TRAVIS AIR FORCE BASE, Calif. – A study examining the association between severity of injury, post-traumatic stress disorder and the long-term development of chronic diseases, such as hypertension, may hold the key to better health outcomes for injured U.S. military members.
The study, conducted by the David Grant USAF Medical Center Clinical Investigative Facility at Travis Air Force Base, California, was published this month in the American Heart Association’s journal Hypertension.
It’s the first study to follow a large group of injured service members and the second in a series focusing on long-term health outcomes after combat injury.
“The implications from the study suggest that those injured in war require a holistic approach encompassing both medical and mental health treatment to improve long-term outcomes,” said Maj. (Dr.) Ian Stewart, 60th Medical Group nephrologist and the study’s senior author. “We’ve shown before that if you’re severely injured, you’re more prone to develop medical problems, to include hypertension, but what we didn’t know was why?”
Researchers hypothesized that the development of chronic medical conditions in combat-injured military members is driven by three pathways: inflammation and metabolic; mental health, including PTSD, depression and anxiety; and behavioral, such as weight gain, smoking and high-risk activities.
Stewart said they reviewed the records of more than 6,000 military personnel injured between Feb. 1, 2002, and Feb. 1, 2011. After excluding records with missing data, patients injured a second time in combat and patients who were ill before they were injured, researchers had a group of 3,846 military members who met the study’s criteria.
Patients were divided into one of three groups: those with no PTSD diagnosis, those with one to 15 diagnoses and those with more than 15 diagnoses. They followed the groups for more than four years and found that the more times a patient was diagnosed with PTSD, the greater their chances to develop hypertension.
“When we compared patients with one to 15 diagnoses to those that didn’t have any, we found that they were at an 85 percent increased risk for hypertension,” said Stewart. “Those who had more than 15 diagnoses had a 114 percent increase in risk for hypertension – more than double.”
Patients also were assigned an Injury Severity Score, which is an established medical score to assess trauma severity. An ISS of 1 means the injury is very minor, while an ISS of 75 is an almost non-survivable injury, said Stewart.
Researchers found that for every five-point increase in ISS, overall risk of high blood pressure rose 5 percent.
“Initially, we postulated that if you were severely injured, you were likely to get PTSD and that would increase your risk for hypertension,” said Stewart. “But what we found was surprising. PTSD does appear to increase the risk of hypertension, but the risk is additive to the injury itself.”
Limitations of the study include the fact that researchers looked for associations retrospectively and had to rely on a doctor’s note saying the patient had high blood pressure. Also, researchers did not have information to account for obesity – based on body mass index – and had no genetic information.
Nonetheless, the study is the best data available on long-term health outcomes because patients were followed for such a long period of time, said Stewart.
The study also initiates the conversation about what to do in the early stages to decrease the risk of poor long-term health outcome while injured military members are still on active duty and what to do to improve outcome when they are discharged and become part of the Veterans Administration healthcare system.
Researchers are in the process of conducting a third but smaller study that follows another group of military members, checking blood samples and blood pressure medications with injury records to determine if there are inflammatory markers.
“Also, we have a collaboration with our VA partners to combine the data available on these injured patients and their long-term outcomes,” said Stewart. “I think that’s going to be the Holy Grail as we combine these data sets.”
Since the United States has been involved in the war in Afghanistan and Iraq, 52,087 U.S. service members have been wounded. More than 23,000 suffered injuries so severe they were admitted to an intensive care unit like Craig Joint-Theater Hospital at Bagram, Afghanistan, where Stewart was deployed.
“I can say with full confidence that our service members get the finest care anywhere, bar none,” said Stewart. “People are surviving injuries they would not have survived 10 to 40 years ago.”
However, the more the military understands about the long-term health effects of those injured in combat, the better able healthcare providers will be to design individualized therapies to treat them, said Stewart.
“But that’s something way down the road,” he said.