Mortality Rates for Pulmonary Thromboembolism Show Significant Decrease Over the Past Two Decades
A ]]>pulmonary thromboembolism (PTE)]]> is the blockage of an artery in the lungs by a blood clot. In nearly all cases, PTE originates as ]]>deep vein thrombosis (DVT)]]> , the formation of a blood clot in a vein deep within the body, such as the veins in the legs or hips. PTE occurs when this blood clot breaks loose and travels through the bloodstream until it becomes lodged in a smaller blood vessel in the lungs. This blockage prevents portions of the affected lung from receiving the oxygen and nutrients it needs, resulting in damage to the lung that often leads to death.
The most recent highly publicized death due to PTE was that of David Bloom, a 39-year old veteran journalist for NBC who was traveling with the U.S. 3rd Infantry Division about 25 miles south of Bagdad when he fell ill. Despite being airlifted to a nearby medical unit, he did not survive.
Past estimates of the mortality rate for PTE have ranged from between 50,000 to 100,000 deaths annually in the U.S. However, because, unlike Bloom, many of these patients also have other major diseases, such as obesity, heart disease, or chronic obstructive pulmonary disease, it has been difficult for researchers to distinguish the number of deaths in which PTE was the direct underlying cause of death from those in which it was a significant contributory factor.
Recently, a group of researchers set out to clarify the matter by sorting through twenty years of death certificates at the National Center for Health Statistics. The results of this study were published in the July 28, 2003 issue of the Archives of Internal Medicine. The researchers made two discoveries: first, that in approximately one third of all PTE-related deaths, PTE was the direct underlying cause of death; second, that over the past 20 years, mortality rates due to PTE have decreased significantly, due in part, they believe, to advances in the prevention, diagnosis, and treatment of this complicated clinical condition.
About the study
Using data from the National Center for Health Statistics, the researchers analyzed the death certificates of 42,932,973 decedents who died between 1979 and 1998. The data was analyzed according to age, sex, and race.
The researches found that of all the death certificates they analyzed, 572,773 listed PTE as a significant contributory factor on the death certificates and 194,389 listed PTE as the underlying cause of death.
They also found that the number of deaths attributed directly to PTE decreased from 191 million in 1979 to 94 million in 1998, an overall reduction of 56% in men and 46% in women.
How does this affect you?
The results of the study demonstrate that PTE is the direct underlying cause of death in approximately one third of all PTE-related deaths.
The researchers also found that the mortality rates for PTE varied substantially among racial groups. For example, mortality rates for blacks were consistently 50% higher than those for whites, which were 50% higher than those for people of other races, such as Asian or American Indian. They also found that within these racial groups, mortality rates for men were consistently 20% to 30% higher than for women. Despite this variability, however, they found that overall the mortality rate for PTE in the United States has dropped by approximately 30% over the past two decades, and that this drop was consistent for both men and women of all ethnic groups.
The researchers offer three possible explanations for this consistent decline: a decrease in the occurrence of PTE itself, a decrease in the number of fatalities from PTE, or changes in diagnostic patterns. As statistics do not bear out the first explanation, the researchers credit the dramatic decrease in the PTE mortality rate to the latter two explanations, that advancements in the prevention, diagnosis, and treatment of PTE are responsible for the dramatic decrease in PTE mortality.
For most, prevention of PTE begins with living a healthful lifestyle. For those who know they area at high risk for blood clots, additional measures include:
- Breaking up long periods of sitting by moving your legs or walking around.
- Taking any medications your doctor recommends.
- Wearing elastic stockings (also called support hose) to improve circulation in your legs.
It is also helpful to be aware of the signs and symptoms of DVT/PTE. Symptoms of DVT may include:
- Swelling of a limb
- Tenderness along the vein
- Redness, paleness or blueness of the skin of the affected limb
Symptoms of PTE may include:
- Shortness of breath that starts suddenly for no obvious reason
- Chest pain, especially when breathing or coughing
- Feeling faint, lightheaded, dizzy
- Cough, sometimes with bloody phlegm
- Rapid heartbeat
- Rapid breathing
- Swollen, distended neck veins
National Heart, Lung, and Blood Institute
Horlander KT, Mannino DM, Leeper KV. Pulmonary embolism mortality in the United States, 1979-1998: An analysis using multiple-cause mortality data. Arch Intern Med. 2003;163:1711-1717.
Last reviewed July 31, 2003 by ]]>Richard Glickman-Simon, MD]]>
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