In chronic obstructive pulmonary disease (COPD) patients, depression is common and has been linked with disease severity and impaired quality of life.
Now, for the first time, researchers at the University of Pittsburgh have linked the systemic inflammation associated with COPD with depression in these patients.
"Systemic inflammation is thought to be an important mediator of comorbidities in COPD, but the relationship between inflammation and depression has not been explored," said researcher Hilary Strollo, M.S., a graduate of the University of Pittsburgh School of Health and Rehabilitation Sciences. "In our study, we found a strong association between depressive symptoms and levels of the inflammatory biomarker interleukin-6 (IL-6) which was independent of the severity of airflow obstruction."
The study included 450 tobacco-exposed patients. Assessment included the Beck Depression Inventory (BDI), the Saint George Respiratory Questionnaire (SGRQ), and the UCSD Shortness of Breath Questionnaire (SOBQ). Spirometry and multi-detector computed tomography (MDCT) of the chest were also performed.
Of 235 male patients enrolled, 37 were depressed, and of 215 females, 49 were depressed. Clinical and biological variables that were found to be significantly associated with depression included the forced expiratory volume or FEV1, a measure of the maximum amount of air that can be exhaled in one second, gender, IL-6 levels, SGRQ Total Score, UCSD SOBQ Total Score, Visual Emphysema Score, and current smoking status.
The strongest associations were seen between depressive symptoms and FEV1, followed by female gender, current smoking status and increased IL-6.
"Depression has been linked with a number of symptoms and comorbidities in COPD patients," said Ms. Strollo. "Our findings add evidence of a strong relationship between depression and one of the hallmarks of COPD, systemic inflammation, independent of the severity of disease."
"The assessment and treatment of depression should be part of the routine care of COPD patients."