Survival and future need of long-term oxygen therapy for chronic obstructive pulmonary disease—gender differences

Sex-differences in COPD: from biological mechanisms to therapeutic considerations

Chronic obstructive pulmonary disease (COPD) is a heterogeneous respiratory condition characterized by symptoms of dyspnea, cough, and sputum production. We review sex-differences in disease mechanisms, structure-function-symptom relationships, responses to therapies, and clinical outcomes in COPD with a specific focus on dyspnea. Females with COPD experience greater dyspnea and higher morbidity compared to males. Imaging studies using chest computed tomography scans have demonstrated that females with COPD tend to have smaller airways than males as well as a lower burden of emphysema. Sex-differences in lung and airway structure lead to critical respiratory mechanical constraints during exercise at a lower absolute ventilation in females compared to males, which is largely explained by sex differences in maximum ventilatory capacity. Females experience similar benefit with respect to inhaled COPD therapies, pulmonary rehabilitation, and smoking cessation compared to males. Ongoing re-assessment of potential sex-differences in COPD may offer insights into the evolution of patterns of care and clinical outcomes in COPD patients over time.

Long-Term Oxygen Therapy and Risk of Fire-Related Events

Introduction

Two large major trials showed that long-term oxygen therapy (LTOT) improved mortality in patients with chronic obstructive pulmonary disease (COPD) and hypoxemia. Although oxygen accelerates combustion and is an obvious fire hazard, LTOT has traditionally been prescribed to veterans who are actively smoking.

Methods

We conducted a retrospective chart review of all veterans with COPD at a single center who were prescribed new LTOT between October 2010 and September 2015. Of the 158 patients who met the study criteria, 152 were male. Bayesian logistic regression was used to model the outcome variable fire-related incident with the predictors smoking status, age, race, depression, posttraumatic stress disorder, and type of oxygen used.

Results

The mean age of the 158 patients with COPD in the study was 71.3 years in nonsmokers and 65.9 years in smokers. The model-estimated odds (SD) of a fire-related incident occurring in a smoker were 31.6 (5.1-372.7) times the odds of a fire-related incident occurring in a nonsmoker.

Conclusions

Patients who smoke and remain on LTOT put themselves at greater risk of having a fire-related incident than do nonsmokers.

Sex differences between women and men with COPD: A new analysis of the 3CIA study

BACKGROUND

There is partial evidence that COPD is expressed differently in women than in men, namely on symptoms, pulmonary function, exacerbations, comorbidities or prognosis. There is a need to improve the characterization of COPD in females.

METHODS

We obtained and pooled data of 17 139 patients from 22 COPD cohorts and analysed the clinical differences by sex, establishing the relationship between these characteristics in women and the prognosis and severity of the disease. Comparisons were established with standard statistics and survival analysis, including crude and multivariate Cox-regression analysis.

RESULTS

Overall, 5355 (31.2%) women were compared with men with COPD. Women were younger, had lower pack-years, greater FEV₁%, lower BMI and a greater number of exacerbations (all p < 0.05). On symptoms, women reported more dyspnea, equal cough but less expectoration (p < 0.001). There were no differences in the BODE index score in women (2.4) versus men (2.4) (p = 0.5), but the distribution of all BODE components was highly variable by sex within different thresholds of BODE. On prognosis, 5-year survival was higher in COPD females (86.9%) than in males (76.3%), p < 0.001, in all patients and within each of the specific comorbidities that we assessed. The crude and adjusted RR and 95% C.I. for death in males was 1.82 (1.69-1.96) and 1.73 (1.50-2.00), respectively.

CONCLUSIONS

COPD in women has some characteristic traits expressed differently than compared to men, mainly with more dyspnea and COPD exacerbations and less phlegm, among others, although long-term survival appears better in female COPD patients.

Oxygen devices and delivery systems

Oxygen use has extended from inpatient to outpatient settings for patients with chronic pulmonary diseases and complications of hypoxaemia. This article presents an overview of oxygen devices (oxygen concentrators, compressed gas cylinders and liquid oxygen) and delivery systems (high- and low-flow). The indications, advantages and disadvantages of each device and delivery system are presented, aiming to offer updated knowledge to the multidisciplinary team members managing patients with respiratory failure, and therefore allowing appropriate selection of devices and delivery systems that are tailored to the needs of each patient.

Home Oxygen in Chronic Obstructive Pulmonary Disease

Two landmark trials conducted more than 35 years ago provided scientific evidence that, under very specific circumstances, long-term oxygen therapy (LTOT) may prolong life. These two trials enrolled 290 patients with chronic obstructive pulmonary disease and severe daytime hypoxemia documented by direct arterial blood gas measurement. From that time, LTOT became a standard of care, and the indications for oxygen therapy expanded to include nocturnal oxygen therapy for isolated nocturnal oxygen desaturation, ambulatory oxygen to correct exercise-induced desaturation, and short-burst oxygen to relieve dyspnea. In most cases, the rationale for broadening the indications for oxygen therapy is that, if hypoxemia exists, correcting it by increasing the Fi_O2 should help. However, with the exception of LTOT in severely hypoxemic patients with chronic obstructive pulmonary disease, randomized controlled trials of oxygen therapy have failed to demonstrate clinically significant benefits. Also, adherence to LTOT is usually suboptimal. Important areas for future research include improving understanding of the mechanisms of action of supplemental oxygen, the clinical and biochemical predictors of responsiveness to LTOT, the methods for measuring and enhancing adherence to LTOT, and the cost-effectiveness of oxygen therapy. A standardization of terminology to describe the use of supplemental oxygen at home is provided.

Patient registries for home oxygen research and evaluation

Randomized clinical trials are the preferred study design to address key research questions about the benefits or harms of interventions. However, randomized trials of oxygen therapy are difficult to conduct and have limitations. The purpose of this article is to offer our view on the potential use of patient registries in the field of home oxygen in COPD as an alternative to randomized trials by referring to the Swedish experience with a national registry for respiratory failure. Patient registries use observational study methods to collect uniform data (clinical and other) to evaluate specified outcomes for a population defined by a particular disease, condition, or exposure. As opposed to administrative databases, patient registries serve one or more predetermined scientific, clinical, or policy purposes. By systematically and prospectively compiling relevant data, patient registries may describe the natural history of a disease, determine effectiveness and cost-effectiveness, assess safety or harm, and measure quality of care. Registry-based randomized trials (ie, randomized trials within a clinical registry) combine the advantages of a prospective randomized trial with the strengths of a large-scale all-comers clinical registry. Challenges and issues in the design and implementation of patient registries include the representativeness of participants, data collection, quality assurance, ownership, and governance. Notwithstanding their limitations, patient registries represent valuable tools in the conduct of research in the area of home oxygen therapy.

Women and COPD: do we need more evidence?

The increasingly female face of chronic obstructive pulmonary disease (COPD) prevalence among women has equalled that of men since 2008, due in part to increased tobacco use among women worldwide and exposure to biomass fuels. This finding is supported by a number of characteristics. There is evidence of susceptibility to smoking and other airborne contaminants, along with epidemiological and phenotypic manifestations. COPD has thus become the leading cause of death in women in the USA. The clinical presentation is characterised by increasingly pronounced dyspnoea with a marked tendency towards anxiety and depression, undernutrition, nonsmall cell lung cancer (especially adenocarcinoma) and osteoporosis. Quality of life is also more significantly impacted. The theories advanced to explain these differences involve the role played by oestrogens, impaired gas exchange in the lungs and smoking habits. While these differences require appropriate therapeutic responses (smoking cessation, pulmonary rehabilitation, long-term oxygen therapy), barriers to the treatment of women with COPD include greater under-diagnosis than in men, fewer spirometry tests and medical consultations. Faced with this serious public health problem, we need to update and adapt our knowledge to the epidemiological changes.

The face of COPD is increasingly female. We need more evidence and a change in how the disease is managed. http://ow.ly/zueL30mWqlS

A nationwide structure for valid long-term oxygen therapy: 29-year prospective data in Sweden

Background

Long-term oxygen therapy (LTOT) improves prognosis in COPD with severe hypoxemia. However, adherence to criteria for eligibility and quality of LTOT is often insufficient and varies between countries. The aim of this study was to evaluate a national structure for prescription and management of LTOT over three decades in Sweden.

Methods

The study was a prospective, population-based study of 23,909 patients on LTOT from 1987 to 2015 in the Swedish National Register of Respiratory Failure (Swedevox). We assessed the prevalence, incidence, and structure of LTOT; completeness of registration in Swedevox; and validity of prescription and management of LTOT in Sweden according to seven published quality indicators.

Results

LTOT was prescribed by 48 respiratory or medicine units and managed mainly by specialized oxygen nurses. Swedevox had a stable completeness of 85% of patients starting LTOT since 1987. The national incidence of LTOT increased from 3.9 to 14.7/100,000 inhabitants over the time period. In 2015, 2,596 patients had ongoing therapeutic LTOT in the registry, a national prevalence of 31.6/100,000. Adherence to prescription recommendations and fulfillment of quality criteria was stable or improved over time. Of patients starting LTOT in 2015, 88% had severe hypoxemia (partial pressure of arterial oxygen [PaO₂] <7.4 kPa) and 97% had any degree of hypoxemia (PaO₂ <8.0 kPa); 98% were prescribed oxygen ≥15 hours/day or more; 76% had both stationary and mobile oxygen equipment; 75% had a mean PaO₂ >8.0 kPa breathing oxygen; and 98% were non-smokers.

Conclusion

We present a structure for prescription, management, and follow-up of LTOT. The national registry effectively monitored adherence to prescription recommendations and most likely contributed to improved quality of care.

Home oxygen therapy: evidence versus reality

INTRODUCTION

LTOT is a well-established treatment option for hypoxemic patients. Scientific evidence for its benefits of LTOT dates back to the 1980s, when two randomized controlled trials showed prolonged survival in COPD-patients undergoing LTOT for at least 15 hours/day. In contrast, the potential benefits of LTOT in non-COPD-patients has not been well researched and the recommendations for its application are primarily extrapolated from trials on COPD-patients. Recently, a large trial confirmed that COPD-patients who don't meet classic indication criteria, and have moderate desaturation at rest or during exercise, do not benefit from oxygen therapy. Also the significant technical evolution of LTOT devices has improved its application. Areas covered: A literature research was performed in pubmed regarding home oxygen therapy (terms: LTOT, ambulatory oxygen therapy, short burst oxygen therapy, nocturnal oxygen therapy). Expert commentary: LTOT proved a survival benefit for COPD patients about 30 years ago. Whether the results of these trials are still valid for patients under modern treatment guidelines remains unknown. Nevertheless, the classic indication criteria for LTOT still persist in guidelines, since there is a lack of updated evidence for the effects of LTOT in more severe hypoxemic patients.

Burn injury during long-term oxygen therapy in Denmark and Sweden: the potential role of smoking

Background

Long-term oxygen therapy (LTOT) increases life expectancy in patients with COPD and severe hypoxemia. Smoking is the main cause of burn injury during LTOT. Policy regarding smoking while on LTOT varies between countries. In this study, we compare the incidence of burn injury that required contact with a health care specialist, between Sweden (a country with a strict policy regarding smoking while on LTOT) and Denmark (a country with less strict smoking policy).

Methods

This was a population-based, cohort study of patients initiating LTOT due to any cause in Sweden and Denmark. Data on diagnoses, external causes, and procedures were obtained from the Swedish and Danish National Patient Registers for inpatient and outpatient care. Patients were followed from January 1, 2000, until the first of the following: LTOT withdrawal, death, or study end (December 31, 2009). The primary end point was burn injury during LTOT.

Results

A total of 23,741 patients received LTOT in Denmark and 7,754 patients in Sweden. Most patients started LTOT due to COPD, both in Sweden (74%) and in Denmark (62%). The rate of burn injury while on LTOT was higher in Denmark than in Sweden; 170 (95% confidence interval [CI], 126–225) vs 85 (95% CI, 44–148) per 100,000 person-years; rate ratio 2.0 (95% CI, 1.0–4.1). The risk remained higher after adjustment for gender, age, and diagnosis in multivariate Cox regression, hazard ratio 1.8 (95% CI, 1.0−3.5). Thirty-day mortality after burn injury was 8% in both countries.

Conclusion

Compared to Sweden, the rate of burn injury was twice as high in Denmark where smoking is not a contraindication for prescribing LTOT.

Long-Term Oxygen Therapy 24 vs 15 h/day and Mortality in Chronic Obstructive Pulmonary Disease

Long-term oxygen therapy (LTOT) ≥ 15 h/day improves survival in hypoxemic chronic obstructive pulmonary disease (COPD). LTOT 24 h/day is often recommended but may pose an unnecessary burden with no clear survival benefit compared with LTOT 15 h/day. The aim was to test the hypothesis that LTOT 24 h/day decreases all-cause, respiratory, and cardiovascular mortality compared to LTOT 15 h/day in hypoxemic COPD. This was a prospective, observational, population-based study of COPD patients starting LTOT between October 1, 2005 and June 30, 2009 in Sweden. Overall and cause-specific mortality was analyzed using Cox and Fine-Gray regression, controlling for age, sex, prescribed oxygen dose, PaO₂ (air), PaCO₂ (air), Forced Expiratory Volume in one second (FEV₁), WHO performance status, body mass index, comorbidity, and oral glucocorticoids. A total of 2,249 included patients were included with a median follow-up of 1.1 years (interquartile range, 0.6–2.1). 1,129 (50%) patients died and no patient was lost to follow-up. Higher LTOT duration analyzed as a continuous variable was not associated with any change in mortality rate (hazard ratio [HR] 1.00; (95% confidence interval [CI], 0.98 to 1.02) per 1 h/day increase above 15 h/day. LTOT exactly 24 h/day was prescribed in 539 (24%) patients and LTOT 15–16 h/day in 1,231 (55%) patients. Mortality was similar between the groups for all-cause, respiratory and cardiovascular mortality. In hypoxemic COPD, LTOT 24 h/day was not associated with a survival benefit compared with treatment 15–16 h/day. A design for a registry-based randomized trial (R-RCT) is proposed.

The risk of burn injury during long-term oxygen therapy: a 17-year longitudinal national study in Sweden

BACKGROUND

Long-term oxygen therapy (LTOT) improves the survival time in hypoxemic chronic obstructive pulmonary disease. Despite warnings about potential dangers, a considerable number of patients continue to smoke while on LTOT. The incidence of burn injuries related to LTOT is unknown. The aim of this study was to estimate the rate of burn injury requiring health care contact during LTOT.

METHODS

Prospective, population-based, consecutive cohort study of people starting LTOT from any cause between January 1, 1992 and December 31, 2009 in the Swedish National Register of Respiratory Failure (Swedevox).

RESULTS

In total, 12,497 patients (53% women) were included. The mean (standard deviation) age was 72±9 years. The main reasons for starting LTOT were chronic obstructive pulmonary disease (75%) and pulmonary fibrosis (15%). Only 269 (2%) were active smokers when LTOT was initiated. The median follow-up time to event was 1.5 years (interquartile range, 0.55-3.1). In total, 17 patients had a diagnosed burn injury during 27,890 person-years of LTOT. The rate of burn injury was 61 (95% confidence interval, 36-98) per 100,000 person-years. There was no statistically significant difference in the rate of burn injury between ever-smokers and never-smokers, or between men and women.

CONCLUSION

The rate of burn injuries in patients on LTOT seems to be low in Sweden. The strict requirements in Sweden for smoking cessation before LTOT initiation may contribute to this finding.

Assessment of health status and program performance in patients on long-term oxygen therapy

BACKGROUND

Despite well established clinical guidelines, performance of long-term oxygen therapy (LTOT) programs shows marked variability among territories. The current study assessed the LTOT program and the health status of patients on LTOT prior to the deployment of community-based integrated care in an urban health district of Barcelona (Spain).

AIMS

To assess: i) the LTOT program and health status of the patients on LTOT in the health district; ii) their frailty profile; and, iii) the requirements for effective deployment of integrated care services for these patients.

METHODS

Cross-sectional observational study design including all patients (n = 406) on LTOT living in the health district. Health status, frailty, arterial blood gases, forced spirometry and hand-grip muscle strength were measured. Network analysis of frailty was carried out.

RESULTS

Adequacy of LTOT prescription (n = 362): 47% and 31% of the patients had PaO2 ≤ 60 mmHg and ≤55 mmHg, respectively. Adherence to LTOT: 31% of all patients used LTOT ≥15 h/d; this figure increased to 67% in those with PaO2≤60 mmHg. Assessment of frailty: Overall, LTOT patients presented moderate to severe frailty. Care complexity was observed in 42% of the patients.

CONCLUSIONS

Adequacy and adherence to LTOT was poor and many patients were frail and complex. The outcomes of the network analysis may contribute to enhance assessment of frailty in LTOT patients. These observations suggest that an integrated care strategy has the potential to improve the health outcomes of these patients.

[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.

Trends in long-term oxygen therapy for COPD in Denmark from 2001 to 2010

OBJECTIVES

To evaluate changes in demographics, incidence, prevalence, treatment modalities, and survival of COPD patients on long-term oxygen therapy (LTOT) from year 2001-2010 in Denmark.

METHODS

All 14,965 COPD patients with COPD treated LTOT in Denmark in the period 2001-2010.

RESULTS

During the study period, the incidence and prevalence of COPD patients on LTOT increased from 30.5 to 32.2 per 100.000, and from 42.0 to 48.1 per 100.000, respectively. Mean age of patients increased from 73.4 to 74.8 years, P < 0.001. An increasing number of patients were prescribed LTOT in connection with discharge after hospitalisation for an exacerbation (2001 vs. 2010: 76.5% vs. 91.7%, P < 0.001); were prescribed oxygen 15-24 h/day (85.8% vs. 89.5%, P < 0.001); had mobile oxygen (56.4% vs. 94.2%, P < 0.001), and stopped LTOT alive within 6 months (20.6% vs. 30.8%, P < 0.001). Ninety-nine percent of the patients received oxygen concentrator or liquid oxygen with no change in the study period (P = 0.66). The median survival on LTOT increased insignificantly from 16.5 to 17.8 months (P = 0.12). Women had a lower risk of dying compared with men, with an adjusted hazard ratio of 0.81 (95% confidence interval (CI) 0.78-0.84), P < 0.001). During the study period, the risk of death for women, compared to men, decreased significantly with a hazard ratio of 0.978 (95% CI: 0.964-0.992) per calendar year.

CONCLUSIONS

The incidence of COPD patients on LTOT in Denmark has levelled of during recent years, and the quality of prescribing LTOT and follow up has improved. Women had better survival than men, and this difference has increased during the study period.

Hospitalizations for chronic obstructive pulmonary disease exacerbations and their impact on disease and subsequent morbidity and mortality

In chronic obstructive pulmonary disease (COPD), progressive airflow limitation is a risk factor for development of disease exacerbations, which, when severe, may require hospitalization. In the discussed study, a large cohort of patients hospitalized for their first COPD exacerbation were analyzed in terms of subsequent hospitalizations and mortality risk. COPD hospitalizations were found to be a risk factor for subsequent COPD-related hospitalizations, to increase their incidence and to increase the disease-related mortality risk. Male gender was also identified as a risk factor for a higher COPD-related morbidity and mortality. Hospitalizations for COPD exacerbation should be considered as additional criterion for disease severity in tailoring the disease management.

Comorbidity and sex-related differences in mortality in oxygen-dependent chronic obstructive pulmonary disease

BACKGROUND

It is not known why survival differs between men and women in oxygen-dependent chronic obstructive pulmonary disease (COPD). The present study evaluates differences in comorbidity between men and women, and tests the hypothesis that comorbidity contributes to sex-related differences in mortality in oxygen-dependent COPD.

METHODS

National prospective study of patients aged 50 years or older, starting long-term oxygen therapy (LTOT) for COPD in Sweden between 1992 and 2008. Comorbidities were obtained from the Swedish Hospital Discharge Register. Sex-related differences in comorbidity were estimated using logistic regression, adjusting for age, smoking status and year of inclusion. The effect of comorbidity on overall mortality and the interaction between comorbidity and sex were evaluated using Cox regression, adjusting for age, sex, Pa(O2) breathing air, FEV(1), smoking history and year of inclusion.

RESULTS

In total, 8,712 patients (55% women) were included and 6,729 patients died during the study period. No patient was lost to follow-up. Compared with women, men had significantly more arrhythmia, cancer, ischemic heart disease and renal failure, and less hypertension, mental disorders, osteoporosis and rheumatoid arthritis (P<0.05 for all odds ratios). Comorbidity was an independent predictor of mortality, and the effect was similar for the sexes. Women had lower mortality, which remained unchanged even after adjusting for comorbidity; hazard ratio 0.73 (95% confidence interval, 0.68-0.77; P<0.001).

CONCLUSIONS

Comorbidity is different in men and women, but does not explain the sex-related difference in mortality in oxygen-dependent COPD.

Tobacco use and cessation among women: research and treatment-related issues

The prevalence of tobacco use in women has increased over the past century. This has resulted in dramatic increases in smoking-related lung diseases, such as chronic obstructive pulmonary disease (COPD) and lung cancer. There is growing literature suggesting that women may be more susceptible than men to the effects of tobacco and to the development of COPD. Women may also have specific barriers that interfere with smoking cessation. This article addresses possible differences in lung function decline and nicotine metabolism in women compared to men. Differences in COPD between the sexes are discussed. Finally, barriers to smoking cessation in women are presented.

Trends in cause-specific mortality in oxygen-dependent chronic obstructive pulmonary disease

RATIONALE

Since the introduction of long-term oxygen treatment (LTOT) in chronic obstructive pulmonary disease (COPD) with chronic hypoxia, the proportion of women and the age of patients starting LTOT have increased markedly. We hypothesize that this might have led to shifts in the causes of death over time.

OBJECTIVES

To test for time trends in cause-specific mortality in COPD with LTOT.

METHODS

Patients starting LTOT for COPD in Sweden between January 1, 1987 and December 31, 2004 were included in a national prospective study and monitored until withdrawal of LTOT, death, or December 31, 2004. The primary end point was cause of death obtained from the Swedish Causes of Death Register.

MEASUREMENTS AND MAIN RESULTS

A total of 7,628 patients (53% women) were monitored for a median of 1.7 years (range, 0-18.0 yr). No patient was lost to follow-up and 5,457 patients died during the study. The crude overall mortality increased by 1.6%/year (95% confidence interval [CI], 0.9-2.2%/yr; P < 0.001). The absolute risk of death increased for circulatory disease by 2.8%/year (95% CI, 1.3-4.3%/yr; P < 0.001) and for digestive organ disease by 7.8%/year (95% CI, 1.9-14.0%/yr; P = 0.009). The absolute risk of death decreased for respiratory disease by 2.7%/year (95% CI, 2.0- 3.3%/yr; P < 0.001) and for lung cancer by 3.4%/year (95% CI, 1.1-5.7%/yr; P = 0.004).

CONCLUSIONS

In oxygen-dependent COPD, mortality has increased over time both overall and of nonrespiratory causes, including cardiovascular disease. This highlights the importance of optimized diagnostics and treatment of comorbidities to decrease morbidity and mortality.

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.

Sex differences in mortality and clinical expressions of patients with chronic obstructive pulmonary disease. The TORCH experience

RATIONALE

There is limited knowledge regarding sex differences and outcomes in patients with chronic obstructive pulmonary disease (COPD).

OBJECTIVES

Determine sex differences in survival, causes of death, and patient-centered outcomes in the 3-year Toward a Revolution in COPD Health (TORCH) study.

METHODS

A total of 1,481 women and 4,631 men with COPD were enrolled in TORCH, a trial comparing salmeterol, 50 μg, plus fluticasone propionate, 500 μg, twice a day and each component individually. Causes of death were determined by an endpoint committee. Sex differences in survival were explored using a Cox proportional hazards model adjusted for other baseline factors. Exacerbation rate was compared using a negative binomial model. Dyspnea was evaluated using the Medical Research Council scale and health status using the St. George's Respiratory Questionnaire.

MEASUREMENTS AND MAIN RESULTS

At baseline, women were younger (63 vs. 66 yr), had higher FEV(1) (47% vs. 44% predicted), and worse St. George's Respiratory Questionnaire (51.3 vs. 48.7) and Medical Research Council score. During the study, 707 (15.3%) men and 168 (11.3%) women died. After adjusting for differences in baseline factors, the risk of dying was 16% higher in men than in women; however, this was not statistically significant (hazard ratio 1.16 [95% CI, 0.98-1.39]). Causes of death were similar in women and men. Exacerbation rate was 25% higher in women than in men.

CONCLUSIONS

Women enrolled in TORCH had a lower mortality rate than men but similar causes of death. The risk of dying was similar in women and men after adjusting for important baseline variables. Women reported more exacerbations, and worse dyspnea and health status scores than men. Clinical trial registered with www.clinicaltrials.gov (NCT00268216).

Increasing Evidence for Gender Differences in Chronic Obstructive Pulmonary Disease

The prevalence of chronic obstructive pulmonary disease (COPD) among women is increasing and differences in both the management of COPD and the results of treatment between men and women have been noted. This article investigates the reasons for this increase in prevalence and the differences in natural history and COPD management between male and female patients. The main reason for the rise in prevalence of COPD in women is increased tobacco use. An additional factor is the greater susceptibility of women to damage from smoke and air pollution. The health-related quality of life is worse in women when compared with men with the same severity of disease. In addition, nutritional status is often worse in women. The most important treatment for COPD is to stop smoking. Women appear to be more dependent on cigarettes than men, and have greater difficulties stopping smoking, especially when they live with a partner who smokes. Rehabilitation is an effective treatment for both male and female COPD patients, but the focus is different: women need more emotional support and social interaction to achieve the best results.