Development and validation of database indexes of asthma severity and control

Association between 25-hydroxy vitamin D and lung function (FEV1, FVC, FEV1/FVC) in children and adults with asthma: A systematic review

Asthma is a chronic respiratory disease that poses significant individual, social, financial and healthcare burdens. Physicians and researchers have recommended 25-hydroxy vitamin D supplementation, in combination with prescribed medication, as a potential means of reducing asthma severity. This systematic review focuses on the association between 25-hydroxy vitamin D levels and lung function in both children and adults with asthma. We identified published work by searching MEDLINE via PubMed, using regular search terms related to 25-hydroxy vitamin D and asthma. Fourteen studies were screened out of 643 eligible citations from MEDLINE research that involved 65 children and 951 adults. A strong positive association was observed in four studies, whereas five showed a moderate association, and two had no correlation. The majority of studies found a negative correlation between 25-hydroxy vitamin D deficiency and mild, uncontrolled and partly controlled asthma. 25-hydroxy vitamin D 25 OH values were below 20 ng/ml in the majority of studies, and those with uncontrolled severe asthma showed the lowest values.

Reductions in inhaler greenhouse gas emissions by addressing care gaps in asthma and chronic obstructive pulmonary disease: an analysis

INTRODUCTION

Climate change from greenhouse gas (GHG) emissions represents one of the greatest public health threats of our time. Inhalers (and particularly metred-dose inhalers (MDIs)) used for asthma and chronic obstructive pulmonary disease (COPD), constitute an important source of GHGs. In this analysis, we aimed to estimate the carbon footprint impact of improving three distinct aspects of respiratory care that drive avoidable inhaler use in Canada.

METHODS

We used published data to estimate the prevalence of misdiagnosed disease, existing inhaler use patterns, medication class distributions, inhaler type distributions and GHGs associated with inhaler actuations, to quantify annual GHG emissions in Canada: (1) attributable to asthma and COPD misdiagnosis; (2) attributable to overuse of rescue inhalers due to suboptimally controlled symptoms; and (3) avoidable by switching 25% of patients with existing asthma and COPD to an otherwise comparable therapeutic option with a lower GHG footprint.

RESULTS

We identified the following avoidable annual GHG emissions: (1) ~49 100 GHG metric tons (MTs) due to misdiagnosed disease; (2) ~143 000 GHG MTs due to suboptimal symptom control; and (3) ~262 100 GHG MTs due to preferential prescription of strategies featuring MDIs over lower-GHG-emitting options (when 25% of patients are switched to lower GHG alternatives). Combined, the GHG emission reductions from bridging these gaps would be the equivalent to taking ~101 100 vehicles off the roads each year.

CONCLUSIONS

Our analysis shows that the carbon savings from addressing misdiagnosis and suboptimal disease control are comparable to those achievable by switching one in four patients to lower GHG-emitting therapeutic strategies. Behaviour change strategies required to achieve and sustain delivery of evidence-based real-world care are complex, but the added identified incentive of carbon footprint reduction may in itself prove to be a powerful motivator for change among providers and patients. This additional benefit can be leveraged in future behaviour change interventions.

Mild asthma: Lessons learned and remaining questions

Patients living with mild disease represent the largest proportion of asthma patients. There are significant challenges in proposing a definition that would best describe these patients, while also accurately identifying at-risk individuals. Current literature suggests considerable inflammatory and clinical heterogeneity within this group. Research has shown that these patients are at risk of poor control, exacerbations, lung function decline, and death. Despite conflicting data on its prevalence, eosinophilic inflammation appears to be a predictor of poorer outcomes in mild asthma. There is an immediate need to better understand phenotypic clusters in mild asthma. It is also important to understand factors that influence disease progression and remission, as it is evident that both vary in mild asthma. Guided by robust literature that supports inhaled corticosteroid-based strategies over short-acting beta-agonist (SABA) reliant regimens, the management of these patients has evolved considerably. Unfortunately, SABA use remains high in clinical practice despite strong advocacy from the Global Initiative for Asthma. Future mild asthma research should explore the role of biomarkers, develop prediction tools based on composite risk scores, and explore targeted therapies at least for at-risk individuals.

Doubly robust adaptive LASSO for effect modifier discovery

Effect modification occurs when the effect of a treatment on an outcome differsaccording to the level of some pre-treatment variable (the effect modifier). Assessing an effect modifier is not a straight-forward task even for a subject matter expert. In this paper, we propose a two-stageprocedure to automatically selecteffect modifying variables in a Marginal Structural Model (MSM) with a single time point exposure based on the two nuisance quantities (the conditionaloutcome expectation and propensity score). We highlight the performance of our proposal in a simulation study. Finally, to illustrate tractability of our proposed methods, we apply them to analyze a set of pregnancy data. We estimate the conditional expected difference in the counterfactual birth weight if all women were exposed to inhaled corticosteroids during pregnancy versus the counterfactual birthweight if all women were not, using data from asthma medications during pregnancy.

Association Between Medication Adherence and Risk of COPD in Adult Asthma Patients: A Retrospective Cohort Study in Canada

Background

Poor adherence to prescribed asthma medications and risk of severe asthma exacerbations have been well established. However, the effects of changes in asthma medication compliance levels and subsequent risk of COPD is unknown and yet to be investigated. This study investigated the independent effect of medication adherence (MA) and asthma severity levels on the risk of COPD.

Methods

We used four linked administrative health databases from the Population data BC to identify asthma patients aged 18 years and older between January 1, 1998 and December 31, 1999 without diagnosis of COPD. The primary event was time-to-COPD diagnosis during the follow-up period (January 1, 2000 to December 31, 2018). The proportion of days covered (PDC) – was used as a surrogate measure for medication adherence (MA) assessed at optimal-level (≥ 0.80), Intermediate-level (0.50–0.79), and low-level (< 0.5) of adherence. A propensity adjusted analysis with Marginal Structural Cox (MSC) model was employed to estimate the adjusted hazard ratios (aHR) and 95% confidence intervals (95% CI) for the effect of medication adherence and asthma severity over time.

Results

At cohort entry, the sample included 68,211 asthma patients with an overall mean age of 48.2 years. The 18-year incidence of COPD in asthma patients was 9.8 per 1000-persons year. In an inverse weighted propensity adjusted analysis of the MSC model, higher MA levels were significantly associated with decreased risk of COPD as follows: optimal-level (aHR: 0.19, 95% CI: 0.17–0.24); Intermediate-level (aHR: 0.20, 95% CI: 0.18, 0.23) compared to the low-level adherence group. A significant increase in COPD risk was observed in severe asthma patients with low medication adherence (aHR: 1.72, 95% CI: 1.52–1.93), independent of other patient factors.

Conclusion

Optimal (≥ 0.80) and intermediate adherence (0.5 to 0.79) levels were associated with reduced risk of COPD incidence over time. Interventions aimed at improving adherence to prescribed medications in adult asthma patients should be intensified to reduce their risk of COPD.

Long-Term Natural History of Severe Asthma Exacerbations and Their Impact on the Disease Course

Rationale: The long-term natural history of asthma in terms of successive severe exacerbations and the influence of each exacerbation on the course of the disease is not well studied. Objectives: To investigate the long-term natural history of asthma among patients who are hospitalized for asthma for the first time in terms of the risk of future severe exacerbations and heterogeneity in this risk across patients. Methods: Using the administrative health databases of British Columbia, Canada (January 1, 1997 to March 31, 2016), we created an incident cohort of patients with at least one asthma exacerbation that required inpatient care. We estimated the 5-year cumulative incidence of severe exacerbations after successive numbers of previous events. We used a joint frailty model to investigate the extent of between-individual variability in exacerbation risk and the associations of each exacerbation with the rate of subsequent events. Analyses were conducted separately for pediatric (<14 years old) and adult (⩾14 years old) patients. Results: Analyses were based on 3,039 pediatric (mean age at baseline, 6.4; 35% female) and 5,442 (mean age at baseline, 50.8; 68% female) adult patients. The 5-year rates of severe exacerbations after the first three events were 0.16, 0.29, and 0.35 for the pediatric group, and 0.14, 0.33, and 0.49 for the adult group. Both groups exhibited substantial variability in patient-specific risks of exacerbation: the mid-95% interval of 5-year risk of experiencing a severe exacerbation ranged from 11% to 24% in pediatric patients and from 8% to 40% in adult patients. After controlling for potential confounders, the first follow-up exacerbation was associated with an increase of 79% (95% confidence interval [CI], 11-189%) in the rate of subsequent events in the pediatric group, whereas this increase was 188% (95% CI, 35-515%) for the adult group. The effects of subsequent exacerbations were not statistically significant. Conclusions: After the first severe exacerbation, the risk of subsequent events is substantially different among patients. The number of previous severe exacerbations carries nuanced prognostic information about future risk. Our results suggest that severe exacerbations in the early course of asthma detrimentally affect the course of the disease and risk of subsequent exacerbations.

Primary Care Severe Asthma Registry and Education Project (PCSAR-EDU): Phase 1 - an e-Delphi for registry definitions and indices of clinician behaviour

INTRODUCTION

Although most asthma is mild to moderate, severe asthma accounts for disproportionate personal and societal costs. Poor co-ordination of care between primary care and specialist settings is recognised as a barrier to achieving optimal outcomes. The Primary Care Severe Asthma Registry and Education (PCSAR-EDU) project aims to address these gaps through the interdisciplinary development and evaluation of both a 'real-world' severe asthma registry and an educational programme for primary care providers. This manuscript describes phase 1 of PCSAR-EDU which involves establishing interdisciplinary consensus on criteria for the: (1) definition of severe asthma; (2) generation of a severe asthma registry and (3) definition of an electronic-medical record data-based Clinician Behaviour Index (CBI).

METHODS AND ANALYSIS

In phase 1, a modified e-Delphi activity will be conducted. Delphi panellists (n≥13) will be invited to complete a 30 min online survey on three separate occasions (i.e., three separate e-Delphi 'rounds') over a 3-month period. Expert opinion will be collected via an open-ended survey ('Open' round 1) and 5-point Likert scale and ranking surveys ('Closed' round 2 and 3). A fourth and final Delphi round will occur via synchronous meeting, whereby panellists approve a finalised ideal 'core criteria list', CBI and corresponding item weighting.

ETHICS AND DISSEMINATION

Ethical approval has been obtained for the activities involved in phase 1 from the University of Toronto's Human Research Ethics Programme (approval number 39695). Future ethics approvals will depend on information gathered in the proceeding phase; thus, ethical approval for phase 2 and 3 of this study will be sought sequentially. Findings will be disseminated through conference presentations, peer-reviewed publications and knowledge translation tools.

Asthma Severity and Control and Their Association With Perinatal Mental Illness

OBJECTIVE

Growing evidence suggests asthma increases perinatal mental illness risk, but few studies have explored the impact of asthma severity and control. Our objective was to explore the association between asthma severity and control and perinatal mental illness risk and the impact of asthma exacerbations during pregnancy on postpartum mental illness risk.

METHODS

This was a population-based retrospective cohort study of all women in Ontario, Canada, from 2005 to 2015 with a singleton live birth who used public drug insurance, excluding women with recent history of mental illness. We constructed modified Poisson regression models to assess the risk of perinatal mental illness, defined as a mood or anxiety, psychotic or substance use disorder, self-harm or other mental illness diagnosed from conception to 365 days postnatally. Models controlled for socio-demographic factors and medical history.

RESULTS

There were 62,583 women in the cohort (46.7% between 15 - 24 years), of whom 22.7% had asthma (94.3% mild, 5.7% moderate/severe; 86.5% controlled and 13.5% uncontrolled). After adjustment, there was increased risk of perinatal mental illness with mild asthma (adjusted relative risk [RR]: 1.12; 95% confidence interval [CI], 1.09 to 1.16) and moderate/severe asthma (aRR: 1.16; 95% CI, 1.04 to 1.30) compared to no asthma. Controlled asthma (aRR: 1.11; 95% CI, 1.08 to 1.15) and uncontrolled asthma (aRR: 1.19; 95% CI, 1.11 to 1.27) were also associated with increased perinatal mental illness risk compared to no asthma. Women with worsened asthma during pregnancy had the highest risk of postpartum mental illness compared to no change in asthma status (by severity: aRR: 1.57; 95% CI, 1.36 to 1.80; by control: aRR: 1.37; 95% CI, 1.22 to 1.54).

CONCLUSION

Asthma is associated with increased risk of perinatal mental illness, particularly in the presence of asthma exacerbations in pregnancy. The results support multidisciplinary collaborative care programmes throughout the perinatal period, especially among women with asthma exacerbations during pregnancy.

Examining Risk Factors Accelerating Time-to-Chronic Obstructive Pulmonary Disease (COPD) Diagnosis among Asthma Patients

Asthma patients may have an increased risk for diagnosis of chronic obstructive pulmonary disease (COPD). However, risk factors accelerating time-to-COPD diagnosis are unclear. This study aims to estimate risk factors associated with the incidence of COPD diagnosis in asthma patients. Canada's Population Data BC (PopData BC) was used to identify asthma patients without prior COPD diagnosis between January 1, 1998, to December 31, 1999. Patients were assessed for time-to-incidence of COPD diagnosis from January 1, 2000, to December 31, 2018. The study estimated the effects of several risk factors in predicting the incidence of COPD in asthma patients during the 18-year follow-up period. Patient factors such as Medication Adherence (MA) were assessed by the proportion of days covered (PDC) and the medication possession ratio (MPR). The log-logistic mixed-effects accelerated failure time model was used to estimate the adjusted failure time ratios (aFTR) and 95% Confidence Interval (95% CI) for factors predicting time-to-COPD diagnosis among asthma patients. We identified 68,211 asthma patients with a mean age of 48.2 years included in the analysis. Risk factors accelerating time-to-COPD diagnosis included: male sex (aFTR: 0.62, 95% CI:0.56-0.68), older adults (age > 40 years) [aFTR: 0.03, 95% CI: 0.02-0.04], history of tobacco smoking (aFTR: 0.29, 95% CI: 0.13-0.68), asthma exacerbations (aFTR: 0.81, 95%CI: 0.70, 0.94), frequent emergency admissions (aFTR:0.21, 95% CI: 0.17-0.25), longer hospital stay (aFTR:0.07, 95% CI: 0.06-0.09), patients with increased burden of comorbidities (aFTR:0.28, 95% CI: 0.22-0.34), obese male sex (aFTR:0.38, 95% CI: 0.15-0.99), SABA overuse (aFTR: 0.61, 95% CI: 0.44-0.84), moderate (aFTR:0.23, 95% CI: 0.21-0.26), and severe asthma (aFTR:0.10, 95% CI: 0.08-0.12). After adjustment, MA ≥0.80 was significantly associated with 83% delayed time-to-COPD diagnosis [i.e. aFTR =1.83, 95%CI: 1.54-2.17 for PDC]. However, asthma severity significantly modifies the effect of MA independent of tobacco smoking history. The targeted intervention aimed to mitigate early diagnosis of COPD may prioritize enhancing medication adherence among asthma patients to prevent frequent exacerbation during follow-up.

Controversies in the treatment of mild asthma. What novelties and practical implications?

Mild asthma is prevalent in childhood and causes as many as 30%-40% asthma exacerbations requiring emergency visits. The management of "intermittent" and "mild persistent" asthma phenotypes is still a matter of debate, even if the role of inhaled corticosteroids, both continuous and intermittent, is a cornerstone in this field. Recent updates of the guidelines on the strategies to manage these patients are coming, since the role of inflammation in these asthma phenotypes is crucial, as well as the potential side effect and risks of short-acting beta 2 agonists overuse, prescribed as the only "as-needed" treatments. In this paper, we overview the new (r)evolution regarding intermittent and mild persistent asthma management.

Copayment policy reforms and effective care utilization by patients with persistent asthma in Taiwan

OBJECTIVES

Reforms to the Taiwan National Health Insurance copayment scheme in 2005 imposed a notable increase in the cost of outpatient visits. This provided an ideal situation to determine whether such reforms lead to a reduction in the utilization of effective care by patients with persistent asthma.

METHODS

This study applied the pretest-posttest non-randomized control group design in our analysis of nationwide claims data (2002 to 2010). Based on propensity score matching, the patients were divided into two groups, subject and not subject to copayment reform. Medication Management for People with Asthma measure was used to identify patients with persistent asthma and instances of effective care.

RESULTS

Matching yielded a final panel of 7,890 individuals with persistent asthma (3,945 individuals in each cohort) eligible for the study. GEE analysis revealed that policy reforms had significant effects over the short-term (OR = 0.745, p < 0.05), medium-term (OR = 0.752, p < 0.01), and long-term (OR = 0.721, p < 0.01).

CONCLUSIONS

Reforms to copayment policy were significantly correlated with a reduction in the utilization of effective care by patients with persistent asthma over the short-, medium- and long-term. Government should develop implementation strategies aimed at protecting the economically disadvantaged patients.

Determining the optimal threshold for medication adherence in adult asthma patients: an analysis of British Columbia administrative health database in Canada

OBJECTIVE

This study investigated the association between varying cutoffs for Medication Adherence (MA) among physician-diagnosed asthma patients and subsequent association with asthma exacerbation.

METHODS

We linked four administrative health databases obtained from the Population Data in British Columbia. Index cases were physician-diagnosed asthma patients between January 1, 1998, to December 31, 1999, aged 18 years and older. Patients were prospectively assessed in the follow-up period from January 1, 2000, to December 31, 2018, to identify asthma exacerbation. Two proxy measures were used to assess MA: the proportion of days covered (PDC) and the medication possession ratio (MPR). Using the generalized estimating equation (GEE) logistic regression adjusted for patient covariates, the outcome of "asthma exacerbation" was modeled against varying MA cutoffs; excellent '≥0.90'; very good '0.80-0.89'; good '0.70-0.799'; moderate '0.6-0.699'; mild '0.50-0.599' compared to poor '<0.50' for both PDC and MPR.

RESULTS

The sample included 68,211 physician-diagnosed asthma patients with a mean age of 48.2 years and 59.3% females. The adjusted odds ratios (OR) and 95% confidence interval (CI) at the various cutoff for PDC-levels predicting asthma exacerbation events were: Excellent MA [OR = 0.84, 95% (0.82-0.86), very good MA [OR: 0.86, (0.83, 0.89), good MA [0.91, (0.88-0.94)]; moderate MA [0.93, (0.90-0.96)]; mild MA [0.95, (0.92-0.98)]; compared to poor MA level. Threshold levels for both the PDC and MPR measure greater than 0.80 provided optimal threshold associated with over 15% reduced likelihood of experiencing asthma exacerbations.

CONCLUSION

Intervention aimed at improving asthma exacerbation events in adult asthma patients should encourage increased medication adherence threshold level greater than 0.80.

Supplemental data for this article is available online at at www.tandfonline.com/ijas .

Is asthma associated with COVID-19 infection? A UK Biobank analysis

Background

The relationship between asthma and coronavirus disease 2019 (COVID-19) risk is not clear and may be influenced by level of airway obstruction, asthma medication and known COVID-19 risk factors. We aimed to investigate COVID-19 risk in people with asthma.

Methods

We used UK Biobank data from all participants tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (n=107 412; 17 979 test positive). Questions at baseline defined ever asthma and asthma medications. Baseline forced expiratory volume in 1 s (FEV₁) was categorised into quartiles. Logistic regression modelled relationships between asthma, and asthma categories (age at onset, medications, FEV₁ quartiles), and risk of SARS-CoV-2 positive test. We investigated modification by sex, ethnic group, smoking and body mass index.

Results

There was a reduced risk of a positive test associated with early-onset asthma (<13 years) (OR 0.91, 95% CI 0.84-0.99). This was found for participants with early-onset asthma who were male (OR 0.87, 95% CI 0.78-0.98), nonsmokers (OR 0.87, 95% CI 0.78-0.98), overweight/obese (OR 0.85, 95% CI 0.77-0.93) and non-Black (OR 0.90, 95% CI 0.82-0.98). There was increased risk amongst early-onset individuals with asthma in the highest compared to lowest quartile of lung function (1.44, 1.05-1.72).

Conclusion

Amongst male, nonsmoking, overweight/obese and non-Black participants, having early-onset asthma was associated with lower risk of a SARS-CoV-2 positive test. We found no evidence of a protective effect from asthma medication. Individuals with early-onset asthma of normal weight and with better lung function may have lifestyle differences placing them at higher risk. Further research is needed to elucidate the contribution of asthma pathophysiology and different health-related behaviour, across population groups, to the observed risks.

Asthma severity and impact on perinatal outcomes: an updated systematic review and meta-analysis

BACKGROUND

Large-scale studies exploring the associations of asthma severity, exacerbations and medication use with adverse perinatal outcomes have been published in recent years.

OBJECTIVES

To update evidence on the associations of asthma severity, exacerbations and medication use with the adverse perinatal outcomes of preterm delivery (PD), low birthweight (LBW) and small-for-gestational-age (SGA).

SEARCH STRATEGY

PubMed, Embase, Wanfang, and China National Knowledge Infrastructure (CNKI) from inception to 1 January 2021.

SELECTION CRITERIA

Cohort studies comparing the likelihood of adverse perinatal outcomes in groups of asthmatic women stratified by asthma severity, asthma exacerbations or medication use, or comparing the likelihood of adverse perinatal outcomes between non-asthmatic women and asthmatics of various levels of severity and exacerbation.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. Random-effects models were used to meta-analyse the results.

MAIN RESULTS

Twenty studies met the inclusion criteria. The odds of delivering SGA babies increased with maternal asthma severity. Pregnant women with an asthma exacerbation had higher odds of delivering LBW babies and SGA babies, compared with pregnant women with asthma but without an exacerbation (pooled adjusted odds ratio [OR] 1.15, 95% CI 1.02-1.29 for LBW; number of studies with adjusted OR 3; I²  = 0%) (pooled adjusted OR 1.13, 95% CI 1.04-1.23 for SGA; number of studies with adjusted OR 4; I²  = 0%) and compared to pregnant women without asthma. Oral corticosteroids use during pregnancy was associated with increased odds of LBW, but not PD.

CONCLUSIONS

The available data suggest that maternal asthma severity and exacerbations are associated with increased odds of LBW and SGA babies.

TWEETABLE ABSTRACT

A systematic review and meta-analysis found that maternal asthma severity and exacerbations are associated with increased odds of delivering low birthweight and small-for-gestational-age babies.

A patient decision aid for mild asthma: Navigating a new asthma treatment paradigm

INTRODUCTION

In mild asthma, as-needed budesonide-formoterol offers similar protection from severe exacerbations as daily inhaled corticosteroids (ICS), with lower ICS exposure but slightly increased symptoms. We sought to develop an electronic decision aid to guide discussions about the pros and cons of these first-line options, while identifying and integrating user preferences.

METHODS

Following International Patient Decision Aid Standards, we created a mild asthma decision aid prototype comparing convenience, clinical outcomes, cumulative ICS dose exposure, costs, and side-effects of each option. After face validation, the prototype was iteratively adapted through rapid-cycle development. Each cycle consisted of a patient focus group and a primary care physician interview. We made user preference-based improvements after each round, until reaching a pre-set stopping criterion (no new critical issues identified). We then performed a summative qualitative content analysis.

RESULTS

Over 5 cycles, we recruited 21 asthma patients (12/21 women, 10/21 ≥ 60 years old) and 5 physicians. Serial changes included simplification and reduction of text and reading level, inclusion of an ICS "myths" section and elaboration of patient-friendly infographics for numerical comparisons. User preferences fell within Content, Format, and tool use Process themes. In response to decision-making preferences, we created a complementary one-page conversation aid for patient-provider use at the point-of-care.

CONCLUSIONS

We present preference-based electronic patient decision and conversation aids for treatment of mild asthma. Our user preference analyses offer useful insights for development of such tools in other chronic diseases. These tools now require integration into point-of-care workflows for measurement of real-world uptake and impact.

Trends in oral corticosteroids use in severe asthma: a 14-year population-based study

BACKGROUND

Oral corticosteroids are important components of pharmacotherapy in severe asthma. Our objective was to describe the extent, trends, and factors associated with exposure to oral corticosteroids (OCS) in a severe asthma cohort.

METHODS

We used administrative health databases of British Columbia, Canada (2000-2014) and validated algorithms to retrospectively create a cohort of severe asthma patients. Exposure to OCS within each year of follow-up was measured in two ways: maintenance use as receiving on average ≥ 2.5 mg/day (prednisone-equivalent) OCS, and episodic use as the number of distinct episodes of OCS exposure for up to 14 days. Trends and factors associated with exposure on three time axes (calendar year, age, and time since diagnosis) were evaluated using Poisson regression.

RESULTS

21,144 patients (55.4% female; mean entry age 28.7) contributed 40,803 follow-up years, in 8.2% of which OCS was used as maintenance therapy. Maintenance OCS use declined by 3.8%/calendar year (p < 0.001). The average number of episodes of OCS use was 0.89/year, which increased by 1.1%/calendar year (p < 0.001). Trends remained significant for both exposure types in adjusted analyses. Both maintenance and episodic use increased by age and time since diagnosis.

CONCLUSIONS

This population-based study documented a secular downward trend in maintenance OCS use in a period before widespread use of biologics. This might have been responsible for a higher rate of exacerbations that required episodic OCS therapy. Such trends in OCS use might be due to changes in the epidemiology of severe asthma, or changes in patient and provider preferences over time.

Impact of discretization of the timeline for longitudinal causal inference methods

In longitudinal settings, causal inference methods usually rely on a discretization of the patient timeline that may not reflect the underlying data generation process. This article investigates the estimation of causal parameters under discretized data. It presents the implicit assumptions practitioners make but do not acknowledge when discretizing data to assess longitudinal causal parameters. We illustrate that differences in point estimates under different discretizations are due to the data coarsening resulting in both a modified definition of the parameter of interest and loss of information about time-dependent confounders. We further investigate several tools to advise analysts in selecting a timeline discretization for use with pooled longitudinal targeted maximum likelihood estimation for the estimation of the parameters of a marginal structural model. We use a simulation study to empirically evaluate bias at different discretizations and assess the use of the cross-validated variance as a measure of data support to select a discretization under a chosen data coarsening mechanism. We then apply our approach to a study on the relative effect of alternative asthma treatments during pregnancy on pregnancy duration. The results of the simulation study illustrate how coarsening changes the target parameter of interest as well as how it may create bias due to a lack of appropriate control for time-dependent confounders. We also observe evidence that the cross-validated variance acts well as a measure of support in the data, by being minimized at finer discretizations as the sample size increases.

Severe asthma-A population study perspective

BACKGROUND

Severe asthma is a considerable challenge for patients, health-care professionals and society. Few studies have estimated the prevalence of severe asthma according to modern definitions of which none based on a population study.

OBJECTIVE

To describe characteristics and estimate the prevalence of severe asthma in a large adult population-based asthma cohort followed for 10-28 years.

METHODS

N = 1006 subjects with asthma participated in a follow-up during 2012-14, when 830 (mean age 59 years, 56% women) still had current asthma. Severe asthma was defined according to three internationally well-known criteria: the ATS workshop definition from 2000 used in the US Severe Asthma Research Programme (SARP), the 2014 ATS/ERS Task force definition and the GINA 2017. All subjects with severe asthma according to any of these criteria were undergoing respiratory specialist care and were also contacted by telephone to verify treatment adherence.

RESULTS

The prevalence of severe asthma according to the three definitions was 3.6% (US SARP), 4.8% (ERS/ATS Taskforce), and 6.1% (GINA) among subjects with current asthma. Although all were using high ICS doses and other maintenance treatment, >90% did not have controlled asthma according to the asthma control test. Severe asthma was related to age >50 years, nasal polyposis, impaired lung function, sensitization to aspergillus, and tended to be more common in women. Further, neutrophils in blood significantly discriminated severe asthma from other asthma.

CONCLUSIONS AND CLINICAL RELEVANCE

Severe asthma differed significantly from other asthma in terms of demographic, clinical and inflammatory characteristics, results suggesting possibilities for improved treatment regimens of severe asthma. The prevalence of severe asthma in this asthma cohort was 4%-6%, corresponding to approximately 0.5% of the general population.

Economic burden of multimorbidity in patients with severe asthma: a 20-year population-based study

BACKGROUND

The economic impact of multimorbidity in severe or difficult-to-treat asthma has not been comprehensively investigated.

AIMS

To estimate the incremental healthcare costs of coexisting chronic conditions (comorbidities) in patients with severe asthma, compared with non-severe asthma and no asthma.

METHODS

Using health administrative data in British Columbia, Canada (1996-2016), we identified, based on the intensity of drug use and occurrence of exacerbations, individuals who experienced severe asthma in an incident year. We also constructed matched cohorts of individuals without an asthma diagnosis and those who had mild/dormant or moderate asthma (non-severe asthma) throughout their follow-up. Health service use records during follow-up were categorised into 16 major disease categories based on the International Classification of Diseases. Incremental costs (in 2016 Canadian Dollars, CAD$1=US$0.75=₤0.56=€0.68) were estimated as the adjusted difference in healthcare costs between individuals with severe asthma compared with those with non-severe asthma and non-asthma.

RESULTS

Relative to no asthma, incremental costs of severe asthma were $2779 per person-year (95% CI 2514 to 3045), with 54% ($1508) being attributed to comorbidities. Relative to non-severe asthma, severe asthma was associated with incremental costs of $1922 per person-year (95% CI 1670 to 2174), with 52% ($1003) being attributed to comorbidities. In both cases, the most costly comorbidity was respiratory conditions other than asthma ($468 (17%) and $451 (23%), respectively).

CONCLUSIONS

Comorbidities accounted for more than half of the incremental medical costs in patients with severe asthma. This highlights the importance of considering the burden of multimorbidity in evidence-informed decision making for patients with severe asthma.

Measuring multimorbidity in older adults: comparing different data sources

Background

Multimorbidity is a global health issue, particularly for older adults in the primary care setting. An adequate portrayal of its epidemiology is essential to properly identify and understand the health care needs of this population. This study aimed to compare the differences in the prevalence of selected chronic conditions and multimorbidity, including its associated characteristics, using health survey/self-reported (SR) information only, administrative (Adm) data only and the combined (either) sources.

Methods

This was a secondary analysis of survey data from the first cycle of the Longitudinal Survey on Senior’s Health and Health Services Use linked to health-Adm data. The analytical sample consisted of 1625 community-dwelling older adults (≥65 years) recruited in the waiting rooms of primary health clinics in a selected administrative region of the province of Quebec. Seventeen chronic conditions were assessed according to two different data sources. We examined the differences in the observed prevalence of chronic conditions and multimorbidity and the agreement between data sources.

Results

The prevalence of each of the 17 chronic conditions ranged from 1.2 to 68.7% depending on the data source. The agreement between different data sources was highly variable, with kappa coefficients (κ) ranging from 0.05 to 0.73. Multimorbidity was very high in this population, with an estimated prevalence of up to 95.9%. In addition, we found that the association between sociodemographic and behavioural factors and the presence of multimorbidity varied according to the different data sources and thresholds.

Conclusions

This is the first study to simultaneously investigate chronic conditions and multimorbidity prevalence among primary care older adults using combined SR and health-Adm data. Our results call attention to (1) the possibility of underestimating cases when using a single data source and (2) the potential benefits of integrating information from different data sources to increase case identification. This is an important aspect of characterizing the health care needs of this fast-growing population.

Electronic supplementary material

The online version of this article (10.1186/s12877-019-1173-4) contains supplementary material, which is available to authorized users.

Extent, trends, and determinants of controller/reliever balance in mild asthma: a 14-year population-based study

BACKGROUND

The majority of patients with asthma have the mild form of the disease. Whether mild asthma patients receive appropriate asthma medications has not received much attention in the literature. We examined the trends in indicators of controller/reliever balance.

METHODS

Using administrative health databases of British Columbia, Canada (2000 to 2013), we created a population-based cohort of adolescents/adults with mild asthma using validated case definition algorithms. Each patient-year of follow-up was assessed based on two markers of inappropriate medication prescription: whether the ratio of controller medications (inhaled corticosteroids [ICS] and leukotriene receptor antagonists [LTRA]) to total asthma-related prescriptions was low (cut-off 0.5 according to previous validation studies), and whether short-acting beta agonists (SABA) were prescribed inappropriately according to previously published criteria that considers SABA in relation to ICS prescriptions. Generalized linear models were used to evaluate trends and to examine the association between patient-, disease-, and healthcare-related factors and medication use.

RESULTS

The final cohort consisted of 195,941 mild asthma patients (59.5% female; mean age at entry 29.6 years) contributing 1.83 million patient-years. In 48.8% of patient-years, controller medications were suboptimally prescribed, while in 7.2%, SABAs were inappropriately prescribed. There was a modest year-over-year decline in inappropriate SABA prescription (relative change - 1.3%/year, P < 0.001) and controller-to-total-medications (relative change - 0.5%/year, P < 0.001). Among the studied factors, the indices of type and quality of healthcare (namely respirologist consultation and receiving pulmonary function test) had the strongest associations with improvement in controller/reliever balance.

CONCLUSIONS

Large number of mild asthma patients continue to be exposed to suboptimal combinations of asthma medications, and it appears there are modifiable factors associated with such phenomenon.

Respiratory tract infection-induced asthma exacerbations in adults with asthma: assessing predictors and outcomes

Objective: To evaluate clinical and economic burden associated with respiratory tract infection (RTI)-induced asthma exacerbations and to identify risk factors associated with these exacerbations. Factors associated with these exacerbations are understudied and little information is available about consequent expenditures. Methods: In this retrospective case-control study, medical records and pharmacy data in King Abdullah University Hospital in Northern Jordan were reviewed for adults with asthma aged 40 years and older, over the period 2013-2016. Cases of RTI-induced asthma exacerbations were identified, and controls were selected randomly from asthmatic adults who did not experience any RTI-induced asthma exacerbation during the same period. Independent-samples t-tests and chi-square tests were conducted to compare patient characteristics of cases and controls. Predictors of RTI-induced asthma exacerbations and the resultant complications were evaluated using multivariable logistic regression. Multivariable regression on log-transformed charges was used to predict expenditures of these exacerbations. Results: A total of 137 cases and 548 controls were identified. Using inhaled corticosteroid + long-acting beta-agonists (ICS + LABA) was significantly associated with lower odds of RTI-induced asthma exacerbations (OR = 0.4; 95% CI, 0.21-0.77; p = 0.006), and lower odds of resultant serious complications (OR = 0.23; 95% CI, 0.07-0.69; p = 0.009), compared to being untreated with any asthma maintenance treatment. Asthma severity and co-morbidities were associated with increased susceptibility to these exacerbations. The average charges of RTI-induced asthma admissions and outpatient exacerbations were 1042.9 JD ($1471.0) and 81.1 JD ($114.4), respectively. Conclusions: ICS + LABA, asthma severity and co-morbidities appeared to affect the clinical and economic burden associated with RTI-induced asthma exacerbations. Efforts to prevent these exacerbations in patients with risk factors are warranted.

INITIAL - An observational study of disease severity in newly diagnosed asthma patients and initial response following 12 weeks' treatment

In China, there are an estimated 30 million people with asthma, a condition that remains poorly controlled in many patients. The INITIAL study (NCT02143739) was a 12-week, multicentre, prospective, observational study comprising 45 centres across Northern and Southern China that aimed to assess asthma severity among newly diagnosed patients as well as their prescribed medications and response to treatment. The primary objective was to evaluate asthma severity using Global Initiative for Asthma (GINA) 2006 research criteria. Secondary objectives included the distribution of asthma medication by GINA severity category and evaluation of GINA 2012-defined control levels. Medications were prescribed as per usual clinical practice. At baseline, among 4491 patients, 3.9%, 12.0%, 22.6% and 61.6% had intermittent, mild persistent, moderate persistent and severe persistent asthma, respectively. Inhaled corticosteroid/long-acting β₂ agonist was the most common initial therapy in 90.2% of patients. GINA 2012-defined controlled asthma levels increased in all groups, rising from 6.1% at baseline to 43.0%, 53.8% and 67.8% at Weeks 4, 8 and 12, respectively. Most patients presented with severe persistent asthma. Newly diagnosed patients with asthma could benefit from at least 3 months of regular treatment followed by long-term pharmacological management.

The Burden of Severe Asthma in France: A Case-Control Study Using a Medical Claims Database

BACKGROUND

Severe asthma (SA) is defined by treatment intensity. The availability of national databases allows accurate estimation of the prevalence, long-term outcomes, and costs of SA.

OBJECTIVE

To provide accurate information on SA, focusing on comorbidities, mortality, health care resource consumption, and associated costs.

METHODS

A cohort of patients with SA identified in 2012 was extracted from a French representative claims database and followed for 3 years. Their characteristics, comorbidities, mortality, and direct costs were compared with a matched control group without asthma.

RESULTS

A total of 690 patients with SA were matched to 2070 patients without asthma (mean age, 61 years; 65.7% women). The prevalence of SA was estimated to be 0.18% to 0.51% of the French adult population. Comorbidities were more frequent in patients with SA (73.9% suffered from cardiovascular disease vs 54.3% in controls; P < .001). A total of 58.7% of patients with SA used oral corticosteroids (OCS) in 2012 with a mean intake of 3.3 boxes/year/patient and 9% received ≥6 dispensings of OCS. A total of 6.7% were treated by omalizumab. Patients with SA were more frequently hospitalized (33.2% vs 19.7%; P < .001), more frequently consulted a general practitioner (97.8% vs 83.9%; P < .001) (9.8 ± 6.8 vs 6.2 ± 5.3 consultations/year; P < .001), and 31% have consulted a private respiratory physician. Compared with controls, 3-year cumulative mortality was higher in SA (7.1% vs 4.5%; P = .007). Direct medical cost was $9227 versus $3950 (P < .001) mostly driven by medication costs.

CONCLUSIONS

The prevalence of SA in the French adult population is at least 18 of 10,000. Burden of disease is high with respect to comorbidities, mortality, and asthma-related health care resource use.

Asthma severity and fertility outcome in women with polycystic ovary syndrome: a registry-based study

Recent research suggests that women with polycystic ovary syndrome (PCOS) have a higher risk of asthma. However, the severity of asthma, use of antiasthma medication and effect on fertility have yet to be investigated.

In a case–control cross-sectional registry study using the Danish National Patient Register and other Danish registries, asthma prevalence, asthma severity, antiasthma medication use and fertility outcome were investigated among two groups of women with PCOS (n=1358 and n=17 123) and a healthy control group (n=5340).

Both asthma prevalence (OR 1.45, 95% CI 1.24–1.70) and mean daily inhaled corticosteroid dose were higher among women with PCOS compared with healthy controls, whereas asthma severity was the same in women with and without PCOS. Women with PCOS and asthma had more in vitro fertilisation treatments than women in the control group with asthma, but the numbers of children per woman and spontaneous abortions were the same.

Women with PCOS have a higher prevalence of asthma and a higher use of inhaled corticosteroids, whereas asthma severity is the same in women with and without PCOS. Asthma is associated with more in vitro fertilisation treatments in women with PCOS.

Asthma and PCOS are associated; asthma is associated with more in vitro fertilisation treatments in women with PCOShttp://ow.ly/BTmh30lTP20

Long-Term Trajectories of Mild Asthma in Adulthood and Risk Factors of Progression

BACKGROUND

Most patients with asthma have mild disease. However, the clinical course of mild asthma and risk factors for progression are not well studied.

OBJECTIVE

To examine the long-term trajectories of mild asthma and the effects of early-stage risk factors on the subsequent disease course.

METHODS

From the administrative health data of British Columbia, Canada, we identified patients aged 14 to 45 years with newly diagnosed mild asthma between January 1997 and December 2012. For each follow-up year, we categorized a patient's asthma severity into mild/dormant, moderate, or severe on the basis of the intensity of asthma medications and occurrence of exacerbations. Ordinal logistic regression was used to estimate the probability of severity or all-cause death in the next year as a function of a patient's severity history in the past 3 years and selected baseline risk factors.

RESULTS

The study included 70,829 patients with incident mild asthma (62% women; mean age, 31 years). Over 10 years, 8% of these patients transitioned to moderate or severe asthma. Inappropriate use of rescue medications and older age were the most influential determinants for progression from mild asthma (odds ratios, 1.79; 95% CI, 1.68-1.90; P < .001; 1.24 per 10-year increase in age; 95% CI, 1.22-1.27; P < .001), whereas the presence of allergic rhinitis had no significant effects (odds ratio, 0.95; 95% CI, 0.91-1.00; P = .063).

CONCLUSIONS

Mild asthma remains largely stable over time. However, potentially modifiable factors such as inappropriate use of rescue medications are associated with a worsened prognosis.

Understanding and diagnosing the potential for bias when using machine learning methods with doubly robust causal estimators

Data-adaptive methods have been proposed to estimate nuisance parameters when using doubly robust semiparametric methods for estimating marginal causal effects. However, in the presence of near practical positivity violations, these methods can produce a separation of the two exposure groups in terms of propensity score densities which can lead to biased estimates of the treatment effect. To motivate the problem, we evaluated the Targeted Minimum Loss-based Estimation procedure using a simulation scenario to estimate the average treatment effect. We highlight the divergence in estimates obtained when using parametric and data-adaptive methods to estimate the propensity score. We then adapted an existing diagnostic tool based on a bootstrap resampling of the subjects and simulation of the outcome data in order to show that the estimation using data-adaptive methods for the propensity score in this study may lead to large bias and poor coverage. The adapted bootstrap procedure is able to identify this instability and can be used as a diagnostic tool.

The obese-asthma phenotype in children: An exacerbating situation?

BACKGROUND

Current evidence regarding the relationship between childhood obesity, decreased response to inhaled corticosteroids (ICSs), and poor asthma control is conflicting.

OBJECTIVES

We assessed whether obesity (1) is associated with time to first exacerbation among children with asthma initiating step 3 maintenance therapies and (2) modifies the effectiveness of step 3 therapies.

METHODS

A retrospective cohort study was conducted from clinical data linked to health and drug administrative databases. The cohort consisted of children aged 2 to 18 years with specialist-confirmed asthma who initiated medium/high-dose ICS monotherapy or low/medium-dose ICS with leukotriene receptor antagonist/long-acting β-agonist (combination therapy) at the Montreal Children's Hospital Asthma Center from 2000 to 2007. Children were classified as exposed to step 3 therapies when they were dispensed a corresponding drug claim during follow-up, whereas those without claims were classified as nonadherers. Marginal structural Cox models were used to estimate the effect of obesity (body mass index > 97th percentile) and treatment on time to exacerbation, which was defined as any emergency department visit, hospitalization, or use of oral corticosteroids for asthma.

RESULTS

Of the 4621 cohort patients, 231 initiated ICS monotherapy, and 97 initiated combination therapy. The hazard ratio (HR) for obesity was 1.67 (95% CI, 1.41-1.98). Compared with nonobese nonadherers, the HR for obese nonadherers was 1.54 (95% CI, 0.97-2.45); the HR for ICS monotherapy in obese and nonobese children was 0.85 (95% CI, 0.47-1.52) and 0.58 (95% CI, 0.37-0.91), respectively; and the HR for combination therapy in obese and nonobese children was 0.50 (95% CI, 0.13-1.89) and 0.46 (95% CI, 0.23-0.92), respectively.

CONCLUSION

Obesity might be a determinant of shorter exacerbation-free time in children with asthma; however, we could not rule out a differential response to step 3 therapies by obesity status, potentially because of a lack of precision.

C-reactive protein for late-onset sepsis diagnosis in very low birth weight infants

BACKGROUND

Late-onset sepsis in very low birth weight (VLBW) infants is a diagnostic challenge. We aimed to evaluate the diagnostic utility of the C-Reactive protein (CRP) and the complete blood count (CBC) for late-onset sepsis in VLBW infants.

METHODS

In a 5-year retrospective cohort of 416 VLBW infants born at less than 1500 g, there were 590 separate late-onset sepsis evaluations. CRP and CBC were drawn at time of initial blood culture (T0), at 16-24 h (T24) and 40-48 h (T48) after. The positive cut-off values for abnormal values were the following: CRP ≥10 mg/L and CBC with at least one anomaly, including white blood cell count < 5000/mm³, immature neutrophil/total neutrophil ratio > 0.10, or platelet count < 100,000/uL. Sensitivity and specificity for predicting late-onset sepsis were calculated for each laboratory test and their combinations. Receiver operating characteristics curves were obtained for each test and for the absolute change from T0 to T24 in the laboratory value of CRP, white blood cell count and immature neutrophil/total neutrophil.

RESULTS

At T0, combining the CBC and the CRP had the highest sensitivity of 66% (95% confidence interval [CI], 58-73) compared to both individual tests for predicting late onset sepsis. At T24, CRP's sensitivity was 84% (95% CI, 78-89) and was statistically higher than the CBC's 59% (95% CI, 51-67). The combination of CBC at T0 and CRP at T24 offered the greatest sensitivity of 88% (95% CI, 82-92) and negative predictive value 93% (95% CI, 89-96), with fewer samples, compared to any other combination of tests. The area under the curve for the change in the white blood cell count from T0 to T24 was 0.82.

CONCLUSION

At initial sepsis evaluation (T0), both CBC and CRP should be performed to increase sensitivity. A highly negative predictive value is reachable with only two tests: a CBC at T0 and a CRP a T24.

Using medication utilization information to develop an asthma severity classification model

Background

Claims data are currently widely used as source data in asthma studies. However, the insufficient information in claims data related to level of asthma severity may negatively impact study findings. The present study develops and validates an asthma severity classification model that uses medication utilization in Taiwan National Health Insurance claims data.

Methods

The National Health Insurance Research Database was used for the years 2006–2012 and included a total of 7221 patients newly diagnosed with asthma in 2007 for model development and in 2008 for model validation. The medication utilization of patients during the first year after the index date was used to classify level of severity, and the acute exacerbation of asthma during the second through fourth years after the index date was used as the outcome variable. Three models were developed, with subjects classified into four, three, and two groups, respectively. The area under the receiver operating characteristic curve (AUC) and the Kaplan-Meier survival curve were used to compare the performances of the classification models.

Results

In development data, the distribution of subjects and acute exacerbation rate among the stage 1 to stage 4 were: 62.71%, 5.54%, 22.79%, and 8.96%, and 8.17%, 9.55%, 11.97%, and 14.91%, respectively. The results also showed the higher severity groups to be more prone to being prescribed oral corticosteroids for asthma control, while lower severity groups were more likely to be prescribed short-acting medication and inhaled corticosteroid treatment. Furthermore, the results of survival analysis showed two-group classification was recommended and yield moderate performance (AUC = 0.671). In validation data, the distribution of subjects, acute exacerbation rates, and medication uses among stages were similar to those in development data, and the results of survival analysis were also the same.

Conclusions

Understanding asthma severity is critical to conducting effective, scholarly research on asthma, which currently uses claims data as a primary data source. The model developed in the present study not only overcomes a gap in the current literature but also provides an opportunity to improve the validity and quality of claims-data-based asthma studies.

Estimating asthma control questionnaire (ACQ) scores from claims data

BACKGROUND

Asthma control is the main focus of treatment guidelines. Valid instruments such as the Asthma Control Questionnaire (ACQ) require prospective survey. These surveys may be challenging for large population health applications.

OBJECTIVE

To develop an algorithm for estimating ACQ-5 scores from commonly available claims data.

METHODS

Data was derived from four prospective surveys including the ACQ-5 combined with retrospective claims of Kaiser Permanente of Colorado (KPCO) patients. The statistical approach consisted of derivation and validation of a prediction algorithm including medical and pharmacy claims data using stepwise regression elimination. Validation was conducted by estimating mean squared error (MSE) and mean absolute error (MAE) in one hundred split-sample iterations. Ordinary least squares (OLS), Tobit and Median regression were used.

RESULTS

There were 2,657 individuals with valid ACQ-5 scores, claims and eligibility at baseline. The following had statistically significant associations with ACQ-5 scores: gender, use of oral corticosteroids and short-acting beta agonists, the number of asthma drug classes, and emergency and outpatient visits. Average MSE and MAE were similar for the estimation and validation samples.

CONCLUSION

This research provides preliminary results of the feasibility of predicting ACQ-5 scores using commonly available medical and pharmacy claims data. The resulting algorithm may facilitate public health and population level analyses of asthma control. Future studies in different populations will be important to validate the algorithm.

Healthcare resource use and costs of severe, uncontrolled eosinophilic asthma in the UK general population

Background

Little is known about the prevalence of severe, uncontrolled eosinophilic asthma (SUEA) and associated costs.

Aims

We sought to determine the prevalence of SUEA and compare asthma-related healthcare resource use (HCRU) and associated costs with overall means for a general asthma population.

Methods

This cohort study evaluated anonymised medical record data (December 1989 through June 2015) from the Clinical Practice Research Datalink and the Optimum Patient Care Research Database to study UK patients with active asthma (diagnostic code and one or more drug prescriptions in the baseline year), aged 5 years and older, without concomitant COPD, and with recorded eosinophil count. SUEA was defined as two or more asthma attacks during 1 baseline year preceding a high blood eosinophil count (≥0.3×10⁹/L) for patients prescribed long-acting β₂-agonist (LABA) and high-dosage inhaled corticosteroids (ICS) during baseline plus 1 follow-up year. We compared asthma-related HCRU and associated direct costs (2015 pounds sterling, £) during the follow-up year for SUEA versus the general asthma population.

Results

Of 363 558 patients with active asthma and recorded eosinophil count, 64% were women, mean (SD) age was 49 (21) years; 43% had high eosinophil counts, 7% had two or more attacks in the baseline year and 10% were prescribed high-dosage ICS/LABA for 2 study years. Overall, 2940 (0.81%; 95% CI 0.78% to 0.84%) patients had SUEA. Total mean per-patient HCRU and associated costs were four times greater for SUEA versus all patients (HCRU and cost ratios 3.9; 95% CI 3.7 to 4.1).

Conclusions

Less than 1% of patients in a general asthma population had SUEA. These patients accounted for substantially greater asthma-related HCRU and costs than average patients with asthma.

Long-Acting β2-Agonists and Risk of Hypertensive Disorders of Pregnancy: A Cohort Study

BACKGROUND

Maternal asthma has been found to be associated with an increased risk of hypertensive disorders of pregnancy (HDP), that is, gestational hypertension, preeclampsia, and eclampsia. There is limited data, however, regarding the relationship between the use of long-acting beta-agonists (LABAs) during pregnancy and these outcomes.

OBJECTIVE

To investigate whether exposure to a LABA in addition to an inhaled corticosteroid increases the risk of HDP or preeclampsia/eclampsia, as compared with nonexposure to LABAs, in pregnant women with asthma.

METHODS

A cohort of 8,936 pregnancies in women with asthma who delivered between 1998 and 2010 was reconstructed using Quebec (Canada) health administrative databases. Cox proportional hazard regression models, adjusted for potential confounders, were used for statistical analyses. The primary exposure was LABA use (yes/no) measured on the first day of the 20th week of pregnancy. HDP were identified on the basis of recorded diagnoses and on prescriptions of antihypertensive drugs filled on or after the first day of week 20 of gestation.

RESULTS

There were 567 (6.3%) cases of HDP and 256 (2.9%) cases of preeclampsia/eclampsia in the cohort, and the rates of both disorders were similar in women exposed or not exposed to LABAs. LABA use was not associated with increased risks of HDP (adjusted hazard ratio, 0.96; 95% CI, 0.69-1.33) or preeclampsia/eclampsia (adjusted hazard ratio, 0.89; 95% CI, 0.53-1.50).

CONCLUSIONS

The results of this study provide evidence suggesting the safety of LABAs for the treatment of asthma in pregnancy, in terms of the risks of HDP and preeclampsia/eclampsia.

Maternal asthma severity and control during pregnancy and risk of offspring asthma

BACKGROUND

Severe and uncontrolled asthma during pregnancy has been linked to several unfavorable perinatal outcomes. However, current knowledge on the association between the severity and control of maternal asthma and offspring asthma is sparse.

OBJECTIVE

We sought to investigate the extent to which offspring asthma is influenced by maternal asthma severity and control during pregnancy.

METHODS

We performed a prospective population-based cohort study. Using linkage of Danish national registers, we constructed a cohort of 675,379 singletons, of which 15,014 children were born to asthmatic mothers. Among them, 7,188 children were born to mothers with active asthma during pregnancy. We categorized mothers with active asthma into 4 groups based on dispensed antiasthma prescriptions and on use of medical services: mild controlled, mild uncontrolled, moderate-to-severe controlled, and moderate-to-severe uncontrolled asthma. The outcomes were offspring early-onset transient, early-onset persistent, and late-onset asthma. We estimated prevalence ratios (PRs) of each phenotype of asthma using a log-binomial model with 95% CIs.

RESULTS

Higher prevalence of early-onset persistent asthma was observed among children of asthmatic mothers with mild uncontrolled (PR, 1.19; 95% CI, 1.05-1.35), moderate-to-severe controlled (PR, 1.33; 95% CI, 1.09-1.63), and moderate-to-severe uncontrolled asthma (PR, 1.37; 95% CI, 1.17-1.61) compared with those of mothers with mild controlled asthma. A borderline increased prevalence of early-onset transient asthma was observed among children of mothers with uncontrolled asthma.

CONCLUSION

Maternal uncontrolled asthma increases the risk of early-onset persistent and transient asthma. If replicated, this could suggest that maintaining asthma control in pregnancy is an area for possible prevention of specific phenotypes of offspring asthma.

Assessing asthma severity based on claims data: a systematic review

INTRODUCTION

Asthma is one of the most common chronic diseases in Germany. Substantial economic evaluation of asthma cost requires knowledge of asthma severity, which is in general not part of claims data. Algorithms need to be defined to use this data source.

AIMS AND OBJECTIVES

The aim of this study was to systematically review the international literature to identify algorithms for the stratification of asthma patients according to disease severity based on available information in claims data.

METHODS

A systematic literature review was conducted in September 2015 using the DIMDI SmartSearch, a meta search engine including several databases with a national and international scope, e.g. BIOSIS, MEDLINE, and EMBASE. Claims data based studies that categorize asthma patients according to their disease severity were identified.

RESULTS

The systematic research yielded 54 publications assessing asthma severity based on claims data. Thirty-nine studies used a standardized algorithm such as HEDIS, Leidy, the GINA based approach or CACQ. Sixteen publications applied a variety of different criteria for the severity categorisation such as asthma diagnoses, asthma-related drug prescriptions, emergency department visits, and hospitalisations.

CONCLUSION

There is no best practice method for the categorisation of asthma severity with claims data. Rather, a combination of algorithms seems to be a pragmatic approach. A transfer to the German context is not entirely possible without considering particular conditions associated with German claims data.

Asthma and Chronic Obstructive Pulmonary Disease Overlap Syndrome: Doubled Costs Compared with Patients with Asthma Alone

BACKGROUND

Patients with asthma and chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) have more rapid disease progression and more exacerbations than do those with either condition alone. Little research has been performed, however, in these patients.

OBJECTIVE

The objective was to summarize the health care utilization, costs, and comorbidities of patients with uncontrolled asthma and patients with ACOS.

METHODS

This retrospective analysis used medical and pharmacy claims from large commercial health plans. The study included patients 6 years or older with a diagnosis of asthma and one or more asthma exacerbation (index event). Patients were classified as having asthma alone or ACOS, and the two groups were matched for age, sex, region, index year, index month, and health plan type. Outcomes included rates of comorbid disease, health care utilization, and costs during the 12 months before and after the index exacerbation.

RESULTS

Among the matched patients with asthma (6,505 ACOS; 26,060 without COPD), mean annual all-cause health care costs were twice as high as for patients with ACOS ($22,393 vs. $11,716; P < 0.0001). Asthma-related costs, representing 29% of total costs, were nearly twice as high among patients with ACOS ($6,319 vs. 3,356; P < 0.0001). Cost differences were driven by large differences in the proportions of patients with an inpatient hospitalization (34.0% vs. 14.6%; P < 0.0001) or emergency department visit (29.6% vs. 19.9%; P < 0.0001). Nearly all prespecified comorbid conditions were more prevalent in the ACOS group.

CONCLUSIONS

Patients with asthma and COPD had nearly double the health care costs as did patients with asthma without COPD. The overall disease profile of patients with asthma should be considered when managing patients, rather than treating asthma as a solitary condition.

Diagnostic accuracy of algorithms to identify hepatitis C status, AIDS status, alcohol consumption and illicit drug use among patients living with HIV in an administrative healthcare database

PURPOSE

This study aims to develop and evaluate diagnostic algorithms for AIDS, hepatitis C status, alcohol abuse and illicit drug use in the administrative healthcare database of the Province of Quebec, Canada (Régie de l'assurance-maladie du Québec (RAMQ)).

METHODS

We selected HIV-positive patients contributing to both the RAMQ database and a local clinical database, which was used as gold standard. We developed algorithms to identify the diagnoses of interest in RAMQ using data from hospital discharge summaries and medical and pharmaceutical claims databases. We estimated and compared sensitivity, specificity, positive predictive and negative predictive values and area under receiver operating curve for each algorithm.

RESULTS

Four hundred twenty patients contributed to both databases. Prevalence of conditions of interest in the clinical database was as follows: AIDS 233 (55%), hepatitis C infection 105 (25%), alcohol abuse 106 (25%), illicit drug use 144 (34%) and intravenous drug use 107 (25%). Sensitivity to detect AIDS, hepatitis C, alcohol abuse, illicit drug use and intravenous drug use was 46% [95%CI: 39-53], 26% [18-35], 50% [37-57], 64% [55-72] and 70% [61-79], respectively. Specificity to detect these conditions was 91% [86-95], 97% [94-98], 92% [88-95], 95% [92-97] and 90% [87-93], respectively. Positive predictive values were 87% [80-92], 71% [54-85], 68% [56-78], 87% [79-93] and 72% [62-80], respectively. Area under receiver operating curve varied from 0.62 [0.57-0.65] for hepatitis C to 0.80 [0.76-0.85] for intravenous drug use.

CONCLUSIONS

Sensitivity was low to detect AIDS, alcohol abuse, illicit drug use and especially hepatitis C in RAMQ. Researchers must be aware of the potential for residual confounding and must consider additional methods to control for confounding.

Oral corticosteroids and the risk of serious infections in patients with elderly-onset inflammatory bowel diseases

OBJECTIVES

Systemic corticosteroids are among the most common anti-inflammatory treatments in elderly-onset inflammatory bowel disease (IBD) patients. Steroid use and older age each independently predisposes to infections, and infections increase mortality in hospitalized older IBD patients. Therefore, our objective was to examine the risk of serious infections in elderly-onset IBD patients treated with oral corticosteroids, and explore how the timing of exposure affects the risk estimates.

METHODS

Using the health-care databases of the province of Quebec, Canada, we conducted a population-based cohort study with a nested case-control analysis. Incident IBD patients aged ≥66 years were identified. Conditional logistic regression was performed to estimate crude and adjusted rate ratios (aRRs) with 95% confidence intervals (CIs).

RESULTS

We identified 3,522 elderly-onset patients, of which 564 cases with serious infections were identified during a mean 4.4 years of follow-up (incidence rate 3.7 per 100 per year) and matched to 2,646 controls. The rate of serious infections was significantly higher in those exposed to oral corticosteroids any time during the previous 6-month period compared with those nonexposed (aRR 2.3; 95% CI 1.8-2.9). Those currently exposed (within 45 days) had a higher risk (aRR 2.8; 95% CI 2.1-3.7). The residual effect of oral corticosteroids remained marginally statistically significant up to the 90-day period before the index date (aRR 1.7; 95% CI 1.0-2.7).

CONCLUSIONS

We found an excess relative risk for serious infections in elderly-onset IBD patients on oral corticosteroid therapy. Those with current exposure demonstrated a higher vulnerability to infections.

Asthma during pregnancy in a population-based study--pregnancy complications and adverse perinatal outcomes

Background

Asthma is one of the most common chronic diseases, and prevalence, severity and medication may have an effect on pregnancy. We examined maternal asthma, asthma severity and control in relation to pregnancy complications, labour characteristics and perinatal outcomes.

Methods

We retrieved data on all singleton births from July 1, 2006 to December 31, 2009, and prescribed drugs and physician-diagnosed asthma on the same women from multiple Swedish registers. The associations were estimated with logistic regression.

Results

In total, 266 045 women gave birth to 284 214 singletons during the study period. Maternal asthma was noted in 26 586 (9.4%) pregnancies. There was an association between maternal asthma and increased risks of pregnancy complications including preeclampsia or eclampsia (adjusted OR 1.15; 95% CI 1.06–1.24) and premature contractions (adj OR 1.52; 95% CI 1.29–1.80). There was also a significant association between maternal asthma and emergency caesarean section (adj OR 1.29; 95% CI 1.23–1.34), low birth weight, and small for gestational age (adj OR 1.23; 95% CI 1.13–1.33). The risk of adverse outcomes such as low birth weight increased with increasing asthma severity. For women with uncontrolled compared to those with controlled asthma the results for adverse outcomes were inconsistent displaying both increased and decreased OR for some outcomes.

Conclusion

Maternal asthma is associated with a number of serious pregnancy complications and adverse perinatal outcomes. Some complications are even more likely with increased asthma severity. With greater awareness and proper management, outcomes would most likely improve.

The prevalence of severe asthma and low asthma control among Danish adults

BACKGROUND

The prevalence of severe asthma is unknown. However, international expert statements estimate that severe asthma represents 5% to 10 % of the entire asthma population.

OBJECTIVE

Based on register data from a nationwide population, we wanted to investigate the prevalence of severe asthma, the extent of asthma control, and contact with specialist care.

METHODS

A descriptive cross-sectional register study was performed. By using a nationwide prescription database, we identified current patients with asthma (age, 18-44 years) in 2010. Severity was classified as severe versus mild-moderate asthma according to the level of antiasthma treatment. We investigated prescription drug use, hospitalizations, emergency department visits, and outpatient clinic visits according to severity.

RESULTS

Among a nationwide population, we identified 61,583 current patients with asthma. Based on the level of antiasthma treatment, 8.1% of identified patients was classified as having severe asthma. Low asthma control (dispensed prescriptions of prednisolone, emergency department visits, hospitalization, or excessive short-acting β₂-agonist use) was more frequent in subjects with severe asthma (36.4% vs 25.2%, P < .0001); 63.8% with severe asthma and low asthma control were not managed by specialist care. Patients with severe asthma with specialist contact more frequently had impaired asthma control compared with subjects not treated by a specialist (44.4% vs 33.1%, P < .0001).

CONCLUSION

Based on the level of treatment, 8.1% of a nationwide population of current patients with asthma was classified as having severe asthma. Low asthma control was more frequent among subjects with severe asthma, and only a minority had access to specialist care. There is room for optimizing asthma management, particularly among patients with severe disease.

Systemic corticosteroids for the treatment of asthma exacerbations during and outside of pregnancy in an acute-care setting

BACKGROUND

Asthma exacerbations are common during pregnancy with a prevalence as high as 51.9% among women with severe asthma.

OBJECTIVE

To compare the treatment of asthma exacerbations in an acute-care setting during and outside of pregnancy.

METHODS

We formed a cohort of women who sought medical care for an asthma exacerbation at a teaching hospital during or in the year preceding pregnancy, between 1998 and 2008. An exacerbation was composed of one or more medical encounters in an acute-care setting (hospital-based outpatient clinic, emergency department, or during hospitalization). Data were retrieved from medical charts and health administrative databases. We compared the use of systemic corticosteroids (SCSs) during and outside of pregnancy with a Cox proportional hazards model.

RESULTS

The cohort was formed of 39 women who had 40 exacerbations during and 39 exacerbations outside of pregnancy. Use of SCSs to treat exacerbations was less frequent (adjusted hazard ratio: 0.51; 95% CI: 0.31-0.84) during pregnancy. Moreover, upon the first medical encounter related to the exacerbation, SCSs, when administered, were given less frequently to women when pregnant than when non-pregnant (83% vs. 100%). The SCS prescription was filled at the community pharmacy 65% and 67% of the time when it was prescribed at discharge to women when pregnant than when non-pregnant, respectively.

CONCLUSION

We observed a reduced and delayed use of SCSs for the treatment of asthma exacerbations in women when pregnant than when non-pregnant, with similar numbers of women in both conditions filling their SCSs prescription in pharmacies.

The relationship between asthma, asthma control and economic outcomes in the United States

OBJECTIVE

Asthma, a serious chronic lung disease affecting approximately 26 million Americans, remains clinical and economic burdens on the healthcare system. Although associations between uncontrolled asthma and poor health outcomes is known, the extent of this impact of uncontrolled asthma on economic outcomes in the United States (US) is unknown. We sought to determine the relationship between asthma, asthma control and economic outcomes in the US.

METHODS

The 2008-2010 Medical Expenditure Panel Surveys were used to estimate the impact of uncontrolled asthma (asthma-related emergency department [ED] visit, use of >3 canisters of quick-relief inhaler in past 3 months or asthma attack in past 12 months) on medical expenditures, utilization and productivity. Estimates were generated using multivariate regression controlling for sociodemographics and comorbidity.

RESULTS

Medical expenditures attributable to asthma were up to $4423 greater for those with markers of uncontrolled asthma compared with those who did not have asthma. Frequency of hospital discharges were up to 4.6-fold greater for those with uncontrolled asthma than those without asthma (p < 0.01), while all others with asthma did not have significantly more discharges. ED visits were up to 1.8-fold greater for those with uncontrolled asthma compared with those without asthma (p < 0.01). Productivity was significantly (p < 0.01) decreased (more likely to be unemployed, more days absent from work and more activity limitations) for those with uncontrolled asthma.

CONCLUSIONS

In recent national data, individuals with asthma and markers of uncontrolled asthma had higher medical expenditures, greater utilization and decreased productivity.

Relative perinatal safety of salmeterol vs formoterol and fluticasone vs budesonide use during pregnancy

BACKGROUND

Recent asthma guidelines endorse the safety of long-acting β2-agonists (LABAs) and of mild and moderate doses of inhaled corticosteroids (ICSs) when required to control asthma during pregnancy, yet do not state a preferred medication within each class.

OBJECTIVE

To estimate the relative perinatal safety with the use of salmeterol and formoterol (LABAs) and that of fluticasone and budesonide (ICSs) during pregnancy.

METHODS

A subcohort of pregnancies from asthmatic women was selected from health care administrative databases of Quebec, Canada. Low birth weight (LBW) was defined as weight less than 2,500 g, preterm birth (PB) as delivery before 37 weeks of gestation, and small for gestational age (SGA) as a birth weight below the 10th percentile. The effect of treatment with salmeterol vs formoterol and fluticasone vs budesonide on the outcomes was determined with generalized estimating equation models.

RESULTS

The LABA and ICS subcohorts were composed of 547 (385 salmeterol and 162 formoterol users) and 3,798 (3,190 fluticasone and 608 budesonide users) pregnancies, respectively. No statistically significant differences were observed for LBW (odds ratio [OR], 0.91; 95% confidence interval [CI], 0.44-1.88), PB (OR, 1.11; 95% CI, 0.56-2.23), and SGA (OR, 1.16; 95% CI, 0.67-2.02) newborns between women exposed to salmeterol vs formoterol or between women exposed to fluticasone vs budesonide (LBW: OR, 1.08; 95% CI, 0.76-1.52; PB: OR, 1.07; 95% CI, 0.78-1.49; and SGA, OR: 1.10; 95% CI, 0.85-1.44).

CONCLUSION

This study does not provide evidence of greater perinatal safety for one LABA or one ICS over the other.