Quarterly assessment of short-acting beta(2)-adrenergic agonist use as a predictor of subsequent health care use for asthmatic patients in the United States

Sex differences in excessive oral corticosteroid exposure in poor adherent adult asthmatics overusing short-acting β-2 agonists

BACKGROUND

We know that excessive short-acting β2-agonists (SABA) use in asthma may be associated to high exacerbation risks. We studied whether such excessive SABA consumption is connected with different higher oral corticosteroid (OC) prescriptions in the two sexes.

METHODS

In our prescribing database, we searched subjects aged 18-40 years that were prescribed at least one SABA package/year and/or at least two ICS or two ICS/LABA boxes/year to identify asthmatics. Their OC prescriptions/year were also examined. Subjects were divided into 4 groups according to SABA packages/year prescribed (0, 1-2,3-6 and ≥7), considering sexes separately.

RESULTS

Individuals recruited were 9,102. Subjects with at least one OC prescription were higher in each group and were females (P<0.001). The OC packages/year number was also more elevated in women especially those with >7 SABA prescriptions/year (0.96 in males vs. 2.64 in females, P<0.001). 94.7%/93.6% males/females, who never used SABA, took at least one ICS/LABA (mean 5.84/5.48 packages/year), while the subject percentage adhering to ICS/LABA dropped to 28-47% (mean 0.94-3.82 packages/year) in those who used SABA (P<0.001). Higher SABA prescriptions were associated with an increasing OC dispensation (β=0.057, P<0.0001). We observed also a greater risk of using >3 OC packages/year in subjects with 3-6 (OR: 2.98 [95% CI: 2.19-4.06], P<0.001) and ≥7 (OR: 3.49 [95% CI: 2.39-5.10], P<0.001) SABA prescriptions compared to those that never used SABA. Besides, we found that using ICS (OR:0.51 [95% CI: 0.35-0.75], P<0.001) or ICS/LABA (OR:0.07 [95% CI: 0.05-0.09], P<0.001) may significantly reduce SABA prescriptions.

CONCLUSIONS

Poor adherence to maintenance treatment appears to associated with excessive SABA prescriptions that may lead to a higher OC consumption particularly noticeable in women.

Landscape of short-acting beta-agonists (SABA) overuse in Europe

This review article provides an overview of short-acting beta-agonist (SABA) use and prescribing trends in Europe, summarizing updated data on the results from the industry-funded SABINA program (SABA use IN asthma) and other studies on this matter. SABA use continues to increase worldwide. Overuse has been defined as ≥3 canisters/year. Almost a third of European patients with asthma, at all severity levels, overuse SABA. Guidelines recommend close monitoring of patients who overuse SABA and avoiding over-reliance on SABA monotherapy. SABA overuse is associated with increased risk of asthma exacerbations and mortality, increased use of health services and negative physical and mental health outcomes. Reliance on SABA monotherapy can be unsafe and therefore it is necessary to change asthma treatment approaches and policies. Changes in physician and patient behaviours towards SABA use are required to ensure that patients with asthma are not over-reliant on SABA monotherapy. Notwithstanding, the limitations of the studies on the use of SABA should be considered, taking into account that the prescription/purchase of medication canisters does not always represent the actual use of the medication and that associations between SABA overuse and poor asthma outcomes may not be directly causal. National health systems and asthma guidelines must align asthma management with global recommendations and adjust them to local needs.

Short-Acting Beta-2-Agonist Exposure and Severe Asthma Exacerbations: SABINA Findings From Europe and North America

BACKGROUND

Expert national/global asthma management recommendations raise the issue whether a safe threshold of short-acting beta-2 agonist (SABA) use without concomitant inhaled corticosteroids (ICS) exists.

OBJECTIVE

To examine SABA and maintenance therapy associations with severe asthma exacerbations across North America and Europe.

METHODS

Observational analyses of 10 SABa use IN Asthma (SABINA) datasets involving 1,033,564 patients (≥12 y) from Canada, France, the Netherlands, Poland, Spain, the United Kingdom, and the United States. Negative binomial models (incidence rate ratio [IRR] [95% CI adjusted for prespecified-covariates]) evaluated associations between SABA and exacerbations.

RESULTS

Across severities, 40.2% of patients were prescribed/possessed 3 or more SABA canisters/y. Per the Global Initiative for Asthma (GINA) 2018 definitions, steps 3 to 5-treated patients prescribed/possessing 3 or more versus 1 or 2 SABAs experienced more severe exacerbations (IRR 1.08 [95% CI 1.04‒1.13], U.S. Medicare; IRR 2.11 [95% CI 1.96‒2.27], Poland). This association was not observed in all step 1 or 2-treated patients (the Netherlands, IRR 1.25 [95% CI 0.91‒1.71]; U.S. commercial, IRR 0.92 [95% CI 0.91‒0.93]; U.S. Medicare, IRR 0.74 [95% CI 0.71‒0.76]). We hypothesize that this inverse association between SABA and severe exacerbations in the U.S. datasets was attributable to the large patient population possessing fewer than 3 SABA and no maintenance therapy and receiving oral corticosteroid bursts without face-to-face health care provider encounters. In U.S. SABA monotherapy-treated patients, 3 or more SABAs were associated with more emergency/outpatient visits and hospitalizations (IRR 1.31 [95% CI 1.29‒1.34]). Most GINA 2 to 5-treated study patients (60.6%) did not have maintenance therapy for up to 50% of the time; however, the association of 3 or more SABAs and severe exacerbations persisted (IRR 1.32 [95% CI 1.18‒1.49]) after excluding these patients and the independent effect was further confirmed when U.K. SABA data were analyzed as a continuous variable in patients with up to 100% annual coverage for ICS-containing medications.

CONCLUSIONS

Increasing SABA exposure is associated with severe exacerbation risk, independent of maintenance therapy. As addressed by GINA, based on studies across asthma severities where as-needed fast-acting bronchodilators with concomitant ICS decrease severe exacerbations compared with SABA, our findings highlight the importance of avoiding a rescue/reliever paradigm utilizing SABA monotherapy.

Management of acute exacerbations of airways disease: advice for the non-respiratory physician

Airways disease encompasses a number of conditions including asthma and chronic obstructive pulmonary disorder (COPD). In this article we describe the management of patients with acute exacerbations of airways disease.

Over-prescription of short-acting beta agonists in the treatment of asthma

BACKGROUND

Despite a clear guideline for asthma medication, excessive use of short-acting β2-agonists (SABAs) is common in clinical practice. Previous research has shown that excessive use of SABAs is associated with poor asthma control.

OBJECTIVE

This study examines current use of asthma medication in primary care and whether excessive use of SABAs is associated with exacerbations.

METHODS

The study design was a retrospective analysis using information from electronical medical records from patients aged 18 and older of five Julius Health Centers located in Utrecht, the Netherlands, in the period of 1 July 2018 through 1 July 2019. Excessive SABA use was defined as ≥400 inhalations per year. An exacerbation was defined as an acute worsening of asthma symptoms with the need for systemic corticosteroids.

RESULTS

A total of 1161 patients were included in the study. Of the patients using SABAs (n = 766), 193 (25%) overused SABAs. Among the patients with inappropriate SABA use (n = 193), 19% had an exacerbation compared with 7% of the appropriate SABA users. For patients using asthma medication the odds of having an exacerbation were 2.9 times higher if they used an inappropriate number of SABAs than if SABAs were used appropriately (odds ratio, 2.897; 95% confidence interval, 1.87-4.48).

CONCLUSIONS

This study shows that overuse of SABAs is still common and that it is associated with asthma exacerbations. It highlights that clinicians need to be aware of inappropriate SABA use as it is a sign of and can even contribute to poor asthma control.

"Tossing a coin:" defining the excessive use of short-acting beta2-agonists in asthma-the views of general practitioners and asthma experts in primary and secondary care

The National Review of Asthma Deaths (NRAD) identified high prescribing of short–acting beta₂-agonists (SABAs) as a key factor in over 40% of deaths. We interviewed asthma experts from both a hospital background (n = 5) and a primary care background (n = 8), and general practitioners delivering asthma care (n = 8), to identify how SABA use is defined and perceived. We identified disparity in how acceptable SABA use is defined, ranging from 0.5 (100 doses/year) to 12 SABA inhalers (2400 doses/year), and complacency in the perception that over-use did not represent a marker for risk of asthma death. Despite current evidence, these findings suggest clinicians of various backgrounds are complacent about excessive SABA use.

The use of electronic alerts in primary care computer systems to identify the excessive prescription of short-acting beta2-agonists for people with asthma: a systematic review

Computers are increasingly used to improve prescribing decisions in the management of long-term conditions however the effects on asthma prescribing remain unclear. We aimed to synthesise the evidence for the use of computerised alerts that identify excessive prescribing of short-acting beta₂-agonists (SABAs) to improve asthma management for people with asthma. MEDLINE, CINAHL, Embase, Cochrane and Scopus databases (1990–2016) were searched for randomised controlled trials using electronic alerts to identify excessive prescribing of SABAs for people with asthma in primary care. Inclusion eligibility, quality appraisal (Cochrane risk of bias tool) and data extraction were performed by two independent reviewers. Findings were synthesised narratively. A total of 2035 articles were screened and four trials were eligible. Three studies had low risk of bias: one reported a positive effect on our primary outcome of interest, excessive SABA prescribing; another reported positive effects on the ratio of inhaled corticosteroid (ICS)-SABA prescribing, and asthma control; a third reported no effect on outcomes of interest. One study at high risk of bias reported a reduction in exacerbations and primary care consultations. There is some evidence that electronic alerts reduce excessive prescribing of SABAs, when delivered as part of a multicomponent intervention in an integrated health care system. However due to the variation in health care systems, intervention design and outcomes measured, further research is required to establish optimal design of alerting and intervening systems.

The Danish National Database for Asthma: establishing clinical quality indicators

Asthma is one of the most common chronic diseases worldwide affecting more than 300 million people. Symptoms are often non-specific and include coughing, wheezing, chest tightness, and shortness of breath. Asthma may be highly variable within the same individual over time. Although asthma results in death only in extreme cases, the disease is associated with significant morbidity, reduced quality of life, increased absenteeism, and large costs for society. Asthma can be diagnosed based on report of characteristic symptoms and/or the use of several different diagnostic tests. However, there is currently no gold standard for making a diagnosis, and some degree of misclassification and inter-observer variation can be expected. This may lead to local and regional differences in the treatment, monitoring, and follow-up of the patients. The Danish National Database for Asthma (DNDA) is slated to be established with the overall aim of collecting data on all patients treated for asthma in Denmark and systematically monitoring the treatment quality and disease management in both primary and secondary care facilities across the country. The DNDA links information from population-based disease registers in Denmark, including the National Patient Register, the National Prescription Registry, and the National Health Insurance Services register, and potentially includes all asthma patients in Denmark. The following quality indicators have been selected to monitor trends: first, conduction of annual asthma control visits, appropriate pharmacological treatment, measurement of lung function, and asthma challenge testing; second, tools used for diagnosis in new cases; and third, annual assessment of smoking status, height, and weight measurements, and the proportion of patients with acute hospital treatment. The DNDA will be launched in 2016 and will initially include patients treated in secondary care facilities in Denmark. In the nearby future, the database aims to include asthma diagnosis codes and clinical data registered by general practitioners and specialised practitioners as well.

Asthma Controller Medication Adherence, Risk of Exacerbation, and Use of Rescue Agents Among Texas Medicaid Patients with Persistent Asthma

BACKGROUND

Adherence to asthma long-term controller medications is one of the key drivers to improve asthma management among patients with persistent asthma. While suboptimal use of controller medications has been found to be associated with more frequent use of oral corticosteroids (OCS), few studies exist regarding the relationship between adherence to controller therapy and the use of short-acting beta2-agonists (SABAs). A better understanding of the association between adherence to asthma controller agents and use of reliever medications will help health care providers and decision makers enhance asthma management.

OBJECTIVE

To determine if there is a relationship between asthma controller adherence, risk of exacerbation requiring OCS, and use of asthma rescue agents.

METHODS

Texas Medicaid claims data from January 1, 2008, to August 31, 2011, were retrospectively analyzed. Continuously enrolled patients aged 5-63 years with a primary diagnosis of asthma (ICD-9-CM code 493) and with 4 or more prescription claims for any asthma medication in 1 year (persistent asthma) were included. The index date was the date of the first asthma controller prescription, and patients were followed for 1 year. The primary outcome variables were SABA (dichotomous: less than  6 vs. ≥ 6) and OCS (continuous) use. The primary independent variable was adherence (proportion of days covered [PDC]) to asthma long-term controller medications. Covariates included demographics and nonstudy medication utilization. Multivariate logistic and linear regression analyses were employed to address the study objective.

RESULTS

The study sample (n = 32,172) was aged 15.0 ± 14.5 years, and adherence to controller therapy was 32.2% ± 19.7%. The mean number of SABA claims was 3.7 ± 3.1, with most patients having 1-5 claims (73.2%), whereas 19.4% had ≥ 6 SABA claims. The mean number of OCS claims was 1.0 ± 1.4. Adherent (PDC ≥ 50%) patients were 96.7% (OR = 1.967; 95% CI = 1.826-2.120) more likely to have ≥ 6 SABA claims when compared with nonadherent (PDC  less than  50%) patients (P  less than  0.001). As for OCS use, adherent patients had 0.11 fewer claims compared with nonadherent patients (P  less than  0.001). Importantly, patients with ≥ 6 SABA claims had 0.7 more OCS claims compared with patients with less than  6 claims for SABA (P  less than  0.001). The odds of having ≥ 6 SABA claims were higher for concurrent dual therapy users, older age, males, African Americans and higher number of nonstudy medications (P  less than  0.001). Dual therapy users, younger age, Hispanic ethnicity, and higher number of nonstudy medications were associated with an increase in OCS use (P  less than  0.005).

CONCLUSIONS

Adherence to long-term controller medications was suboptimal among patients with asthma. Adherent patients had fewer OCS claims, indicating that adherence to controller therapy is critical in preventing asthma exacerbations requiring OCS use. Although there was a positive relationship between adherence to long-term controller medication and SABA use, increased SABA use served as a predictor of increased OCS use, which indicates poor asthma control. Health care providers should be aware of OCS and SABA use among patients who are both adherent and nonadherent to asthma controller medications.

Asthma prescribing, ethnicity and risk of hospital admission: an analysis of 35,864 linked primary and secondary care records in East London

Inappropriate prescribing in primary care was implicated in nearly half of asthma deaths reviewed in the UK’s recent National Review of Asthma Deaths. Using anonymised EMIS-Web data for 139 ethnically diverse general practices (total population 942,511) extracted from the North and East London Commissioning Support Unit, which holds hospital Secondary Uses Services (SUS)–linked data, we examined the prevalence of over-prescribing of short-acting β₂-agonist inhalers (SABA), under-prescribing of inhaled corticosteroid (ICS) inhalers and solo prescribing of long-acting β₂-agonists (LABA) to assess the risk of hospitalisation for people with asthma for 1 year ending August 2015. In a total asthma population of 35,864, multivariate analyses in adults showed that the risk of admission increased with greater prescription of SABA inhalers above a baseline of 1–3 (4–12 SABA: odds ratio (OR) 1.71; 95% confidence interval (CI) 1.20–2.46, ⩾13 SABA: OR 3.22; 95% CI 2.04–5.07) with increasing British Thoracic Society step (Step 3: OR 2.90; 95% CI 1.79–4.69, Step 4/5: OR 9.42; 95% CI 5.27–16.84), and among Black (OR 2.30; 95% CI 1.64–3.23) and south Asian adult populations (OR 1.83; 95% CI 1.36–2.47). Results in children were similar, but risk of hospitalisation was not related to ethnic group. There is a progressive risk of hospital admission associated with the prescription of more than three SABA inhalers a year. Adults (but not children) from Black and South Asian groups are at an increased risk of admission. Further work is needed to target care for these at-risk groups.

Antileukotriene Agents Versus Long-Acting Beta-Agonists in Older Adults with Persistent Asthma: A Comparison of Add-On Therapies

OBJECTIVES

To compare the effectiveness and cardiovascular safety of long-acting beta-agonists (LABAs) with those of leukotriene receptor antagonists (LTRAs) as add-on treatments in older adults with asthma already taking inhaled corticosteroids (ICSs).

DESIGN

Retrospective cohort study.

SETTING

Medicare fee-for-service (FFS) claims (2009-10) for a 10% random sample of beneficiaries continuously enrolled in Parts A, B, and D in 2009.

PARTICIPANTS

Medicare beneficiaries aged 66 and older continuously enrolled in FFS Medicare with Part D coverage with a diagnosis of asthma before 2009 treated exclusively with ICSs plus LABAs or ICSs plus LTRAs (N = 14,702).

MEASUREMENTS

The augmented inverse propensity-weighted estimator was used to compare the effect of LABA add-on therapy with that of LTRA add-on therapy on asthma exacerbations requiring inpatient, emergency, or outpatient care and on cardiovascular (CV) events, adjusting for demographic characteristics, comorbidities, and county-level healthcare-access variables.

RESULTS

The primary analysis showed that LTRA add-on treatment was associated with greater odds of asthma-related hospitalizations or emergency department visits (odds ratio (OR) = 1.4, P < .001), as well as outpatient exacerbations requiring oral corticosteroids or antibiotics (OR = 1.41, P < .001) than LABA treatment. LTRA add-on therapy was also less effective in controlling acute symptoms, as indicated by greater use of short-acting beta agonists (rate ratio = 1.58, P < .001). LTRA add-on treatment was associated with lower odds of experiencing a CV event than LABA treatment (OR = 0.86, P = .006).

CONCLUSION

This study provides new evidence specific to older adults to help healthcare providers weigh the risks and benefits of these add-on treatments. Further subgroup analysis is needed to personalize asthma treatments in this high-risk population.

Albuterol Overuse: A Marker of Psychological Distress?

BACKGROUND

Albuterol overuse, 3 or more canisters per year, is associated with poor asthma control and frequent exacerbations.

OBJECTIVE

To describe albuterol use on symptom and symptom-free days and identify predictors of albuterol overuse and controller medication underuse.

METHODS

Secondary analyses of data from adults with mild asthma from the Trial of Asthma Patient Education were carried out. Based on albuterol use of 80% or more on symptom days and less than 20% on symptom-free days, participants were characterized as expected users, overusers, or underusers of albuterol. Good controller medication adherence was defined as 80% or more of prescribed doses. Data included demographic characteristics, diary data, spirometry, and scores from standardized questionnaires. Bivariate associations were examined between categorization of medication use and measured characteristics.

RESULTS

Of the 416 participants, 212 (51%) were expected users, 114 (27%) were overusers, and 90 (22%) were underusers of albuterol. No differences were observed among the user groups by demographic characteristics or lung function. Expected users demonstrated the highest asthma-related knowledge, attitudes, and efficacy. Overusers reported the greatest symptom burden, worst asthma control, and highest frequency of symptom days. Overusers also had the highest burden of depression symptoms. More frequent symptom days accounted for 15% of overuse, greater use on symptom days accounted for 31%, and greater use on symptom free days accounted for 54% of overuse. Mean controller adherence was high across all groups, and there were no differences between the groups.

CONCLUSIONS

Although overusers experienced more frequent symptom days and used more albuterol on those days, most overuse was attributable to unexpected use on symptom-free days. High levels of comorbid depression were observed, particularly among overusers and among those nonadherent to controller medication.

Real-time asthma outreach reduces excessive short-acting β2-agonist use: a randomized study

BACKGROUND

Excessive use of short-acting β2-agonists (SABA) indicates impaired asthma control.

OBJECTIVE

To determine whether real-time outreach to excessive SABA users reduces SABA canister dispensings.

METHODS

After real-time determination of a seventh SABA canister dispensing in the prior 12 months by using informational pharmacy technology, 12 to 56 year old patients with physician-coded asthma and inhaled corticosteroid dispensing were block randomized by prior asthma specialist care and medication step-care level into intervention (n = 1001) and control groups (n = 998). Intervention included real-time letter notification to patients and an electronic message to their physician with management suggestions, including facilitated allergy referral for patients without prior asthma specialist care. The control group received this organization's standard asthma care management without research contact. Frequency of the seventh SABA canister dispensing in the follow-up year was the primary outcome.

RESULTS

Compared with controls, intervention patients reached 7 SABA canister dispensings less frequently (50.7% vs 57.1%; risk ratio 0.89 [95% CI, 0.82-0.97]; P = .007) and later (hazard ratio 0.80 [95% CI, 0.71-0.91; P < .001). SABA canister dispensings (mean ± SD) were less in intervention (7.5 ± 4.9 canisters) than controls (8.6 ± 5.3 canisters) (rate ratio 0.87 [95% CI, 0.82-0.93]; P < .001). The intervention reduced the risk of ≥7 SABA canister dispensings in patients without specialist care compared with patients with specialist care in the prior 3 years (P < .001) (P = .04 for interaction by prior specialist care). Visits to allergists were more frequent for intervention patients (30.9%) than for control patients (16.8%) (risk ratio 1.83 [95% CI, 1.54-2.16]; P < .001). Asthma exacerbations were unaffected.

CONCLUSIONS

A novel administrative-based asthma outreach program improves markers of asthma impairment in patients without prior asthma specialist care and is adaptable to managed care organizations with electronic medical records.

Effect of combination fluticasone propionate and salmeterol or inhaled corticosteroids on asthma-related outcomes in a Medicare-eligible population

BACKGROUND

National asthma treatment guidelines recommend either the use of inhaled corticosteroids (ICS) or ICS in combination with a long-acting bronchodilator for the treatment of moderate to severe asthma. Even though asthma is common among older adults, few studies have assessed the differences in effectiveness between these two recommended therapies in patients over 65 years of age.

OBJECTIVE

The aim of this study was to assess the association of the fluticasone-salmeterol combination (FSC) or ICS initiation on asthma-related events in Medicare-eligible asthma patients.

METHODS

This was a retrospective observational study using a large health claims database (July 1, 2001 to June 30, 2008). Subjects 65 to 79 years of age with 12-month preindex and 3- to 12-month postindex eligibility, an asthma diagnosis (ICD-493.xx), and with 1 or more FSC or ICS claims at index were included. Subjects with an FSC or ICS claim in the preindex and any claim for chronic obstructive pulmonary disease were excluded. Subjects were observed until they had an event (emergency department [ED] inpatient hospitalization [IP], combined IP/ED or oral corticosteroid [OCS] use) or were no longer eligible in the database, whichever came first. Cox proportional hazards regression was used to assess risk of an asthma-related event (IP, ED, or IP/ED). Baseline characteristics (age, sex, region, index season, comorbidities, preindex use of short-acting β-agonists, OCS, other asthma controllers, and asthma-related ED/IP visits) were independent covariates in the model.

RESULTS

A total of 10,837 met the criteria (4843 ICS and 5994 FSC). Age (70.4 and 70.5 years, respectively) and the percentage of female subjects (65.5% and 64.8%, respectively) were similar. Asthma-related events were also similar at baseline. Postindex unadjusted rates occurring after >30 days were ED (1.8% vs 1.5%, P = 0.18), IP (2.7% vs 1.7%, P < 0.001), and ED/IP (4.1% vs 2.8%, P < 0.001) for ICS and FSC, respectively. Subjects who received FSC were associated with a 32% (adjusted HR = 0.68; 95% CI, 0.51-0.91) lower risk of experiencing an IP visit and a 22% (HR = 0.78; 95% CI, 0.62-0.98) lower risk of experiencing an ED/IP visit. No differences were observed for ED visits (HR = 0.94; 95% CI, 0.68-1.29).

CONCLUSIONS

In Medicare-eligible asthma patients, FSC use was associated with lower rates of asthma-related serious exacerbations compared with ICS.

Short-acting β-agonist use and its ability to predict future asthma-related outcomes

BACKGROUND

Short-acting β-agonist (SABA) use is well established in predicting asthma events in adults. However, this predictive ability has yet to be established in a pediatric population together with an assessment of amount of use.

OBJECTIVE

To identify the number of SABA canisters that best predicts future asthma-related exacerbations and the optimal length of time for measurement of SABA use in pediatric and adult asthma patients.

METHODS

Asthma patients were identified from a Medicaid and a commercially insured database (January 1, 2004, through December 31, 2005, and January 1, 2004, through June 30, 2006, respectively). Following the date of first asthma medication, an assessment period (3, 6, or 12 months) was used to measure SABA use. Asthma-related exacerbations were identified in the subsequent 12-month period. Receiver operating characteristic curve analyses and logistic regression were used to select the critical values of SABA use and optimal assessment periods and to conduct incremental analysis, respectively.

RESULTS

A total of 33,793 Medicaid and 101,437 commercial patients met the study criteria. Use of 3 or more SABA canisters during 12 months was identified in both pediatric Medicaid and commercial populations to best predict an increased risk of an asthma-related exacerbation. For adults, use of 2 or more SABA canisters was found as the critical value with shorter optimal assessment periods of 3 and 6 months. Each additional SABA canister resulted in an 8% to 14% and 14% to 18% increase in risk of an asthma-related exacerbation in children and adults, respectively.

CONCLUSION

The study identified critical values of SABA use that predict future asthma events. Each additional SABA canister predicted increases in exacerbation risk in children and adults.