Outcomes before and after treatment escalation to Global Initiative for Asthma steps 4 and 5 in severe asthma

Economic evaluation of biological treatments in patients with severe asthma: a systematic review

BACKGROUND

Asthma is a highly prevalent disease, one of the chronic diseases with the highest economic costs; thus, it imposes a high economic burden on society, the healthcare system, patients, and third-party payers. Contrary to this study, until now, systematic reviews of economic evaluations (EEs) of treatments for severe asthma have not been exclusively focused on biological treatments, and have included a small number of studies and only model-based EEs.

METHODS

This study systematically reviews EEs of biological therapies for severe asthma published until December 2022 using PRISMA guidelines. The review analyzes the cost-effectiveness of biologicals in comparison to SOC, or SOC plus OCS. The quality of the EEs is assessed using Consensus on Health Economics Checklist extended (CHEC-extended).

RESULTS

Thirty-nine studies were eligible: 15 based on a Markov model, and 19 trial-based; eight adopting societal and NHS perspectives, and seven the payer's perspective. The reviewed EEs addressed cost-effectiveness, cost-utility, and incremental costs and outcomes comparison. Their findings were mainly expressed through ICER-incremental cost-effectiveness ratio (24 studies: 13 concluded that biological were cost-effective) and cost comparison analysis (14 studies: 6 concluded that biological were cost-effective), and were sensitive to a wide variety of factors (e.g. medication cost, treatment response, time horizon, utility benefits, mortality, exacerbation rate, discount rate, etc.).

CONCLUSIONS

There has been some ambiguity concerning the EE of biological therapies due to variation in choice of study design and contradictory results. Nevertheless, it can be concluded that biological treatments improve health outcomes, in many contexts at a high cost.

Cost-Effectiveness of Fractional Exhaled Nitric Oxide Suppression Testing as an Adherence Screening Tool Among Patients With Difficult-to-Control Asthma

BACKGROUND

Approximately 50% of adults on long-term asthma medication are nonadherent. Current methods to detect nonadherence have had limited effect. Fractional exhaled nitric oxide suppression testing (FeNOSuppT) has demonstrated clinical effectiveness as an adherence screening tool to detect poor adherence to inhaled corticosteroids in difficult-to-control asthma prior to initiation of expensive biologic therapy.

OBJECTIVE

Estimate the cost effectiveness and budget impact of FeNOSuppT as a screen prior to the initiation of biologic therapy among U.S. adults with difficult-to-control asthma and high fractional exhaled nitric oxide (≥45 ppb).

METHODS

A decision tree simulated the progression of a cohort of patients over a 1-year time horizon into 1 of 3 states ([1] discharged from or [2] remain in specialist care; or [3] progress to biologics). Two strategies, with and without FeNOSuppT, were examined and the incremental net monetary benefit estimated using a discount rate of 3% and a willingness-to-pay threshold of $100,000 per quality-adjusted life year (QALY). Sensitivity analysis and a budget impact analysis were also undertaken.

RESULTS

In the baseline scenario, FeNOSuppT prior to the initiation of biologic therapy was associated with lower costs ($4,435/patient) and fewer QALYs (0.0023 QALY/patient) compared with no FeNOSuppT over 1 year and was considered cost effective (incremental net monetary benefit = $4,207). The FeNOSuppT was consistently found to be cost effective across a range of scenarios and in deterministic and probabilistic sensitivity analyses. Assuming differential levels of FeNOSuppT uptake (20%-100%), this was associated with budget savings ranging from USD $5 million to $27 million.

CONCLUSIONS

The FeNOSuppT is likely to be cost effective as a protocol-driven, objective, biomarker-based tool for identifying nonadherence in difficult-to-control asthma. This cost effectiveness is driven by cost savings from patients not progressing to expensive biologic therapy.

Assessment of Real-World Escalation to Biologics in US Patients With Asthma

BACKGROUND

Previous studies indicate that suboptimal medication adherence may contribute to uncontrolled asthma. Global Initiative for Asthma (GINA) guidelines recommend treatment escalation to biologics for patients with uncontrolled asthma despite adherence to high-dose maintenance medication and who have eosinophilic/allergic biomarkers or require maintenance oral corticosteroids.

OBJECTIVE

This study aimed to describe the clinical status of patients with asthma escalated to biologic therapy.

METHODS

This retrospective claims database analysis enrolled US patients with asthma who were escalated to biologics between January 2016 and June 2020. Exacerbations, control status, GINA step, and maintenance medication adherence during the 12 months before biologic therapy initiation were analyzed. Asthma control was assessed using both the European Respiratory Society/American Thoracic Society (ERS/ATS) and Stempel criteria. Adherence was defined as the proportion of days covered (PDC) by maintenance medication claims.

RESULTS

Of 1786 patients escalated to biologics, 506 were included for analysis. During the 12 months before escalation, 346 patients had confirmed exacerbations. Uncontrolled asthma status was estimated in 55% and 70% of patients (ERS/ATS and Stempel criteria, respectively). GINA step was inferred for 395 patients: 154 were at step 2, 11 at step 3, 104 at step 4, and 126 at step 5. Of 403 patients with maintenance medication claims, 63% had suboptimal maintenance medication adherence (PDC <80%).

CONCLUSION

In this study, most patients initiating biologic therapy had mild-to-moderate asthma or suboptimal maintenance medication adherence, possibly indicating inappropriate escalation. Incorporating objective medication adherence monitoring into existing guidelines may reduce inappropriate escalation to biologics.

A Meta Analysis of Physical Exercise on Improving Lung Function and Quality of Life Among Asthma Patients

Objective

This paper aims to perform a systematic assessment of the influence of physical exercise on asthma patients and discuss the intervention effects of different exercises on the lung function FEV1 (%pred) and quality of life among asthma patients so as to lay a scientific foundation for improving asthma symptoms.

Methods

Both Chinese and English databases were retrieved, including PubMed, Web of Science, Embase, The Cochrane Library, CBM, CNKI, Wan Fang Data, and VIP, whose retrieval period started from the founding date of each database to 1st, November 2021. Randomized controlled trials (RCT) studying the symptom indicators of asthma patients were collected. Those collected papers were screened according to the Inclusion Criteria and Exclusion Criteria. Then, methodological quality assessments were conducted on the included papers, and combined effect sizes were analyzed by using software ReMan 5.3.5.

Results

The meta analysis showed that physical exercise could significantly improve lung function FEV1 (%pred) and quality of life score. Trails containing breathing exercise are the main source of heterogeneity, and the subgroup of breathing exercise may have better performance than the subgroup of aerobic exercise in improving FEV1 (%pred).

Conclusion

Physical exercise can significantly improve the symptoms and quality of life of asthma patients. Except the breathing exercise that showed heterogeneity, the subgroup of aerobic exercise could improve the capacity of FEV1 (%pred) more effectively, which led to a significant difference in the influence of quality of life. However, with regard to the gymnastic exercise including breathing exercise, there are limited same intervention methods and insufficient same outcome indicators. Therefore, more precise and high-quality researches are needed to make deeper verification in the future.

Recent Advances in the Inhibition of the IL-4 Cytokine Pathway for the Treatment of Allergen-Induced Asthma

The IL-4 and IL-13 cytokine pathways play integral roles in stimulating IgE inflammation, with the IL-4 cytokine being a major cytokine in the etiology of thunderstorm asthma, atopic dermatitis, and allergic rhinitis. The increasing prevalence of thunderstorm asthma in the younger population and the lessening efficacy of corticosteroids and other anti-inflammatories has created a need for more effective pharmaceuticals. This review summarizes the IL-4 and IL-13 pathways while highlighting and discussing the current pathway inhibitors aimed at treating thunderstorm asthma and atopic dermatitis, as well as the potential efficacy of peptide therapeutics in this field.

Risk of Treatment Escalation in Recipients vs Nonrecipients of Spinal Manipulation for Musculoskeletal Cervical Spine Disorders: An Analysis of Insurance Claims

OBJECTIVE

The purpose of this study was to evaluate the relationship between treatment escalation and spinal manipulation in a retrospective cohort of people diagnosed with musculoskeletal disorders of the cervical spine.

METHODS

We used retrospective analysis of insurance claims data (2012-2018) from a single Fortune 500 company. After isolating the first episode of care, we categorized 58 147 claims into 7951 unique patient episodes. Treatment escalation included claims where imaging, injection, emergency room, or surgery was present. Modified Poisson regression was used to determine the relative risk of treatment escalation comparing recipients vs nonrecipients of spinal manipulation, adjusted for age, sex, episode duration, and risk scores.

RESULTS

The sample was 55% women, with a mean age of 44 years (range, 18-103). Treatment escalation was present in 42% of episodes overall: 2448 (46%) associated with other care and 876 (26%) associated with spinal manipulation. The estimated risk of any treatment escalation was 2.38 times higher in those who received other care than in those who received spinal manipulation (95% confidence interval, 2.22-2.55, P = .001).

CONCLUSION

Among episodes of care associated with neck pain diagnoses, those associated with other care had twice the risk of any treatment escalation compared with those associated with spinal manipulation. In the United States, over 90% of spinal manipulation is provided by doctors of chiropractic; therefore, these findings are relevant and should be considered in addressing solutions for neck pain. Additional research investigating the factors influencing treatment escalation is necessary to moderate the use of high-cost and guideline-incongruent procedures in people with neck pain.

Systematic Literature Review of Systemic Corticosteroid Use for Asthma Management

Systemic corticosteroid use to manage uncontrolled asthma and its associated healthcare burden may account for important health-related adverse effects. We conducted a systematic literature review to investigate the real-world extent and burden of systemic corticosteroid use in asthma. We searched MEDLINE and Embase databases to identify English-language articles published in 2010–2017, using search terms for asthma with keywords for oral corticosteroids and systemic corticosteroids. Observational studies, prescription database analyses, economic analyses, and surveys on oral/systemic corticosteroid use in children (>5 yr old), adolescents (12–17 yr old), and adults with asthma were included. We identified and reviewed 387 full-text articles, and our review included data from 139 studies. The included studies were conducted in Europe, North America, and Asia. Overall, oral/systemic corticosteroids were commonly used for asthma management and were more frequently used in patients with severe asthma than in those with milder disease. Long-term oral/systemic corticosteroid use was, in general, less frequent than short-term use. Compared with no use, long-term and repeated short-term oral/systemic corticosteroid use were associated with an increased risk of acute and chronic adverse events, even when doses were comparatively low. Greater oral/systemic corticosteroid exposure was also associated with increased costs and healthcare resource use. This review provides a comprehensive overview of oral/systemic corticosteroid use and associated adverse events for patients with all degrees of asthma severity and exposure duration. We report that oral/systemic corticosteroid use is prevalent in asthma management, and the risks of acute and chronic complications increase with the cumulative oral corticosteroid dosage.

Dupilumab: Basic aspects and applications to allergic diseases

Interleukin (IL)-4 and IL-13, signature type 2 cytokines, exert their actions by binding to two types of receptors sharing the IL-4R α chain (IL-4Rα). Since IL-4 and IL-13 play important and redundant roles in the pathogenesis of allergic diseases, blocking both the IL-4 and IL-13 signals would be a powerful and effective strategy for treating allergic diseases. Dupilumab (Dupixent®) is a fully human monoclonal antibody recognizing IL-4Rα and blocking both the IL-4 and IL-13 signals. Dupilumab was first prescribed for atopic dermatitis (AD) patients and has been widely approved for adult patients with moderate to severe AD since 2018. Dupilumab has since been used for asthma, receiving approval for uncontrolled asthma in 2019. A phase 3 study using dupilumab for chronic rhinosinusitis with nasal polyps (CRSwNP) has been just completed, with positive results. Several clinical trials of dupilumab for other diseases in which type 2 inflammation is dominant are now underway. It is hoped that dupilumab will open the door to a new era for treating allergic patients with AD, asthma, and CRSwNP, and for more patients with type 2 inflammations.

Development and initial validation of the Asthma Severity Scoring System (ASSESS)

BACKGROUND

Tools for quantification of asthma severity are limited.

OBJECTIVE

We sought to develop a continuous measure of asthma severity, the Asthma Severity Scoring System (ASSESS), for adolescents and adults, incorporating domains of asthma control, lung function, medications, and exacerbations.

METHODS

Baseline and 36-month longitudinal data from participants in phase 3 of the Severe Asthma Research Program (NCT01606826) were used. Scale properties, responsiveness, and a minimally important difference were determined. External replication was performed in participants enrolled in the Severe Asthma Research Program phase 1/2. The utility of ASSESS for detecting treatment response was explored in participants undergoing corticosteroid responsiveness testing with intramuscular triamcinolone and participants receiving biologics.

RESULTS

ASSESS scores ranged from 0 to 20 (8.78 ± 3.9; greater scores reflect worse severity) and differed among 5 phenotypic groups. Measurement properties were acceptable. ASSESS was responsive to changes in quality of life with a minimally important difference of 2, with good specificity for outcomes of asthma improvement and worsening but poor sensitivity. Replication analyses yielded similar results, with a 2-point decrease (improvement) associated with improvements in quality of life. Participants with a 2-point or greater decrease (improvement) in ASSESS scores also had greater improvement in lung function and asthma control after triamcinolone, but these differences were limited to phenotypic clusters 3, 4, and 5. Participants treated with biologics also had a 2-point or greater decrease (improvement) in ASSESS scores overall.

CONCLUSIONS

The ASSESS tool is an objective measure that might be useful in epidemiologic and clinical research studies for quantification of treatment response in individual patients and phenotypic groups. However, validation studies are warranted.

Increased Ratio of Matrix Metalloproteinase-9 (MMP-9)/Tissue Inhibitor Metalloproteinase-1 from Alveolar Macrophages in Chronic Asthma with a Fast Decline in FEV1 at 5-Year Follow-up

Chronic asthma is associated with progressive airway remodeling, which may contribute to declining lung function. An increase in matrix metalloproteinases-9 (MMP-9)/tissue inhibitor metalloproteinase-1 (TIMP-1) may indicate airway inflammation and bronchial injury. Bronchial biopsy specimens and alveolar macrophages (AMs) were obtained from patients with asthma under regular treatment with inhaled corticosteroids or combination therapy and normal subjects (n = 10). Asthmatics included those with a slow forced expiratory volume in one second (FEV₁) decline (<30 mL/year, n = 13) and those with a fast FEV₁ decline (≥30 mL/year, n = 8) in 5-year follow-up. Immunostaining expression of MMP-9 and TIMP-1 was detected in airway tissues. MMP-9 and TIMP-1 was measured from AMs cultured for 24 h. After the 5-year treatment, the methacholine airway hyperresponsiveness of the slow FEV₁ decline group was decreased, but that of the fast FEV₁ decline group was increased (PC₂₀, provocative concentration causing a 20% decrease in FEV₁, 3.12 ± 1.10 to 1.14 ± 0.34 mg/dL, p < 0.05). AMs of asthma with a fast FEV₁ decline released a higher level of MMP-9 (8.52 ± 3.53 pg/mL, p < 0.05) than those of a slow FEV₁ decline (0.99 ± 0.20 pg/mL). The MMP-9/TIMP ratio in the fast FEV₁ decline group (0.089 ± 0.032) was higher than that of the slow FEV₁ decline group (0.007 ± 0.001, p < 0.01). The annual FEV₁ decline in 5 years was proportional to the level of MMP-9 (r = 57, p < 0.01) and MMP-9/TIMP-1 ratio (r = 0.58, p < 0.01). The airways of asthma with greater yearly decline in FEV₁ showed an increased thickness of submucosa and strong expression of MMP-9. An increase in MMP-9 and MMP-9/TIMP-1 in airways or AMs could be indicators of chronic airway inflammation and contribute to a greater decline in lung function of patients with chronic asthma.

Systematic literature review of the clinical, humanistic, and economic burden associated with asthma uncontrolled by GINA Steps 4 or 5 treatment

OBJECTIVE

This study sought to characterize the epidemiologic, clinical, humanistic, and economic burden of patients with asthma uncontrolled by GINA Steps 4 or 5 treatment (severe, uncontrolled asthma [SUA]).

METHODS

A systematic literature review adhering to PRISMA guidelines was performed. Relevant publications were searched for in MEDLINE and EMBASE from January 2004 to September 2016 and in a conference proceedings database from January 2012 to October 2016. Studies were screened using the Population, Intervention, Comparator, Outcomes, Study Design, and Time (PICOS-T) framework. Studies of SUA with observational (prospective and retrospective), randomized, or nonrandomized study designs; adult patient populations; sample sizes ≥20 patients; epidemiologic or clinical outcomes, patient-reported outcomes (PROs), or economic outcomes were included. For our analysis, SUA was defined as inadequate control of asthma, despite the use of medium- to high-dosage inhaled corticosteroids and at least one additional treatment.

RESULTS

A total of 195 articles reporting unique study populations were included. Prevalence of SUA was as great as 87.4% for patients with severe asthma, although values varied depending on the criteria used to define asthma control. Compared with patients with severe asthma who were controlled, patients with SUA experienced more symptoms, night-time awakenings, rescue medication use, and worse PROs. SUA-associated costs were 3-times greater than costs for patients with severe, controlled disease.

CONCLUSION

Despite the availability of approved asthma treatments, this literature analysis confirms that SUA poses a substantial epidemiologic, clinical, humanistic, and economic burden. Published data are limited for certain aspects of SUA, highlighting a need for further research.

Adverse outcomes from initiation of systemic corticosteroids for asthma: long-term observational study

Purpose

Prior work suggests a threshold of four courses/year of systemic corticosteroid (SCS) therapy is associated with adverse consequences. The objective of this study was to investigate the onset of adverse outcomes beginning at SCS initiation in a broad asthma population.

Patients and methods

This historical matched cohort study utilized anonymized, longitudinal medical record data (1984–2017) of patients (≥18 years) with active asthma. Matched patients with first SCS prescription (SCS arm) and no SCS exposure (non-SCS arm) were followed until first outcome event. Associations between time-varying exposure measures and onset of 17 SCS-associated adverse outcomes were estimated using Cox proportional hazard regression, adjusting for confounders, in separate models.

Results

We matched 24,117 pairs of patients with median record availability before SCS initiation of 9.9 and 8.7 years and median follow-up 7.4 and 6.4 years in SCS and non-SCS arms, respectively. Compared with patients in the non-SCS arm, patients prescribed SCS had significantly increased risk of osteoporosis/osteoporotic fracture (adjusted hazard ratio 3.11; 95% CI 1.87–5.19), pneumonia (2.68; 2.30–3.11), cardio-/cerebrovascular diseases (1.53; 1.36–1.72), cataract (1.50; 1.31–1.73), sleep apnea (1.40; 1.04–1.86), renal impairment (1.36; 1.26–1.47), depression/anxiety (1.31; 1.21–1.41), type 2 diabetes (1.26; 1.15–1.37), and weight gain (1.14; 1.10–1.18). A dose-response relationship for cumulative SCS exposure with most adverse outcomes began at cumulative exposures of 1.0–<2.5 g and for some outcomes at cumulative exposures of only 0.5–<1 g (vs >0–<0.5 g reference), equivalent to four lifetime SCS courses.

Conclusion

Our findings suggest urgent need for reappraisal of when patients need specialist care and consideration of nonsteroid therapy.

Inhaled Corticosteroid-Containing Treatment Escalation and Outcomes for Patients with Asthma in a U.S. Health Care Organization

BACKGROUND

Asthma is a common disorder that affects approximately 8% of the U.S.

POPULATION

Treatment guidelines indicate inhaled corticosteroids (ICS) as the mainstay treatment, yet poor asthma control is common among ICS-treated patients. Treatment escalation (ICS dose increase and other controller therapy add-ons) is used to manage symptoms. Real-world studies of postescalation outcomes may inform treatment decisions.

OBJECTIVES

To (a) describe characteristics and treatment patterns among asthma patients who escalated treatment and (b) assess outcomes (exacerbations, uncontrolled asthma, and health care resource utilization [HCRU]) after escalation.

METHODS

The study cohort was identified from a large U.S. administrative claims database via ICD-9-CM codes for asthma (493.xx on ≥ 2 dates) and initiation (defining index date) of long-term (> 1 fill) ICS-containing treatment between January 1, 2009, and September 30, 2014. One year of continuous enrollment was required before and after the index date. Escalation was defined as ≥ 1 of the following: ICS dose increase; a switch between ICS, long-acting beta-2 agonists (LABA), or leukotriene modifiers (LTRM) to a different ICS, LABA, or LTRM; or add-on of controller medications (e.g., antibody biologic). Escalation patterns were examined. Rates of exacerbation (defined by inpatient admission, emergency department [ED] visit, or office visit with a pharmacy claim for an oral corticosteroid [OCS] within 7 days) and occurrence of uncontrolled asthma (defined by > 4 fills for a short-acting beta agonist [SABA] in a 1-year period, ≥ 1 OCS fill, or ≥ 1 asthma-related ED visit or inpatient admission) were calculated. Per-patient-per-year (PPPY) HCRU was estimated.

RESULTS

Among 35,126 patients (mean [SD] age 38 [16] years) who initiated long-term ICS-containing treatment, 5,044 (14%) patients escalated their index regimens at 136 (105) days post-index (i.e., pre-escalation period). The most frequent changes, alone or in combination, included ICS dose increase (68%) or LABA (27%) or LTRM (25%) add-ons. Before escalation, the exacerbation rate was 1.60 (5.10) PPPY, and 1,108 (22%) patients experienced exacerbation. During the postescalation period of 251.6 (138.9) days, the exacerbation rate was 0.75 (2.9) PPPY, and 1,038 (21%) patients experienced exacerbation. A majority (> 85%) of exacerbations in the periods before and after escalation were associated with an office visit plus an OCS pharmacy claim within 7 days. Uncontrolled asthma was experienced by 41.5% and 41.0% of patients before and after escalation, respectively. Ambulatory care visits were common before (mean [SD] 24.0 [26.7] all-cause and 8.5 [13.4] asthma-related PPPY) and after escalation (19.3 [21.3] all-cause and 4.6 [8.1] asthma-related PPPY).

CONCLUSIONS

Among asthma patients who initiated a long-term ICS-containing regimen, approximately 14% escalated therapy within a year of initiation. Yet, 21% of those patients had ≥ 1 exacerbation, and 41% of patients had uncontrolled asthma within 1 year after treatment escalation. The results demonstrate an unmet need among asthma patients who escalated their ICS-containing treatment.

DISCLOSURES

This study was sponsored and funded by Boehringer-Ingelheim, which contracted with Optum to conduct the research. The sponsor collaborated with Optum on the preparation, writing, revision, and approval of the manuscript. Bengston, Cao, Hulbert, Wolbeck, Elliott, and Buikema are employees of Optum. Yu and Wang are employed by Boehringer-Ingelheim. Study concept and design were contributed by Bengston, Yu, and Wang. Cao, Hulbert, and Wolbeck collected the data, and data analysis was performed by Bengston, Yu, and Wang. The manuscript was written by Bengston, along with Yu and Wang, and revised by Bengston, Yu, and Wang, along with the other authors.

Approaching Current and New Drug Therapies for Pediatric Asthma

As new therapies for pediatric asthma are approved by the Food and Drug Administration, clinicians should be aware of their benefits and limitations. Accompanying these therapies are potential obstacles, including the delivery of inhaled therapies and age-specific issues regarding implementation and adherence. New insights are being added to well-established controller medications, including inhaled corticosteroids and long-acting β-agonists, while new medications previously approved in adults, including tiotropium and biologics, are now being evaluated for use in children. These drugs can be useful additive therapies to treat patients who are currently not responding to guidelines-based therapy.

Dupilumab in the management of moderate-to-severe asthma: the data so far

Severe asthma constitutes illness in a relatively small proportion of all patients with asthma, but it is a major public health problem - with considerable effect on morbidity, mortality, as well as a high burden on health care resources. Regardless of effective treatments being widely available and the existence of treatment guidelines, a large population of severe asthma cases remain uncontrolled. Achieving and maintaining asthma control in this group of patients is, therefore, of utmost importance. The recognition of distinct inflammatory phenotypes within this population has driven the development of targeted biological therapies - particularly, selective targeted monoclonal antibodies (mAbs). It is noteworthy that in approximately 50% of these patients, there is strong evidence of the pathogenic role of T helper type-2 (Th2) cytokines, such as interleukin (IL)-4 and IL-13, orchestrating the eosinophilic and allergic inflammatory processes. Among the recently developed antiasthma biologic drugs, the mAb dupilumab is very promising given its ability to inhibit the biological effects of both IL-4 and IL-13. In this review, we focused on IL-4 and IL-13, as these interleukins are considered to play a key role in the pathophysiology of asthma, and on dupilumab, an anti-IL-4 receptor human mAb, as a forthcoming treatment for uncontrolled severe asthma in the near future.

Defining asthma and assessing asthma outcomes using electronic health record data: a systematic scoping review

There is currently no consensus on approaches to defining asthma or assessing asthma outcomes using electronic health record-derived data. We explored these approaches in the recent literature and examined the clarity of reporting.

We systematically searched for asthma-related articles published between January 1, 2014 and December 31, 2015, extracted the algorithms used to identify asthma patients and assess severity, control and exacerbations, and examined how the validity of these outcomes was justified.

From 113 eligible articles, we found significant heterogeneity in the algorithms used to define asthma (n=66 different algorithms), severity (n=18), control (n=9) and exacerbations (n=24). For the majority of algorithms (n=106), validity was not justified. In the remaining cases, approaches ranged from using algorithms validated in the same databases to using nonvalidated algorithms that were based on clinical judgement or clinical guidelines. The implementation of these algorithms was suboptimally described overall.

Although electronic health record-derived data are now widely used to study asthma, the approaches being used are significantly varied and are often underdescribed, rendering it difficult to assess the validity of studies and compare their findings. Given the substantial growth in this body of literature, it is crucial that scientific consensus is reached on the underlying definitions and algorithms.