The present study of a large cohort of COPD patients managed in primary care and currently prescribed ICS showed that 54% of the patients had no exacerbation within the last 12 months, whereas 21% had a history of two or more exacerbations. Among patients with no history of exacerbations, 30% had a blood-eosinophil count ≥ 0.3 x 109/L.
Contrary to the strategy document by GOLD, which provides guidelines for physicians on when to consider ICS treatment, the Danish Society of Respiratory Medicine provides recommendations on de-escalation of ICS maintenance therapy in COPD patients without exacerbations or hospitalizations for at least one year due to COPD [15]. In short, a physician may consider halve the dose of ICS and await results for 3 months. If FEV1 is more than fifty percent complete withdrawal of ICS may happen followed by a follow-up 3 months later for lung function measurement and assessment of clinical condition. These recommendations may also apply to COPD patients, who have been in ICS and LABA treatment for a long period of time without clear indication.
Consideration of ICS add-on maintenance treatment can be made, according to GOLD, based on exacerbations and symptoms. More specifically in those with a blood-eosinophil count of ≥ 0.1 x 109/L and a history of two or more moderate exacerbations or a blood-eosinophil count of ≥ 0.3 x 109/L [1]. These recommendations facilitate the use of ICS treatment for the prevention of exacerbations in accordance with recent clinical trials presented by a recent post-hoc analysis, which regards blood-eosinophils as a determinant of the benefit of ICS in preventing future COPD exacerbations and presents results indicating a greater benefit of ICS in patients with higher eosinophil count [11]. Almost no effect was reported in those with a blood-eosinophil count less than 0.1 x 109/L, which naturally has been the threshold where patients are most unlikely to benefit from ICS maintenance treatment [11]. Conversely, patients with a blood-eosinophil count of ≥ 0.3 x 109/L have the most benefit from ICS treatment [9]. However, the idea of blood-eosinophils being a biomarker for exacerbation risk is insufficient. Studies have found that blood-eosinophils have less likelihood in determining the future exacerbation risk [16]. Our findings indicate that a substantial proportion of COPD patients prescribed ICS are likely not to benefit from this treatment, as almost one-fifth of the included COPD patients had no exacerbations and blood-eosinophils of less than 0.1 x 109/L and were hence not candidates for ICS maintenance therapy according to guidelines.
This study also assessed whether exacerbation treatment had a correlation to blood-eosinophil count in COPD patients in primary care. Our results indicated that prescription of ICS in patients with two or more moderate exacerbations was made despite a blood-eosinophil count < 0.1 x 109/L. Our study found no correlation between blood-eosinophil count and differences in treatment with corticosteroids and/or antibiotics in COPD exacerbation. According to GOLD, ICS treatment can be considered in patients with two or more moderate exacerbations of COPD per year, while blood-eosinophils < 0.1 x 109/L is an argument against ICS treatment [14]. Moreover, a treatment strategy including LAMA/LABA is preferred in patients with a blood-eosinophil count ≤ 0.1 x 109/L, while LABA/ICS has proven more effective in patients with high blood-eosinophil counts (> 0.3 x 109/L) [17]. However, we found that the proportion of patients prescribed LAMA was only slightly different between patients with a blood-eosinophil count ≤ 0.1 x 109/L and > 0.3 x 109/L, respectively (n = 49 vs 42). On the other hand, if patients experience repeated exacerbations despite appropriate long-acting bronchodilator treatment, add-on treatment with ICS may be considered [14].
Some limitations are worth mentioning in this study. First, this analysis did not include information on exacerbations leading to hospital admittance defined as severe exacerbations. Second, among all patient data provided by GPs only 1,567 COPD patients were included due to missing data on blood-eosinophils and/or exacerbation history. This might have over- or underestimated the prevalence of exacerbations and altered the results. In addition, a few variables in this study had rather considerable missing information (Figure 4). One could argue whether variables with much missing information are comparable to each other. In this study missing information in most variables is almost equally distributed across the groups compared, which makes comparison of groups feasible. This is, however, not the case for the variables MRC-score and pack-years, which may have distorted results. Further details are given in Figure 5.
A significant correlation between patients with higher blood-eosinophil count and increased risk of exacerbations has previously been proposed indicating that patients might have higher blood-eosinophil count with increasing exacerbation frequency. However, this was not the case in our study [8]. Furthermore, COPD patients in ICS treatment followed in primary care were enrolled in 2017 prior to the release of the newest strategy document by GOLD. This analysis might be considered incomprehensive in the investigation of an endpoint such as general practitioner’s use of the GOLD report on exacerbations and blood-eosinophils to guide the prescription of ICS. One could argue on the validity of the application of recent recommendations by GOLD on this population-based large cohort of COPD patients currently prescribed ICS. Nevertheless, this analysis gives an initial retrospective assessment on the ICS prescription pattern in general practice.
There is a need for future studies to evaluate whether primary care physicians have changed ICS prescription behavior due to recent GOLD strategy document. The recent studies pointing to a more beneficial treatment regimen guided by exacerbations and blood-eosinophils could alter the risk-benefit ratio by reducing future incidence of ICS adverse effects and potentially promote the reduction of mortality and COPD-related morbidity in ICS prescribed COPD patients in general practice. Further research is needed to determine to what extent ICS maintenance therapy, in accordance with the recent strategy report by GOLD, benefit COPD patients managed in general practice, and by that, presumably, have less severe disease, as this may pave the way for a more personalized approach to the management of COPD, also in general practice.