Emphysema and DLCO predict a clinically important difference for 6MWD decline in COPD. Issue 7 (July 2015)

• Record Type: Journal Article
• Authors: Díaz, Alejandro A.; Pinto-Plata, Victor; Hernández, Camila; Peña, Javier; Ramos, Cristóbal; Díaz, Juan C.; Klaassen, Julieta; Patino, Cecilia M.; Saldías, Fernando; Díaz, Orlando
• Is Part Of: Respiratory medicine. Volume 109:Issue 7(2015)
• Page Start: 882
• Page End: 889
• Publication Date: 2015-07
• Subjects: Chest -- Diseases -- Periodicals; Chest -- Diseases -- Great Britain -- Periodicals; Respiratory organs -- Diseases -- Periodicals; Respiratory Tract Diseases -- Periodicals; Appareil respiratoire -- Maladies -- Périodiques; Thorax -- Maladies -- Périodiques; Appareil respiratoire -- Maladies -- Traitement -- Périodiques; Electronic journals; 616.2
• DOI: 10.1016/j.rmed.2015.04.009
• Languages: English
• ISSNs: 0954-6111

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Summary</title> <sec> <title id="sectitle0015">Background</title> <p id="abspara0010">Exercise impairment is a central feature of chronic obstructive pulmonary disease (COPD), and a minimal clinically important difference (MCID) for 6-min walk distance (6MWD) decline (>30 m) has been associated with increased mortality. The predictors of the MCID are not fully known. We hypothesize that physiological factors and radiographic measures predict the MCID.</p> </sec> <sec> <title id="sectitle0020">Methods</title> <p id="abspara0015">We assessed 121 COPD subjects during 2 years using clinical variables, computed tomographic (CT) measures of emphysema, and functional measures including diffusion lung capacity for carbon monoxide (DL<sub>CO</sub>). The association between an MCID for 6MWD and clinical, CT, and physiologic predictors was assessed using logistic analysis. The C-statistic was used to assess the predictive ability of the models.</p> </sec> <sec> <title id="sectitle0025">Results</title> <p id="abspara0020">Forty seven (39%) subjects had an MCID. In an imaging-based model, log emphysema and age were the best predictors of MCID (emphysema Odds Ratio [OR] 2.47 95%CI [1.28–4.76]). In a physiologic model, DL<sub>CO</sub>, age, and male gender were selected the best predictors (DL<sub>CO</sub> OR 1.19 [1.08–1.31]). The C-statistic for the ability of these models to predict an MCID was 0.71 and 0.75, respectively.</p> </sec> <sec> <title id="sectitle0030">Conclusion</title> <p id="abspara0025">In COPD patients the burden of emphysema on CT scan and DL<sub>CO</sub> predict a clinically meaningful decline in exercise capacity.</p> </sec> </abstract>