This study was undertaken to test the hypothesis that a reduction in midthigh muscle cross-sectional area obtained by CT scan (MTCSA(CT)) is a better predictor of mortality in chronic obstructive pulmonary disease (COPD) than low body mass index (BMI). We also wished to evaluate whether anthropometric measurements could be used to estimate MTCSA(CT). One hundred forty-two patients with COPD (age = 65 +/- 9 years, mean +/- SD, 26 F, BMI = 26 +/- 6 kg/m(2), FEV(1) = 42 +/- 16% predicted) were recruited from September 1995 to April 2000 with a mean follow-up of 41 +/- 18 months. The primary end-point was all-cause mortality during the study period. A Cox proportional hazards regression model was used to predict mortality using the following independent variables: age, sex, daily use of corticosteroid, FEV(1), DL(CO), BMI, thigh circumference, MTCSA(CT), peak exercise workrate, Pa(O2), and Pa(CO2). Only MTCSA(CT) and FEV(1) were found to be significant predictors of mortality (p = 0.0008 and p = 0.01, respectively). A second analysis was also performed with FEV(1) and MTCSA(CT) dichotomized. Patients were divided into four subgroups based on FEV(1) (< or >or= 50% predicted) and MTCSA(CT) (< or >or= 70 cm(2)). Compared with patients with an FEV(1) >or= 50% predicted and a MTCSA(CT) >or= 70 cm(2), those with an FEV(1) < 50% predicted and a MTCSA(CT) >or= 70 cm(2) had a mortality odds ratio of 3.37 (95% confidence interval, 0.41-28.00), whereas patients with an FEV(1) < 50% predicted and a MTCSA(CT) < 70 cm(2) had a mortality odds ratio of 13.16 (95% confidence interval, 1.74-99.20). MTCSA(CT) could not be estimated with sufficient accuracy from anthropometric measurements. In summary, we found in this cohort of patients with COPD that (1) MTCSA(CT) was a better predictor of mortality than BMI, and (2) MTCSA had a strong impact on mortality in patients with an FEV(1) < 50% predicted. These findings suggest that the assessment of body composition may be useful in the clinical evaluation of these patients.

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C ardiovascular disease is the leading cause of mortality in patients with chronic kidney disease. 1,2 Aortic stiffness, which results in increased pulse pressure (PP), cardiac overload, and left ventricular hypertrophy, is an established predictor for cardiovascular morbidity and mortality in chronic kidney disease. [3][4][5] Physiologically, the aorta is much more elastic than peripheral muscular arteries providing a physiological stiffness gradient. This physiological gradient of stiffness generates reflecting sites, which dampens the transmission of forward travelling pressure into the microcirculation. In normal aging, aortic stiffness increases to a greater extent than peripheral muscular arteries, resulting in equalization or even reversal of stiffness gradient (aortic stiffness>muscular artery stiffness), referred to as stiffness mismatch. 6-9 Attenuation or reversal of physiological stiffness gradient has been proposed to cause vascular damage through enhanced transmission of forward travelling wave energy into the microcirculation. 9,10In a longitudinal study with repeated measures of aortic and brachial stiffness in hemodialysis patients, we observed an accelerated progression of aortic stiffness and a significant reduction in brachial stiffness. 11 The regression of brachial stiffness was associated to higher degree of aortic stiffness, therefore, leading to an enhanced aortic-brachial stiffness mismatch. In the context of this study, we hypothesized that aortic-brachial stiffness mismatch, as evaluated by the ratio of aortic and brachial pulse wave velocity (PWV) ratio, may prove to be a better prognostic predictor of mortality in dialysis population than aortic PWV. Therefore, the objectives of this study were to examine the nonadjusted and adjusted effect of the PWV ratio on overall mortality and to study its relative predictive value as compared with well-known central and peripheral hemodynamic parameters.Abstract-We hypothesized that increased aortic stiffness (central elastic artery) combined with a decrease in brachial stiffness (peripheral muscular artery) leads to the reversal of the physiological stiffness gradient (ie, mismatch), promoting end-organ damages through increased forward pressure wave transmission into the microcirculation. We, therefore, examined the effect of aortic-brachial stiffness mismatch on mortality in patients in need of dialysis. In a prospective observational study, aortic-brachial arterial stiffness mismatch (pulse wave velocity ratio) was assessed using carotid-femoral pulse wave velocity divided by carotid-radial pulse wave velocity in 310 adult patients on dialysis. After a median follow-up of 29 months, 146 (47%) deaths occurred. The hazard ratio (HR) for mortality related to PWV ratio in a Cox regression analysis was 1.43 (95% confidence interval [CI], 1.24-1.64; P<0.001 per 1 SD) and was still significant after adjustments for confounding factors, such as age, dialysis vintage, sex, cardiovascular disease, diabetes mellitus, smoking status, and weight (HR...