A historical perspective of the New Zealand asthma mortality epidemics

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.

Observational studies assessing the pharmacological treatment of obstructive lung disease: strengths, challenges and considerations for study design

Randomised controlled trials (RCTs) are the gold standard for evaluating treatment efficacy in patients with obstructive lung disease. However, due to strict inclusion criteria and the conditions required for ascertaining statistical significance, the patients included typically represent as little as 5% of the general obstructive lung disease population. Thus, studies in broader patient populations are becoming increasingly important. These can be randomised effectiveness trials or observational studies providing data on real-world treatment effectiveness and safety data that complement efficacy RCTs. In this review we describe the features associated with the diagnosis of asthma and chronic obstructive pulmonary disease (COPD) in the real-world clinical practice setting. We also discuss how RCTs and observational studies have reported opposing outcomes with several treatments and inhaler devices due to differences in study design and the variations in patients recruited by different study types. Whilst observational studies are not without weaknesses, we outline recently developed tools for defining markers of quality of observational studies. We also examine how observational studies are capable of providing valuable insights into disease mechanisms and management and how they are a vital component of research into obstructive lung disease. As we move into an era of personalised medicine, recent observational studies, such as the NOVEL observational longiTudinal studY (NOVELTY), have the capacity to provide a greater understanding of the value of a personalised healthcare approach in patients in clinical practice by focussing on standardised outcome measures of patient-reported outcomes, physician assessments, airway physiology, and blood and airway biomarkers across both primary and specialist care.

Combination corticosteroid/β-agonist inhaler as reliever therapy: a solution for intermittent and mild asthma?

The recommended treatment of mild asthma is regular maintenance inhaled corticosteroids (ICSs) with a short-acting β-agonist as a separate inhaler used when needed for symptom relief. However, the benefits of regular ICS use in actual clinical practice are limited by poor adherence and low prescription rates. An alternative strategy would be the symptom-driven (as-required or "prn") use of a combination ICS/short-acting β-agonist or ICS/long-acting β-agonist inhaler as a reliever rather than regular maintenance use. The rationale for this approach is to titrate both the ICS and β-agonist dose according to need and enhance ICS use in otherwise poorly adherent patients who overrely on their reliever β-agonist inhaler. This strategy will only work if the β-agonist component has a rapid onset of action for symptom relief. There is evidence to suggest that this regimen has advantages over regular ICS therapy and might represent an effective, safe, and novel therapy for the treatment of intermittent and mild asthma. In this commentary we review this evidence and propose that randomized controlled trials investigating different combination ICS/β-agonist inhaler products prescribed according to this regimen in intermittent and mild asthma are an important priority.

Increased mortality in groups of cattle administered the β-adrenergic agonists ractopamine hydrochloride and zilpaterol hydrochloride

The United States Food and Drug Administration (FDA) approved two β-adrenergic agonists (βAA) for in-feed administration to cattle fed in confinement for human consumption. Anecdotal reports have generated concern that administration of βAA might be associated with an increased incidence of cattle deaths. Our objectives, therefore, were to a) quantify the association between βAA administration and mortality in feedlot cattle, and b) explore those variables that may confound or modify this association. Three datasets were acquired for analysis: one included information from randomized and controlled clinical trials of the βAA ractopamine hydrochloride, while the other two were observational data on zilpaterol hydrochloride administration to large numbers of cattle housed, fed, and cared for using routine commercial production practices in the U.S. Various population and time at-risk models were developed to explore potential βAA relationships with mortality, as well as the extent of confounding and effect modification. Measures of effect were relatively consistent across datasets and models in that the cumulative risk and incidence rate of death was 75 to 90% greater in animals administered the βAA compared to contemporaneous controls. During the exposure period, 40 to 50% of deaths among groups administered the βAA were attributed to administration of the drug. None of the available covariates meaningfully confounded the relationship between βAA and increased mortality. Only month of slaughter, presumably a proxy for climate, consistently modified the effect in that the biological association was generally greatest during the warmer months of the year. While death is a rare event in feedlot cattle, the data reported herein provide compelling evidence that mortality is nevertheless increased in response to administration of FDA-approved βAA and represents a heretofore unquantified adverse drug event.

Asthma: a simple concept but in reality a complex disease

BACKGROUND

Asthma is a disorder of the conducting airways that contract too easily and too much to cause variable airflow obstruction with symptoms of wheeze, cough, chest tightness and shortness of breath. Based on this knowledge, initial treatments were directed to dilating the contracted airways with anticholinergic and adrenergic drugs. The recognition that allergic-type inflammation underlay the hyperresponsive airways in asthma led to the introduction of anti-inflammatory drugs such as sodium cromoglicate and corticosteroids. Over the 2 decades that followed, these drugs have been progressively improved by increasing their therapeutic index and duration of action.

METHODS

A review of the recent literature indicates that since the 1980s, the explosive increase in knowledge of the cell and mediator mechanisms of asthma has only led to modest improvements in therapy including the introduction of leukotriene modifiers and a blocking monoclonal antibody against IgE. Indeed, biologics targeting allergic cytokines and effector cells have on the whole proven disappointing despite initial promise being shown in animal models.

RESULTS

Part of the difficulty lies in the oversimplified concept that asthma is only driven by allergic processes when in reality there are many environmental causes and triggers and the view that it is a homogeneous disorder only varying in severity.

CONCLUSIONS

The more recent views that asthma is a complex disorder made up of different subtypes with differing causes, treatment responses and natural histories creates a new opportunity for stratified medicine in which therapies acting upstream selectively target specific disease subtypes identified by specific diagnostic biomarkers.

Age and risks of FDA-approved long-acting β₂-adrenergic receptor agonists

OBJECTIVE

To determine the risk, by age group, of serious asthma-related events with long-acting β(2)-adrenergic receptor agonists marketed in the United States for asthma.

METHODS

The US Food and Drug Administration performed a meta-analysis of controlled clinical trials comparing the risk of LABA use with no LABA use for patients 4 to 11, 12 to 17, 18 to 64, and older than 64 years old. The effects of age on a composite of asthma-related deaths, intubations, and hospitalizations (asthma composite index) and the effects of concomitant inhaled corticosteroid (ICS) use were analyzed.

RESULTS

One hundred ten trials with 60 954 patients were included in the meta-analysis. The composite event incidence difference for all ages was 6.3 events per 1000 patient-years (95% confidence interval [CI]: 2.2-10.3) for using LABAs compared with not using LABAs. The largest incidence difference was observed for the 4- to 11-year age group (30.4 events per 1000 patient-years [95% CI: 5.7-55.1]). Differences according to age were statistically significant (P = .020). Results for the subgroup of patients with concomitant ICS use (n = 36 210) were similar to the overall results; with assigned ICSs (n = 15 192), the incidence difference was 0.4 events per 1000 patient-years (95% CI: -3.8 to 4.6), and there was no statistically significant difference according to age group.

CONCLUSIONS

The excess of serious asthma-related events attributable to LABAs was greatest among children. Additional data are needed to assess risks of LABA use for children with simultaneous ICS use.

Safety of long-acting beta2-agonists in the treatment of asthma

Several studies suggested an association between the regular use of beta2-agonists and asthma deaths. Whether this association represents adverse effects of beta -agonist use or is entirely due to disease severity is a matter of ongoing debate. Previous literature indicates that confounding by poor asthma control may explain the apparent deleterious effects of inhaled beta2-agonists. Tolerance to nonbronchodilator effects of beta2-agonists may account for the increase in reactivity to indirect bronchoconstrictor challenges and explain why some studies have demonstrated enhanced bronchoconstriction in patients with asthma after regular beta 2-agonist therapy. Nonetheless, the salmeterol multi-centre asthma research trial (SMART) found more asthma deaths (13 vs 3) and life-threatening asthma events (37 vs 22) in the salmeterol-treated asthmatic patients, although it was documented that among African-Americans, 5 times as many deaths and near-deaths from asthma occurred in those given salmeterol than in those given placebo, and among patients with asthma not using an inhaled corticosteroid (ICS) as a preventive (controller) medication, again more deaths and near-deaths from asthma occurred in those given salmeterol than in those given placebo. Only 38% of the African-Americans who participated in the study used an ICS. As a result of the findings from the SMART, FDA issued a public health advisory to highlight that long-acting beta2-agonists (LABAs) should not be the first medicine used to treat asthma. LABAs should be added to the asthma treatment plan only if other medicines, including the use of low-or-medium dose ICSs, do not control asthma. However, despite all of the concerns raised by the SMART, inhaled beta2-agonists remain the most effective bronchodilators available for the immediate relief of asthma symptoms and, as such, remain an important component of asthma management. Obviously, there are concerns about LABA treatment as monotherapy for asthma. Patients with asthma should be initiated and maintained on sufficiently high doses of ICSs and only patients whose asthma cannot be controlled should receive additional LABAs on a regular basis.

High-dose inhaled corticosteroids versus add-on long-acting beta-agonists in asthma: an observational study

BACKGROUND

Guidelines recommend that for patients uncontrolled on inhaled corticosteroids (ICSs), step-up options include an increase in ICS dosage or addition of a long-acting beta-agonist (LABA). Controversy persists about the best option in routine practice.

OBJECTIVE

To compare asthma outcomes in patients whose first step-up from ICS monotherapy was by addition of LABA (LABA cohort) or increase in ICS dosage or formulation (ICS cohort).

METHODS

Observational study using the General Practice Research Database, comparing outcomes in the following 12 months with regression modeling allowing for baseline cohort differences: age, sex, socioeconomic status, body mass index, comorbidity (rhinitis, heart disease), smoking status, short-acting beta-agonist (SABA) use, oral corticosteroid use, and use of asthma complicating medication.

RESULTS

We found 46,930 patients in the ICS and 17,418 in the LABA cohort. In adjusted analysis, the odds ratio (95% CI) of successful treatment (no hospitalization, no oral corticosteroid use, average daily SABA use <1 dose/d) was lower in the ICS cohort (0.75; 0.72-0.79). The adjusted odds ratio of needing rescue SABA prescriptions was higher in the ICS cohort (1.67; 1.59-1.76). However, the adjusted odds of using any oral corticosteroids were lower (0.75; 0.71-0.78), particularly of using 3 or more courses (0.50, 0.46-0.55), and the adjusted odds of respiratory hospitalization were lower (0.69; 0.59-0.81).

CONCLUSION

Although symptomatic control and rescue bronchodilator use may be improved by the addition of a LABA to ICS, there may be a lower risk of severe exacerbations and hospitalizations from ICS dose increase.

Three generations of ongoing controversies concerning the use of short acting beta-agonist therapy in asthma: a review

An increase in asthma mortality in 1960s noted by British authors stirred a debate about the use of beta-adrenergic therapy that has persisted in the medical literature. The cause appears to be isoproterenol and fenoterol overuse. A second debate evolved around the possible deleterious, pro-inflammatory effects, of the albuterol distomer. Most clinical studies showed improved bronchodilatation, but limited benefits from using levalbuterol. Recently, genotyping has uncovered a single nucleotide polymorphism at codon 16 that appears to affect the long term response to both regular and as needed use of albuterol, calling for a new genotype based therapeutic approach in asthma.