneurysm is the widening of a small section of an artery that can burst once the vessel wall becomes weakened. An AAA occurs near the aorta, the main artery from the heart that passes through the abdomen. The condition is frequently symptomless, but a rupture is life-threatening and requires immediate surgery.
The decision to screen symptomless people for any disease should be based on its prevalence and the likelihood of successful treatment. Elderly men are six times more likely to have an AAA than elderly women. Most AAA deaths occur in men over 65; whereas most AAA deaths in women occur when they are older than 80. Men are more likely to survive AAA surgery (probably because they are younger at the time of aneurysm repair).
The USPSTF and, more recently, the Cochrane Collaboration conducted separate reviews of all relevant studies and came to similar conclusions in favor of AAA ultrasound screening for men, age 65 to 75 years (who have ever smoked), which will reduce AAA-mortality. (The potential benefit to men who have never smoked is too small to be worthwhile.) An aneurysm larger than 5.5 cm requires surgery because it has a higher risk of rupture than smaller aneurysms, which can be followed with ultrasound.
Both the USPSTF and the Cochrane review based their conclusions on the same four studies, which provided the best evidence about AAA screening. They had a combined total of 127,891 men and 9,342 women. (Only one trial included women.) The studies randomly assigned people over age 65 to receive an invitation to be screened or continue “usual care”. Significantly, the men who received AAA screening had more AAA operations, but not one of the four studies provided information regarding surgical complications or quality of life.
Life Line is exactly the type of business that would emerge from a profit-driven medical care system. It preys on people’s fear of death and counts on the prevailing overly optimistic belief that early detection is always beneficial. The company’s justifications for testing are based primarily on the high prevalence of a particular condition and its symptomless early stages. There is no evidence to show that the benefits of screening for stroke or peripheral artery disease outweigh the risks.
As for AAA screening, it could be summed up this way: We have to die of something. Four studies showed that it lowered the AAA-related death rate for the elderly male smokers but they didn’t live any longer than their non-screened counterparts. The rate of death from all causes was exactly the same in both groups 3 to 5 years after screening. Here’s another way of explaining this finding: By the time a male smoker reaches advanced age, he is more likely to die of heart disease or cancer than an AAA.
- USPSTF recommendations at www.ahrq.gov/clinic/uspstfix.htm#recommendations
- Ever wonder why the public has an overly optimistic view of screening? Read: “Unhealthy Advocacy: Journalists and Health Screening Tests” by Gary Schwitzer at www.poynter.org/column.asp?id=101&aid=123044
Maryann Napoli, Center for Medical Consumers ©