Prognostic factors in chronic obstructive pulmonary disease

Oxidative stress associated with impaired autonomic control and severity of lung function in chronic obstructive pulmonary disease patients

Oxidative stress has been suggested to play a role in the pathogenesis of chronic obstructive pulmonary disease (COPD). This study aimed to investigate a link between malondialdehyde (MDA) levels, pulmonary function, and cardiac autonomic control in patients with COPD. Plasma levels of MDA, heart rate variability, and pulmonary function were measured in 50 clinically stable COPD patients and 50 normal male controls. COPD patients exhibited lower means of the standard deviations of all normal to normal (NN) intervals (SDNN), the square root of the mean of the sum of the squares of differences between adjacent NN intervals (RMSSD), and high frequency (HF). Nevertheless, they presented greater low frequency (LF) and low frequency/high frequency ratio (LF/HF ratio) in supine and head-up tilt positions than controls (P<0.001). More-over, a negative correlation between MDA levels with SDNN (P<0.001) and a positive correlation with LF (P<0.01) and LF/HF ratio (P<0.05) were observed in both positions. In COPD patients, plasma MDA levels were 2.3 times greater than controls (4.33±2.03 μM vs. 1.89±0.39 μM, P<0.001), and they were inversely correlated with forced vital capacity, forced expiratory volume in 1 sec, midexpiratory flow, and peak expiratory flow (P<0.001). Our findings suggest a potential role for oxidative stress in impaired cardiac autonomic control and clinical relevance of plasma MDA levels as a predictor of severity of COPD in COPD patients.

Long-term oxygen therapy in COPD patients: population-based cohort study on mortality

Purpose

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death worldwide and is associated with a growing and substantial socioeconomic burden. Long-term oxygen therapy (LTOT), recommended by current treatment guidelines for COPD patients with severe chronic hypoxemia, has shown to reduce mortality in this population. The aim of our study was to assess the standardized mortality ratios of incident and prevalent LTOT users and to identify predictors of mortality.

Patients and methods

We conducted a 2-year follow-up population-based cohort study comprising all COPD patients receiving LTOT in the canton of Bern, Switzerland. Comparing age- and sex-adjusted standardized mortality ratios, we examined associations between all-cause mortality and patient characteristics at baseline. To avoid immortal time bias, data for incident (receiving LTOT <6 months) and prevalent users were analyzed separately.

Results

At baseline, 475 patients (20% incident users, n=93) were receiving LTOT because of COPD (48/100,000 inhabitants). Mortality of incident and prevalent LTOT users was 41% versus 27%, respectively, p<0.007, and standardized mortality ratios were 8.02 (95% CI: 5.64–11.41) versus 5.90 (95% CI: 4.79–7.25), respectively. Type 2 respiratory failure was associated with higher standardized mortality ratios among incident LTOT users (60.57, 95% CI: 11.82–310.45, p=0.038).

Conclusion

Two-year mortality rate of COPD patients on incident LTOT was somewhat lower in our study than in older cohorts but remained high compared to the general population, especially in younger patients receiving LTOT <6 months. Type 2 respiratory failure was associated with mortality.

Utility of the NECPAL CCOMS-ICO© tool and the Surprise Question as screening tools for early palliative care and to predict mortality in patients with advanced chronic conditions: A cohort study

BACKGROUND

The Surprise Question (SQ) identifies patients with palliative care needs. The NECPAL CCOMS-ICO^© (NECPAL) tool combines the Surprise Question with additional clinical parameters for a more comprehensive assessment. The capacity of these screening tools to predict mortality is still unknown.

AIM

To explore the predictive validity of the NECPAL and SQ to determine 12- to 24-month mortality.

DESIGN

Longitudinal, prospective and observational cohort study.

SETTING/PARTICIPANTS

Three primary care centres, one general hospital, one intermediate care centre, and four nursing homes. Population cohort with advanced chronic conditions and limited life prognosis. Patients were classified according to SQ and NECPAL criteria and followed for 24 months.

RESULTS

Data available to assess 1059 of 1064 recruited patients (99.6%) at 12 and 24 months: 837 patients were SQ+ and 780 were NECPAL+. Mortality rates at 24 months were as follows: 44.6% (SQ+) versus 15.8% (SQ-) and 45.8% (NECPAL+) versus 18.3% (NECPAL-) ( p = 0.000). SQ+ and NECPAL+ identification was significantly correlated with 24-month mortality risk (hazard ratios: 2.719 and 2.398, respectively). Both tools were highly sensitive (91.4, CI: 88.7-94.1 and 87.5, CI: 84.3-90.7) with high negative predictive values (84.2, CI: 79.4-89.0 and 81.7, CI: 77.2-86.2), with low specificity and positive predictive value. The prognostic accuracy of SQ and NECPAL was 52.9% and 55.2%, respectively. The predictive validity was slightly better for NECPAL.

CONCLUSION

SQ and NECPAL are valuable screening instruments to identify patients with limited life prognosis who may require palliative care. More research is needed to increase its prognostic utility in combination with other parameters.

Oxygen therapy in COPD patients with isolated nocturnal hypoxemia; comparison of quality of life and sleep between bronchitis and emphysema phenotype: A prospective observational study

BACKGROUND

COPD is a heterogeneous disease composed by two main phenotypes: bronchitis (COPDb) and emphysema (COPDe) with different clinical presentation, physiology, imaging, response to therapy and decline in lung function. The aim of this study is to evaluate whether nocturnal hypoxemic COPDb and COPDe have a different behaviour during sleep and the effect of nocturnal oxygen supplementation (nO₂LT).

MATERIALS AND METHODS

75 COPDb and 120 COPDe were enrolled. All patients performed polysomnography, Pittsburgh and Maugeri Foundation Respiratory Failure questionnaire, and pulmonary function before and after six months of nO₂LT.

RESULTS

At baseline, compared to COPDb, COPDe have decreased sleep efficiency (SE) (67.5±6% vs. 76.9±3% p<0.05) and higher arousals (A/I) (18.1±3 event/h vs. 8.7±1 event/h p<0.05). Oxygen desaturation index (ODI) was increased during REM (7.1±1 event/h vs. 2.3±0.5 event/h p<0.05). nO₂LT in COPDe improves SE (77±4% vs. 67.5±6% p<0.05) and decreases A/I (9±5 event/h vs. 18.1±3 event/h p<0.05). ODI during REM (3.5±2 event/h vs. 7.1±1 p<0.05) decreases and quality of life (QoL) improves (MFR-28 total 56±22 vs 45±20 p<0.05), due to an improvement in cognitive abilities (45±30 vs 33±31 p<0.05) and daily activities (61±29 vs 53±21 p>0.05). In COPDb nO₂LT reduces ST90 (15±6% vs. 43±8% p<0.05) less than in COPDe (15±6% vs. 8±4% p<0.05); improves A/I (10±2 event/h vs. 8.7±1 p<0.05) and there is no evidence of an improvement in QoL.

CONCLUSIONS

Six months of nO₂LT improve quality of life in COPDe, not in COPDb. We found a difference in sleep quality between COPDe and COPDb.

The Manchester Respiratory Activities of Daily Living questionnaire for use in COPD patients: translation into Portuguese and cross-cultural adaptation for use in Brazil

OBJECTIVE

To translate The Manchester Respiratory Activities of Daily Living (MRADL) questionnaire into Portuguese and to create a version of the MRADL that is cross-culturally adapted for use in Brazil.

METHODS

The English-language version of the MRADL was translated into Portuguese by two health care researchers who were fluent in English. A consensus version was obtained by other two researchers and a pulmonologist. That version was back-translated into English by another translator who was a native speaker of English and fluent in Portuguese. The cognitive debriefing process consisted in having 10 COPD patients complete the translated questionnaire in order to test its understandability, clarity, and acceptability in the target population. On the basis of the results, the final Portuguese-language version of the MRADL was produced and approved by the committee and one of the authors of the original questionnaire.

RESULTS

The author of the MRADL questioned only a few items in the translated version, and some changes were made to the mobility and personal hygiene domains. Cultural differences regarding the domestic activities domain were found, in particular regarding the item "Do you have the ability to do a full clothes wash and hang them out to dry?", due to socioeconomic and climatic issues. The item "Do you take care of your garden?" was questioned by the participants who lived in apartments, being modified to "Do you take care of your garden or plants in your apartment?"

CONCLUSIONS

The final Portuguese-language version of the MRADL adapted for use in Brazil was found to be easy to understand and easily applied.

GOLD B-C-D groups or GOLD II-III-IV grades: Which one better reflects the functionality of patients with chronic obstructive pulmonary disease?

The aim of this article is to investigate which global initiative for chronic obstructive lung disease (GOLD) classification (B-C-D or II-III-IV) better reflects the functionality of patients with moderate to very severe chronic obstructive pulmonary disease (COPD). Ninety patients with COPD were classified according to the GOLD B-C-D and II-III-IV classifications. Functionality was assessed by different outcomes: 6-min walk test (6MWT), activities of daily living (ADL) (London Chest ADL Scale), and daily life activity/inactivity variables assessed by activity monitoring (SenseWear armband, Pittsburgh, Pennsylvania, USA). The 6MWT was the only outcome significantly associated with both the GOLD classifications. Good functionality as assessed by the 6MWT was observed in 80%, 69%, and 43.5% (GOLD B, C, and D, respectively) and 81%, 59%, and 29% (GOLD II, III, and IV, respectively) of the patients. Association (V Cramer's) and correlation (Spearman) coefficients of 6MWT with GOLD B-C-D and II-III-IV were V = 0.30, r = -0.35, and V = 0.37, r = -0.25, respectively. Neither GOLD classification showed V or r ≥ 0.30 with any other functionality outcome. Both the GOLD B-C-D and II-III-IV classifications do not reflect well COPD patients' functionality. Despite low association and correlation coefficients in general, both GOLD classifications were better associated with functional exercise capacity (6MWT) than with subjectively assessed ADL and objectively assessed outcomes of physical activity/inactivity.

Intensive Care: Who Benefits?

Intensive care has saved many lives but there are still those patients who are so ill at the time of presentation that the benefit of escalating intensive care support is not clear-cut. To be fair to these patients and the others who can benefit from our services, it is vital that decisions concerning how far organ supporting measures should be pursued are made as reliably and robustly as possible. This review describes some of the prognostic features available at presentation or shortly afterwards, pertaining to five clinical scenarios associated with a perceived poor survival rate (ie, acute-on-chronic liver failure, haematological malignancy, chronic lung disease, cardiac arrest and morbid obesity).

Prediction of disease progression, treatment response and dropout in chronic obstructive pulmonary disease (COPD)

Purpose

Drug development in chronic obstructive pulmonary disease (COPD) has been characterised by unacceptably high failure rates. In addition to the poor sensitivity in forced expiratory volume in one second (FEV₁), numerous causes are known to contribute to this phenomenon, which can be clustered into drug-, disease- and design-related factors. Here we present a model-based approach to describe disease progression, treatment response and dropout in clinical trials with COPD patients.

Methods

Data from six phase II trials lasting up to 6 months were used. Disease progression (trough FEV₁ measurements) was modelled by a time–varying function, whilst the treatment effect was described by an indirect response model. A time-to-event model was used for dropout

Results

All relevant parameters were characterised with acceptable precision. Two parameters were necessary to model the dropout patterns, which was found to be partly linked to the treatment failure. Disease severity at baseline, previous use of corticosteroids, gender and height were significant covariates on disease baseline whereas disease severity and reversibility to salbutamol/salmeterol were significant covariates on E_max for salmeterol active arm.

Conclusion

Incorporation of the various interacting factors into a single model will offer the basis for patient enrichment and improved dose rationale in COPD.

Electronic supplementary material

The online version of this article (doi:10.1007/s11095-014-1490-4) contains supplementary material, which is available to authorized users.

Electrocardiographic differences between COPD patients evaluated for lung transplantation with and without pulmonary hypertension

INTRODUCTION

Pulmonary hypertension (PH) is an indicator of poor prognosis in COPD patients; particularly in those with mean pulmonary artery pressure ≥ 40 mm Hg. Electrocardiography (ECG) might be useful for screening of this condition.

METHODS

Retrospective study of COPD patients evaluated for lung transplantation in whom we analyzed the 12-lead ECG performed closest to the time of right heart catheterization.

RESULTS

We included 142 patients. PH was present in 90 patients (63%) and 16 (11%) had a mean PAP ≥ 40 mmHg. The PR interval was longer in PH patients (151 (29) versus 139 (22) ms, p = 0.01) and T wave axis had a left shift (56.9 (32) versus 68.7 (19) degrees, p = 0.006). PR interval was longer (178.5 (35) versus 142.2 (23) ms, p = 0.001), T wave axis had a leftward deflection (63.6 (24) versus 42.8 (46) degrees, p = 0.005) and S wave in lead I was larger (0.19 (0.13) versus 0.12 (0.12) mV, p = 0.03) in patients with mean PAP ≥ 40 mmHg. A PR interval > 137 ms and S wave in DI > 0.02 mV had a sensitivity of 100% and a specificity of 59.5% to identify COPD patients with a mean PAP ≥ 40 mmHg.

CONCLUSION

There are significant ECG differences between advanced COPD patients with and without PH; however the ECG is an inadequate tool to differentiate between the groups. A prolonged PR interval suggests the presence of severe PH.

Palliative care for patients with chronic obstructive pulmonary disease: exploring the landscape

Patients with chronic obstructive pulmonary disease experience a substantial symptom burden, high levels of psychosocial need and significant mortality. This epidemiological study reveals that the majority of patients are cared for in the public hospital system (64%) and generally die in hospital (72%) with a number of identifiable predictors of 6-month mortality. Our results suggest that palliative care services need to be redirected from a community-based admission focus to a model that is responsive to emergency and acute care hospital systems.

Hypo- and hypercapnia predict mortality in oxygen-dependent chronic obstructive pulmonary disease: a population-based prospective study

BACKGROUND

The prognostic role of the arterial blood gas tension of carbon dioxide (PaCO2) in severe Chronic Obstructive Pulmonary Disease (COPD) remains unknown. The aim of this study was to estimate the association between PaCO2 and mortality in oxygen-dependent COPD.

METHODS

National prospective study of patients starting long-term oxygen therapy (LTOT) for COPD in Sweden between October 1, 2005 and June 30, 2009, with all-cause mortality as endpoint. The association between PaCO2 while breathing air, PaCO2 (air), and mortality was estimated using Cox regression adjusted for age, sex, arterial blood gas tension of oxygen (PaO2), World Health Organization performance status, body mass index, comorbidity, and medications.

RESULTS

Of 2,249 patients included, 1,129 (50%) died during a median 1.1 years (IQR 0.6-2.0 years) of observation. No patient was lost to follow-up. PaCO2 (air) independently predicted adjusted mortality (p < 0.001). The association with mortality was U-shaped, with the lowest mortality at approximately PaCO2 (air) 6.5 kPa and increased mortality at PaCO2 (air) below 5.0 kPa and above 7.0 kPa.

CONCLUSION

In oxygen-dependent COPD, PaCO2 (air) is an independent prognostic factor with a U-shaped association with mortality.

Two distinct chronic obstructive pulmonary disease (COPD) phenotypes are associated with high risk of mortality

RATIONALE

In COPD patients, mortality risk is influenced by age, severity of respiratory disease, and comorbidities. With an unbiased statistical approach we sought to identify clusters of COPD patients and to examine their mortality risk.

METHODS

Stable COPD subjects (n = 527) were classified using hierarchical cluster analysis of clinical, functional and imaging data. The relevance of this classification was validated using prospective follow-up of mortality.

RESULTS

The most relevant patient classification was that based on three clusters (phenotypes). Phenotype 1 included subjects at very low risk of mortality, who had mild respiratory disease and low rates of comorbidities. Phenotype 2 and 3 were at high risk of mortality. Phenotype 2 included younger subjects with severe airflow limitation, emphysema and hyperinflation, low body mass index, and low rates of cardiovascular comorbidities. Phenotype 3 included older subjects with less severe respiratory disease, but higher rates of obesity and cardiovascular comorbidities. Mortality was associated with the severity of airflow limitation in Phenotype 2 but not in Phenotype 3 subjects, and subjects in Phenotype 2 died at younger age.

CONCLUSIONS

We identified three COPD phenotypes, including two phenotypes with high risk of mortality. Subjects within these phenotypes may require different therapeutic interventions to improve their outcome.

How do dyspnoea scales compare with measurement of functional capacity in patients with COPD and at risk of COPD?

BACKGROUND

In primary care, formal functional capacity testing is not always feasible. Guidelines for family practitioners suggest the use of dyspnoea scales to assess exercise tolerance in patients with chronic obstructive pulmonary disease (COPD).

AIMS

To examine whether the use of activity-based dyspnoea scales can substitute for actual functional capacity testing.

METHODS

128 subjects (49% at risk of COPD, 24% GOLD stage I, 17% GOLD stage II, 9% GOLD stage III) performed an Incremental Shuttle Walk Test (ISWT) and completed the Medical Research Council dyspnoea scale (MRC), Baseline Dyspnoea Index (BDI), Oxygen Cost Diagram (OCD), Clinical COPD Questionnaire (CCQ), and St George's Respiratory Questionnaire (SGRQ).

RESULTS

Analysis of variance showed that the relationship between the ISWT and the MRC dyspnoea scale was statistically significant but moderate (p < 0.001, R2 = 0.166). Correlations between the ISWT and the other dyspnoea scales were also moderate (correlation coefficients 0.34-0.42). Combining the dyspnoea scales in one analysis resulted in a proportion of explained variance of the ISWT of 21.4% (R2 = 0.214).

CONCLUSIONS

Dyspnoea scales cannot substitute for formal functional capacity testing. Authors of COPD guidelines should consider stating more specifically that the MRC and similar scales measure (self-reported) activity-related dyspnoea but cannot replace objectively measured functional capacity.

Midregional proatrial natriuretic peptide predicts survival in exacerbations of COPD

BACKGROUND

Recently, the use of systemic biomarkers to monitor and assess the clinical evolution of respiratory disease has gained interest. We investigated whether midregional proatrial natriuretic peptide (MR-proANP) predicts survival in patients with COPD when they are admitted to the hospital for exacerbation.

METHODS

One hundred sixty-seven patients (mean age 70 years old, 75 men) admitted to the hospital for exacerbation were followed up for 2 years. MR-proANP was measured on admission, after 14 days, and at 6 months. The predictive value of clinical, functional, and laboratory parameters on admission were assessed by Cox regression analyses. The time to death was analyzed by Kaplan-Meier survival curves.

RESULTS

MR-proANP level was significantly higher on admission for exacerbation, compared with recovery and stable state (P = .004 for the comparison among all time points). MR-proANP correlated with the Charlson condition and age-related score (P < .0001), left ventricular ejection fraction (P < .0001), C-reactive protein (P = .037), and FEV(1)% predicted (P = .004). MR-proANP levels were similar in patients requiring ICU treatment and in those treated in the medical ward (P = .086). Thirty-seven patients (22%) died within 2 years. MR-proANP levels were higher in nonsurvivors compared with survivors (median [interquartile range] 185 pmol/L [110-286] vs 92 pmol/L [56-158], P < .001). Mortality was higher across MR-proANP quartiles (log rank P < .0001). Charlson condition and age-related score (P = .001), Paco(2) (P < .0001), and MR-proANP (P = .001) predicted mortality in the univariate Cox-regression model. Both MR-proANP and Paco(2) were independent predictors of mortality in the multivariate Cox regression model.

CONCLUSIONS

MR-proANP at exacerbation is associated with 2-year long-term survival in patients with exacerbation of COPD.

Treatment of respiratory failure in COPD

Patients with advanced COPD and acute or chronic respiratory failure are at high risk for death. Beyond pharmacological treatment, supplemental oxygen and mechanical ventilation are major treatment options. This review describes the physiological concepts underlying respiratory failure and its therapy, as well as important treatment outcomes. The rationale for the controlled supply of oxygen in acute hypoxic respiratory failure is undisputed. There is also a clear survival benefit from long-term oxygen therapy in patients with chronic hypoxia, while in mild, nocturnal, or exercise-induced hypoxemia such long-term benefits appear questionable. Furthermore, much evidence supports the use of non-invasive positive pressure ventilation in acute hypercapnic respiratory failure. It application reduces intubation and mortality rates, and the duration of intensive care unit or hospital stays, particularly in the presence of mild to moderate respiratory acidosis. COPD with chronic hypercapnic respiratory failure became a major indication for domiciliary mechanical ventilation, based on pathophysiological reasoning and on data regarding symptoms and quality of life. Still, however, its relevance for long-term survival has to be substantiated in prospective controlled studies. Such studies might preferentially recruit patients with repeated hypercapnic decompensation or a high risk for death, while ensuring effective ventilation and the patients’ adherence to therapy.

[Clinical value of forced expiratory volume in 1 s (FEV1) in chronic obstructive pulmonary disease]

There is overwhelming evidence from large-scale placebo-controlled trials but also from epidemiologic COPD (chronic obstructive pulmonary disease) studies and meta-analyses supporting FEV(1) (forced expiratory volume in 1 s) as a strong diagnostic and prognostic marker that predicts future morbidity and mortality. Specifically, attenuation of reduced FEV(1) is a powerful indicator of successful medical intervention and vice versa. FEV(1) decline indicates an increasing risk for advanced disease stage eventually leading to further deterioration. However, it remains to be determined whether reducing the frequency of exacerbations or pharmacological improvement of FEV(1) can help to slow lung function decline and consequently improve clinical outcome in these patients. All in all, FEV(1) and its change over time are essential parameters in the assessment of COPD progression and efficacy of therapeutic intervention.

Genetic associations with hypoxemia and pulmonary arterial pressure in COPD

BACKGROUND

Hypoxemia, hypercarbia, and pulmonary arterial hypertension are known complications of advanced COPD. We sought to identify genetic polymorphisms associated with these traits in a population of patients with severe COPD from the National Emphysema Treatment Trial (NETT).

METHODS

In 389 participants from the NETT Genetics Ancillary Study, single-nucleotide polymorphisms (SNPs) were genotyped in five candidate genes previously associated with COPD susceptibility (EPHX1, SERPINE2, SFTPB, TGFB1, and GSTP1). Linear regression models were used to test for associations among these SNPs and three quantitative COPD-related traits (Pao(2), Paco(2), and pulmonary artery systolic pressure). Genes associated with hypoxemia were tested for replication in probands from the Boston Early-Onset COPD Study.

RESULTS

In the NETT Genetics Ancillary Study population, SNPs in microsomal epoxide hydrolase (EPHX1) [p = 0.01 to 0.04] and serpin peptidase inhibitor, clade E, member 2 (SERPINE2) [p = 0.04 to 0.008] were associated with hypoxemia. One SNP within surfactant protein B (SFTPB) was associated with pulmonary artery systolic pressure (p = 0.01). In probands from the Boston Early-Onset COPD Study, SNPs in EPHX1 and in SERPINE2 were associated with the requirement for supplemental oxygen.

CONCLUSIONS

In participants with severe COPD, SNPs in EPHX1 and SERPINE2 were associated with hypoxemia in two separate study populations, and SNPs from SFTPB were associated with pulmonary artery pressure in the NETT participants.

Inspiratory capacity, exercise limitation, markers of severity, and prognostic factors in chronic obstructive pulmonary disease

OBJECTIVE

To correlate the postbronchodilator (post-BD) inspiratory capacity (IC), % of predicted, with other markers of severity and prognostic factors in chronic obstructive pulmonary disease (COPD).

METHODS

Eighty stable patients with COPD performed forced vital capacity and slow vital capacity maneuvers, as well as the 6-min walk test, prior to and after receiving albuterol spray (400 microg). Patients were divided into four groups, based on post-BD forced expiratory volume in one second. Several variables were tested to establish correlations with the post-BD distance walked, using univariate and multivariate analysis. Post-BD IC was found to correlated with Global Initiative for Chronic Obstructive Lung Disease (GOLD) staging and with the Body mass index, airway Obstruction, Dyspnea, and Exercise capacity (BODE) index.

RESULTS

Multivariate regression analysis revealed that the distance walked, % predicted, correlated significantly with the IC post-BD, % predicted (p = 0.001), long-term oxygen use (p = 0.014), and number of medications used in the treatment (p = 0.044). IC < 70% was observed in 56% patients in GOLD stages 3 or 4 vs. 20% in GOLD 1 or 2 (p < 0.001). IC < 70% was observed in (60%) patients with BODE score 3 or 4 vs. (33%) BODE score 1 or 2 (p = 0.02).

CONCLUSION

Post-BD IC% predicted is the best functional predictor of distance walked and is significantly associated with GOLD staging and BODE index. Therefore, We propose that the inspiratory capacity should be added to the routine evaluation of the COPD patients.

Phenotypes of chronic obstructive pulmonary disease

The current clinical classification of smoking-related lung disease fails to take into account the heterogeneity of chronic obstructive pulmonary disease (COPD). With an increased understanding of pathophysiologic variation, COPD now clearly represents a spectrum of overlapping diseases with important extrapulmonary consequences. A "phenotype" describes the outward physical manifestations of a particular disease, and compromises anything that is part of the observable structure, function or behavior of an individual. Such phenotypic distinctions in COPD include: frequent exacerbator, pulmonary cachectic, rapid decliner, airways hyperresponsiveness, impaired exercise tolerance, and emphysema versus airways disease. These variable manifestations, each with unique prognostic, clinical and physiologic ramifications, represent distinct phenotypes within COPD. While all of these phenotypes have smoking as a common risk factor, the other risk factors that determine these phenotypes remain poorly understood. An individual smoker has variable expression of each phenotype and there is mounting evidence that COPD phenotypes have different clinical outcomes. These phenotypes can be broadly classified into one of three groups: clinical, physiologic and radiographic. This review presents the evidence for the spectrum of COPD phenotypes with a focused discussion on the pathophysiologic, epidemiologic and clinical significance of each subtype.

Pulmonary rehabilitation in chronic obstructive pulmonary disease

Pulmonary rehabilitation, a multidisciplinary and structured intervention for patients with chronic pulmonary diseases, has been shown to improve exercise tolerance, reduce dyspnea and improve health-related quality of life. Pulmonary rehabilitation appears to be cost-effective, since it reduces health care utilization. Exercise training represents the cornerstone of every pulmonary rehabilitation program. To obtain clinically relevant effects, training should closely supervised, of high intensity, lasting 30-45 min for at least 3 days/week. Patients should undertake a minimum of 20 sessions, but longer programs result in larger and more long-lasting effects. Education and self-management programs have been shown to result in a substantial reduction in hospital admissions. Nutritional intervention should be considered for patients who are underweight or those with body composition abnormalities. Patients reporting fear and anxiety may benefit from psychosocial support, and the integration of occupational therapy in a pulmonary rehabilitation program can improve independence in activity. Multidisciplinary pulmonary rehabilitation is preferably implemented in an outpatient hospital- or community-based setting. Inpatient programs are suited for patients with limited transportation capabilities or severe deconditioning. The most convincing effects of home-based rehabilitation are in maintaining the improvements obtained in an outpatient setting.

Predictors of Survival in COPD Patients With Chronic Hypercapnic Respiratory Failure Receiving Noninvasive Home Ventilation

BACKGROUND

Patients with COPD and chronic hypercapnic respiratory failure (CHRF) are at high risk, and noninvasive ventilation at home is increasingly being used. Knowledge of prognostic parameters under these conditions is limited but may be clinically helpful and highlight the role of noninvasive ventilation.

METHODS

In 188 patients with COPD (mean +/- SD FEV1, 31.0 +/- 9.6% of predicted; PaCo2, 56.3 +/- 9.4 mm Hg) discharged from the hospital receiving NIV between July 1994 and July 2004, the prognostic value of body mass index (BMI), lung function, laboratory parameters, and blood gas levels was assessed by univariate and multivariate Cox regression analyses. Moreover, the impact of changes in risk factors on mortality assessed 6.7 +/- 2.8 months after the initiation of noninvasive ventilation was evaluated.

RESULTS

Overall, the mortality rate during follow-up (duration, 32.2 +/- 24.3 months) was 44.7%, with 1-year, 2-year, and 5-year survival rates of 84.0%, 65.3%, and 26.4%. Deaths resulted predominantly from respiratory causes (73.8%). Univariate regression analyses revealed age, BMI, hemoglobin, FEV1, specific airway resistance, residual volume (RV)/total lung capacity (TLC), pH, and base excess (BE) to be associated with prognosis (p < 0.01 each), whereas multivariate analysis identified only age, BMI, RV/TLC, and BE as independent predictors (p < 0.05). In patients at risk (BMI < 25 km/m2, RV/TLC >or= 73%, or BE >or= 9 mmol/L), changes in these predictors were also associated with survival.

CONCLUSIONS

In patients with COPD and CHRF, nutritional status, hyperinflation, and BE, which turned out to be reliable and consistent markers in CHRF, were independent prognostic factors for mortality. These data favor a multidimensional approach in these patients, including the use of noninvasive ventilation.

Chronic obstructive pulmonary disease: clinical signs and infections

Chronic obstructive pulmonary disease (COPD) is a pathological condition that involves excessive production of mucus, chronic cough and inflammatory changes leading to airway limitation. The most common cause of COPD is cigarette smoking. COPD can be categorized into either chronic bronchitis or emphysema; both conditions can be differentiated by age and the production of copious, tenacious sputum. Patients with COPD are susceptible to pulmonary infections of bacterial or viral origin. Nurses should be aware of the subtle differences in conditions and the usefulness of antibiotics in the treatment of acute bacterial exacerbations of chronic bronchitis.

Comparison of clinical characteristics and outcomes of patients with COPD exacerbation with or without venous thromboembolism

BACKGROUND

Although some studies evaluated venous thromboembolism (VTE) prevalence in patients with chronic obstructive pulmonary disease (COPD), they contain no detailed description of the patients' characteristics.

OBJECTIVES

It was the aim of this study to investigate the frequency and clinical characteristics and outcomes of VTE in patients with COPD exacerbation.

METHODS

Between October 2004 and February 2005, 120 consecutive patients were included in the study. On admission, Doppler examination of lower extremities in all cases and spiral computed tomography of the thorax in cases with a suspicion of pulmonary thromboembolism were performed. A questionnaire was used to take a detailed history. In addition to routine laboratory tests, chest X-ray, postbronchodilator spirometry, arterial blood gas analysis and serum levels of D-dimer and C-reactive protein were evaluated, as well as dyspnea score and performance status before exacerbation. The hospitalization durations and mechanical ventilation requirements were also recorded.

RESULTS

VTE was determined in 16 cases (13.3%). In patients with VTE, the travel history was higher (p < 0.001), the dyspnea score worse (p = 0.005), the duration of hospitalization longer (p < 0.001) and the mechanical ventilation requirement increased (p < 0.001); a change in mental status was highly associated with the presence of VTE (p < 0.001).

CONCLUSIONS

It seems that VTE occurrence was higher in the presence of a risk factor causing immobility such as travel history and increased dyspnea. The cases with severe disease are more likely to have VTE. Preventive measures may be considered in such patients because their hospitalization stay and mechanical ventilation requirement are increased.