New test effective in identifying deployment-related lung disease in military personnel

A test called the lung clearance index (LCI) is superior to standard tests in identifying patients with lung disease related to military deployment, suggests a study in the August Journal of Occupational and Environmental Medicine.

Silpa Dhoma Krefft, MD, MPH, of National Jewish Health, Denver, and colleagues evaluated the LCI as a test for deployment-related lung disease. An "unknown number" of military personnel deployed to Iraq and Afghanistan have developed respiratory symptoms unexplained by traditional lung function tests and chest CT scans. This condition may be linked to burn pit emissions, desert dust, and other exposures during deployment.

The LCI detects abnormalities of the small airways; it is most often used to assess early lung damage in children with cystic fibrosis (CF). The researchers evaluated its use in 28 patients with definite (17 cases) or probable (11 cases) deployment-related lung disease. Currently, a surgical sample of lung tissue (biopsy) is needed to confirm the diagnosis.

The average LCI score was were higher for patients with symptoms of deployment-related lung disease, compared to a non-deployed control group. The difference narrowed and become nonsignificant on adjustment for age, body mass index, and smoking.

An abnormal LCI score was more sensitive in identifying patients with deployment-related lung disease, compared to standard lung function tests or CT scans. An elevated LCI score was also a better indicator of abnormal results on lung biopsy.

A noninvasive test such as the LCI could be a major advantage in detecting underlying lung disease in veterans with respiratory symptoms. Dr. Krefft and coauthors note the lack of "normative data" on LCI results in healthy adults-;most previous studies of this test have focused on younger patients with CF.

With further research, the LCI might prove useful in monitoring for stability or progression of deployment-related lung disease. It might also aid in assessing small airway abnormalities in larger groups of patients at risk of other occupational lung diseases.