Blood eosinophil count correlates with severity of respiratory failure in life-threatening asthma and predicts risk of subsequent exacerbations

Predicting the risk of acute respiratory failure among asthma patients-the A2-BEST2 risk score: a retrospective study

Objectives

Acute respiratory failure (ARF) is a common complication of bronchial asthma (BA). ARF onset increases the risk of patient death. This study aims to develop a predictive model for ARF in BA patients during hospitalization.

Methods

This was a retrospective cohort study carried out at two large tertiary hospitals. Three models were developed using three different ways: (1) the statistics-driven model, (2) the clinical knowledge-driven model, and (3) the decision tree model. The simplest and most efficient model was obtained by comparing their predictive power, stability, and practicability.

Results

This study included 398 patients, with 298 constituting the modeling group and 100 constituting the validation group. Models A, B, and C yielded seven, seven, and eleven predictors, respectively. Finally, we chose the clinical knowledge-driven model, whose C-statistics and Brier scores were 0.862 (0.820-0.904) and 0.1320, respectively. The Hosmer-Lemeshow test revealed that this model had good calibration. The clinical knowledge-driven model demonstrated satisfactory C-statistics during external and internal validation, with values of 0.890 (0.815-0.965) and 0.854 (0.820-0.900), respectively. A risk score for ARF incidence was created: The A2-BEST2 Risk Score (A2 (area of pulmonary infection, albumin), BMI, Economic condition, Smoking, and T2(hormone initiation Time and long-term regular medication Treatment)). ARF incidence increased gradually from 1.37% (The A2-BEST2 Risk Score ≤ 4) to 90.32% (A2-BEST2 Risk Score ≥ 11.5).

Conclusion

We constructed a predictive model of seven predictors to predict ARF in BA patients. This predictor's model is simple, practical, and supported by existing clinical knowledge.

Real-World Effectiveness Study of Benralizumab for Severe Eosinophilic Asthma: ZEPHYR 2

BACKGROUND

Benralizumab is an mAb therapy for severe eosinophilic asthma. Real-world data on its clinical impact in various patient populations such as patients with varying eosinophil levels, previous biologic use, and extended follow-up in the United States are limited.

OBJECTIVE

To determine the effectiveness of benralizumab in different asthmatic patient cohorts and its long-term clinical impact.

METHODS

Patients with asthma treated with benralizumab from November 2017 to June 2019 with 2 or more exacerbations in the 12 months before benralizumab initiation (index) were included in this pre-post cohort study that used medical, laboratory, and pharmacy US insurance claims. Asthma exacerbation rates in the 12 months pre and post index were compared. Nonmutually exclusive patient cohorts were defined by blood eosinophil counts (<150, ≥150, 150-<300, <300, and ≥300 cells/μL), a switch from another biologic, or follow-up for 18 or 24 months post index.

RESULTS

There were 429 patients in the eosinophil cohort, 349 in the biologic-experienced cohort, and 419 in the extended follow-up cohort. In all eosinophil cohort subgroups, the asthma exacerbation rate decreased from 3.10-3.55 per patient-year (PPY) pre index to 1.11-1.72 PPY post index (52%-64% decrease; P < .001). Similar decreases were observed in patients switching from omalizumab (3.25 to 1.25 PPY [62%]) or mepolizumab (3.81 to 1.78 PPY [53%]) to benralizumab and those followed up for 18 months (3.38 to 1.18 PPY [65%]) or 24 months (3.38 to 1.08 PPY [68%]) (all P < .001). In the extended follow-up cohort, 39% and 49% had no exacerbations in the 0 to 12 months and the 12 to 24 months post index, respectively.

CONCLUSIONS

Benralizumab achieved significantly improved asthma control in real-world patients with different blood eosinophil counts, including eosinophil counts ranging from less than 150 to greater than or equal to 300 cells/μL, switching from other biologics, or treated for up to 24 months.

Different Impacts of Blood and Sputum Eosinophil Counts on Lung Function and Clinical Outcomes in Asthma: Findings from the COREA Cohort

PURPOSE

Blood (EOS-B) and sputum (EOS-S) eosinophil counts may contribute differently to asthma pathogenesis. We compared the impact of the baseline EOS-B and EOS-S levels on lung function, asthma control, and exacerbation in Korean asthma patients.

METHODS

Asthma patients with baseline EOS-B (n = 4257) and EOS-S (n = 1049) levels from a multicenter cohort (COREA) were included. Pulmonary function test (%FEV1 predicted), asthma control test (ACT), and asthma exacerbation incidence were followed-up every 3 months for one year. Linear mixed-effect models and survival analyses were used to examine the association between eosinophilic groups defined by EOS-B or EOS-S and outcomes.

RESULTS

High eosinophilic groups were associated with a low baseline value and a high improvement in the %FEV1 predicted and ACT scores over time. The magnitude of group difference in %FEV1 predicted was twofold higher in the EOS-S versus EOS-B classification [mean and 95% CI: 4.7 (0.6-8.8) versus 2.0 (0.2-3.7) for the baseline value and - 1.5 (- 2.3 to - 0.8) versus - 0.8(- 1.1 to -0.4) for the slope of change], whereas it was identical in ACT score. The magnitude of the impact increased linearly with the elevation of the cut-off level for the EOS-B but remained stable for the EOS-S classification. Patients with an elevation of both their EOS-B and EOS-S showed a higher increment in the %FEV1 predicted and ACT over time. Neither the EOS-B nor EOS-S was associated with asthma exacerbation.

CONCLUSION

EOS-S and EOS-B contribute differently to the clinical outcomes and should be taken into account independently to improve asthma care.

Is Overreliance on SABA Associated with Health Risks in the Older Asthma Population?

Recent Global Initiative for Asthma (GINA) recommendations reduce the role of short-acting β₂-agonist (SABA) premised on the associated exacerbation risk. The widely accepted SABA risk profile is based on limited data described 30 years ago. This GINA paradigm shift demands an examination of SABA risks in a modern therapeutic era. Recent studies confirm that SABA overuse is common and associated with adverse outcomes. This study aimed to determine associations between SABA use, all-cause mortality and asthma exacerbations in an older North American asthma population.

In this population-based cohort study, individuals with prevalent asthma (2006–2015) aged ≥65 years, eligible for provincial drug coverage, were included. Annual SABA canisters filled (0, 1–2, 3–5, ≥6) was the primary exposure. Hazard ratios (HRs) with 95% CIs were estimated using Cox proportional hazard regression, adjusted for confounders.

There were 59 533 asthma individuals; 14% overused SABA (≥3 canisters annually). Compared to those who used <3 canisters, the adjusted HRs of death for those who used 3–5 and ≥6 canisters were 1.11 (95% CI: 1.02–1.22, p=0.0157) and 1.56 (95% CI: 1.41–1.71, p<0.0001), respectively. Severe asthma exacerbation rates for ≥3 and <3 canisters/year were 7.5% and 2.1%, respectively. The adjusted HRs of severe asthma exacerbations were 1.59 (95% CI: 1.40–1.82, p<0.0001) and 2.26 (95% CI: 1.96–2.60, p<0.0001) in those who used 3–5 and ≥6 SABA canisters per year, respectively.

In Canada, 1 in 7 individuals with asthma overused SABA associated with increased risks of severe asthma exacerbations and death. The adverse impacts of SABA overuse continue 30 years after early publications.

These results in older people with asthma add strength to previously documented associations of SABA use, severe asthma exacerbations and death. Clinicians may consider these safety results when prescribing and assessing new therapeutic recommendations.https://bit.ly/34Gr56P

Will the asthma revolution fostered by biologics also benefit adult ICU patients?

PURPOSE

Asthma exacerbations are inflammatory events that rarely result in full hospitalization following an ER visit. Unfortunately, certain patients require prolonged support, including occasional external lung support through ECMO or ECCOR (with subsequent further exposure to other life-threatening issues), and some die. In parallel, biologics are revolutionizing severe asthma management, mostly in T2 high patients.

METHODS

We extensively reviewed the current unmet needs surrounding ICU-admitted asthma exacerbations, with a focus on currently available drugs and the underlying biological processes involved. We explored whether currently available T2-targeting drugs can reasonably be seen as potential players not only for relapse prevention but also as candidate drugs for a faster resolution of such episodes. The patient's perspective was also sought.

RESULTS

About 30% of asthma exacerbations admitted to the ICU do not resolve within five days. Persistent severe airway obstruction despite massive doses of corticosteroids and maximal pharmacologically induced bronchodilation is the main cause of treatment failure. Previous ICU admission is the main risk factor for such episodes and may eventually be considered as a T2 surrogate marker. Fatal asthma cases are hallmarked by poorly steroid-sensitive T2-inflammation associated with severe mucus plugging. New, fast-acting T2-targeting biologics (already used for preventing asthma exacerbations) have the potential to circumvent steroid sensitivity pathways and decrease mucus plugging. This unmet need was confirmed by patients who reported highly negative, traumatizing experiences.

CONCLUSIONS

There is room for improvement in the management of ICU-admitted severe asthma episodes. Clinical trials assessing how biologics might improve ICU outcomes are direly needed.

Blood eosinophil count as predictor of asthma exacerbation. A meta-analysis

BACKGROUND

Evidence about the association of high blood eosinophil count with asthma exacerbation is inconsistent and unclear. The objective of this meta-analysis was to determine whether elevated blood eosinophil count predicts asthma exacerbation.

METHODS

We searched MEDLINE, EMBASE, and additional databases, without any language restriction. We also checked the reference lists of the included studies and of relevant systematic reviews. The main outcome was the occurrence of asthma exacerbation. We calculated global pooled odds ratios (ORs) and their 95% confidence intervals (CIs) and performed predefined subgroup analyses. We appraised the quality of the studies using Newcastle-Ottawa Scale, examined the heterogeneity between studies, assessed publication bias, and carried out sensitivity analyses.

RESULTS

Among 1567 retrieved publications, 23 observational studies comprising 155,772 participants met the inclusion criteria. High blood eosinophil count was associated with higher odds of asthma exacerbation [OR: 1.31 (95% CI: 1.16, 1.49)], specifically with asthma-related outpatient visits [OR: 1.46 (95% CI: 1.25, 1.70)] and emergency department visits [OR: 1.63 (95% CI: 1.29, 2.07)]. A significant association was observed starting from an eosinophils' cutoff value of 200 cells/μl. The association was observed for cohort studies [OR: 1.30 (95%CI: 1.13, 1.49)], North American studies [OR: 1.43 (95%CI: 1.31, 1.57)], Asian populations [OR: 1.67 (95%CI: 1.34, 2.08)], children [OR: 1.38 (95%CI: 1.22, 1.56)], and studies that adjusted for inhaled corticosteroids therapy [OR: 1.42 (95%CI: 1.28, 1.56)].

CONCLUSIONS

Blood eosinophil counts ≥ 200 cells/µL are associated with asthma exacerbation. Blood eosinophil count is a modifiable factor that could be addressed in asthma management strategies.

Developments allergy in 2019 through the eyes of Clinical and Experimental Allergy, Part II clinical allergy

In the second of two linked articles, we describe the development in clinical as described by Clinical & Experimental Allergy and other journals in 2019. Epidemiology, clinical allergy, asthma and rhinitis are all covered. In this article, we described the development in the field of allergy as described by Clinical and Experimental Allergy in 2019. Epidemiology, clinical allergy, asthma and rhinitis are all covered.

Assessing the cost-effectiveness of mepolizumab as add-on therapy to standard of care for severe eosinophilic asthma in Singapore

OBJECTIVE

To evaluate the cost-effectiveness of mepolizumab added to standard of care (SOC) compared with SOC alone among patients with severe uncontrolled eosinophilic asthma in the Singapore setting.

METHODS

A Markov model with three health states (asthma on mepolizumab and SOC, asthma on SOC alone, and death) was developed from a healthcare system perspective over a lifetime horizon. During each 4-week cycle, patients in the non-death health states could experience asthma exacerbations requiring oral corticosteroid burst, emergency department visit, or hospitalization. Asthma-related mortality following an exacerbation or all-cause mortality could also occur at each cycle. The model was populated using local costs while utilities were derived from international literature. Transition probabilities were obtained from a mixture of Singapore-specific and internationally published data.

RESULTS

The base-case analysis comparing mepolizumab plus SOC with SOC alone resulted in an incremental cost-effectiveness ratio (ICER) of SGD335 486 (USD238 195) per quality-adjusted life-year (QALY) gained. Sensitivity analysis demonstrated that the ICER was most sensitive to the price of mepolizumab, followed by the proportion of exacerbations which required hospital intensive care. Despite restricting mepolizumab use to patients with a higher baseline exacerbation rate (3 in the past year) in a scenario analysis, the ICER remained high at SGD238 876 (USD 169 602) per QALY gained.

CONCLUSION

At its current price, mepolizumab is not considered a cost-effective use of healthcare resources in Singapore. Substantial price reductions for mepolizumab are required to improve its cost-effectiveness to an acceptable range. These results will be useful to inform national funding decisions.

Real-Life effects of benralizumab on exacerbation number and lung hyperinflation in atopic patients with severe eosinophilic asthma

BACKGROUND

The humanized monoclonal antibody benralizumab targets the α subunit of the interleukin-5 (IL-5) receptor and the FcγRIIIa receptor expressed by natural killer cells. Through this dual mechanism of action, benralizumab neutralizes the pro-eosinophil functions of IL-5 and promotes eosinophil apoptosis.

OBJECTIVES AND METHODS

The present real-life study aimed to evaluate, in 22 allergic patients with severe eosinophilic asthma, the effects of benralizumab on asthma exacerbations and lung hyperinflation.

RESULTS

In this regard here we show that, after 24 weeks of add-on treatment, benralizumab completely depleted peripheral blood eosinophils (from 810 to 0 cells/μL; p < 0.0001), and significantly decreased both asthma exacerbation number (from 4 to 0; p < 0.0001) and residual volume (from 2720 to 2300 mL; p < 0.01). Moreover, at the same time point (24 weeks) benralizumab also increased pre-bronchodilator FEV₁ (from 1295 to 1985 mL; p < 0.0001), FVC (from 2390 to 2974 mL; p < 0.0001), FEF_25-75 (from 0.6 to 1.42 L/sec; p < 0.0001), IC (from 1940 to 2460 mL; not significant), and ACT score (from 14.73 to 22.95; p < 0.0001), as well as reduced prednisone intake (from 25 to 0 mg; p < 0.0001).

CONCLUSION

In conclusion, our results suggest that via its anti-eosinophil actions benralizumab improved airflow limitation, lung hyperinflation, and respiratory symptoms, as well as lowered asthma exacerbation rate and abrogated OCS consumption in most patients.

Improving asthma care with Asthma-COPD Afterhours Respiratory Nurse at Emergency (A-CARE)

BACKGROUND

Emergency departments (ED) are important providers of asthma care, particularly after-hours. We identified gaps for quality improvement such as suboptimal adherence rates to three key recommendations from the Global Initiative for Asthma (GINA) guidelines for discharge management asthma guidelines. These were: the prescription of oral and inhaled corticosteroids (OCS and ICS) and issuance of outpatient follow-up for patients discharged from the ED.

AIM

To achieve an adherence rate of 80% to GINA guidelines for ED discharge management by providing after-hours asthma counselling services.

METHODS

We implemented Asthma-COPD Afterhours Respiratory Nurse at Emergency (A-CARE) according to the Plan-Do-Study-Act (PDSA) framework to provide after-hours asthma counselling and clinical decision support to ED physicians three nights a week. Data on adherence rates to the GINA guidelines were collected and analysed on a run chart.

RESULTS

After 17 months' follow-up, a sustained improvement was observed in patients reviewed by A-CARE in the median adherence rates to OCS prescription (58% vs 86%), ICS initiation (27% vs 67%) and issuance of follow-up (69% vs 92%), respectively. The overall impact was, however, limited by a suboptimal referral rate to A-CARE (16%) in a clinical audit of all ED patients with asthma. Nonetheless, in this audit, attendance rates for patients referred to our respiratory department for follow-up were higher in those receiving asthma counselling compared with those who did not (41.7% vs 15.9%, p=0.0388).

CONCLUSION

Sustained improvements in the adherence rates to guidelines were achieved for patients reviewed by A-CARE but were limited in overall impact due to suboptimal referral rate. We plan to improve the quality of asthma care by implementing further PDSA cycles to increase the referral rates to A-CARE.

Needs for Systems Approaches to Better Treat Individuals With Severe Asthma: Predicting Phenotypes and Responses to Treatments

Asthma is a frequent heterogeneous multifactorial chronic disease whose severe forms remain largely uncontrolled despite the availability of many drugs and educational therapy. Several phenotypes and endotypes of severe asthma have been described over the last two decades. Typical type-2-immunity-driven asthma remains the most frequent phenotype, and several targeted therapies have been developed and are now available. On the contrary, non-type-2 immunity-driven severe asthma is less understood and still requires efficient innovative therapies. A personalized approach would allow improving asthma control with the help of robust biomarkers able to predict phenotypes/endotypes, exacerbations, response to targeted treatments and, in the future, possible curative options. Some data from large multicenter cohorts have emerged in recent years, especially in transcriptomics. These data have to be integrated and reproduced longitudinally to provide a systems approach for asthma care. In this focused review, the needs for such an approach and the available data will be reviewed as well as the next steps for achieving personalized medicine in asthma.