Airway inflammation contributes to health status in COPD: a cross-sectional study.
BACKGROUND
Chronic obstructive pulmonary disease (COPD) is characterized by irreversible airflow limitation and airway inflammation, accompanied by decreased health status. It is still unknown which factors are responsible for the impaired health status in COPD. We postulated that airway inflammation negatively contributes to health status in COPD.


METHODS
In 114 COPD patients (99 male, age: 62 +/- 8 yr, 41 [31-55] pack-years, no inhaled or oral corticosteroids, postbronchodilator FEV1: 63 +/- 9% pred, FEV1/IVC: 48 +/- 9%) we obtained induced sputum and measured health status (St. George's respiratory questionnaire (SGRQ)), postbronchodilator FEV1, hyperinflation (RV/TLC), and airway hyperresponsiveness to methacholine (PC20). Sputum was induced by hypertonic saline and differential cell counts were obtained in 102 patients.


RESULTS
Univariate analysis showed that SGRQ total and symptom score were positively associated with % sputum macrophages (r = 0.20, p = 0.05; and r = 0.20, p = 0.04, respectively). Multiple regression analysis confirmed these relationships, providing significant contributions of % sputum macrophages (B = 0.25, p = 0.021) and RV/TLC (B = 0.60, p = 0.002) to SGRQ total score. Furthermore, SGRQ symptom score was associated with % sputum macrophages (B = 0.30, p = 0.03) and RV/TLC (B = 0.48, p = 0.044), whilst SGRQ activity score was associated with % sputum macrophages (B = 0.46, p = 0.002), RV/TLC (B = 0.61, p = 0.015), and PC20 (B = -9.3, p = 0.024). Current smoking and FEV1 were not significantly associated with health status in the multiple regression analysis.


CONCLUSIONS
We conclude that worse health status in COPD patients is associated with higher inflammatory cell counts in induced sputum. Our findings suggest that airway inflammation and hyperinflation independently contribute to impaired health status in COPD. This may provide a rationale for anti-inflammatory therapy in this disease.
Snoeck-Stroband
Jiska B
JB
General Practice, Leiden University Medical Center, Leiden, The Netherlands. J.B.Snoeck-Stroband@lumc.nl
Postma
Dirkje S
DS
Lapperre
Thérèse S
TS
Gosman
Margot M E
MM
Thiadens
Henk A
HA
Kauffman
Henk F
HF
Sont
Jacob K
JK
Jansen
Désirée F
DF
Sterk
Peter J
PJ
D000328:Adult; D015984:Causality; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011014:Pneumonia / Q000453:epidemiology / Q000276:immunology; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology* / Q000276:immunology*; D012130:Respiratory Hypersensitivity / Q000453:epidemiology* / Q000276:immunology*; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013183:Sputum / Q000276:immunology