Chronic Obstructive Pulmonary Disease Hospitalizations Research Articles

Physical Activity, Health Status and Risk of Hospitalization in Patients with Severe Chronic Obstructive Pulmonary Disease

Background: Chronic obstructive pulmonary disease (COPD) is a leading cause of death and 70% of the cost of COPD is due to hospitalizations. Self-reported daily physical activity and health status have been reported as predictors of a hospitalization in COPD but are not routinely assessed. Objectives: We tested the hypothesis that self-reported daily physical activity and health status assessed by a simple question were predictors of a hospitalization in a well-characterized cohort of patients with severe emphysema. Methods: Investigators gathered daily physical activity and health status data assessed by a simple question in 597 patients with severe emphysema and tested the association of those patient-reported outcomes to the occurrence of a hospitalization in the following year. Multiple logistic regression analyses were used to determine predictors of hospitalization during the first 12 months after randomization. Results: The two variables tested in the hypothesis were significant predictors of a hospitalization after adjusting for all univariable significant predictors: >2 h of physical activity per week had a protective effect [odds ratio (OR) 0.60; 95% confidence interval (95% CI) 0.41–0.88] and self-reported health status as fair or poor had a deleterious effect (OR 1.57; 95% CI 1.10–2.23). In addition, two other variables became significant in the multivariate model: total lung capacity (every 10% increase) had a protective effect (OR 0.88; 95% CI 0.78–0.99) and self-reported anxiety had a deleterious effect (OR 1.75; 95% CI 1.13–2.70). Conclusion: Self-reported daily physical activity and health status are independently associated with COPD hospitalizations. Our findings, assessed by simple questions, suggest the value of patient-reported outcomes in developing risk assessment tools that are easy to use.

Variabilidad intra GRD relacionada con los servicios de enfermería

The method of GRD prospective payment, used in Spain and around the European Union, contemplates the nursing attention linked to the main and secondary diagnosis of the patients that motivated its hospitalization. This fact conditions a variability of the nursing practice that guides the activities that nurses carry out toward those derived of the clinical diagnosis, preventing to incorporate the activities required by the patients in function of their characteristics to maintain its autonomy. The GRD pattern is very conditioned by the hospital stay, in occasions it causes different cares in the same patients, not explained by their characteristics, but for the pattern of hospitalization. The cost of the hospitalization for GRD conceals the required attention of nursing services, making invisible the cares in the mark of the GRD pattern; it seems advisable to adapt the pattern with the inclusion of levels of autonomy, related with the nursing practice. Objective: To analyze the variability in the nursing care for the same type of patients, grouped in the GRD 088 COPD (Chronic obstructive pulmonary disease), in two units of hospitalization. Method: A Study of 200 patients with an episode of hospitalization for COPD in the year 2004, in units of Pulmonology with a stay of 6.9 days and short-stay average of 2.8 days. Data Sources: clinical histories and databases of hospital SET between August 1 in 2005 and April 30 2006, collection in questionnaire produced by themselves and analyzed by statistical program SPSS. Results: analyzed 200 episodes of hospitalization. Average age of 74.4 years, hospitalized in conventional units or short stay. 3.2% of the total are women. 97 Episodes are conventional hospitalization, compared to 103 in short stay. Conclusions: There is a variability of the activity nurse not evaluated, for the same type of patients, according to the unity of hospitalization.

Chronic obstructive pulmonary disease hospitalization rates in Massachusetts: a trend analysis

Chronic Obstructive Pulmonary Disease (COPD) causes a huge economic burden and >80% of COPD cases are attributable to smoking. Massachusetts introduced a comprehensive Tobacco Control Program (MTCP) in January 1993. A trend analysis of COPD hospitalization rates might indirectly reflect the potential impact of such comprehensive tobacco control programs. Age-adjusted COPD hospitalization rates/100,000 was abstracted from the Massachusetts Community Health Information Profile Database between 1989 and 2005. Joinpoint Regression Analyses program was employed to estimate annual percent changes (APC) in COPD rates by age, sex and race. In 1989, 265/100,000 age-adjusted COPD hospitalization rates were reported that increased to 423/100,000 in 1993, and then declined to 329/100,000 in 2005. A significant annual decline of 5.6 percentage points was observed in overall COPD rates from 1993 onwards. A similar temporal pattern, with an age-gradient and a slower annual decline in female COPD rates relative to male COPD rates, was observed. COPD rates in both Blacks and Whites were similar to the general overall pattern. Such consistent annual declines in COPD hospitalization rates from 1993 onwards in Massachusetts also closely correspond to the introduction of the MTCP in January 1993. The findings indirectly suggest that smoking cessation should remain the cornerstone strategy for the prevention and control of COPD burden. However, additional studies across different population settings are essential for a definitive conclusion with regard to the immediate impact of a comprehensive tobacco control program on COPD hospitalization rates showing possible gender susceptibility.

Comorbidity, Hospitalization, and Mortality in COPD: Results from a Longitudinal Study

We evaluated comorbidity, hospitalization, and mortality in chronic obstructive pulmonary disease (COPD), with special attention to risk factors for frequent hospitalizations (more than three during the follow-up period), and prognostic factors for death. Two hundred eighty-eight consecutive COPD patients admitted to respiratory medicine wards in four hospitals for acute exacerbation were enrolled from 1999 to 2000 in a prospective longitudinal study, and followed up until December 2007. The Charlson index without age was used to quantify comorbidity. Clinical and biochemical parameters and pulmonary function data were evaluated as potential predictive factors of mortality and hospitalization. FEV(1), RV, PaO(2), and PaCO(2) were used to develop an index of respiratory functional impairment (REFI index). Hypertension was the most common comorbidity (64.2%), followed by chronic renal failure (26.3%), diabetes mellitus (25.3%), and cardiac diseases (22.1%). Main causes of hospitalization were exacerbation of COPD (41.2%) and cardiovascular disease (34.4%). Most of the 56 deaths (19.4%) were due to cardiovascular disease (67.8%). Mortality risk depended on age, current smoking, FEV(1), PaO(2), the REFI index, the presence of cor pulmonale, ischemic heart disease, and lung cancer. Number and length of hospital admissions depended on the degree of dyspnea and REFI index. The correct management of respiratory disease and the implementation of aggressive strategies to prevent or treat comorbidities are necessary for better care of COPD patients.

New and Controversial Therapies for Chronic Obstructive Pulmonary Disease

There is a medical need in chronic obstructive pulmonary disease (COPD) for novel therapies with improved anti-inflammatory activity and the potential to affect disease progression. The concept of "super bronchodilators" is currently in development. Nonsteroidal antiinflammatory approaches are now being developed and are going under investigation. Restoration of steroid sensitivity is also a potential target in COPD. This could be done by increasing HDAC-2 expression and/or activation, by decreasing p38-kinase or delta-isoform of PI3K. Disease modification that may impact on long-term health status and survival of the patient is the primary and most challenging target for novel therapy in COPD. There is need, however, for new methods and biomarkers to follow disease progression. There has been significant innovation in the nonpharmacological management of COPD including team-based approaches with collaborative self-management. Information and guidelines about self-management, coupled with interventions that provide patients with needed skills to increase their confidence, have potential impact on patient health. Recently, it has been shown that self-management programs reduce the probability of COPD hospital admissions. We should certainly be enthusiastic about these results, but there is need to increase our understanding of the relative effectiveness of specific components and how to best support COPD patients in self-management. Conceptualization of a research plan for COPD self-management is needed for future research to be successful.

Mortality Risk in Patients Receiving Drug Regimens with Theophylline for Chronic Obstructive Pulmonary Disease

To evaluate outcomes associated with six treatment regimens with theophylline versus each regimen without theophylline in patients with chronic obstructive pulmonary disease (COPD). Retrospective cohort study. Veterans Affairs health care system. A total of 183,573 patients aged 45 years or older who had a diagnosis of COPD and were receiving respiratory drug therapy. Patients' treatment regimens were identified by using data from October 1, 2002-March 31, 2003, and patients were followed for events by using data from April 1, 2003-September 30, 2005. Data from October 1, 2001-September 30, 2002, were used to define the patients' baseline characteristics. Primary outcome measures were all-cause mortality, COPD exacerbations, and COPD-related hospitalizations. Two approaches were used: first, treatment assignment was based on drug therapy at baseline, and second, exposure was measured as a time-varying covariate. Treatment groups were stratified based on propensity to receive theophylline. Mortality was compared by using Cox proportional hazards models, and other outcomes were compared with use of negative binomial models. Comparisons were conducted within individual treatment regimens that were the same with the exception of theophylline. Patients treated with ipratropium plus theophylline (largest group) compared with those treated with ipratropium alone had a 1.11-fold increase in the risk of death (95% confidence interval [CI] 1.04-1.18). For each of the other regimens, the risk of mortality associated with theophylline was greater than that in the regimens without theophylline (hazard ratios [HRs] 1.17-1.31). In the time-varying exposure analysis, theophylline (HR 1.23, 95% CI 1.09-1.39) was associated with an increased mortality risk. Patients receiving regimens that included theophylline had slightly increased risks of mortality, COPD exacerbations, and COPD hospitalizations compared with patients receiving the same regimens without theophylline. However, the benefits of theophylline on other factors, including symptoms, quality of life, and activities of daily living, were not measured. Clinicians should consider all of the potential benefits and harms associated with theophylline when making treatment recommendations.

Outcomes Associated With Tiotropium Use in Patients With Chronic Obstructive Pulmonary Disease

To date, there is mixed evidence on the safety and effectiveness of tiotropium. Our objective was to evaluate the comparative effectiveness of regimens containing tiotropium bromide vs other medication regimens for chronic obstructive pulmonary disease (COPD) in real-world clinical settings. We conducted a cohort study on 2 separate cohorts with a diagnosis of COPD in the Veterans Affairs health care system. Patients with a diagnosis of COPD prescribed tiotropium and patients in a historic cohort prior to the introduction of tiotropium were selected for comparison using propensity scores, with the base case including scores from 0.1 to 0.4. Outcomes identified during follow-up were all-cause mortality, COPD exacerbations, and COPD hospitalizations. Exposure to COPD medication regimens was defined in a time-varying manner and Cox proportional hazards regression were used to evaluate outcomes. For 42 090 patients in the base case, the regimen of tiotropium + inhaled corticosteroids (ICS) + long-acting beta-agonists (LABA) was associated with 40% reduced risk of death (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.45-0.79) compared with ICS + LABA. This combination was associated with reduced rates of COPD exacerbations (HR, 0.84; 95% CI, 0.73-0.97) and COPD hospitalizations (HR, 0.78; 95% CI, 0.62-0.98). Tiotropium in combination with 2 other medications was associated with increased risk of mortality, exacerbations, and hospitalizations. When used with ICS and LABA, tiotropium use was associated with a decreased risk of mortality compared with treatment with ICS and LABA. However, this result was not consistent in other medication regimens that included tiotropium [corrected].

Predictors of Outcome After Exacerbation of Chronic Obstructive Pulmonary Disease

The outcome after hospitalization for an exacerbation of chronic obstructive pulmonary disease (COPD) is unfavorable and uncertainty exists about factors predicting short and long-term prognosis. To identify clinical predictors of length of hospital stay (LOS) and three-year mortality after COPD exacerbations requiring hospitalization. Retrospective analysis of prospectively collected data. All consecutive patients hospitalized with COPD exacerbation were enrolled. Disease severity was estimated by FEV(1,) body mass index (BMI), Medical Research Council (MRC) chronic dyspnoea scale, previous hospitalizations, need for long-term oxygen treatment (LTOT), arterial oxygen and carbon dioxide partial pressures (PaO(2) and PaCO(2)), pH and respiratory rate. Outcome was assessed by LOS and three-year mortality. Out of 81 patients enrolled, three-year mortality data were available for 61. LOS was related to BMI, MRC scale and respiratory rate. Three-year mortality was related to FEV(1), BMI, MRC scale, LTOT, and PaCO(2). Multiple logistic regression analysis demonstrated that MRC scale was the only independent determinant of LOS, [p = 0.001, odds ratio (OR) 7.67 (95% CI 2.50-23.41)], whereas MRC scale and BMI predicted three-year mortality, [p = 0.001, OR 8.28 (95% CI 2.25-30.47) and p = 0.006, OR 6.91 (95% CI 1.74-27.48), respectively]. Cox regression analysis demonstrated identical results. Using receiver-operator-optimized thresholds for these variables (MRC > 2 and BMI < 25 kg/m(2)), we propose a prediction model that accurately determines three-year mortality risk. In this study, MRC scale and BMI predicted outcome after COPD hospitalization. Pending further validation, this predictive model may contribute to identify patients with poor outcome even when spirometric data are unavailable.

Inhaled corticosteroids in COPD: the case against: Fig. 1—

Chronic obstructive pulmonary disease (COPD), a disease that encompasses emphysema, chronic obstructive bronchitis and small airway obstruction and that is characterised by largely irreversible airflow obstruction, now affects around 10% of the population over the age of 40 yrs 1. The sixth commonest global cause of death in 1990, currently fourth in developed countries, it is expected rise to third place globally by 2020 2. This increase is linked to the trends of its foremost risk factor, tobacco consumption during the twentieth century, and will track the worldwide smoking trends of this century. Besides smoking cessation and pulmonary rehabilitation, the treatment of COPD has previously consisted of bronchodilators early in the disease and oxygen in the late stages. However, because of the presence of inflammation in COPD, short courses of systemic corticosteroids have been used for decades in the treatment of exacerbations, often along with antibiotics. Their side-effects, however, made them unsuitable for the long-term treatment of stable COPD. In the early 1980s, inhaled formulations of corticosteroids were shown to be highly effective for the treatment of asthma and were readily adopted in COPD with no scientific evidence of their benefit in this indication. This transition from asthma to COPD was so natural to prescribers that a Canadian survey conducted in 1994 found that one-third of patients admitted to hospital for COPD were already using inhaled corticosteroids (ICS) 3, despite the fact that no randomised controlled trials had evaluated their effectiveness in COPD. Today, market research studies estimate that the use of these drugs has increased to the point that they are used by >70% of patients with COPD in the USA and Europe, and are currently given as initial therapy to >50% of patients newly diagnosed with COPD, mostly in combination with a long-acting β-agonist (LABA) 4 …

The impact of SHS exposure on health status and exacerbations among patients with COPD

Secondhand smoke (SHS) is a major contributor to indoor air pollution. Because it contains respiratory irritants, it may adversely influence the clinical course of persons with chronic obstructive pulmonary disease (COPD). We used data from nonsmoking members of the FLOW cohort of COPD (n = 809) to elucidate the impact of SHS exposure on health status and exacerbations (requiring emergency department visits or hospitalization). SHS exposure was measured by a validated survey instrument (hours of exposure during the past week). Physical health status was measured by the SF-12 Physical Component Summary Score and disease-specific health-related quality of life (HRQL) by the Airways Questionnaire 20-R. Health care utilization for COPD was determined from Kaiser Permanente Northern California computerized databases. Compared to no SHS exposure, higher level SHS exposure was associated with poorer physical health status (mean score decrement -1.78 points; 95% confidence interval [CI] -3.48 to -0.074 points) after controlling for potential confounders. Higher level SHS exposure was also related to poorer disease-specific HRQL (mean score increment 0.63; 95% CI 0.016 to 1.25) and less distance walked during the Six-Minute Walk test (mean decrement -50 feet; 95% CI -102 to 1.9). Both lower level and higher level SHS exposure was related to increased risk of emergency department (ED) visits (hazard ratio [HR] 1.40; 95% CI 0.96 to 2.05 and HR 1.41; 95% CI 0.94 to 2.13). Lower level and higher level SHS exposure were associated with a greater risk of hospital-based care for COPD, which was a composite endpoint of either ED visits or hospitalizations for COPD (HR 1.52; 95% CI 1.06 to 2.18 and HR 1.40; 95% CI 0.94 to 2.10, respectively). In conclusion, SHS was associated with poorer health status and a greater risk of COPD exacerbation. COPD patients may comprise a vulnerable population for the health effects of SHS.

Comorbidities, Patient Knowledge, and Disease Management in a National Sample of Patients with COPD

Objective Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States but is often undertreated. COPD often overlaps with other conditions such as hypertension and osteoporosis, which are less morbid but may be treated more aggressively. We evaluated the prevalence of these comorbid conditions and compared testing, patient knowledge, and management in a national sample of patients with COPD. Methods A survey was administered by telephone in 2006 to 1003 patients with COPD to evaluate the prevalence of comorbid conditions, diagnostic testing, knowledge, and management using standardized instruments. The completion rate was 87%. Results Among 1003 patients with COPD, 61% reported moderate or severe dyspnea and 41% reported a prior hospitalization for COPD. The most prevalent comorbid diagnoses were hypertension (55%), hypercholesterolemia (52%), depression (37%), cataracts (31%), and osteoporosis (28%). Only 10% of respondents knew their forced expiratory volume in 1 second (95% confidence interval [CI], 8-12) compared with 79% who knew their blood pressure (95% CI, 76-83). Seventy-two percent (95% CI, 69-75) reported taking any medication for COPD, usually a short-acting bronchodilator, whereas 87% (95% CI, 84-90) of patients with COPD and hypertension were taking an antihypertensive medication and 72% (95% CI, 68-75) of patients with COPD and hypercholesterolemia were taking a statin. Conclusion Although most patients with COPD in this national sample were symptomatic and many had been hospitalized for COPD, COPD self-knowledge was low and COPD was undertreated compared with generally asymptomatic, less morbid conditions such as hypertension.

Der Effekt von einem Jahr ambulanter pneumologischer Rehabilitation auf Patienten mit COPD

The aim of our study was to determine the effect of one year of pulmonary rehabilitation (PR) on functional parameters and exacerbation rates in patients with chronic obstructive pulmonary disease (COPD). A total of 100 patients were enrolled in a multidisciplinary PR program. PR included endurance, resistance and respiratory muscle training. We performed spiroergometry, a modified Bruce Test and measurements of upper and lower limb contractility as well as inspiratory muscle strength before, six and 12 months after beginning rehabilitation. Additionally, we assessed the quality of life and the number of exacerbations and exacerbation days one year before and after starting rehabilitation. 100 patients (42 female/58 male) with COPD (COPD IV-N=36, COPD III-N=42, COPD II-N=22), a mean age of 60.5+/-9.6 years, BMI 25.8+/-6.0 attended a rehabilitation training program over a time period of one year. Spiroergometry (VO2max from 1.1 to 1.3 l/min, P<0.05), modified Bruce Test (from 13+/-7 Min to 18+/-9 Min; P<0.001), upper limb (from 39.9+/-3 to 52.9+/-8 kg; P<0.001) and lower limb strength increased significantly (from 85.3+/-45 to 131.5+/-57 kg; P<0.001). The maximal inspiratory pressure rose from 81.1 mbar to 108.8 mbar (p<0.001). There was no improvement in FEV1 or FEV1/FVC but Saint Georges Respiratory Questionnaire (total score) improved from 37.2+/-3.6 to 26.5+/-2.8; P<0.001. The same was true for exacerbation rates (they dropped from 2.8 to 0.8; P=0.006) and the number of hospitalization days (from 27.3 to 3.3, P<0.001). One year of outpatient pulmonary rehabilitation is an effective intervention leading to a significant improvement in exercise tolerance and quality of life in patients with COPD also reducing COPD exacerbation rates and hospitalizations.

Identifying Individuals with Physcian Diagnosed COPD in Health Administrative Databases

Chronic Obstructive Pulmonary Disease (COPD) is a common chronic respiratory disease responsible for significant morbidity and mortality. Population-based health administrative databases provide a powerful and unbiased way of studying COPD in the population, however, their ability to accurately identify patients with this disease must first be confirmed. The objective was to validate population-based health administrative definitions of COPD. Previously abstracted medical records of adults over the age of 35 randomly selected from primary care practices in Ontario, Canada were reviewed by an expert panel to establish if an individual did or did not have a diagnosis of COPD. These reference designations were then linked to each individual's respective health administrative database record and compared with predefine health administrative data definitions of COPD. Concepts of diagnostic test evaluation were used to calculate and compare their test characteristics. The most sensitive health administrative definition of COPD was 1 or more ambulatory claims and/or 1 or more hospitalizations for COPD that yielded a sensitivity of 85.0% (95% confidence interval 77.0 to 91.0) and a specificity of 78.4% (95% confidence interval 73.6 to 82.7). As number of ambulatory claims in the definition increased, sensitivity decreased and specificity increased. Individuals with COPD can be accurately identified in health administrative data, and therefore it may be used to create an unbiased population cohort for surveillance and research. This offers a powerful means of generating evidence to inform strategies that optimize the prevention and management of COPD.

The Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) field study methodology

The Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) field study examined indoor and outdoor exposure to traffic-generated air pollution by studying the individual processes of generation of traffic emissions, transport and dispersion of air contaminants along a roadway, and infiltration of the contaminants into a residence. Real-time instrumentation was used to obtain highly resolved time-series concentration profiles for a number of air pollutants. The B-TRAPPED field study was conducted in the residential Sunset Park neighborhood of Brooklyn, NY, USA, in May 2005. The neighborhood contained the Gowanus Expressway (Interstate 278), a major arterial road (4(th) Avenue), and residential side streets running perpendicular to the Gowanus Expressway and 4(th) Avenue. Synchronized measurements were obtained inside a test house, just outside the test house façade, and along the urban residential street canyon on which the house was located. A trailer containing Federal Reference Method (FRM) and real-time monitors was located next to the Gowanus Expressway to assess the source. Ultrafine particulate matter (PM), PM(2.5), nitrogen oxides (NO(x)), sulfur dioxide (SO(2)), carbon monoxide (CO), carbon dioxide (CO(2)), temperature, relative humidity, and wind speed and direction were monitored. Different sampling schemes were devised to focus on dispersion along the street canyon or infiltration into the test house. Results were obtained for ultrafine PM, PM(2.5), criteria gases, and wind conditions from sampling schemes focused on street canyon dispersion and infiltration. For comparison, the ultrafine PM and PM(2.5) results were compared with an existing data set from the Los Angeles area, and the criteria gas data were compared with measurements from a Vancouver epidemiologic study. Measured ultrafine PM and PM(2.5) concentration levels along the residential urban street canyon and at the test house façade in Sunset Park were demonstrated to be comparable to traffic levels at an arterial road and slightly higher than those in a residential area of Los Angeles. Indoor ultrafine PM levels were roughly 3-10 times lower than outdoor levels, depending on the monitor location. CO, NO(2), and SO(2) levels were shown to be similar to values that produced increased risk of chronic obstructive pulmonary disease hospitalizations in the Vancouver studies.

Plasma markers of inflammation and incidence of hospitalisations for COPD: results from a population-based cohort study

Background:The relationship between plasma markers of inflammation and the incidence of chronic obstructive pulmonary disease (COPD) is still unclear. This population-based study explored whether raised levels of five inflammation-sensitive plasma...

Independent Effect of Depression and Anxiety on Chronic Obstructive Pulmonary Disease Exacerbations and Hospitalizations

Depression and anxiety are significant comorbid and potentially modifiable conditions in chronic obstructive pulmonary disease (COPD), but their effects on exacerbations are not clear. To investigate the independent effect of depression and anxiety on the risk of COPD exacerbations and hospitalizations. A multicenter prospective cohort study in 491 patients with stable COPD in China. Multivariate Poisson and linear regression analyses were used, respectively, to estimate adjusted incidence rate ratios (IRRs) and adjusted effects on duration of events. Depression and anxiety were measured using the Hospital Anxiety and Depression Scale (HADS) at baseline. Other measurements included sociodemographic, clinical, psychosocial, and treatment characteristics. Patients were then monitored monthly for 12 months to document the occurrence and characteristics of COPD exacerbations and hospitalizations. Exacerbation was determined using both symptom-based (worsening of > or =1 key symptom) and event-based definitions (> or =1 symptom worsening plus > or =1 change in regular medications). A total of 876 symptom-based and 450 event-based exacerbations were recorded, among which 183 led to hospitalization. Probable depression (HADS depression score > or = 11) was associated with an increased risk of symptom-based exacerbations (adjusted IRR, 1.51; 95% confidence interval [CI], 1.01-2.24), event-based exacerbations (adjusted IRR, 1.56; 95% CI, 1.02-2.40), and hospitalization (adjusted IRR, 1.72; 95% CI, 1.04-2.85) compared with nondepression (score < or = 7). The duration of event-based exacerbations was 1.92 (1.04-3.54) times longer for patients with probable anxiety (HADS anxiety score > or = 11) than those with no anxiety (score < or = 7). This study suggests a possible causal effect of depression on COPD exacerbations and hospitalizations. Further studies are warranted to confirm this finding and to test the effectiveness of antidepressants and psychotherapies on reducing exacerbations and improving health resource utilizations.

Time-Dependent Confounding in the Study of the Effects of Regular Physical Activity in Chronic Obstructive Pulmonary Disease: An Application of the Marginal Structural Model

Results from longitudinal studies about the association between physical activity and chronic obstructive pulmonary disease (COPD) may have been biased because they did not properly adjust for time-dependent confounders. Marginal structural models (MSMs) have been proposed to address this type of confounding. We sought to assess the presence of time-dependent confounding in the association between physical activity and COPD development and course by comparing risk estimates between standard statistical methods and MSMs. By using the population-based cohort Copenhagen City Heart Study, 6,568 subjects selected from the general population in 1976 were followed up until 2004 with three repeated examinations. Moderate to high compared with low physical activity was associated with a reduced risk of developing COPD both in the standard analysis (odds ratio [OR] 0.76, p = 0.007) and in the MSM analysis (OR 0.79, p = 0.025). In the subgroup with COPD (n = 2,226), high physical activity was associated with a reduced risk of COPD admissions during follow-up (standard, incidence rate ratio, 0.74; p = 0.096; MSM, 0.68, p = 0.044), and with a reduced risk of mortality (standard, hazard ratio 0.80, p = 0.001; MSM, 0.81, p = 0.008). These results support the previously reported associations between physical activity and reduced risk of COPD development, hospitalizations, and mortality, thereby suggesting they were not due to time-dependent confounding.

Superoxide Dismutase 3 Polymorphism Associated with Reduced Lung Function in Two Large Populations

Superoxide dismutase (SOD) 3 inhibits oxidative fragmentation of lung matrix components collagen I, hyaluronan, and heparan sulfate. Inherited change in SOD3 expression or function could affect lung matrix homeostasis and influence pulmonary function. To identify novel SOD3 polymorphisms that are associated with lung function or chronic obstructive pulmonary disease (COPD). Resequencing of 182 individuals identified two novel polymorphisms, E1 (rs8192287) and I1 (rs8192288), in a conserved region of the SOD3 gene of potential relationship to lung function. We next genotyped 9,093 individuals from the Copenhagen City Heart Study for the polymorphisms and recorded spirometry, and admissions and deaths due to COPD during 26-year follow-up. Finally, we validated our findings in a cross-sectional analysis of 35,635 individuals from the Copenhagen General Population Study. Genotyping the Copenhagen City Heart Study identified 35 E1/I1 homozygotes, 1,050 heterozygotes, and 8,008 noncarriers (Hardy-Weinberg equilibrium: P = 0.93). Using quadruple lung function measurements, we found that E1/I1 homozygotes had 7% lower FVC % predicted (P = 0.006) and 4% lower FEV(1) % predicted (P = 0.12) compared with noncarriers. In the Copenhagen General Population Study, E1/I1 homozygotes also had lower FVC % predicted than noncarriers (P = 0.03), confirming an association between E1/I1 genotype and reduced lung function. E1/I1 homozygotes had adjusted hazard ratios for COPD hospitalization and COPD mortality of 2.5 (95% confidence interval, 1.0-5.9) and 3.7 (95% confidence interval, 0.9-15), respectively; the results were independent of influence from the R213G allele of the SOD3 gene. We identified two novel polymorphisms in a conserved region of the SOD3 gene and show that individuals that are homozygous for these polymorphisms have reduced FVC % predicted in two large, population-based studies.

Responses to tiotropium in African-American and Caucasian patients with chronic obstructive pulmonary disease

Sparse information exists about chronic obstructive pulmonary disease (COPD) outcomes among different ethnic groups. To determine whether the effect of tiotropium on COPD exacerbation differs between African Americans and Caucasians, we performed a post hoc analysis of African-American (n = 150) and Caucasian (n = 1670) subgroups from a previously reported 6-month trial of tiotropium in patients with moderate-to-very-severe COPD. Compared with placebo, tiotropium reduced the likelihood of having at least 1 exacerbation in the entire group (RR, 0.81; 95% CI, 0.66-0.99, P = 0.037) with no statistically significant difference between African-American and Caucasian subgroups (P = 0.34). For African Americans, tiotropium significantly reduced the number of antibiotic days for COPD, hospitalizations for exacerbations, and hospitalization days for COPD. For Caucasians, tiotropium significantly reduced the number of exacerbations, exacerbation days, unscheduled clinic visits for COPD, and hospitalizations for exacerbations. Tiotropium reduced the frequencies of antibiotic days and of COPD hospital days to a significantly greater extent in African Americans compared with Caucasians (P = 0.027 and P = 0.025, respectively). No statistically significant ethnic-related differences were observed in the effect of tiotropium on the frequencies of exacerbations, exacerbation days, systemic corticosteroid days, unscheduled clinic visits, or COPD hospitalizations. Spirometry improved to a similar extent in both subgroups for the entire duration of the 6-month trial. African Americans used fewer respiratory medications than Caucasians in this study. We conclude that tiotropium reduces COPD exacerbations and associated health-care use to a similar extent in African Americans compared with Caucasians.

Urban air pollution, and asthma and COPD hospital emergency room visits

Background:There is little previous information of the effects of size fractioned particulate air pollution and source specific fine particles (PM2.5; <2.5 μm) on asthma and chronic obstructive pulmonary disease (COPD)...