Copyright ©ERS Journals Ltd 2006 Stable COPD: predicting benefit from high-dose inhaled corticosteroid treatment1 Firestone Institute for Respiratory Health, St. Joseph's Healthcare and McMaster University, Hamilton, ON, and 3 Centre de recherche, Hôpital Laval, Institut universitaire de cardiologie et de pneumologie de l'Université Laval, QC, Canada, 2 NUPAIVA (Nucleo da Pesquisa em Asma e Inflamação das Vias Aéreas) Universidade Federal de Santa Catarina, Florianopólis, Brazil. CORRESPONDENCE: E. Pizzichini, NUPAIVA, Hospital Universitário, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina 88040390, Brazil. Fax: 55 482347711. E-mail: pizzichi{at}matrix.com.br Keywords: Airway inflammation, chronic obstructive pulmonary disease, eosinophils, induced sputum, inhaled corticosteroids
Received: June 20, 2005
The role of inhaled corticosteroids in the management of chronic obstructive pulmonary disease (COPD) remains controversial. The purpose of this study was to evaluate whether sputum eosinophilia (defined as eosinophils 3%) predicts clinical benefit from inhaled corticosteroid treatment in patients with smoking-related clinically stable moderate-to-severe COPD. Forty consecutive patients with effort dyspnoea (mean age 67 yrs; 52 pack-yr smoking history; post-bronchodilator forced expiratory volume in one second (FEV1) <60% predicted, consistent with moderate-to-severe smoking-related chronic airflow limitation) were enrolled. Subjects were treated with inhaled placebo followed by inhaled budesonide (Pulmicort Turbuhaler® 1,600 µg·day1), each given for 4 weeks. While the treatment was single-blind (subject level), sputum cell counts before and after treatment interventions were double-blind, thus removing bias. Outcome variables included spirometry, quality-of-life assessment and 6-min walk test. Sputum eosinophilia was present in 38% of subjects. In these, budesonide treatment normalised the eosinophil counts and, in comparison to placebo treatment, resulted in clinically significant improvement in the dyspnoea domain of the disease-specific chronic respiratory questionnaire (0.8 versus 0.3) and a small but statistically significant improvement in post-bronchodilator spirometry (FEV1 100 mL versus 0 mL; p<0.05). In conclusion, sputum eosinophilia predicts short-term clinical benefit from high-dose inhaled corticosteroid treatment in patients with stable moderate-to-severe chronic obstructive pulmonary disease. The role of inhaled corticosteroids (ICS) in the management of stable chronic obstructive pulmonary disease (COPD) remains controversial 1, 2. The results of several large, multicentre randomised controlled trials 37 suggest that there may be a small clinical benefit from ICS treatment, particularly in patients with more severe disease. Nonetheless, despite the lack of compelling evidence for their use, many COPD patients are treated with regular ICS therapy 8. COPD is heterogeneous 9, 10, and there are likely to be subgroups of patients who will benefit from ICS treatment. It is probable that such benefit within phenotypic subgroups will be lost when the data from large randomised controlled trials are analysed within a heterogeneous study population.
As yet, no useful predictor of clinical response to ICS treatment in patients with COPD has been identified 11, 12. Having considered previous studies showing that sputum eosinophilia predicts short-term clinical benefit from prednisone (or prednisolone) treatment in patients with COPD 13, 14, the present authors reasoned that sputum eosinophilia may also be a valid predictor of clinical benefit from ICS treatment. The purpose of this study was therefore to determine whether sputum eosinophilia (defined in this study as eosinophils
Subjects From the respiratory clinics of three university centres, 44 adults with a physician diagnosis of COPD 15 and the following characteristics were consecutively recruited. All subjects were 40 yrs old, current or ex-smokers of 20 pack-yrs, and had effort dyspnoea and moderate-to-severe COPD (Global Initiative for Chronic Obstructive Lung Disease stage II or III) as indicated by a post-bronchodilator forced expiratory volume in one second (FEV1)/slow vital capacity (SVC) of <70% and an FEV1 <60% predicted. Partial post-bronchodilator airflow reversibility was not an exclusion criterion since the objective of the study was to investigate the predictive value of sputum eosinophilia. The subjects were stable on treatment with salbutamol or ipatropium; none had used either inhaled corticosteroids or prednisone for 2 months. The study was approved by the research ethics boards of each study site, and all subjects gave written informed consent before participating in the study.
Study design
Methods
Subject characteristics were documented by questionnaire. Effort dyspnoea was assessed with the Medical Research Council dyspnoea scale 16. Allergy skin tests were performed using the modified prick technique 17 with common allergen extracts and a negative and positive control. Pre- and post-salbutamol (400 µg) FEV1, SVC and inspiratory capacity (IC) were measured according to American Thoracic Society specifications 18, after withholding inhaled ß-agonists or ipratropium bromide for
Analysis Descriptive statistics were used to summarise the baseline characteristics of the study patients. The results were expressed as mean±SD if the data were normally distributed and as median (interquartile range) if the data were non-normally distributed. Repeated measures ANOVA were used to test for the effects of treatment on the dependent variables, with post hoc analysis used to identify the source of significant variation when present. All comparisons were two-tailed and p-values <0.05 were considered significant.
Of the 44 subjects enrolled in the study, four were excluded from the final analysis; two developed infective exacerbations during the study, one was non-compliant with treatment, and one died of an acute coronary thrombosis (confirmed at autopsy) during placebo treatment. The baseline characteristics of the remaining 40 subjects were stratified by sputum eosinophil counts (tables 1 3%, and were more likely to be male and to have a greater degree of chronic airflow limitation compared to patients without sputum eosinophilia. There was no difference in other sputum characteristics between the two groups. Sputum eosinophilia did not predict the presence of atopy or of bronchodilator reversibility; 16 (40%) subjects had bronchodilator reversibility >10% pred and four (10%) >15% pred (fig. 1
The effects of budesonide treatment on sputum cell counts in the eosinophilic and non-eosinophilic groups were examined (fig. 2
The effects of budesonide treatment on clinical outcome variables were examined. Budesonide produced a small but statistically significant increase in mean and absolute change in post-bronchodilator FEV1 compared with placebo in subjects who had sputum eosinophilia (table 2
Thirty-four (85%) subjects (13 eosinophilic, 21 non-eosinophilic) agreed to participate in the prednisone arm of the study. Prednisone treatment resulted in further reduction of sputum eosinophils to <1% in both the eosinophilic (p<0.001 compared to baseline) and non-eosinophilic groups (fig. 2
The authors also examined the outcomes in all study participants without categorising them into eosinophilic or non-eosinophilic sub-groups. Budesonide and prednisone resulted in a significant attenuation of sputum eosinophilia (p<0.01) when compared to placebo treatment, but neither treatment had any significant effect on CRQ or FEV1 (table 3
In this study, treatment with inhaled budesonide 1,600 µg·day1 for 4 weeks produced a clinically important and statistically significant effect on dyspnoea during day-to-day activities, and a small, statistically significant improvement in post-bronchodilator FEV1 in subjects who had sputum eosinophilia 3% compared with treatment with inhaled placebo. In contrast, subjects without sputum eosinophilia did not show benefit from inhaled budesonide treatment. These findings suggest that sputum cell counts are a useful measurement in the clinical management of COPD. They provide substantive evidence that sputum eosinophilia predicts clinical benefit from high-dose inhaled corticosteroid treatment. The results are consistent with previous publications, indicating that sputum eosinophilia is a predictor of clinical benefit from either prednisone or prednisolone treatment in patients with COPD 13, 14, and they extend this knowledge to treatment with high-dose ICS. Sputum eosinophilia is a relatively common finding in patients with clinically stable, moderate-to-severe, smoking-related COPD. It occurred in 38% of consecutively enrolled subjects in the present study, which is similar to the prevalence reported by others 13, 14, 26 in similar cohorts of patients. The results differ from those recently reported by Brightling et al. 26 in similar patients in a randomised, double-blind, crossover trial of inhaled mometasone 800 µg daily and placebo, each given for 6 weeks with a 4-week washout period between treatments. The modest dose of mometasone was followed by a small but significant improvement in FEV1 of 0.11 L only in those patients with sputum eosinophils >3.9%. However, there was no improvement in CRQ or sputum eosinophils. The latter, when considered in relation to the reduction of eosinophils seen in the present study, suggests that the dose of mometasone and its relative potency were too low to have optimal effects. While it would have been preferable to identify a predictive marker of ICS benefit that would be easier to measure than sputum eosinophilia, neither the presence of atopy alone (as defined by positive allergy skin-prick tests) nor the presence of post-salbutamol reversibility alone were able to predict clinical benefit of inhaled budesonide. When considering the validity of these results, it is necessary to look at the characteristics of the subjects studied, the study design, the sample size and the outcomes of CRQ and FEV1. Subjects with partial ß2-agonist bronchodilator reversible airflow limitation were not excluded because it is recognised that a proportion of patients with COPD demonstrate significant post-bronchodilator reversibility (i.e. by definition, they also have asthma) 27. In elderly patients, with a significant smoking history and the presence of moderate-to-severe chronic airflow limitation, the primary clinical diagnosis is still likely to be that of smoking-related COPD, regardless of whether or not there is an additional element of ß2-agonist reversible airflow limitation present. In the current study, all participants were >40 yrs and had a smoking history of >20 pack-yrs, the vast majority (>80%) were non-atopic on allergy skin testing, and they all had objective evidence of persistent chronic airflow limitation after salbutamol. There was no relationship between salbutamol reversibility and sputum eosinophilia, indicating that sputum eosinophilia is not necessarily characteristic of the asthma phenotype 28. The authors therefore feel that, from a clinical perspective, most physicians would label these patients as having smoking-related COPD, regardless of whether or not there is also partial ß2-agonist bronchodilator reversibility. Thus, it is likely that the results from the present study can be broadly generalised to other patients with clinically stable, physician-diagnosed COPD who are attending other outpatient clinics. When the study protocol was developed, it was reasoned that a parallel-group randomised controlled trial would require a substantially greater number of study subjects in order to complete the study, and even then, as evidenced by a recent study by Humbert et al. 29, there is no guarantee that randomisation leads to matched study groups at baseline. The authors also carefully considered the merits of a randomised crossover study design but were aware of a number of potential methodological limitations that may be associated with such a design, including the uncertainty of the time needed for budesonide washout, which might have resulted in a treatment order effect. Thus, while they recognized the limitations of a single-blind sequential order study design a priori, it was felt that a single-blind design was a methodologically acceptable approach to addressing this specific study question, particularly given that bias was removed by the sputum cell counts being performed in a double-blind fashion. The authors therefore decided to use a sequential, single-blind crossover study design, rather than a randomised two-period crossover design, because of the increased possibility of the confounding influence of infective exacerbations, the uncertainty regarding the maximum washout period of high-dose inhaled budesonide and the possibility of persistent clinical improvement beyond the active treatment period. The study was adequately powered to detect statistically significant differences in dyspnoea scores, quality of life and FEV1 measurements between the treatment groups at, or below, thresholds of what are regarded as minimally important clinical differences. The results of this study support previous observations that measurements of quality of life in severe COPD are more sensitive to detecting changes in functional status than FEV1 3033. The dyspnoea domain of the CRQ seems to be more discriminatory than the global score and could be more easily applied in practice. O'Donnell et al. 34 have drawn attention to the importance of hyperinflation in patients with advanced COPD and that, when there is subjective improvement with little or no change in FEV1, there may be a reduction in hyperinflation identified by an increase in inspiratory capacity. This was not observed in the present study. Neither was any improvement in the 6-min walk test recorded. A possible reason for the small FEV1 improvement is that ICS cannot penetrate to more distal airways where much of the inflammation occurs. In this situation prednisone should be more effective. In the present study, this was assessed by adding an optional third period of prednisone treatment; in patients with sputum eosinophilia, prednisone treatment was associated with a seven-fold reduction in sputum eosinophil counts, compared to budesonide treatment, which was associated with only a three-fold reduction. This suggests that there may be a degree of inhaled steroid resistance in these patients, and the absence of apparent clinical benefit from a short burst of prednisone cannot necessarily be used to refute such an argument. Another reason for the small improvement in FEV1 is that the clinical improvement resulted primarily from reduction of the inflammatory component, as occurs in patients with eosinophilic bronchitis and without asthma. The present study assessed the short-term effects of ICS treatment in patients with moderate-to-severe COPD. However, several large randomised, controlled trials have demonstrated that ICS treatment is associated with a reduction in the number of clinical exacerbations 57. Therefore, clinicians prescribing ICS for patients with moderate-to-severe COPD are likely to do so with the expectation of preventing or reducing COPD exacerbations. In the context of this study, readers will be interested to note that the reduction in exacerbations seen with fluticasone in the Inhaled Steroids in Obstructive Lung Disease study was largely confined to subjects who had a good short-term response to corticosteroid treatment 35. Thus, it is possible that the presence of sputum eosinophilia may, in addition to predicting short-term benefits from ICS treatment, also predict longer-term benefits, including the reduction of exacerbations. Patients with smoking-related chronic airflow limitation were eligible for entry into the study provided they had an FEV1 <60% pred; this cut-off was chosen as being the degree of physiological impairment at which patients with chronic airflow limitation might begin to experience symptoms of dyspneoa. As such, it was useful for such patients to be identified as being potentially suitable for this study. While the results from this study demonstrate the clinical benefit of budesonide treatment in patients with moderate-to-severe COPD and sputum eosinophilia, it provides no justification for the extension of the current COPD guidelines, which recommend that ICS in COPD only be initiated in patients when their FEV1 <50% of predicted value. The results of this study are important, since current guidelines do not recognise a predictor for clinical benefit of ICS treatment in patients with COPD 11, 15, 3638. They provide two potential reasons as to why previous large multicentre trials in COPD have failed to convincingly show clinical benefit from inhaled steroid treatment 37. One reason is that they have not identified the subgroup of patients with eosinophilic bronchitis who will benefit from corticosteroid treatment. If the authors of this study had not done so, they would also have failed to identify improvement in CRQ or FEV1. The other reason for failure to show benefit in the multicentre trials is that they may have used too low a dose of inhaled steroid. It could be that the results of the present study underestimate the true benefit of inhaled budesonide in patients with moderate-to-severe COPD. While the authors did not specifically discontinue ICS in otherwise eligible patients in order to qualify them for the study, it is possible that patients who had previously benefited from a trial of ICS were unlikely to have discontinued them, and thus they would not have been eligible for participation in this study.
While it is true that similar beneficial effects are seen in the great majority of patients treated with inhaled long-acting anti-cholinergics or long-acting ß-agonists, the use if these agents in COPD is well accepted and forms the cornerstone of pharmacological therapy as recommended by current COPD guidelines 11, 3638. However, the guidelines are less clear in defining the role of ICS in COPD, perhaps in part because it is a heterogeneous condition, and there remains some debate as to which patients within this diagnostic group are likely to benefit significantly from the addition of ICS treatment. The aim of this study was to determine which phenotypes of patients with COPD are likely to benefit maximally from ICS therapy. Objective measurements of airway inflammation were applied to identify patients with COPD who would be likely to demonstrate a clinical response to ICS. The data indicate that patients with clinically stable COPD who have sputum eosinophilia should be treated with high-dose ICS, while those who do not have sputum eosinophilia ( Patients with sputum eosinophilia who showed clinical benefit from high-dose ICS were not necessarily those with frequent clinical exacerbations. In order to be eligible for entry into this study, patients needed to have been clinically stable for the preceding 8 weeks. Once randomised, the two patients who experienced a clinical exacerbation during the 10-week study period were discontinued from the study and their data was not included in the final analysis. The predictive benefit of budesonide in patients with sputum eosinophilia was nonetheless evident in patients who had been clinically stable for the 8 weeks prior to study entry, as well as for the 10-week duration of the study. In summary, about one-third of patients with clinically stable, moderate-to-severe smoking-related chronic obstructive pulmonary disease present with sputum eosinophilia. In the present study, this was associated with a clinically important response to high-dose inhaled budesonide therapy as measured by effects on dyspnoea during day-to-day activities. This improvement in dyspnoea (which could be measured in practice by the Chronic Respiratory Questionnaire dyspnoea domain) was associated with a small but statistically significant improvement in forced expiratory volume in one second (which may be easily missed in clinical practice) and in the global Chronic Respiratory Questionnaire score. Improvements in these outcome variables were paralleled by a significant reduction in sputum eosinophil counts to within the normal range in patients with sputum eosinophilia. The authors conclude that sputum eosinophilia predicts clinical benefit from inhaled high-dose corticosteroid treatment in patients with smoking-related moderate-to-severe chronic obstructive pulmonary disease, and that sputum cell counts are useful in the clinical management of these patients.
The authors would like to thank: the patients who participated in this study; L. Berman, S. Pugsley, G. Cox, A. Chterpensque and P. Moritz, for help with recruiting the patients; A. Efthimiadis, for supervising the examination of sputum and the quality control between centres; and S. Weston, S. Carruthers, S. Ferreira and M. Bélanger, for technical support.
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