[Contemporary interpretation of lung function test results]. / Eigentijdse interpretatie van longfunctiegegevens.

OBJECTIVE: To determine which changes take place in the interpretation of spirometric examination results when the transition is made from reference values for children (Zapletal) and adults (European Community for Steel and Coal (ECSC)) to those from the Global Lung Function Initiative (GLI). DESIGN: Retrospective study. METHOD: We analysed spirometric data (forced expiratory volume in 1 s, FEV1 and forced vital capacity, FVC) obtained pre- and post-bronchodilation in patients: 1012 children (aged 6-17 years, 47.1% girls) and 4653 adults (aged 18-91 years, 48.6% females). Prevalence rates of airway obstruction based on the lower limit of predicted values (FEV1/FVC < 5th percentile) and an abnormally low FVC (FEV1/FVC > 0.85, FVC < 5th percentile) were calculated in 9 groups of patients. Airway obstruction was also classified based on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criterion: FEV1/FVC < 0.70. RESULTS: Predicted values for FEV1 and FVC according to ECSC and Zapletal were too low. The prevalence rates of spirometrically determined airway obstruction using the three prediction equations varied little; an abnormally low FVC occurred more frequently, especially in young adults. GOLD-defined airway obstruction led to 13.5% underdiagnosis in those aged < 45 years, and about 33% overdiagnosis in elderly subjects, being markedly age-dependent. CONCLUSION: The prevalence rate of spirometrically determined airway obstruction is little affected by adopting the GLI reference values. The GOLD criterion for airway obstruction leads to underdiagnosis in adults aged < 45 years, and appreciable overdiagnosis in those aged > 45 years. Using z-scores to interpret test results removes biases related to age, height and sex and ethnic group and is clinically valid.

Predictive value of NT-proBNP in vascular surgery patients with COPD and normal left ventricular systolic function.

N-terminal pro-B-type natriuretic peptide (NT-proBNP) is commonly used to identify a cardiac cause of dyspnoea. However, patients with chronic obstructive pulmonary disease (COPD) may also have increased plasma NT-proBNP levels because of right-sided myocardial stress caused by pulmonary hypertension. We investigated the relationship between COPD and elevated NT-proBNP levels as well as the impact of elevated NT-proBNP levels on mortality in vascular surgery patients with normal left ventricular systolic function. Prior to vascular surgery, NT-proBNP levels, pulmonary function and left ventricular ejection fraction (LVEF) were assessed in 376 patients. Only patients with a LVEF > 40% were included; n = 261. Elevated NT-proBNP levels were defined as > or =500 pg/ml. Firstly, we assessed the relationship between COPD and NT-proBNP levels. Secondly, we investigated the association between elevated NT-proBNP levels and one-year mortality. COPD was independently associated with elevated NT-proBNP levels (OR 3.36, 95%CI 1.30-8.65) with significant associations found for mild and severe COPD. Elevated NT-proBNP levels were associated with increased one-year mortality in patients with (HR 7.73, 95%CI 1.60-37.43) and without COPD (HR 3.44, 95%CI 1.10-10.73). COPD was associated with elevated NT-proBNP levels in patients with a normal LVEF undergoing vascular surgery. Elevated NT-proBNP levels independent of other well-established risk factors were associated with increased one-year mortality. NT-proBNP may be useful biomarker to risk stratify patients with COPD.

Beta-blockers and health-related quality of life in patients with peripheral arterial disease and COPD.

BACKGROUND: Beta-blockers are frequently withheld in patients with cardiovascular disease who also have chronic obstructive pulmonary disease (COPD) because of concerns that they might provoke bronchospasm and cause deterioration in health status. Although beta1-selective beta-blockers are associated with reduced mortality in COPD patients, their effects on health status are unknown. The aim of this study was to investigate the relationship between beta-blockers and health-related quality of life (HRQOL) in patients with peripheral arterial disease and COPD. METHODS: Of the original cohort of 3371 vascular surgery patients, 1310 had COPD of whom 469 survived during long-term follow-up. These COPD patients were sent the Short Form-36 (SF-36) health-related quality of life questionnaire, which was completed and returned by 326 (70%) patients. RESULTS: No significant differences in any of the SF-36 domains were observed between COPD patients who did and did not use beta-blockers (p > 0.05 for all). Furthermore, beta-blockers were not associated with any impairment in HRQOL among patients with COPD. CONCLUSION: Beta-blockers had no material impact on the HRQOL of patients with peripheral arterial disease who also had COPD. This suggests that beta-blockers can, in most circumstances, be administered to patients with COPD without impairment in HRQOL.

Association between chronic obstructive pulmonary disease and chronic kidney disease in vascular surgery patients.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is recognized as a source of systemic inflammation and is associated with the development of cardiovascular disease. However, little is known about the association between COPD and chronic kidney disease (CKD). Therefore, we investigated the relationship between COPD and CKD and the association between COPD and mortality in patients with CKD. METHODS: We conducted a cohort study of 3358 vascular surgery patients between 1990 and 2006. CKD was defined according to the Modification of Diet in Renal Disease equation as an estimated glomerular filtration rate (GFR) <60 mL/min/1.73 m(2). In addition, the patients were divided into three categories based on the baseline estimated GFR: > or =90 mL/min/1.73 m(2); 60-89 mL/min/1.73 m(2) and <60 mL/min/1.73 m(2). Multivariable logistic regression analysis was used to evaluate the independent association between prevalent COPD and CKD. RESULTS: The prevalence of COPD was inversely related to kidney function. COPD was present in 47, 38 and 32% of patients with an estimated GFR <60, 60-89 and > or =90 mL/min/1.73 m(2), respectively. COPD was independently associated with CKD (OR 1.22; 95% CI 1.03-1.44; P = 0.03). This association was strongest in patients with moderate COPD (OR 1.33; 95% CI 1.07-1.65; P = 0.01). Both moderate and severe COPD were associated with increased long-term mortality in patients with CKD (HR 1.27; 95% CI 1.03-1.56; P = 0.03 and HR 1.61; 95% CI 1.10-2.35; P = 0.01, respectively), compared to patients without COPD. CONCLUSIONS: Our findings indicate that COPD is moderately associated with CKD in a large cohort of vascular surgery patients. In addition, moderate and severe COPD are related to increased long-term mortality in patients with CKD.

Effect of statin therapy on mortality in patients with peripheral arterial disease and comparison of those with versus without associated chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) and peripheral arterial disease (PAD) are both inflammatory conditions. Statins are commonly used in patients with PAD and have anti-inflammatory properties, which may have beneficial effects in patients with COPD. The relation between statin use and mortality was investigated in patients with PAD with and without COPD. From 1990 to 2006, we studied 3,371 vascular surgery patients. Statin use was noted at baseline and, if prescribed, converted to <25% (low dose) and > or =25% (intensified dose) of the maximum recommended therapeutic dose. The diagnosis of COPD was based on the Global Initiative for Chronic Obstructive Lung Disease guidelines using pulmonary function test. End points were short- (30-day) and long-term (10-year) mortality. A total of 330 patients with COPD (25%) used statins, and 480 patients (23%) without COPD. Statin use was independently associated with improved short- and long-term survival in patients with COPD (odds ratio 0.48, 95% confidence interval [CI] 0.23 to 1.00; hazard ratio 0.67, 95% CI 0.52 to 0.86, respectively). In patients without COPD, statins were also associated with improved short- and long-term survival (odds ratio 0.42, 95% CI 0.20 to 0.87; hazard ratio 0.76, 95% CI 0.60 to 0.95, respectively). In patients with COPD, only an intensified dose of statins was associated with improved short-term survival. However, for the long term, both low-dose and intensive statin therapy were beneficial. In conclusion, statin use was associated with improved short- and long-term survival in patients with PAD with and without COPD. Patients with COPD should be treated with an intensified dose of statins to achieve an optimal effect on both the short and long term.

Impact of cardioselective beta-blockers on mortality in patients with chronic obstructive pulmonary disease and atherosclerosis.

RATIONALE: beta-Blocker use is associated with improved health outcomes in patients with cardiovascular disease. There is a general reluctance to prescribe beta-blockers in patients with chronic obstructive pulmonary disease (COPD) because they may worsen symptoms. OBJECTIVES: We investigated the relationship between cardioselective beta-blockers and mortality in patients with COPD undergoing major vascular surgery. METHODS: We evaluated 3,371 consecutive patients who underwent major vascular surgery at one academic institution between 1990 and 2006. The patients were divided into those with and without COPD on the basis of symptoms and spirometry. The major endpoints were 30-day and long-term mortality after vascular surgery. Patients were defined as receiving low-dose therapy if the dosage was less than 25% of the maximum recommended therapeutic dose; dosages higher than this were defined as intensified dose. MEASUREMENTS AND MAIN RESULTS: There were 1,205 (39%) patients with COPD of whom 462 (37%) received cardioselective beta-blocking agents. beta-Blocker use was associated independently with lower 30-day (odds ratio, 0.37; 95% confidence interval, 0.19-0.72) and long-term mortality in patients with COPD (hazards ratio, 0.73; 95% confidence interval, 0.60-0.88). Intensified dose was associated with both reduced 30-day and long-term mortality in patients with COPD, whereas low dose was not. CONCLUSIONS: Cardioselective beta-blockers were associated with reduced mortality in patients with COPD undergoing vascular surgery. In carefully selected patients with COPD, the use of cardioselective beta-blockers appears to be safe and associated with reduced mortality.

Comparison of total-breath and single-breath diffusing capacity in healthy volunteers and COPD patients.

BACKGROUND: The measurement of single-breath diffusing capacity (Dlco(SB)) assumes that diffusing capacity per liter of alveolar volume (Dlco/VA) determined in a 750-mL gas sample represents the diffusing capacity (Dlco) of the entire lung. Fast-responding gas analyzers provide the opportunity to verify this assumption because of the possibility to measure CO and CH(4) fractions continuously throughout the entire expiration. Continuous gas sampling provides more information per measurement, but this information cannot be expressed in the traditional parameters. Our goals were to find new parameters to express the extra information of the continuous gas sampling, and to compare these new parameters with the traditional parameters. METHODS: We compared a new method to determine Dlco with the traditional method in 62 healthy volunteers and 26 COPD patients. Traditionally, Dlco(SB) is determined by multiplying Dlco/VA with alveolar volume, both calculated from gas concentrations in a 750-mL gas sample. The new method calculates total-breath Dlco (Dlco(TB)) by integration of Dlco/VA against exhaled volume. RESULTS: In healthy volunteers, Dlco/VA shows a slight upward slope during exhalation, while in COPD patients Dlco/VA shows a horizontal line. Total-breath total lung capacity (TLC) is larger than single-breath TLC both in healthy volunteers and in COPD patients, leading to a Dlco(TB) that is significantly larger than Dlco(SB) in both groups (p < 0.001). CONCLUSION: The assumption that a 750-mL gas sample represents the entire lung seems to be correct for Dlco/VA but not for the CH(4) fraction in case of ventilation inhomogeneity.