Targeting the COPD exacerbation

Prevention of exacerbation in patients with moderate-to-very severe COPD with the intent to modulate respiratory microbiome: a pilot prospective, multi-center, randomized controlled trial

Introduction

Considering the role of bacteria in the onset of acute exacerbation of COPD (AECOPD), we hypothesized that the use of influenza-Streptococcus pneumoniae vaccination, oral probiotics or inhaled amikacin could prevent AECOPD.

Methods

In this pilot prospective, muti-central, randomized trial, moderate-to-very severe COPD subjects with a history of moderate-to-severe exacerbations in the previous year were enrolled and assigned in a ratio of 1:1:1:1 into 4 groups. All participants were managed based on the conventional treatment recommended by GOLD 2019 report for 3 months, with three groups receiving additional treatment of inhaled amikacin (0.4 g twice daily, 5-7 days monthly for 3 months), oral probiotic Lactobacillus rhamnosus GG (1 tablet daily for 3 months), or influenza-S. pneumoniae vaccination. The primary endpoint was time to the next onset of moderate-to-severe AECOPD from enrollment. Secondary endpoints included CAT score, mMRC score, adverse events, and survival in 12 months.

Results

Among all 112 analyzed subjects (101 males, 96 smokers or ex-smokers, mean ± SD age 67.19 ± 7.39 years, FEV1 41.06 ± 16.09% predicted), those who were given dual vaccination (239.7 vs. 198.2 days, p = 0.044, 95%CI [0.85, 82.13]) and oral probiotics (248.8 vs. 198.2 days, p = 0.017, 95%CI [7.49, 93.59]) had significantly delayed onset of next moderate-to-severe AECOPD than those received conventional treatment only. For subjects with high symptom burden, the exacerbations were significantly delayed in inhaled amikacin group as compared to the conventional treatment group (237.3 vs. 179.1 days, p = 0.009, 95%CI [12.40,104.04]). The three interventions seemed to be safe and well tolerated for patient with stable COPD.

Conclusion

The influenza-S. pneumoniae vaccine and long-term oral probiotic LGG can significantly delay the next moderate-to-severe AECOPD. Periodically amikacin inhalation seems to work in symptomatic patients. The findings in the current study warrants validation in future studies with microbiome investigation.Clinical trial registration:https://clinicaltrials.gov/, identifier NCT03449459.

Smoking load reduction is insufficient to downregulate miR-301b, a lung cancer promoter

Several circulating miRNAs identified in the plasma of smokers have been implicated as promoters of nasopharyngeal and lung carcinoma. To investigate the plasma profile of miRNAs in subjects who reduces the number of smoked cigarettes and who quit after six months. We accompanied 28 individuals enrolled in a Smoking Cessation Program over 6 months. At Baseline, clinical characteristics, co-morbidities, and smoking history were similar among subjects. After 6 months, two groups were defined: who successfully quitted smoking (named "quitters", n = 18, mean age 57 years, 11 male) and who reduced the number of cigarettes smoked (20-90%) but failed to quit smoking (named "smokers", n = 10, mean age 52 years, 3 male). No significant clinical changes were observed between groups at baseline and after a 6-month period, however, quitters showed significant downregulations in seven miRNAs at baseline: miR-17 (- 2.90-fold, p = 0.029), miR-20a (- 3.80-fold, p = 0.021); miR-20b (- 4.71-fold, p = 0.027); miR-30a (- 3.95-fold, p = 0.024); miR-93 (- 3.63-fold, p = 0.022); miR-125a (- 1.70-fold, p = 0.038); and miR-195 (- 5.37-fold, p = 0.002), and after a 6-month period in 6 miRNAs: miR-17 (- 5.30-fold, p = 0.012), miR-20a (- 2.04-fold, p = 0.017), miR-20b (- 5.44-fold, p = 0.017), miR-93 (- 4.00-fold, p = 0.041), miR-101 (- 4.82-fold, p = 0.047) and miR-125b (- 3.65-fold, p = 0.025). Using time comparisons, only quitters had significant downregulation in miR-301b (- 2.29-fold, p = 0.038) after 6-month. Reductions in the number of smoked cigarettes was insufficient to change the plasma profile of miRNA after 6 months. Only quitting smoking (100% reduction) significantly downregulated miR-301b related to hypoxic conditions, promotion of cell proliferation, decreases in apoptosis, cancer development, and progression as increases in radiotherapy and chemotherapy resistance.

Impact and prevention of severe exacerbations of COPD: a review of the evidence

Severe exacerbations of COPD, ie, those leading to hospitalization, have profound clinical implications for patients and significant economic consequences for society. The prevalence and burden of severe COPD exacerbations remain high, despite recognition of the importance of exacerbation prevention and the availability of new treatment options. Severe COPD exacerbations are associated with high mortality, have negative impact on quality of life, are linked to cardiovascular complications, and are a significant burden on the health-care system. This review identified risk factors that contribute to the development of severe exacerbations, treatment options (bronchodilators, antibiotics, corticosteroids [CSs], oxygen therapy, and ventilator support) to manage severe exacerbations, and strategies to prevent readmission to hospital. Risk factors that are amenable to change have been highlighted. A number of bronchodilators have demonstrated successful reduction in risk of severe exacerbations, including long-acting muscarinic antagonist or long-acting β₂-agonist mono- or combination therapies, in addition to vaccination, mucolytic and antibiotic therapy, and nonpharmacological interventions, such as pulmonary rehabilitation. Recognition of the importance of severe exacerbations is an essential step in improving outcomes for patients with COPD. Evidence-based approaches to prevent and manage severe exacerbations should be implemented as part of targeted strategies for disease management.

Influence of SIGLEC9 polymorphisms on COPD phenotypes including exacerbation frequency

BACKGROUND AND OBJECTIVE

The exacerbation-prone phenotype of COPD is particularly important, as exacerbations lead to poor quality of life and disease progression. We previously found that COPD patients who lack Siglec-14, a myeloid cell protein that recognizes bacteria and triggers inflammatory responses, are less prone to exacerbation. We hypothesized that the variations in other SIGLEC genes could also influence COPD exacerbation frequency, and investigated the association between SIGLEC9 polymorphisms and the exacerbation-prone phenotype of COPD.

METHODS

We examined whether SIGLEC9 polymorphisms affect the frequency of COPD exacerbation in 135 subjects within our study population, and also analysed the correlation between the genotypes and the severity of airflow obstruction and emphysema in 362 Japanese smokers including 244 COPD patients. The association between these single nucleotide polymorphisms (SNPs) and COPD phenotypes were also assessed in a Caucasian population of ECLIPSE study. The effects of these coding SNPs (cSNPs) on Siglec-9 protein functions were analysed using in vitro assays.

RESULTS

The G allele of rs2075803 and rs2075803 G/rs2258983 A(GA) haplotype in SIGLEC9 was associated with higher frequency of exacerbations and the extent of emphysema in COPD. These results did not replicate in the ECLIPSE study. A myeloid cell line expressing the Siglec-9 variant corresponding to GA haplotype produced more TNF-α than the one expressing the variant corresponding to the other major haplotype.

CONCLUSION

The SIGLEC9 rs2075803 G/rs2258983 A haplotype, which corresponds to a Siglec-9 variant that is less effective at suppressing inflammatory response, may be a risk factor for the development of emphysema.

The effects of smoking and smoking cessation on nasal mucociliary clearance, mucus properties and inflammation

OBJECTIVE

The aim of the present study was to assess nasal mucociliary clearance, mucus properties and inflammation in smokers and subjects enrolled in a Smoking Cessation Program (referred to as quitters).

METHOD

A total of 33 subjects with a median (IQR) smoking history of 34 (20-58) pack years were examined for nasal mucociliary clearance using a saccharine transit test, mucus properties using contact angle and sneeze clearability tests, and quantification of inflammatory and epithelial cells, IL-6 and IL-8 concentrations in nasal lavage fluid. Twenty quitters (mean age: 51 years, 9 male) were assessed at baseline, 1 month, 3 months and 12 months after smoking cessation, and 13 smokers (mean age: 52 years, 6 male) were assessed at baseline and after 12 months. Clinicaltrials.gov: NCT02136550.

RESULTS

Smokers and quitters showed similar demographic characteristics and morbidities. At baseline, all subjects showed impaired nasal mucociliary clearance (mean 17.6 min), although 63% and 85% of the quitters demonstrated significant nasal mucociliary clearance improvement at 1 month and 12 months, respectively. At 12 months, quitters also showed mucus sneeze clearability improvement (∼26%), an increased number of macrophages (2-fold) and no changes in mucus contact angle or cytokine concentrations.

CONCLUSION

This study showed that smoking cessation induced early improvements in nasal mucociliary clearance independent of mucus properties and inflammation. Changes in mucus properties were observed after only 12 months of smoking cessation.

Diesel exhaust: current knowledge of adverse effects and underlying cellular mechanisms

Diesel engine emissions are among the most prevalent anthropogenic pollutants worldwide, and with the growing popularity of diesel-fueled engines in the private transportation sector, they are becoming increasingly widespread in densely populated urban regions. However, a large number of toxicological studies clearly show that diesel engine emissions profoundly affect human health. Thus the interest in the molecular and cellular mechanisms underlying these effects is large, especially concerning the nature of the components of diesel exhaust responsible for the effects and how they could be eliminated from the exhaust. This review describes the fundamental properties of diesel exhaust as well as the human respiratory tract and concludes that adverse health effects of diesel exhaust not only emerge from its chemical composition, but also from the interplay between its physical properties, the physiological and cellular properties, and function of the human respiratory tract. Furthermore, the primary molecular and cellular mechanisms triggered by diesel exhaust exposure, as well as the fundamentals of the methods for toxicological testing of diesel exhaust toxicity, are described. The key aspects of adverse effects induced by diesel exhaust exposure described herein will be important for regulators to support or ban certain technologies or to legitimate incentives for the development of promising new technologies such as catalytic diesel particle filters.

Exacerbations in patients with chronic obstructive pulmonary disease receiving physical therapy: a cohort-nested randomised controlled trial

BACKGROUND

Physical exercise training aims at reducing disease-specific impairments and improving quality of life in patients with chronic obstructive pulmonary disease (COPD). COPD exacerbations in particular negatively impact COPD progression. Physical therapy intervention seems indicated to influence exacerbations and their consequences. However, information on the effect of physical therapy on exacerbation occurrence is scarce. This study aims to investigate the potential of a protocol-directed physical therapy programme as a means to prevent or postpone exacerbations, to shorten the duration or to decrease the severity of exacerbations in patients with COPD who have recently experienced an exacerbation. Besides, this study focuses on the effect of protocol-directed physical therapy on health status and quality of life and on cost-effectiveness and cost-utility in patients with COPD who have recently experienced an exacerbation.

METHODS/DESIGN

A prospective cohort of 300 COPD patients in all GOLD stages will be constructed. Patients will receive usual multidisciplinary COPD care including guideline-directed physical therapy. Patients in this cohort who have GOLD stage 2 to 4 (post-bronchodilator FEV1/FVC < 0.7 and FEV1 < 80% of predicted), who receive reimbursement by health insurance companies for physical therapy (post-bronchodilator Tiffeneau-index < 0.6) and who experience a COPD exacerbation will be asked within 56 days to participate in a cohort-nested prospective randomised controlled trial (RCT). In this RCT, the intervention group will receive a strict physical therapy programme for patients with COPD. This protocol-directed physical therapy (pdPT) will be compared to a control group that will receive sham-treatment, meaning no or very low-intensity exercise training (ST). An economic evaluation will be embedded in the RCT. Anthropometric measurements, comorbidities, smoking, functional exercise capacity, peripheral muscle strength, physical activity level, health related quality of life, patients' perceived benefit, physical therapy compliance, motivation level, level of effective mucus clearance, exacerbation symptoms and health care contacts due to COPD will be recorded. Follow-up measurements are scheduled at 3 and 6 weeks, 3, 6, 12 and 24 months after inclusion.

DISCUSSION

Ways to minimise potential problems regarding the execution of this study will be discussed.

TRIAL REGISTRATION

The Netherlands National Trial Register NTR1972.

The complexity of managing COPD exacerbations: a grounded theory study of European general practice

OBJECTIVES

To understand the concerns and challenges faced by general practitioners (GPs) and respiratory physicians about primary care management of acute exacerbations in patients with chronic obstructive pulmonary disease (COPD).

DESIGN

21 focus group discussions (FGDs) were performed in seven countries with a Grounded Theory approach. Each country performed three rounds of FGDs.

SETTING

Primary and secondary care in Norway, Germany, Wales, Poland, Russia, The Netherlands, China (Hong Kong).

PARTICIPANTS

142 GPs and respiratory physicians were chosen to include urban and rural GPs as well as hospital-based and out patient-clinic respiratory physicians.

RESULTS

Management of acute COPD exacerbations is dealt with within a scope of concerns. These concerns range from 'dealing with comorbidity' through 'having difficult patients' to 'confronting a hopeless disease'. The first concern displays medical uncertainty regarding diagnosis, medication and hospitalisation. These clinical processes become blurred by comorbidity and the social context of the patient. The second concern shows how patients receive the label 'difficult' exactly because they need complex attention, but even more because they are time consuming, do not take responsibility and are non-compliant. The third concern relates to the emotional reactions by the physicians when confronted with 'a hopeless disease' due to the fact that most of the patients do not improve and the treatment slows down the process at best. GPs and respiratory physicians balance these concerns with medical knowledge and practical, situational knowledge, trying to encompass the complexity of a medical condition.

CONCLUSIONS

Knowing the patient is essential when dealing with comorbidities as well as with difficult relations in the consultations on exacerbations. This study suggests that it is crucial to improve the collaboration between primary and secondary care, in terms of, for example, shared consultations and defined work tasks, which may enhance shared knowledge of patients, medical decision-making and improved management planning.

Missing potential opportunities to reduce repeat COPD exacerbations

INTRODUCTION

Long-acting beta-agonists (LABA) and/or inhaled corticosteroids (ICS) have been shown to reduce COPD exacerbation risk. Using data from a large integrated health-care system, we sought to examine whether these medication classes were initiated after an exacerbation of COPD.

METHODS

We identified patients who experienced an inpatient or outpatient COPD exacerbation within the Veterans Affairs Integrated Service Network (VISN)-20. We assessed the addition of a new inhaled therapy (an ICS, LABA or both) within 180 days after the exacerbation. We assessed independent predictors of adding treatment using logistic regression.

RESULTS

We identified 45,780 patients with COPD, of whom 2,760 patients experienced an exacerbation of COPD. Of these individuals, 2,570 (93.1 %) were on either none or only one long-acting medication studied (LABA or ICS). In the subsequent 180-day period after their exacerbation, only 875 (34.1 %) patients had at least one of these additional therapies dispensed from a VA pharmacy. Among patients who were treated in the outpatient setting, older age [OR 0.98/year, 95 % CI (0.97-0.99)], current tobacco use [OR 0.74, 95 % CI (0.60-0.90)], greater use of ipratropium bromide [OR 0.97/canister, 95 % CI (0.96-0.98)], prior COPD exacerbation [OR 0.55, 95 % CI (0.46-0.67)], depression [OR 0.77, 95 % CI (0.61-0.98)], CHF [OR 0.74, 95 % CI (0.57-0.97)], and diabetes (OR 0.77 (0.60-0.99)] were associated with lower odds of additional therapy. Patients who were treated in the hospital had similar associated predictors.

CONCLUSION

Among patients treated for an exacerbation of COPD, we found relatively few were subsequently prescribed inhaled therapies known to reduce exacerbations.

Loss of Siglec-14 reduces the risk of chronic obstructive pulmonary disease exacerbation

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality worldwide. COPD exacerbation, or episodic worsening of symptoms, often results in hospitalization and increased mortality rates. Airway infections by new bacterial strains, such as nontypeable Haemophilus influenzae (NTHi), are a major cause of COPD exacerbation. NTHi express lipooligosaccharides that contain sialic acids, and may interact with Siglec-14, a sialic acid recognition protein on myeloid cells that serves as an activating signal transduction receptor. A null allele polymorphism in SIGLEC14 may attenuate the inflammatory responses to NTHi by eliminating Siglec-14 expression. We asked if the loss of Siglec-14 attenuates the inflammatory response by myeloid cells against NTHi, and if the SIGLEC14-null polymorphism has any effect on COPD exacerbation. We found that NTHi interacts with Siglec-14 to enhance proinflammatory cytokine production in a tissue culture model. Inhibitors of the Syk tyrosine kinase suppress this response. Loss of Siglec-14, due to SIGLEC14-null allele homozygosity, is associated with a reduced risk of COPD exacerbation in a Japanese patient population. Taken together, Siglec-14 and its downstream signaling pathway facilitate the "infection-inflammation-exacerbation" axis of COPD disease progression, and may represent promising targets for therapeutic intervention.

Transition of patients with COPD across different care settings: challenges and opportunities for hospitalists

Hospitalists play an important role in treating current and preventing future acute exacerbations of chronic obstructive pulmonary disease (AECOPD), which are associated with high rates of medical resource use and morbidity. Comprehensive admission screening and diagnostic tests are important in enabling hospitalists to reliably identify patients with AECOPD, the severity of the episode, and related issues that may prolong patients' hospital length of stay. Recurring exacerbations, especially those that require repeated acute care, can reduce physical activity and accelerate pulmonary decline and risk of death. Recommended pharmacotherapies for AECOPD should include short-acting bronchodilators, systemic corticosteroids, and appropriate antibiotics in cases of suspected bacterial infection. Patients with demonstrable hypoxemia or respiratory failure may benefit from oxygen and/or ventilatory support. Long-term disease management with the goal of preventing future exacerbations should include ongoing emphasis toward smoking cessation and up-to-date vaccination, in addition to prescribing maintenance pharmacotherapies in accordance with respiratory treatment guidelines. Additional benefits may be derived from nonpharmacologic therapies, such as pulmonary rehabilitation, weight-loss recommendations, and treatment of obstructive sleep dyspnea when present. Effective communication among members of the inpatient and outpatient health care teams, the patient, and his or her caregivers is an important aspect of care transitions. Hospital discharge summaries should be transmitted to the patient's primary care physician and be readily available at the first follow-up visit. Discharge coaches and other allied health care providers can aid hospitalists in reinforcing self-management skills and patient education, and in emphasizing the importance of follow-up visits. Recent findings suggest that health and cost benefits are associated with improved COPD management. This article focuses on the pivotal role of the hospitalist in promoting and facilitating the steps toward improving quality outcomes and transitions of care for patients with COPD.

Triple therapy for the management of COPD: a review

Triple therapy for COPD consists of a long-acting anti-cholinergic bronchodilator, a long-acting beta-agonist bronchodilator, and an inhaled corticosteroid. Guidelines from the Canadian Thoracic Society advocate triple therapy for some patients with moderate-to-severe COPD. The objective of this review was to evaluate the evidence based clinical efficacy of triple therapy compared to dual bronchodilator therapy (long-acting anti-cholinergic bronchodilator + beta-agonist bronchodilator) or long-acting anti-cholinergic bronchodilator monotherapy for managing COPD. A systematic literature search was conducted to identify relevant clinical evaluations of triple therapy in the management of moderate to severe COPD. Databases searched included: Medline; EMBASE; CINAHL and PubMed (non-Medline records only). Of 2,314 publications, 4 articles evaluated triple therapy for the management of COPD. Hospitalization rates for COPD exacerbations, reported in 2 trials, were significantly reduced with triple therapy compared to long-acting anti-cholinergic bronchodilator monotherapy, with reported relative risks of 0.53 (95% CI: 0.33, 0.86, p = 0.01) and 0.35 (95% CI: 0.16-0.78, p = 0.011). Exacerbation data is inconsistent between the two trials reporting this outcome. Lung function, dyspnea and quality of life data show statistical significant changes with triple therapy compared to long-acting anti-cholinergic bronchodilator monotherapy but the changes do not reach clinical importance. Triple therapy does decrease the number of hospitalizations for severe/acute COPD exacerbations compared with long-acting anti-cholinergic bronchodilator monotherapy. There is insufficient evidence to determine if triple therapy is superior to dual bronchodilator therapy.

Prophylactic vaccinations in chronic obstructive pulmonary disease: current status

PURPOSE OF REVIEW

Acute exacerbations of chronic obstructive pulmonary disease (COPD) are a major cause of morbidity and mortality worldwide. Most acute exacerbations are triggered by community-acquired respiratory infections. Medications to treat COPD exacerbations are limited; therefore, identifying effective ways to prevent exacerbations are needed. Influenza and pneumococcal vaccines are currently recommended for all persons with COPD. However, current immunization rates are far lower than the Healthy People 2010 Goals. The reasons for nonadherence are multifactorial and strategies for overcoming these barriers are discussed.

RECENT FINDINGS

Influenza vaccine clearly reduces the number of acute exacerbations that occur in persons with COPD. Influenza vaccine may reduce hospitalizations and mortality from COPD, but the evidence is not conclusive. Pneumococcal vaccine reduces the incidence of invasive pneumococcal disease. However, there is not enough evidence to conclude that pneumococcal vaccination in persons with COPD has a significant impact on reducing morbidity or mortality. Vaccination with both influenza and pneumococcal vaccine may produce an additive effect that reduces exacerbations more effectively than either vaccine alone. Whole genome sequencing of bacteria and genome mining may represent a powerful way to identify novel potential vaccine antigens for future vaccine development.

SUMMARY

Although clinical trial data are limited, vaccinations can prevent some of the infections that cause COPD exacerbations and should be administered to all patients with COPD. Vaccines do not cause exacerbations of COPD. Patient and physician barriers to vaccination can be overcome with targeted education and system-wide interventions. Further research efforts should focus on improving current vaccines and identifying novel targets for future vaccine development.

Bibliography. Current world literature

This bibliography is compiled by clinicians from the journals listed at the end of this publication. It is based on literature entered into our database between 1 November 2007 and 31 October 2008 (articles are generally added to the database about two and a half months after publication). In addition, the bibliography contains every paper annotated by reviewers; these references were obtained from a variety of bibliographic databases and published between the beginning of the review period and the time of going to press. The bibliography has been grouped into topics that relate to the reviews in this issue.

New drugs for exacerbations of chronic obstructive pulmonary disease

Tobacco smoking is the dominant risk factor for chronic obstructive pulmonary disease (COPD), but viral and bacterial infections are the major causes of exacerbations in later stages of disease. Reactive oxygen species (ROS), pathogen-associated molecular patterns (PAMPs), and damage-associated molecular patterns (DAMPs) activate families of pattern recognition receptors (PRRs) that include the toll-like receptors (TLRs). This understanding has led to the hypothesis that COPD is an archetypal disease of innate immunity. COPD is characterised by abnormal response to injury, with altered barrier function of the respiratory tract, an acute phase reaction, and excessive activation of macrophages, neutrophils, and fibroblasts in the lung. The activated non-specific immune system then mediates the processes of inflammation and repair, fibrosis, and proteolysis. COPD is also associated with corticosteroid resistance, abnormal macrophage and T-cell populations in the airway, autoinflammation and autoimmunity, aberrant fibrosis, accelerated ageing, systemic and concomitant disease, and defective regeneration. Such concepts have been used to generate a range of molecular targets, and clinical trials are taking place to identify effective drugs for the prevention and treatment of COPD exacerbations.

Healthcare costs associated with initial maintenance therapy with fluticasone propionate 250 μg/salmeterol 50 μg combination versus anticholinergic bronchodilators in elderly US Medicare-eligible beneficiaries with COPD

OBJECTIVE

To compare, in elderly Medicare beneficiaries, chronic obstructive pulmonary disease (COPD)-related healthcare costs for patients initiating treatment with fluticasone propionate/salmeterol 250 μg/50 μg (FSC) with those for patients initiating treatment with ipratropium bromide/albuterol (IPA), ipratropium bromide (IPR), and tiotropium bromide (TIO).

METHODS

In this retrospective, observational, cohort study, COPD-related medical costs (inpatient/emergency department, outpatient) and pharmacy costs were assessed in Medicare beneficiaries ≥ 65 years old who were enrolled in a commercial Medicare health maintenance organization plan and had a diagnosis of COPD (ICD-9-CM codes 491.xx, 492.xx, or 496.xx) within 12 months before initial treatment with FSC, IPA, IPR, or TIO.

RESULTS

In these ≥ 65-year-old patients (N=14,689), initial maintenance treatment with FSC was associated with total COPD-related cost savings (medical + pharmacy) of $295 versus IPA, $1,235 versus IPR, and $110 versus TIO (p<0.05, each comparison) over a 1-year follow-up period.

CONCLUSIONS

Initiation of maintenance therapy with FSC was associated with significant reduction in total costs (medical + pharmacy) relative to costs associated with the short-acting anticholinergic bronchodilators IPR and IPA and the long-acting anticholinergic bronchodilator TIO in an elderly Medicare-eligible population. These data considered in the context of the substantial efficacy and effectiveness data suggest that early introduction of maintenance treatment with FSC has both clinical and economic benefits. Limitations inherent in handling of administrative data include lack of objective clinical measures such as spirometry and smoking status. Furthermore, accuracy of diagnosis codes cannot be verified.