ATS 2013, PHILADELPHIA ─ Depression is common in patients with chronic obstructive pulmonary disease (COPD) 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 results will be presented at the ATS 2013 International Conference in Philadelphia.
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."
* Please note that numbers in this release may differ slightly from those in the abstract. Many of these investigations are ongoing; the release represents the most up-to-date data available at press time.
Systemic Inflammation Associated With Depression In COPD Independent Of Airflow Obstruction Severity
Type: Scientific Abstract
Category: 09.03 - COPD: Comorbidities (CP)
Authors: H.C. Strollo, J.M. Bon, J.R. Tedrow, C.M. Karoleski, S.R. Duncan, J.L. Weissfeld, Y. Zhang, R.A. Branch, F.C. Sciurba; University of Pittsburgh - Pittsburgh, PA/US
Rationale: Depression is a prevalent comorbidity of chronic obstructive pulmonary disease (COPD). Systemic inflammation associated with COPD has been proposed to be a potential mediator linking COPD with comorbidities. While depression has been associated with severity of obstruction, symptoms and quality of life, the association with inflammatory biomarkers, such as interleukin-6 (IL-6) has not been described. Methods: Four-hundred fifty tobacco exposed participants in the University of Pittsburgh SCCOR cohort were evaluated using the Beck Depression Inventory (BDI) (score ≥ 10 defined as depression). Participants completed the Saint George Respiratory Questionnaire (SGRQ) and UCSD Shortness of Breath Questionnaire (UCSD SOBQ). Post-bronchodilator spirometry, lung volumes and DLCO were measured. Multi-detector Computed Tomography (MDCT) of the chest was scored using a five-point semiquantitative visual emphysema score and quantitative parenchymal and airway scoring. Plasma IL-6 was measured using ELISA. T-test, univariate and multivariate analyses were performed to identify determinants of depression. SGRQ and UCSD SOBQ were considered dependent rather than independent variables relative to BDI in analyses. Results: Participants (N=450) included: 235 males (37 depressed), 215 females (49 depressed), age 65.3 ± 6.4 years, BMI 28.0 ± 4.0 kg/m2, GOLD distribution included Gold 0 (43.6%), GOLD 1 (15.6%), GOLD 2 (26.9%), GOLD 3/4 (7.1%), GOLD Unclassified (6.9%) current smokers. Univariate analysis demonstrated BDI significantly associated with low FEV1 % predicted, increased IL-6 (2.428 pg/ml ± 3.30 depressed, 1.790 pg/ml ± 1.82 not depressed), high visual emphysema score, current smoking status, female gender, high SGRQ total score and high UCSD SOBQ total score. Age and BMI were not significantly associated with BDI. A stepwise regression showed that low FEV1 % predicted (p=0.0031) was most strongly correlated with increased depressive symptoms, followed by female gender (0.0133), current smoking status (p=0.0204) and increased IL-6 (p=0.0227). Conclusion: Plasma IL-6 is increased in COPD patients experiencing depression. These results suggest that systemic inflammatory biomarkers may play a role in depression associated with COPD.