Relative survival analysis of 252 patients with COPD receiving long-term oxygen therapy

High-intensity non-invasive ventilation during exercise-training versus without in people with very severe COPD and chronic hypercapnic respiratory failure: a randomised controlled trial

BACKGROUND

People with very severe chronic obstructive pulmonary disease (COPD) using nocturnal non-invasive ventilation (NIV) for chronic hypercapnic respiratory failure (CHRF) experience reduced exercise capacity and severe dyspnoea during exercise training (ET). The use of NIV during ET can personalise training during pulmonary rehabilitation (PR) but whether high-intensity NIV (HI-NIV) during exercise is accepted and improves outcomes in these extremely physically limited patients is unknown. The aim of this trial was to determine if ET with HI-NIV during PR was more effective than without at improving exercise capacity and reducing dyspnoea during exercise.

METHODS

Patients with COPD, CHRF and nocturnal-NIV were randomised to supervised cycle-ET as part of PR with HI-NIV or without (control). Primary outcome was change in cycle endurance time (ΔCETtime), while secondary outcomes were dyspnoea at isotime during the cycle endurance test and during ET-sessions and for the HI-NIV group, post-trial preferred exercising method.

RESULTS

Twenty-six participants (forced expiratory volume in 1 s 22±7%pred, PaCO251±7 mm Hg) completed the trial (HI-NIV: n=13, ET: IPAP 26±3/EPAP 6±1 cm H2O; control n=13). At completion of a 3 week ET-programme, no significant between-group differences in ΔCETtime were seen (HI-NIV-control: Δ105 s 95% CI (-92 to 302), p=0.608). Within-group ΔCETtime was significant (HI-NIV: +246 s 95% CI (61 to 432); control: +141 s 95% CI (60 to 222); all p<0.05). The number of responders (Δ>minimal important difference (MID)101 s: n=53.8%) was the same in both groups for absolute ΔCETtime and 69.2% of control and 76.9% of the HI-NIV group had a %change>MID33%.Compared with control, the HI-NIV group reported less isotime dyspnoea (Δ-2.0 pts. 95% CI (-3.2 to -0.8), p=0.005) and during ET (Δ-3.2 pts. 95% CI (-4.6 to -1.9), p<0.001). Most of the HI-NIV group (n=12/13) preferred exercising with NIV.

CONCLUSION

In this small group of patients with very severe COPD requiring nocturnal NIV, participation in an ET-programme during PR significantly improved exercise capacity irrespective of HI-NIV use. Reported dyspnoea was in favour of HI-NIV.

TRIAL REGISTRATION NUMBER

NCT03803358.

Home High-Flow Nasal Cannula Oxygen Therapy for Stable Hypercapnic COPD: A Randomized Clinical Trial

Rationale: The long-term effects of using a high-flow nasal cannula for chronic hypercapnic respiratory failure caused by chronic obstructive pulmonary disease remain unclear. Objectives: To assess whether long-term high-flow nasal cannula use reduces the number of exacerbations and improves other physiological parameters in patients with chronic hypercapnic respiratory failure caused by chronic obstructive pulmonary disease. Methods: We enrolled 104 participants (aged ⩾40 yr) with daytime hypercapnia (Global Initiative for Chronic Obstructive Lung Disease stages 2-4) receiving long-term oxygen therapy (⩾16 h/d for ⩾1 mo) and randomly assigned them to high-flow nasal cannula/long-term oxygen therapy and long-term oxygen therapy groups. The primary endpoint was the moderate or severe exacerbation rate. We compared changes from baseline in arterial blood gas values, peripheral oxygen saturation, pulmonary function, health-related quality-of-life scores, and the 6-minute-walk test. Measurements and Main Results: High-flow nasal cannula use significantly reduced the rate of moderate/severe exacerbations (unadjusted mean count 1.0 vs. 2.5, a ratio of the adjusted mean count between groups [95% confidence interval] of 2.85 [1.48-5.47]) and prolonged the duration without moderate or severe exacerbations. The median time to first moderate or severe exacerbation in the long-term oxygen therapy group was 25 (14.1-47.4) weeks; this was not reached in the high-flow nasal cannula/long-term oxygen therapy group. High-flow nasal cannula use significantly improved health-related quality of life scores, peripheral oxygen saturation, and specific pulmonary function parameters. No safety concerns were identified. Conclusions: A high-flow nasal cannula is a reasonable therapeutic option for patients with stable hypercapnic chronic obstructive pulmonary disease and a history of exacerbations. Clinical trial registered with www.umin/ac.jp (UMIN000028581) and www.clinicaltrials.gov (NCT03282019).

Sleep-Related Breathing Complaints in Chronic Obstructive Pulmonary Disease

This review presents the normal physiologic changes in ventilation during sleep and how they can be detrimental to chronic obstructive pulmonary disease (COPD). Sleep-related breathing disorders (SRBDs) in COPD lead to higher morbidity and mortality if left unrecognized and untreated. The diagnosis of SRBDs requires a high index of suspicion, as symptoms may overlap with other sleep disorders. Mortality risk is improved when patients with COPD with OSA (overlap syndrome) are treated with positive airway pressure and when long-term nocturnal noninvasive ventilation is started on chronic stable hypercapnic COPD. Treatment of isolated nocturnal oxygen desaturation has not been associated with improved survival.

Survival Analysis of COPD Patients in a 13-Year Nationwide Cohort Study of the Brazilian National Health System

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has an appreciable socioeconomical impact in low- and middle-income countries, but most epidemiological data originate from high-income countries. For this reason, it is especially important to understand survival and factors associated with survival in COPD patients in these countries.

OBJECTIVE

To assess survival of COPD patients in Brazil, to identify risk factors associated with overall survival, including treatment options funded by the Brazilian National Health System (SUS).

METHODOLOGY

We built a retrospective cohort study of patients dispensed COPD treatment in SUS, from 2003 to 2015 using a National Database created from the record linkage of administrative databases. We further matched patients 1:1 based on sex, age and year of entry to assess the effect of the medicines on patient survival. We used the Kaplan-Meier method to estimate overall survival of patients, and Cox's model of proportional risks to assess risk factors.

RESULT

Thirty seven thousand and nine hundred and thirty eight patients were included. Patient's survival rates at 1 and 10 years were 97.6% (CI 95% 97.4-97.8) and 83.1% (CI 95% 81.9-84.3), respectively. The multivariate analysis showed that male patients, over 65 years old and underweight had an increased risk of death. Therapeutic regimens containing a bronchodilator in a free dose along with a fixed-dose combination of corticosteroid and bronchodilator seem to be a protective factor when compared to other regimens.

CONCLUSION

Our findings contribute to the knowledge of COPD patients' profile, survival rate and related risk factors, providing new evidence that supports the debate about pharmacological therapy and healthcare of these patients.

Management of Chronic Respiratory Failure in Chronic Obstructive Pulmonary Disease: High-Intensity and Low-Intensity Ventilation

A significant body of literature supports the benefit of noninvasive ventilation (NIV) for acute hypercapnia in the setting of exacerbations of chronic obstructive pulmonary disease (COPD). In those with severe COPD with chronic hypercapnic respiratory failure, however, the role of NIV has been more controversial. This article reviews the physiologic basis for considering NIV in patients with COPD, summarizes existing evidence supporting the role of NIV in COPD, highlights the patient population and ventilatory approach most likely to offer benefit, and suggests a potential clinical pathway for managing patients.

Noninvasive Ventilation in Chronic Obstructive Pulmonary Disease

The role of noninvasive positive pressure ventilation (NIV) in severe chronic obstructive pulmonary disease (COPD) has been controversial. Over the past two decades, data primarily obtained from Europe have begun to define the clinical characteristics of patients likely to respond, the role of high-intensity NIV, and the potential best timing of initiating therapy. These approaches, however, have not been validated in the context of the U.S. healthcare delivery system. Use of NIV in severe COPD in the United States is limited by the practicalities of doing in-hospital titrations as well as a complex system of reimbursement. These systematic complexities, coupled with a still-emerging clinical trial database regarding the most effective means to deliver NIV, have led to persistent uncertainty regarding when in stable severe COPD treatment with NIV is actually appropriate. In this review, we propose an assessment algorithm and treatment plan that can be used in clinical practice in the United States, but we acknowledge that the absence of pivotal clinical trials largely precludes a robust evidence-based approach to this potentially valuable therapy.

A Proposed Approach to Chronic Airway Disease (CAD) Using Therapeutic Goals and Treatable Traits: A Look to the Future

Chronic airflow obstruction affects a wide range of airway diseases, the most frequent of which are asthma, COPD, and bronchiectasis; they are clearly identifiable in their extremes, but quite frequently overlap in some of their pathophysiological and clinical characteristics. This has generated the description of new mixed or overlapping disease phenotypes with no clear biological grounds. In this special article, a group of experts provides their perspective and proposes approaching the treatment of chronic airway disease (CAD) through the identification of a series of therapeutic goals (TG) linked to treatable traits (TT) - understood as clinical, physiological, or biological characteristics that are quantifiable using biomarkers. This therapeutic approach needs validating in a clinical trial with the strategy of identification of TG and treatment according to TT for each patient independently of their prior diagnosis.

European Respiratory Society guidelines on long-term home non-invasive ventilation for management of COPD

Background

While the role of acute non-invasive ventilation (NIV) has been shown to improve outcome in acute life-threatening hypercapnic respiratory failure in COPD, the evidence of clinical efficacy of long-term home NIV (LTH-NIV) for management of COPD is less. This document provides evidence-based recommendations for the clinical application of LTH-NIV in chronic hypercapnic COPD patients.

Materials and methods

The European Respiratory Society task force committee was composed of clinicians, methodologists and experts in the field of LTH-NIV. The committee developed recommendations based on the GRADE (Grading, Recommendation, Assessment, Development and Evaluation) methodology. The GRADE Evidence to Decision framework was used to formulate recommendations. A number of topics were addressed under a narrative format which provides a useful context for clinicians and patients.

Results

The task force committee delivered conditional recommendations for four actionable PICO (target population-intervention-comparator-outcome) questions, 1) suggesting for the use of LTH-NIV in stable hypercapnic COPD; 2) suggesting for the use of LTH-NIV in COPD patients following a COPD exacerbation requiring acute NIV 3) suggesting for the use of NIV settings targeting a reduction in carbon dioxide and 4) suggesting for using fixed pressure support as first choice ventilator mode.

Conclusions

Managing hypercapnia may be an important intervention for improving the health outcome of COPD patients with chronic respiratory failure. The task force conditionally supports the application of LTH-NIV to improve health outcome by targeting a reduction in carbon dioxide in COPD patients with persistent hypercapnic respiratory failure. These recommendations should be applied in clinical practice by practitioners that routinely care for chronic hypercapnic COPD patients.

Lung transplantation for chronic obstructive pulmonary disease: past, present, and future directions

PURPOSE OF REVIEW

Lung transplantation offers an effective treatment modality for patients with end-stage chronic obstructive pulmonary disease (COPD). The exact determination of when to refer, list, and offer transplant as well as the preferred transplant procedure type remains unclear. Additionally, there are special considerations specific to patients with COPD being considered for lung transplantation, including the implications of single lung transplantation on lung cancer risk, native lung hyperinflation, and overall survival.

RECENT FINDINGS

The International Society for Heart and Lung Transplantation's most recent recommendations rely on an assessment of COPD severity based on BODE index. Despite the lack of evidence supporting a mortality benefit of bilateral over single lung transplantation for COPD patients, the majority of transplants performed in this population remain bilateral. Some of the concerns specific to single lung transplantation remain the possibility of de novo native lung cancer and the hemodynamic and physiologic implications of acute native lung hyperinflation.

SUMMARY

COPD remains the most common worldwide indication for lung transplantation. Ongoing study is still required to assess the overall survival benefit of lung transplantation and assess the overall quality of life impact on the COPD patient population.

[Long-term oxygen therapy: mortality rate, short-term predictive mortality factors]

OBJECTIVES

The aims of this study were to assess the survival rate at one year of patients receiving long-term oxygen therapy (LTOT) as prescribed by the National Institute for Health and Disability Insurance's imposed criteria based on international recommendations, to search for short-term predictive factors for mortality and to measure the impact of LTOT on the frequency of hospitalization due to COPD exacerbations.

METHODS

We conducted a retrospective analysis of 416 patients suffering from chronic respiratory insufficiency and started on long-term oxygen therapy between 2012 and 2014. The survival curves were estimated by the Kaplan-Meier method. Cox regression models were used to estimate the impact of the variables on survival. The evolution of patients hospitalized for COPD exacerbation was analysed by the McNemar test.

RESULTS

The average age of our cohort was 70±10 years. It included 57% women and 78% patients with COPD. The one-year survival rate (n=416) under LTOT was 75%. Identified predictive mortality factors were coronary insufficiency [HR (95% CI): 1.8 (1.2-2.8); P=0.0083], reduction of the left ventricular ejection fraction [HR (95% CI): 2.5 (1.3-4.9); P=0.0080], the presence of osteoporosis [HR (95% CI): 1.7 (1.0-2.9); P=0.040]. There was a 28% reduction in the frequency of hospitalization for exacerbations of COPD during the year after starting LTOT.

CONCLUSIONS

Mortality at one year with LTOT was about 25%. Factors predictive of mortality at one year included coronary insufficiency, reduction of the left ventricular ejection fraction and osteoporosis. LTOT seems to reduce hospitalizations due to exacerbations of COPD.

Prospective cross-sectional multicenter study on domiciliary noninvasive ventilation in stable hypercapnic COPD patients

Background

Domiciliary noninvasive ventilation (NIV) use in stable hypercarbic COPD is becoming increasingly widespread. However, treatment compliance criteria and factors related to compliance remain to be defined.

Methods

This research was designed as a prospective, cross-sectional, multicenter real-life study. Chronic hypercapnic COPD patients who were using domiciliary NIV for at least 1 year and being followed up in 19 centers across Turkey were included in the study. The patients who used NIV regularly, night or daytime and ≥5 hours/d, were classified as “high-compliance group,” and patients who used NIV irregularly and <5 hours/d as “low-compliance group.”

Results

Two hundred and sixty-six patients with a mean age of 64.5±10.3 years were enrolled, of whom 75.2% were males. They were using domiciliary NIV for 2.8±2 years. Spontaneous time mode (p<0.001) and night use (p<0.001) were more frequent in the high-compliance group (n=163). Also, mean inspiratory positive airway pressure values of the high-compliance group were significantly higher than the low-compliance group (n=103; p<0.001). Cardiac failure (p=0.049) and obesity (p=0.01) were significantly more frequent in the high-compliance group. There were no difference between 2 groups regarding hospitalization, emergency department and intensive care unit admissions within the last year, as well as modified Medical Research Council dyspnea and COPD Assessment Test scores. With regard to NIV-related side effects, only conjunctivitis was observed more frequently in the high-compliance group (p=0.002).

Conclusion

Determination of the patients who have better compliance to domiciliary NIV in COPD may increase the success and effectiveness of treatment. This highly comprehensive study on this topic possesses importance as it suggests that patient and ventilator characteristics may be related to treatment compliance.

Respiratory parameters predict poor outcome in COPD patients, category GOLD 2017 B

Background

Respiratory parameters are important predictors of prognosis in the COPD population. Global Initiative for Obstructive Lung Disease (GOLD) 2017 Update resulted in a vertical shift of patients across COPD categories, with category B being the most populous and clinically heterogeneous. The aim of our study was to investigate whether respiratory parameters might be associated with increased all-cause mortality within GOLD category B patients.

Methods

The data were extracted from the Czech Multicentre Research Database, a prospective, noninterventional multicenter study of COPD patients. Kaplan-Meier survival analyses were performed at different levels of respiratory parameters (partial pressure of oxygen in arterial blood [PaO₂], partial pressure of arterial carbon dioxide [PaCO₂] and greatest decrease of basal peripheral capillary oxygen saturation during 6-minute walking test [6-MWT]). Univariate analyses using the Cox proportional hazard model and multivariate analyses were used to identify risk factors for mortality in hypoxemic and hypercapnic individuals with COPD.

Results

All-cause mortality in the cohort at 3 years of prospective follow-up reached 18.4%. Chronic hypoxemia (PaO₂ <7.3 kPa), hypercapnia (PaCO₂ >7.0 kPa) and oxygen desaturation during the 6-MWT were predictors of long-term mortality in COPD patients with forced expiratory volume in 1 second ≤60% for the overall cohort and for GOLD B category patients. Univariate analyses confirmed the association among decreased oxemia (<7.3 kPa), increased capnemia (>7.0 kPa), oxygen desaturation during 6-MWT and mortality in the studied groups of COPD subjects. Multivariate analysis identified PaO₂ <7.3 kPa as a strong independent risk factor for mortality.

Conclusion

Survival analyses showed significantly increased all-cause mortality in hypoxemic and hypercapnic GOLD B subjects. More important, PaO₂ <7.3 kPa was the strongest risk factor, especially in category B patients. In contrast, the majority of the tested respiratory parameters did not show a difference in mortality in the GOLD category D cohort.

Treating Chronic Hypoventilation With Automatic Adjustable Versus Fixed EPAP Intelligent Volume-Assured Positive Airway Pressure Support (iVAPS): A Randomized Controlled Trial

Objectives

New noninvasive ventilation (NIV) modes can automatically adjust pressure support settings to deliver effective ventilation in response to varying ventilation demands. It is recommended that fixed expiratory positive airway pressure (FixedEPAP) is determined by attended laboratory polysomnographic (PSG) titration. This study investigated whether automatically determined EPAP (AutoEPAP) was noninferior to FixedEPAP for the control of obstructive sleep apnea (OSA) during intelligent volume-assured pressure support (iVAPS) treatment of chronic hypoventilation.

Methods

In this randomized, double-blind, crossover study, patients with chronic hypoventilation and OSA used iVAPS with AutoEPAP or FixedEPAP over two separate nights of attended PSG. PSG recordings were scored by an independent scorer using American Academy of Sleep Medicine 2012 criteria.

Results

Twenty-five adults (14 male) with chronic hypoventilation secondary to obesity hypoventilation syndrome (n = 11), chronic obstructive pulmonary disease (n = 9), or neuromuscular disease (n = 5), all of whom were on established home NIV therapy, were included (age 57 ± 7 years, NIV for ≥3 months, apnea-hypopnea index [AHI] >5/hour). AutoEPAP was noninferior to FixedEPAP for the primary outcome measure (median [interquartile range] AHI 2.70 [1.70-6.05]/hour vs. 2.40 [0.25-5.95]/hour; p = .86). There were no significant between-mode differences in PSG sleep breathing and sleep quality, or self-reported sleep quality, device comfort, and patient preference. Mean EPAP with the Auto and Fixed modes was 10.8 ± 2.0 and 11.8 ± 3.9 cmH2O, respectively (p = .15).

Conclusions

In patients with chronic hypoventilation using iVAPS, the AutoEPAP algorithm was noninferior to FixedEPAP over a single night's therapy.

Survival of Hypercapnic Patients with COPD and Obesity Hypoventilation Syndrome Treated with High Intensity Non Invasive Ventilation in the Daily Routine Care

BACKGROUND

Home ventilation is an effective treatment option for obesity hypoventilation syndrome (OHS). This therapy is still controversial for stable chronic obstructive pulmonary disease (COPD). A recent study showed reduced mortality for COPD patients receiving home ventilation with high inflation pressures and back-up respiratory rates [so called High Intensity non-invasive ventilation (NIV)].

OBJECTIVE

The purpose of this study is whether High Intensity NIV applied in the routine care of COPD and OHS patients can lead to CO2 reduction and survival data comparable to data from controlled studies.

METHOD

In this prospective non interventional study fifty-one patients with COPD (FEV1 0.95l, corr. 32.8%) and 34 patients with OHS (VC 1.74l, corr. 50.7%) with chronic hypercapnic respiratory failure, who were treated with NIV were followed up for four years.

RESULTS

Elevated CO2 values before NIV in COPD patients (8.6kPa), and in OHS patients (8.3kPa), could be lowered significantly to the upper normal range (COPD: 5.9kPa; OHS: 5.85kPa). The one-, two-, and three-year survival rates for COPD patients were 83%, 73%, and 55%, respectively. The one-, two-, and three-year survival rates for OHS patients were 85%, 72%, and 68%, respectively.

CONCLUSION

High intensity NIV within routine care is effective in reducing blood CO2 levels in COPD- and in OHS- related chronic respiratory insufficiency. The survival rates obtained here are comparable to data from controlled clinical trials on COPD.

Outdoor activity and performance status as predictors of survival in hypoxaemic chronic obstructive pulmonary disease (COPD)

Background: Performance status has been associated with survival in hypoxaemic chronic obstructive pulmonary disease (COPD) patients on long-term oxygen therapy.

Objective: To determine whether self-reported outdoor activity and performance status are independent predictors of survival in hypoxaemic COPD patients on long-term oxygen therapy.

Design, subjects and main measure: In a prospective design, survival over an eight-year period was studied in 226 Danish patients on long-term oxygen therapy. They were subdivided according to self-reported mobility (&plusmn;outdoor activity) and World Health Organization (WHO) performance status (score 0-4).

Results: A total of 148 patients (65.5%) reported outdoor activity. Compared to the immobile patients, those reporting outdoor activity had higher performance status, higher body mass index and lower duration of oxygen administration. In multivariate analyses adjusting for body mass index, gender and age, both poor performance status and lack of outdoor activity were associated with poor survival (p-levels 0.006 and 0.045, respectively). Lack of outdoor activity was associated with increased mortality (relative risk (RR) and 95% confidence interval of dying was 1.39 (1.01-1.91)) and significantly higher risk was found among those with age in the youngest tertile (less than 66.4 years), the relative risk of dying was 2.18 (1.20-3.95).

Conclusions: This study shows that self-reported performance status and outdoor activity are independent predictors of survival in hypoxaemic COPD patients on long-term oxygen therapy. However, our study suggests that in the most elderly patients, outdoor activity does not predicting survival. Further studies are needed to determine whether interventions that facilitate outdoor activity (e.g., pulmonary rehabilitation) have an effect on survival in this group of patients.

Advances and New Approaches to Managing Sleep-Disordered Breathing Related to Chronic Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a common disease affecting about 20 million US adults. Sleep-disordered breathing (SDB) problems are frequent and poorly characterized for patients with COPD. Both the well-known success of noninvasive ventilation (NIV) in the acute COPD exacerbation in the hospital setting and that NIV is the cornerstone of chronic therapy for SDBs have urged the attention of the medical community to determine the impact of NIV on chronic COPD management with and without coexisting SDBs. Early observational studies showed decreased long-term survival rates on patients with COPD with concomitant chronic hypercapnia when compared with normocapnic patients.

Predictors of Mortality in Patients with COPD and Chronic Respiratory Failure: The Quality-of-Life Evaluation and Survival Study (QuESS): A Three-Year Study

Previous studies sought to identify survival or outcome predictors in patients with COPD and chronic respiratory failure, but their findings are inconsistent. We identified mortality-associated factors in a prospective study in 21 centers in 7 countries. Follow-up data were available in 221 patients on home mechanical ventilation and/or long-term oxygen therapy.

MEASUREMENTS

diagnosis, co-morbidities, medication, oxygen therapy, mechanical ventilation, pulmonary function, arterial blood gases, exercise performance were recorded. Health status was assessed using the COPD-specific SGRQ and the respiratory-failure-specific MRF26 questionnaires. Date and cause of death were recorded in those who died. Overall mortality was 19.5%. The commonest causes of death were related to the underlying respiratory diseases. At baseline, patients who subsequently died were older than survivors (p = 0.03), had a lower forced vital capacity (p = 0.03), a higher use of oxygen at rest (p = 0.003) and a worse health status (SGRQ and MRF26, both p = 0.02). Longitudinal analyses over a follow-up period of 3 years showed higher median survival times in patients with use of oxygen at rest less than 1.75 l/min and with a better health status. In contrast, an increase from baseline levels of 1 liter in O2 flow at rest, 1 unit in SGRQ or MRF26, or 1 year increase in age resulted in an increase of mortality of 68%, 2.4%, 1.3%, and 6%, respectively. In conclusion, the need for oxygen at rest, and health status assessment seems to be the strongest predictors of mortality in COPD patients with chronic respiratory failure.

Lung transplantation in chronic obstructive pulmonary disease: patient selection and special considerations

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality and morbidity. Lung transplantation is one of the few treatments available for end-stage COPD with the potential to improve survival and quality of life. The selection of candidates and timing of listing present challenges, as COPD tends to progress fairly slowly, and survival after lung transplantation remains limited. Though the natural course of COPD is difficult to predict, the use of assessments of functional status and multivariable indices such as the BODE index can help identify which patients with COPD are at increased risk for mortality, and hence which are more likely to benefit from lung transplantation. Patients with COPD can undergo either single or bilateral lung transplantation. Although many studies suggest better long-term survival with bilateral lung transplant, especially in younger patients, this continues to be debated, and definitive recommendations about this cannot be made. Patients may be more susceptible to particular complications of transplant for COPD, including native lung hyperinflation, and development of lung cancer.

Update: Non-Invasive Positive Pressure Ventilation in Chronic Respiratory Failure Due to COPD

Long-term non-invasive positive pressure ventilation (NPPV) has widely been accepted to treat chronic hypercapnic respiratory failure arising from different etiologies. Although the survival benefits provided by long-term NPPV in individuals with restrictive thoracic disorders or stable, slowly-progressing neuromuscular disorders are overwhelming, the benefits provided by long-term NPPV in patients with chronic obstructive pulmonary disease (COPD) remain under question, due to a lack of convincing evidence in the literature. In addition, long-term NPPV reportedly failed in the classic trials to improve important physiological parameters such as arterial blood gases, which might serve as an explanation as to why long-term NPPV has not been shown to substantially impact on survival. However, high intensity NPPV (HI-NPPV) using controlled NPPV with the highest possible inspiratory pressures tolerated by the patient has recently been described as a new and promising approach that is well-tolerated and is also capable of improving important physiological parameters such as arterial blood gases and lung function. This clearly contrasts with the conventional approach of low-intensity NPPV (LI-NPPV) that uses considerably lower inspiratory pressures with assisted forms of NPPV. Importantly, HI-NPPV was very recently shown to be superior to LI-NPPV in terms of improved overnight blood gases, and was also better tolerated than LI-NPPV. Furthermore, HI-NPPV, but not LI-NPPV, improved dyspnea, lung function and disease-specific aspects of health-related quality of life. A recent study showed that long-term treatment with NPPV with increased ventilatory pressures that reduced hypercapnia was associated with significant and sustained improvements in overall mortality. Thus, long-term NPPV seems to offer important benefits in this patient group, but the treatment success might be dependent on effective ventilatory strategies.

Personalized pulmonary rehabilitation and occupational therapy based on cardiopulmonary exercise testing for patients with advanced chronic obstructive pulmonary disease

Take-home summary

Personalized pulmonary rehabilitation including occupational therapy improves the prognosis of patients with advanced COPD.

Purpose

We previously reported that patients with chronic obstructive pulmonary disease (COPD) exhibit three exercise-induced life-threatening conditions: hypoxemia, sympathetic overactivity, and respiratory acidosis. We aimed to verify whether mortality in patients with advanced COPD could be reduced by a personalized pulmonary rehabilitation (PPR) program in hospital, which determines individual safe ranges and includes occupational therapy (PPR-OT), to prevent desaturation and sympathetic nerve activation during daily activities.

Patients and methods

The novel PPR-OT program was evaluated in a retrospective study of patients with COPD (Global Initiative for Chronic Obstructive Lung Disease [GOLD] Grade D) who underwent cardiopulmonary exercise testing (CPET) between April 1990 and December 1999. They received regular treatment without the proposed therapy (control group: n=61; male-to-female ratio [M:F] =57:4; mean age: 68.5±6.7 years) or with the proposed therapy (PPR-OT group: n=46; M:F =44:2; mean age: 68.7±7.1 years). A prospective observational study included patients with COPD receiving home oxygen therapy (HOT) between April 1995 and March 2007 to compare the survival rates of the control group (n=47; M:F ratio =34:13; mean age: 71.3±10.0 years) and the PPR-OT group (n=85; M:F =78:7; mean age: 70.7±6.1 years) who completed the proposed therapy. Survival after CPET or HOT was analyzed using Cox proportional-hazards regression and Kaplan–Meier analyses.

Results

In both studies, the program significantly improved all-cause mortality (retrospective study: risk ratio =0.389 [range: 0.172–0.800]; P=0.0094; log-rank test, P=0.0094; observational study: risk ratio =0.515 [range: 0.296–0.933]; P=0.0291; log-rank test, P=0.0232]. At 5 years and 7 years, all-cause mortality was extremely low in patients in the PPR-OT group receiving HOT (18.8% and 28.2%, respectively), compared to that in the control group (34.0% and 44.7%, respectively). Survival of patients with life-threatening pathophysiological conditions also greatly improved.

Conclusion

The PPR-OT program improved the survival of patients with advanced COPD probably because it modified life-threatening conditions.

Non-invasive positive pressure ventilation for the treatment of severe stable chronic obstructive pulmonary disease: a prospective, multicentre, randomised, controlled clinical trial

BACKGROUND

Evidence is weak for the ability of long-term non-invasive positive pressure ventilation (NPPV) to improve survival in patients with stable hypercapnic chronic obstructive pulmonary disease (COPD). Previous prospective studies did not target a reduction in hypercapnia when adjusting ventilator settings. This study investigated the effect of long-term NPPV, targeted to markedly reduce hypercapnia, on survival in patients with advanced, stable hypercapnic COPD.

METHODS

This investigator-initiated, prospective, multicentre, randomised, controlled clinical trial enrolled patients with stable GOLD stage IV COPD and a partial carbon dioxide pressure (PaCO2) of 7 kPa (51.9 mm Hg) or higher and pH higher than 7.35. NPPV was targeted to reduce baseline PaCO2 by at least 20% or to achieve PaCO2 values lower than 6.5 kPa (48.1 mm Hg). Patients were randomly assigned (in a 1:1 ratio) via a computer-generated randomisation sequence with a block size of four, to continue optimised standard treatment (control group) or to receive additional NPPV for at least 12 months (intervention group). The primary outcome was 1-year all-cause mortality. Analysis was by intention to treat. The intervention was unblinded, but outcome assessment was blinded to treatment assignment. This study is registered with ClinicalTrials.gov, number NCT00710541.

FINDINGS

Patients were recruited from 36 respiratory units in Germany and Austria, starting on Oct 29, 2004, and terminated with a record of the vital status on July 31, 2011. 195 patients were randomly assigned to the NPPV group (n=102) or to the control group (n=93). All patients from the control group and the NPPV group were included in the primary analysis. 1-year mortality was 12% (12 of 102 patients) in the intervention group and 33% (31 of 93 patients) in the control group; hazard ratio 0.24 (95% CI 0.11-0.49; p=0.0004). 14 (14%) patients reported facial skin rash, which could be managed by changing the type of the mask. No other intervention-related adverse events were reported.

INTERPRETATION

The addition of long-term NPPV to standard treatment improves survival of patients with hypercapnic, stable COPD when NPPV is targeted to greatly reduce hypercapnia.

FUNDING

German Lung Foundation; ResMed, Germany; Tyco Healthcare, Germany; and Weinmann, Germany.

Identification of three exercise-induced mortality risk factors in patients with COPD

The survival rate of chronic obstructive pulmonary disease (COPD) patients with severely reduced exercise capacity is extremely low. We recently identified three life-threatening pathophysiological conditions during cardiopulmonary exercise testing (CPET): (1) exercise-induced hypoxemia, (2) sympathetic overactivity, and (3) progressive respiratory acidosis at low-intensity exercise. The present prospective observation study aimed to determine whether these parameters constitute risk factors of mortality in moderate-to-very severe COPD. Ninety-six COPD patients were followed-up, monthly, for >3 years. Subsequently, spirometry and CPET were performed to examine parameters of exercise-induced hypoxemia ([PaO2 slope, mmHg/L · min(-1)] = Decrease in PaO2/ΔV˙ O2 (Difference in ΔV˙ O2 between at rest and at peak exercise)), progression of acidosis ([ΔpH/ΔV˙ O2,/L · min(-1)] = Decrease in pH/ΔV˙ O2), and sympathetic overactivity ([Δnorepinephrine (NE)/ΔV˙ O2, ng/mL/L · min(-1)] = Increase in NE/ΔV˙ O2). Univariate analysis revealed a significant association between the three conditions with increased mortality. Kaplan-Meier analysis showed that the quartile combining the steepest PaO2 slope (≤-55 mmHg/ΔV˙ O2 [L/min]), steepest decrease in arterial blood pH (≤ -1.72/ΔV˙ O2 [L/min]), and most rapid increase in plasma NE level (≥ 5.2 ng/VO2 [L/min]) during incremental exercise was associated with higher all-cause mortality. These conditions showed cumulative effects on COPD patients' survival. Multivariate analyses revealed that these three life-threatening factors are also independent predictors of mortality based on age, heart rate and PaO2 at rest, body mass index, and forced expiratory volume in 1 s. Thus, these new exercise-induced mortality risk factors may lead to more efficient pulmonary rehabilitation programs for COPD patients based on patient-specific exercise-induced pathophysiological profiles.

[Long-term oxygen therapy in France, 2006-2011]

OBJECTIVE

The study aimed to describe the main characteristics of people treated with long-term oxygen therapy (LTOT) and the trends between 2006 and 2011 for prevalence and incidence.

METHODS

Data were provided from a sample comprising 1/97 of the permanent beneficiaries of the French health insurance. The sample contains anonymous socio-demographic characteristics and data on health care reimbursements. The analyses were carried out among adults aged 20 years and above who had received benefits on account of LTOT.

RESULTS

In 2011, 2.6% of adults were treated with LTOT, corresponding to around 135,000 people. The crude incidence rate was 0.9‰. The prescription of LTOT included LTOT alone (70%), LTOT associated with assisted ventilation (23%) and LTOT associated with continuous positive airway pressure (7%). About 45% of the patients were supported financially in the long-term illness program of the French Social Security because of severe chronic respiratory failure. Between 2006 and 2011, the age-adjusted prevalence rates increased by 2.9% per year in men and by 6.7% per year in women. The age-adjusted incidence rates remained stable in men (+1.6% per year, P=0.45) but increased in women (+4.7% per year, P=0.04). The median survival was 27 months.

CONCLUSION

This analysis of the data demonstrates an increasing burden associated with LTOT in France from 2006 to 2011.

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.

Invasive Mechanical Ventilation in Acute Exacerbation of COPD: Prognostic Indicators to Support Clinical Decision Making

Although non-invasive ventilation is the mainstay of management for patients with hypercapnic acute exacerbation of COPD, invasive mechanical ventilation (IMV) still has an important role to play. IMV can be used successfully to reduce mortality and still maintain quality of life in a subset of patients. Despite this, the evidence to support which patients will benefit from IMV is limited. This article reviews the literature available to guide clinician decision-making. Age is not a reliable independent predictor of survival for COPD patients receiving IMV, nor are levels of PaO2, PCO2, or use of long-term oxygen therapy. Body composition and nutritional status are independent predictors of survival and the presence of co-morbidities, such as cor pulmonale, cardiovascular disease and diabetes mellitus are negative prognostic indicators. Length of time in hospital prior to ICU admission also is an adverse prognostic factor. Although scoring systems exist, their ability to predict outcome for individual patients has limitations. Work needs to be done to improve end-of-life planning in COPD with the encouragement of discussion about advance directives when patients are reaching advanced stage of the disease.

Mixed acid-base disorders, hydroelectrolyte imbalance and lactate production in hypercapnic respiratory failure: the role of noninvasive ventilation

Background

Hypercapnic Chronic Obstructive Pulmonary Disease (COPD) exacerbation in patients with comorbidities and multidrug therapy is complicated by mixed acid-base, hydro-electrolyte and lactate disorders. Aim of this study was to determine the relationships of these disorders with the requirement for and duration of noninvasive ventilation (NIV) when treating hypercapnic respiratory failure.

Methods

Sixty-seven consecutive patients who were hospitalized for hypercapnic COPD exacerbation had their clinical condition, respiratory function, blood chemistry, arterial blood gases, blood lactate and volemic state assessed. Heart and respiratory rates, pH, PaO₂ and PaCO₂ and blood lactate were checked at the 1st, 2nd, 6th and 24th hours after starting NIV.

Results

Nine patients were transferred to the intensive care unit. NIV was performed in 11/17 (64.7%) mixed respiratory acidosis–metabolic alkalosis, 10/36 (27.8%) respiratory acidosis and 3/5 (60%) mixed respiratory-metabolic acidosis patients (p = 0.026), with durations of 45.1±9.8, 36.2±8.9 and 53.3±4.1 hours, respectively (p = 0.016). The duration of ventilation was associated with higher blood lactate (p<0.001), lower pH (p = 0.016), lower serum sodium (p = 0.014) and lower chloride (p = 0.038). Hyponatremia without hypervolemic hypochloremia occurred in 11 respiratory acidosis patients. Hypovolemic hyponatremia with hypochloremia and hypokalemia occurred in 10 mixed respiratory acidosis–metabolic alkalosis patients, and euvolemic hypochloremia occurred in the other 7 patients with this mixed acid-base disorder.

Conclusions

Mixed acid-base and lactate disorders during hypercapnic COPD exacerbations predict the need for and longer duration of NIV. The combination of mixed acid-base disorders and hydro-electrolyte disturbances should be further investigated.

Predicting outcomes following hospitalization for acute exacerbations of COPD

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are a frequent cause of hospital admission and are associated with significant morbidity, mortality, high readmission rates and high resource utilization. More accurate prediction of survival and readmission in patients hospitalized with AECOPD should help to optimize clinical management and allocation of resources, including targeting of palliative care and strategies to reduce readmissions. We have reviewed the published retrospective and prospective studies in this field to identify the factors most likely to be of value in predicting in-hospital and post-discharge mortality, and readmission of patients hospitalized for AECOPD. The prognostic factors which appear most important vary with the particular outcome under consideration. In-hospital mortality is related most clearly to the patient's acute physiological state and to the development of acute comorbidity, while post-discharge mortality particularly reflects the severity of the underlying COPD, as well as specific comorbidities, especially cardiac disease. Important factors influencing the frequency of readmission include functional limitation and poor health-related quality of life. Large prospective studies which incorporate all the potentially relevant variables are required to refine prediction of the important outcomes of AECOPD and thus to inform clinical decision making, for example on escalation of care, facilitated discharge and provision of palliative care.

Potentially modifiable predictors of mortality in patients treated with long-term oxygen therapy

INTRODUCTION

Anemia is considered a systemic manifestation of Chronic Obstructive Pulmonary Disease (COPD); however, few studies have described its influence on chronic respiratory failure (CRF) prognosis. We aimed to test the hypotheses that anemia negatively influences survival and also to identify the cut-off points of hematocrit (Htc) and hemoglobin (Hb) associated with higher mortality in CRF patients using long-term oxygen therapy (LTOT).

METHODS

One-hundred forty two patients with CRF in use of LTOT were evaluated at baseline and followed for three years or until death. Baseline assessment included identification, diagnosis, body composition, dyspnea, health status (HS), spirometry, arterial blood gases, Hb and Htc. Univariate and Cox proportional hazard models were used to evaluate predictors of mortality. We performed ROC curve to identify the best cut-off point of the variables related to survival to construct the Kaplan-Meier curves.

RESULTS

Eight-three patients (58%) died after three years. Baseline values of Hb and Htc were significantly lower in the non-survivors group and both, Htc (HR, 0.96; 95%CI 0.91-0.99; p = 0.04), Hb (HR, 0.86; 95%CI 0.76-0.98; p = 0.02) were selected as predictors of mortality after three years. The cut-off points determined were: the value of HB is < 11 g/dl (sensitivity 95% specificity 85%), Htc ≤ 33% (sensitivity 97% specificity 89%). Other prognostic factors were: male gender, low PaCO(2) and SpO(2), higher dyspnea perception and impairment of HS.

CONCLUSIONS

Our study shows that anemia is a predictor of mortality in patients with CRF under LTOT treatment. Although anemia is potentially modifiable, the effects of raising hemoglobin on mortality remain undetermined.

Predictors of first-year survival in patients with advanced COPD treated using long-term oxygen therapy

Little evidence-based guidance is available to aid clinicians in determining short-term prognoses in very severe COPD patients. Therefore, the present study was designed to provide a prospective assessment (1) of the mortality rates and (2) whether the baseline measurements may be determinants of 1-year mortality in hypoxemic COPD patients receiving long-term oxygen therapy (LTOT). Seventy-eight clinically stable patients with advanced COPD treated using LTOT were enrolled in a prospective cohort study.

OUTCOME VARIABLE

first-year mortality. Baseline measurements: categorical variables: age (<60 or > or = 60 years); gender; body mass index (<20 or > or = 20 kg/m(2)); fat-free mass (FFM) index (<16 [men] and <15 kg/m(2) [women]; baseline dyspnea index (BDI) (< or = 3 or >3); and corticosteroid use. Continuous variables: smoking history; lung function; FFM; fat mass; hemoglobin; hematocrit; arterial blood gases; forearm muscle strength; St. George's Respiratory Questionnaire (SGRQ); and comorbidity score. By the end of 1-year of follow-up, 12 patients (15.4%) had died. Kaplan-Meier curves showed that BDI < or = 3 was the only variable associated with higher mortality. Cox proportional hazards analysis revealed that lower PaO(2) and SpO(2), higher PaCO(2) and SGRQ scores were associated with reduced survival. In the multivariate analysis, BDI remained predictive of mortality (hazard ratio [HR], 0.50; 95% confidence interval [CI], 0.31-0.81), as did PaO(2) (HR, 0.49; 95% CI, 0.26-0.95). These data suggest that readily available parameters as dyspnea intensity and hypoxemia severity may be useful in predicting first-year survival rates in advanced COPD patients receiving LTOT.

The influence of oxygenotherapy on the hypercapnia in patients with chronic obstructive pulmonary disease

Background/Aim. Oxygen therapy is a necessary therapeutic method in treatment of severe chronic respiratory failure (CRF), especially in phases of acute worsening. Risks which are to be taken into consideration during this therapy are: unpredictable increase of carbon dioxide in blood, carbonarcosis, respiratory acidosis and coma. The aim of this study was to show the influence of oxygen therapy on changes of arterial blood carbon dioxide partial pressure. Methods. The study included 93 patients in 104 admittances to the hospital due to acute exacerbation of CFR. The majority of the patients (89.4%) had chronic obstructive pulmonary disease (COPD), while other causes of respiratory failure were less common. The effect of oxygenation was controlled through measurement of PaO2 and PaCO2 in arterial blood samples. To analyze the influence of oxygen therapy on levels of carbon dioxide, greatest values of change of PaO2 and PaCO2 values from these measurements, including corresponding PaO2 values from the same blood analysis were taken. Results. The obtained results show that oxygen therapy led to the increase of PaO2 but also to the increase of PaCO2. The average increase of PaO2 for the whole group of patients was 2.42 kPa, and the average increase of PaCO2 was 1.69 kPa. There was no correlation between the initial values of PaO2 and PaCO2 and changes of PaCO2 during the oxygen therapy. Also, no correlation between the produced increase in PaO2 and change in PaCO2 during this therapy was found. Conclusion. Controlled oxygen therapy in patients with severe respiratory failure greatly reduces the risk of unwanted increase of PaCO2, but does not exclude it completely. The initial values of PaO2 and PaCO2 are not reliable parameters which could predict the response to oxygen therapy.

Predictors of mortality in patients with emphysema and severe airflow obstruction

PURPOSE

Limited data exist describing risk factors for mortality in patients having predominantly emphysema.

SUBJECTS AND METHODS

A total of 609 patients with severe emphysema (ages 40-83 yr; 64.2% male) randomized to the medical therapy arm of the National Emphysema Treatment Trial formed the study group. Cox proportional hazards regression analysis was used to investigate risk factors for all-cause mortality. Risk factors examined included demographics, body mass index, physiologic data, quality of life, dyspnea, oxygen utilization, hemoglobin, smoking history, quantitative emphysema markers on computed tomography, and a modification of a recently described multifunctional index (modified BODE).

RESULTS

Overall, high mortality was seen in this cohort (12.7 deaths per 100 person-years; 292 total deaths). In multivariate analyses, increasing age (p=0.001), oxygen utilization (p=0.04), lower total lung capacity % predicted (p=0.05), higher residual volume % predicted (p=0.04), lower maximal cardiopulmonary exercise testing workload (p=0.002), greater proportion of emphysema in the lower lung zone versus the upper lung zone (p=0.005), and lower upper-to-lower-lung perfusion ratio (p=0.007), and modified BODE (p=0.02) were predictive of mortality. FEV1 was a significant predictor of mortality in univariate analysis (p=0.005), but not in multivariate analysis (p=0.21).

CONCLUSION

Although patients with advanced emphysema experience significant mortality, subgroups based on age, oxygen utilization, physiologic measures, exercise capacity, and emphysema distribution identify those at increased risk of death.

Survival of chronic hypercapnic COPD patients is predicted by smoking habits, comorbidity, and hypoxemia

STUDY OBJECTIVES

Chronic hypercapnia in patients with COPD has been associated with a poor prognosis. We hypothesized that, within this group of chronic hypercapnic COPD patients, factors that could mediate this hypercapnia, such as decreased maximum inspiratory mouth pressure (P(I(max))), decreased maximum expiratory mouth pressure (P(E(max))), and low hypercapnic ventilatory response (HCVR), could be related to survival. Other parameters, such as arterial blood gas values, airway obstruction (FEV1), body mass index (BMI), current smoking status, and the presence of comorbidity were studied as well.

METHODS

A cohort of 47 chronic hypercapnic COPD patients recruited for short-term trials (1 to 3 weeks) in our institute was followed up for 3.8 years on average. Survival was analyzed using a Cox proportional hazards model. The risk factors considered were analyzed, optimally adjusted for age and gender.

RESULTS

At the time of analysis 18 patients (10 male) were deceased. After adjusting for age and gender, P(I(max)), P(E(max)), and HCVR were not correlated with survival within this hypercapnic group. Current smoking (hazard ratio [HR], 7.0; 95% confidence interval [CI], 1.4 to 35.3) and the presence of comorbidity (HR, 5.5; 95% CI, 1.7 to 18.7) were associated with increased mortality. A higher Pa(O2) affected survival positively (HR, 0.6 per 5 mm Hg; 95% CI, 0.4 to 1.0). Pa(CO2) tended to be lower in survivors, but this did not reach statistical significance (HR, 2.0 per 5 mm Hg; 95% CI, 0.9 to 4.3). FEV1 and BMI were not significantly related with survival in hypercapnic COPD patients.

CONCLUSION

In patients with chronic hypercapnia, only smoking status, the presence of comorbidity, and Pa(O2) level are significantly associated with survival. Airway obstruction, age, and BMI are known to be predictors of survival in COPD patients in general. However, these parameters do not seem to significantly affect survival once chronic hypercapnia has developed.

The impact of the Danish Oxygen Register on adherence to guidelines for long-term oxygen therapy in COPD patients

OBJECTIVES

To evaluate the impact of The Danish Oxygen Register on COPD patients' treatment modalities, survival, and adherence to guidelines for long-term oxygen therapy (LTOT).

DESIGN

The Danish Oxygen Register.

SUBJECTS

8487 COPD patients who received LTOT in the study period from November 1, 1994, to December 31, 2000.

MAIN OUTCOME MEASURES

Follow-up, smoking status, correct prescription of LTOT (15-24h/day), and survival.

RESULTS

During the study period an increasing number of patients were prescribed LTOT in connection with discharge after hospitalisation for an exacerbation (1995 vs. 2000: 74.4% vs. 82.2%, P<0.001), were prescribed oxygen 15-24h/day (66.2% vs. 85.5%, P<0.001), had delivered oxygen concentrator or liquid oxygen (77.8% vs. 96.9%, P<0.001), and had mobile oxygen (29.9% vs. 42.8%, P<0.001). Only 65.8% of the patients were followed-up in an outpatient clinic with the possibility of re-evaluation of the criteria for LTOT and adjustment for oxygen flow, with no change during the study period (P=0.43). In a representative subsample, 77.1% had smoking habits or measurement of CO-level registered in 1995 compared to 79.6% in year 2000 (P=0.65), and 25.1% vs. 21.2% (P=0.34) were considered current smokers. The median survival increased from 1.07 to 1.40 years (P=0.032).

CONCLUSIONS

Adherence to guidelines for LTOT has improved concerning administration of oxygen, but has remained poor concerning follow-up of the patients and smoking cessation. Survival of COPD patients on LTOT has improved during the observation period.

Outcomes and health-related quality of life following hospitalization for an acute exacerbation of COPD

OBJECTIVE

The purpose of this study was to understand the outcomes for patients admitted to hospital for an acute exacerbation of COPD, and to determine the factors influencing quality of life and health service utilization of patients with COPD.

METHODOLOGY

Hospital outcomes of 282 patients with moderate and severe COPD, for an acute exacerbation, were retrospectively evaluated. After 24 months of follow up, health-related quality of life (QoL) and health service utilization (emergency room (ER) visit and readmission) in 54 patients admitted previously, were surveyed by questionnaires.

RESULTS

Of 282 COPD patients admitted for an acute exacerbation, 28 patients (9.9%) died during hospitalization, 241 patients (85.5%) were discharged home, and only 13 patients (4.6%) needed long-term care facilities. Although over 50% of the patients had survived over 2 years after discharge, their QoL was poor. Patients who frequently went to the ER or were admitted, were those with poor QoL, severe dyspnoea and frequent exacerbation. COPD exacerbation and dyspnoea were the main factors influencing QoL of the patients. Age, comorbidity, QoL, FEV1, frequency of COPD exacerbation, long-term oxygen therapy, and family doctor were the factors determining the likelihood of patients visiting the ER. Frequency of COPD exacerbation, family doctor and living alone were the factors determining which patients were likely to be admitted to hospital.

CONCLUSION

The outcomes and QoL of patients admitted for an acute exacerbation of COPD were poor. The major factors influencing QoL were frequency of COPD exacerbation and severity of dyspnoea. Improvement of social and medical networks (e.g. reducing the number of patients living alone and providing family doctors for patients) may reduce health care service utilization.

Comparison of Cox's and relative survival models when estimating the effects of prognostic factors on disease-specific mortality: a simulation study under proportional excess hazards

In many prognostic studies focusing on mortality of persons affected by a particular disease, the cause of death of individual patients is not recorded. In such situations, the conventional survival analytical methods, such as the Cox's proportional hazards regression model, do not allow to discriminate the effects of prognostic factors on disease-specific mortality from their effects on all-causes mortality. In the last decade, the relative survival approach has been proposed to deal with the analyses involving population-based cancer registries, where the problem of missing information on the cause of death is very common. However, some questions regarding the ability of the relative survival methods to accurately discriminate between the two sources of mortality remain open. In order to systematically assess the performance of the relative survival model proposed by Esteve et al., and to quantify its potential advantages over the Cox's model analyses, we carried out a series of simulation experiments, based on the population-based colon cancer registry in the French region of Burgundy. Simulations showed a systematic bias induced by the 'crude' conventional Cox's model analyses when individual causes of death are unknown. In simulations where only about 10 per cent of patients died of causes other than colon cancer, the Cox's model over-estimated the effects of male gender and oldest age category by about 17 and 13 per cent, respectively, with the coverage rate of the 95 per cent CI for the latter estimate as low as 65 per cent. In contrast, the effect of higher cancer stages was under-estimated by 8-28 per cent. In contrast to crude survival, relative survival model largely reduced such problems and handled well even such challenging tasks as separating the opposite effects of the same variable on cancer-related versus other-causes mortality. Specifically, in all the cases discussed above, the relative bias in the estimates from the Esteve et al.'s model was always below 10 per cent, with the coverage rates above 81 per cent.

Continuous Oxygen Therapy for Hypoxic Pulmonary Disease

Continuous oxygen therapy (COT) has become widely accepted in the last 20 years in patients with continuous hypoxemia. This review focuses on guidelines for COT, adherence to these guidelines, and the effect of COT on survival, hospitalization, and quality of life. Guidelines for COT are mainly based on three randomized studies where documentation of hypoxemia (P(a)O2 <60mm Hg) and administration of oxygen at least 15 hours/day, are essential. There is less certainty concerning the required correction for hypoxemia, the attitude against current smokers with hypoxemia, the frequency and methods of follow up, and the effect of prescribing domiciliary oxygen to patients with temporary hypoxemia due to a clinically unstable condition (i.e. short-term oxygen therapy [STOT]). The administration of COT to patients with hypoxemic conditions other than COPD rests on extrapolation of data from COPD patients in the NOTT (Nocturnal Oxygen Therapy Trial) and MRC (British Medical Research Council) studies. Adherence to these guidelines is low in general, and very low in some cases. In some countries, STOT accounts for the majority of all prescriptions of domiciliary oxygen, and because nearly half of these patients do not meet the hypoxemia criteria at 3-month follow-up, re-evaluation is mandatory. Only 35%, approximately, of the patients are followed up, and this is one of the main reasons for poor adherence to the hypoxemia criteria. In order to improve the quality of surveillance of COT, more effort has to be put into education of the patients and staff responsible for COT, centralization of the domiciliary organizations, better equipment for ambulation and traveling, and regular follow-up preferably with home visits. The role of an oxygen register on the quality of surveillance of COT has to be determined. The beneficial effect of COT on survival is well established, and some evidence suggests that COT reduces hospitalization. It appears that ambulatory oxygen from liquid source or lightweight cylinders improves disease-specific quality of life modestly in selected patients who partake in regular outdoor activity. Whether COT from oxygen concentrators improves quality of life significantly is, at present, less clear.

The relative survival of COPD patients on long-term oxygen therapy in Australia: A comparative study

OBJECTIVE

The survival of patients with COPD on long-term oxygen therapy (LTOT) has been studied using both univariate and multivariate procedures. There has been only one previous report of relative survival. Relative survival takes into account the risk of death due to increasing age. The objective of this study was to determine the relative survival of a group of South Australian patients prescribed home oxygen therapy for COPD.

METHODOLOGY

A method proposed by Hakulinen was used to determine relative survival. The results were compared with the relative survival of a similar group of French COPD patients.

RESULTS

A total of 505 COPD patients (249 males, 256 females) were included in the survival analysis. Relative survival corrected for life expectancy was 78.1%, 56.7%, 23.1% and 1.1% at 1, 2, 5 and 10 years, respectively, which was less than that reported in a recent French study of comparable patients. Our patients were similar with respect to age, severity of hypoxaemia and oxygen usage to those in the French study.

CONCLUSIONS

Using relative survival analysis, Australian LTOT patients with COPD have worse outcomes than some European patients. Factors contributing to the excess mortality in South Australian COPD patients need to be investigated.

Comparison of acetazolamide and medroxyprogesterone as respiratory stimulants in hypercapnic patients with COPD

BACKGROUND

Acetazolamide and medroxyprogesterone acetate (MPA) are two respiratory stimulants that can be used in patients with stable hypercapnic COPD.

DESIGN AND METHODS

The effects of acetazolamide, 250 mg bid, and MPA, 30 mg bid, on daytime and nighttime blood gas values and the influences on the hypercapnic and hypoxic ventilatory and mouth occlusion pressure (P(0.1)) at 100 ms response were studied in a crossover design in 12 hypercapnic patients with stable COPD (FEV(1), 33 +/- 4% predicted [mean +/- SEM]).

RESULTS

Daytime PaCO(2) decreased from 47.3 +/- 0.8 mm Hg (placebo) to 42.0 +/- 1.5 mm Hg during acetazolamide treatment (p < 0.05) and to 42.8 +/- 1.5 mm Hg during MPA treatment (p < 0.05). Daytime PaO(2) improved with acetazolamide from 65.2 +/- 2.3 to 75.0 +/- 3.0 mm Hg (p < 0.05), whereas no significant changes were seen with MPA. Mean nocturnal end-tidal carbon dioxide tension decreased with both treatments, from 42.0 +/- 2.3 to 35.3 +/- 2.3 mm Hg with acetazolamide (p < 0.05) and to 34.5 +/- 0.8 mm Hg with MPA (p < 0.05). The percentage of time that the nocturnal arterial oxygen saturation was < 90% was reduced significantly with acetazolamide, from 34.9 +/- 10.7% to 16.3 +/- 7.5% (p < 0.05). Mean nocturnal saturation did not change with MPA. Resting minute ventilation increased significantly only with MPA from 9.6 +/- 0.7 to 10.8 +/- 0.8 L/min (p < 0.05). The slope of the hypercapnic ventilatory response did not change during acetazolamide and MPA therapy. The hypoxic ventilatory response increased from - 0.2 +/- 0.05 to - 0.4 +/- 0.1 L/min/% during acetazolamide (p < 0.05) and to - 0.3 +/- 0.1 L/min/% during MPA (p < 0.05). The hypoxic P(0.1) response improved with acetazolamide treatment from - 0.05 +/- 0.008 to - 0.15 +/- 0.02 mm Hg/% (p < 0.05).

CONCLUSIONS

This study shows that acetazolamide and MPA both have favorable effects on daytime and nighttime blood gas parameters in ventilatory-limited patients with stable COPD. However, the use of acetazolamide is preferred because of its extra effect on nocturnal saturation.

Discontinuation of furosemide decreases PaCO(2) in patients with COPD

STUDY OBJECTIVE

To evaluate whether the discontinuation of furosemide treatment resulted in a decrease in PaCO(2) and an increase in daytime and nocturnal oxygenation.

BACKGROUND

Furosemide is widely prescribed in patients with COPD for the treatment of peripheral edema. It is known that furosemide causes a metabolic alkalosis. A diminished chemoreceptor stimulation may cause a decreased alveolar ventilation.

DESIGN

Randomized, double-blind, placebo-controlled, crossover trial.

SETTING

Department of Pulmonology, Rijnstate Hospital Arnhem, the Netherlands.

PATIENTS

Twenty patients with stable COPD (10 men; median age, 70 years [range, 58 to 81 years]; FEV(1) 35% predicted [range, 19 to 70% predicted]). Subjects were included if they had received furosemide, 40 mg/d, for the treatment of peripheral edema for at least a month and if they had a mean nocturnal arterial oxygen saturation (SaO(2)) < 92%. Patients with cardiac left and/or right ventricular dysfunction, sleep apneas, and patients receiving other diuretics, angiotensin-converting enzyme inhibitors, potassium or chloride replacement therapy, or long-term oxygen treatment were excluded.

INTERVENTION

Furosemide was discontinued for 1 week and replaced by placebo treatment in the first or the second week.

MEASUREMENTS AND RESULTS

Ventilation, daytime arterial blood gas levels, and nocturnal SaO(2) were measured at baseline, after 1, and after 2 weeks. Sixteen subjects completed the study. Ventilation increased from 10.4 L/min (range, 6.7 to 15.4 L/min) at baseline to 11.6 L/min (range, 8.7 to 14.0 L/min) after discontinuation of furosemide (p < 0.05). PaCO(2) decreased from 45 mm Hg (range, 35 to 64 mm Hg) to 41 mm Hg (range, 32 to 61 mm Hg; p < 0.01). Daytime and nocturnal oxygenation did not improve.

CONCLUSIONS

Although it does not improve oxygenation, the discontinuation of furosemide decreases PaCO(2) in patients with COPD.

Update on pharmacologic therapy for chronic obstructive pulmonary disease

As described throughout this article, significant improvements continue to occur in the pharmacologic management of COPD. These improvements range from improved medication targeting to better understanding of mechanisms of action, to better delivery of medications, to lower side effects. New areas of pharmacologic intervention, if not ready for use today, hold great promise for the not-too-distant future. In addition to the many agents described here, multiple mediator antagonists and anti-inflammatory agents are also under investigation for use in COPD. Interestingly, repair of alveolar tissue may be possible. Indeed, preliminary animal studies suggest that retinoic acid may be able to induce regeneration of lung alveoli. Overall, more effort is needed to broaden awareness and provide for the appropriate diagnosis of COPD, better explain pharmacologic therapies for COPD, simplify and disseminate guidelines, and highlight key differences between asthma and COPD, including their treatment strategies. As interest in COPD continues to grow, future updates on COPD management will continue to add new pharmacologic options for this devastating and preventable disease.