Depression and functional status are strongly associated with dyspnea in interstitial lung disease.
BACKGROUND
Little is understood about the characteristics of dyspnea in patients with interstitial lung disease (ILD), and its severity is likely influenced by multiple factors. Depression and functional status are known to influence dyspnea in patients with COPD. The aim of this study was to determine the relationship of dyspnea with clinical parameters, including depression and functional status, in patients with ILD.


METHODS
Dyspnea was measured with the Baseline Dyspnea Index and the University of California San Diego Shortness of Breath Questionnaire. Clinical parameters were recorded. Regression analysis was performed to determine independent correlates of dyspnea.


RESULTS
Fifty-two subjects were enrolled. The two dyspnea scales were strongly correlated (r=-0.79; P<.00005). The mean levels of dyspnea were 6.5 and 41.0, representing a moderate degree of dyspnea. Clinically meaningful depressive symptoms were found in 23% of subjects. Independent correlates of dyspnea severity for each dyspnea scale were depression score (P=.002 and P<.0005), 4-m walk time (P=.001 and P=.06), FVC (P=.07 and P=.004), and diffusing capacity of the lung for carbon monoxide (P=.007). BMI had borderline significant association with the Baseline Dyspnea Index (P=.10).


CONCLUSIONS
In patients with ILD, dyspnea is associated with depression score, functional status, and pulmonary function. These results suggest that attention to depression and functional status is important in these patients and that treatment directed at these comorbidities may improve dyspnea and quality of life.


BACKGROUND
ClinicalTrials.gov; No.: NCT00611182 ; URL: www. clinicaltrials.gov.
Ryerson
Christopher J
CJ
Department of Medicine, School of Medicine, University of California San Francisco, San Francisco, CA.
Berkeley
Jane
J
Department of Medicine, School of Medicine, University of California San Francisco, San Francisco, CA.
Carrieri-Kohlman
Virginia L
VL
Department of Physiological Nursing, School of Nursing, University of California San Francisco, San Francisco, CA.
Pantilat
Steven Z
SZ
Department of Medicine, School of Medicine, University of California San Francisco, San Francisco, CA.
Landefeld
C Seth
CS
Department of Medicine, School of Medicine, University of California San Francisco, San Francisco, CA.
Collard
Harold R
HR
Department of Medicine, School of Medicine, University of California San Francisco, San Francisco, CA. Electronic address: hal.collard@ucsf.edu.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003863:Depression / Q000453:epidemiology / Q000503:physiopathology* / Q000523:psychology*; D004417:Dyspnea / Q000453:epidemiology / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D006306:Health Surveys; D006801:Humans; D008168:Lung / Q000503:physiopathology; D017563:Lung Diseases, Interstitial / Q000453:epidemiology / Q000503:physiopathology* / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015995:Prevalence; D011446:Prospective Studies; D011788:Quality of Life / Q000523:psychology; D012189:Retrospective Studies; D012720:Severity of Illness Index