Timeliness of diagnosis of asthma in children and its predictors

Association of delayed asthma diagnosis with asthma exacerbations in children

Background

There is a significant delay between symptom onset and diagnosis of childhood asthma, but the impact of this delay on asthma outcomes has not been well understood.

Objectives

We sought to study the association of delayed diagnosis of asthma with asthma exacerbations (AEs) in children.

Methods

Using the Mayo Clinic birth cohort, we identified children with a diagnosis of asthma from electronic health records. We defined onset date as the date when subjects first met predetermined asthma criteria ascertained by an electronic health records-based natural language processing algorithm. Delay in diagnosis (DD) was defined as first diagnosis >30 days from onset date (vs timely diagnosis [TD] within 30 days). The primary outcome was AE after the index date (for DD: first diagnosis date vs for TD: clinic visit at similar delay from diagnosis as matched DD counterpart). A Cox proportional hazard model was used to test the association between delayed diagnosis status and risk of AE, adjusting for sociodemographics, care quality, and asthma severity.

Results

Among 537 matched pairs of DD and TD (median age at index date: 4.1 years), a total of 344 and 253 children in DD and TD, respectively, had ≥1 AE during median follow-up period of 9.3 years. Children in the DD group had a significantly increased risk of AE compared to TD (adjusted hazard ratio: 1.53; 95% CI: 1.28, 1.80; P < .001).

Conclusions

DD of asthma in children is associated with an increased risk of AE compared to TD. TD of asthma should be an important priority in childhood asthma management.

Clinical Outcomes for Young Children Diagnosed With Asthma Versus Reactive Airway Disease

OBJECTIVE

Clinical diagnoses of asthma and reactive airway disease (RAD) in young children are subjective. We examined how often children were diagnosed with asthma versus RAD, and whether preventive care and 2-year clinical outcomes differed based on initial diagnosis.

METHODS

We conducted a retrospective cohort analysis of children (2-7 years) from a university-based general pediatrics practice who had been diagnosed with RAD or asthma. We performed adjusted comparisons between groups for time until subsequent asthma-related care. We also compared delivery of asthma-related healthcare services, corticosteroid and controller prescriptions, and action plans within 2 years of index diagnosis, using bivariate and regression analyses.

RESULTS

Four hundred three children were included (64% male, 67% Black, 25% Hispanic). RAD was diagnosed in 62% of index visits, and was more likely than asthma to be diagnosed in emergency settings. In the full sample, the time between index visit and subsequent asthma care did not differ between groups, after adjustment for index location. For subjects with complete 24-month follow-up (N = 300), no between-group differences were found in adjusted analyses. Most children with RAD received action plans and controller medications only after a subsequent asthma diagnosis, on average, 9 months after their index visit.

CONCLUSIONS

RAD diagnoses were linked to delayed delivery of preventive care measures, but within 2 years of initial diagnosis, clinical outcomes for those diagnosed with RAD and asthma did not differ. To facilitate clear communication and timely treatment, a prompt diagnosis of asthma, rather than RAD, should be considered for children with asthma symptoms.

Artificial intelligence-assisted clinical decision support for childhood asthma management: A randomized clinical trial

RATIONALE

Clinical decision support (CDS) tools leveraging electronic health records (EHRs) have been an approach for addressing challenges in asthma care but remain under-studied through clinical trials.

OBJECTIVES

To assess the effectiveness and efficiency of Asthma-Guidance and Prediction System (A-GPS), an Artificial Intelligence (AI)-assisted CDS tool, in optimizing asthma management through a randomized clinical trial (RCT).

METHODS

This was a single-center pragmatic RCT with a stratified randomization design conducted for one year in the primary care pediatric practice of the Mayo Clinic, MN. Children (<18 years) diagnosed with asthma receiving care at the study site were enrolled along with their 42 primary care providers. Study subjects were stratified into three strata (based on asthma severity, asthma care status, and asthma diagnosis) and were blinded to the assigned groups.

MEASUREMENTS

Intervention was a quarterly A-GPS report to clinicians including relevant clinical information for asthma management from EHRs and machine learning-based prediction for risk of asthma exacerbation (AE). Primary endpoint was the occurrence of AE within 1 year and secondary outcomes included time required for clinicians to review EHRs for asthma management.

MAIN RESULTS

Out of 555 participants invited to the study, 184 consented for the study and were randomized (90 in intervention and 94 in control group). Median age of 184 participants was 8.5 years. While the proportion of children with AE in both groups decreased from the baseline (P = 0.042), there was no difference in AE frequency between the two groups (12% for the intervention group vs. 15% for the control group, Odds Ratio: 0.82; 95%CI 0.374-1.96; P = 0.626) during the study period. For the secondary end points, A-GPS intervention, however, significantly reduced time for reviewing EHRs for asthma management of each participant (median: 3.5 min, IQR: 2-5), compared to usual care without A-GPS (median: 11.3 min, IQR: 6.3-15); p<0.001). Mean health care costs with 95%CI of children during the trial (compared to before the trial) in the intervention group were lower than those in the control group (-$1,036 [-$2177, $44] for the intervention group vs. +$80 [-$841, $1000] for the control group), though there was no significant difference (p = 0.12). Among those who experienced the first AE during the study period (n = 25), those in the intervention group had timelier follow up by the clinical care team compared to those in the control group but no significant difference was found (HR = 1.93; 95% CI: 0.82-1.45, P = 0.10). There was no difference in the proportion of duration when patients had well-controlled asthma during the study period between the intervention and the control groups.

CONCLUSIONS

While A-GPS-based intervention showed similar reduction in AE events to usual care, it might reduce clinicians' burden for EHRs review resulting in efficient asthma management. A larger RCT is needed for further studying the findings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02865967.

Early Identification of Childhood Asthma: The Role of Informatics in an Era of Electronic Health Records

Emerging literature suggests that delayed identification of childhood asthma results in an increased risk of long-term and various morbidities compared to those with timely diagnosis and intervention, and yet this risk is still overlooked. Even when children and adolescents have a history of recurrent asthma-like symptoms and risk factors embedded in their medical records, this information is sometimes overlooked by clinicians at the point of care. Given the rapid adoption of electronic health record (EHR) systems, early identification of childhood asthma can be achieved utilizing (1) asthma ascertainment criteria leveraging relevant clinical information embedded in EHR and (2) innovative informatics approaches such as natural language processing (NLP) algorithms for asthma ascertainment criteria to enable such a strategy. In this review, we discuss literature relevant to this topic and introduce recently published informatics algorithms (criteria-based NLP) as a potential solution to address the current challenge of early identification of childhood asthma.

Natural Language Processing for Asthma Ascertainment in Different Practice Settings

BACKGROUND

We developed and validated NLP-PAC, a natural language processing (NLP) algorithm based on predetermined asthma criteria (PAC) for asthma ascertainment using electronic health records at Mayo Clinic.

OBJECTIVE

To adapt NLP-PAC in a different health care setting, Sanford Children Hospital, by assessing its external validity.

METHODS

The study was designed as a retrospective cohort study that used a random sample of 2011-2012 Sanford Birth cohort (n = 595). Manual chart review was performed on the cohort for asthma ascertainment on the basis of the PAC. We then used half of the cohort as a training cohort (n = 298) and the other half as a blind test cohort to evaluate the adapted NLP-PAC algorithm. Association of known asthma-related risk factors with the Sanford-NLP algorithm-driven asthma ascertainment was tested.

RESULTS

Among the eligible test cohort (n = 297), 160 (53%) were males, 268 (90%) white, and the median age was 2.3 years (range, 1.5-3.1 years). NLP-PAC, after adaptation, and the human abstractor identified 74 (25%) and 72 (24%) subjects, respectively, with 66 subjects identified by both approaches. Sensitivity, specificity, positive predictive value, and negative predictive value for the NLP algorithm in predicting asthma status were 92%, 96%, 89%, and 97%, respectively. The known risk factors for asthma identified by NLP (eg, smoking history) were similar to the ones identified by manual chart review.

CONCLUSIONS

Successful implementation of NLP-PAC for asthma ascertainment in 2 different practice settings demonstrates the feasibility of automated asthma ascertainment leveraging electronic health record data with a potential to enable large-scale, multisite asthma studies to improve asthma care and research.

Clinical documentation variations and NLP system portability: a case study in asthma birth cohorts across institutions

Objective

To assess clinical documentation variations across health care institutions using different electronic medical record systems and investigate how they affect natural language processing (NLP) system portability.

Materials and Methods

Birth cohorts from Mayo Clinic and Sanford Children’s Hospital (SCH) were used in this study (n = 298 for each). Documentation variations regarding asthma between the 2 cohorts were examined in various aspects: (1) overall corpus at the word level (ie, lexical variation), (2) topics and asthma-related concepts (ie, semantic variation), and (3) clinical note types (ie, process variation). We compared those statistics and explored NLP system portability for asthma ascertainment in 2 stages: prototype and refinement.

Results

There exist notable lexical variations (word-level similarity = 0.669) and process variations (differences in major note types containing asthma-related concepts). However, semantic-level corpora were relatively homogeneous (topic similarity = 0.944, asthma-related concept similarity = 0.971). The NLP system for asthma ascertainment had anF-score of 0.937 at Mayo, and produced 0.813 (prototype) and 0.908 (refinement) when applied at SCH.

Discussion

The criteria for asthma ascertainment are largely dependent on asthma-related concepts. Therefore, we believe that semantic similarity is important to estimate NLP system portability. As the Mayo Clinic and SCH corpora were relatively homogeneous at a semantic level, the NLP system, developed at Mayo Clinic, was imported to SCH successfully with proper adjustments to deal with the intrinsic corpus heterogeneity.

A methodological comparison of two European primary care databases and replication in a US claims database: inhaled long-acting beta-2-agonists and the risk of acute myocardial infarction

PURPOSE

Results from observational studies on inhaled long-acting beta-2-agonists (LABA) and acute myocardial infarction (AMI) risk are conflicting, presumably due to variation in methodology. We aimed to evaluate the impact of applying a common study protocol on consistency of results in three databases.

METHODS

In the primary analysis, we included patients from two GP databases (Dutch-Mondriaan, UK-CPRD GOLD) with a diagnosis of asthma and/or COPD and at least one inhaled LABA or a "non-LABA inhaled bronchodilator medication" (short-acting beta-2-agonist or short-/long-acting muscarinic antagonist) prescription between 2002 and 2009. A claims database (USA-Clinformatics) was used for replication. LABA use was divided into current, recent (first 91 days following the end of a treatment episode), and past use (after more than 91 days following the end of a treatment episode). Adjusted hazard ratios (AMI-aHR) and 95 % confidence intervals (95 % CI) were estimated using time-dependent multivariable Cox regression models stratified by recorded diagnoses (asthma, COPD, or both asthma and COPD).

RESULTS

For asthma or COPD patients, no statistically significant AMI-aHRs (age- and sex-adjusted) were found in the primary analysis. For patients with both diagnoses, a decreased AMI-aHR was found for current vs. recent LABA use in the CPRD GOLD (0.78; 95 % CI 0.68-0.90) and in Mondriaan (0.55; 95 % CI 0.28-1.08), too. The replication study yielded similar results. Adjusting for concomitant medication use and comorbidities, in addition to age and sex, had little impact on the results.

CONCLUSIONS

By using a common protocol, we observed similar results in the primary analysis performed in two GP databases and in the replication study in a claims database. Regarding differences between databases, a common protocol facilitates interpreting results due to minimized methodological variations. However, results of multinational comparative observational studies might be affected by bias not fully addressed by a common protocol.

A systematic review of predictive models for asthma development in children

BACKGROUND

Asthma is the most common pediatric chronic disease affecting 9.6 % of American children. Delay in asthma diagnosis is prevalent, resulting in suboptimal asthma management. To help avoid delay in asthma diagnosis and advance asthma prevention research, researchers have proposed various models to predict asthma development in children. This paper reviews these models.

METHODS

A systematic review was conducted through searching in PubMed, EMBASE, CINAHL, Scopus, the Cochrane Library, the ACM Digital Library, IEEE Xplore, and OpenGrey up to June 3, 2015. The literature on predictive models for asthma development in children was retrieved, with search results limited to human subjects and children (birth to 18 years). Two independent reviewers screened the literature, performed data extraction, and assessed article quality.

RESULTS

The literature search returned 13,101 references in total. After manual review, 32 of these references were determined to be relevant and are discussed in the paper. We identify several limitations of existing predictive models for asthma development in children, and provide preliminary thoughts on how to address these limitations.

CONCLUSIONS

Existing predictive models for asthma development in children have inadequate accuracy. Efforts to improve these models' performance are needed, but are limited by a lack of a gold standard for asthma development in children.

Risk of Asthma in Late Preterm Infants: A Propensity Score Approach

BACKGROUND

The risk of asthma, specifically in former late preterm infants, has not been well defined. Covariate imbalance and lack of controlling for this has led to inconsistent results in prior studies.

OBJECTIVE

The objective of this study was to determine the risk of asthma in former late preterm infants using a propensity score approach.

METHODS

The study was a population-based birth cohort study. Study subjects were all children born in Rochester, Minn, between 1976 and 1982. Asthma status during the first 7 years of life was assessed by applying predetermined criteria. The propensity score was formulated using 15 covariates by fitting a logistic regression model for late preterm birth versus term birth. We applied the propensity score method to match late preterm infants (34 0/7 to 36 6/7 weeks of gestation) to term infants (37 0/7 to 40 6/7 weeks of gestation) within a caliper of 0.2 standard deviation of logit of propensity score.

RESULTS

Of the eligible 7040 infants, 5915 children had complete data. Before propensity score matching, late preterm infants had a higher risk of asthma (20 of 262, 7.6%) compared with full-term infants (272 of 5653, 4.8%) (P = .039). There was significant covariate imbalance between comparison groups. After matching with propensity scores, we found that former late preterm infants had a similar risk of asthma to the matched full-term infants (6.6% vs 7.7%, respectively, P = .61), and the result was consistent with covariate-adjustment Cox regression models controlling for significant covariates (P = .57).

CONCLUSION

A late preterm birth history is not independently associated with childhood asthma, as the reported risk of asthma among former late preterm infants appears to be due to covariate imbalance.

Recurrent wheeze and cough in young children: is it asthma?

A clinical diagnosis of asthma is often considered when a child presents with recurrent cough, wheeze and breathlessness. However, there are many other causes of wheeze in a young child. These range from recurrent viral infections to chronic suppurative lung disease, gastro-oesophageal reflux disease and rare structural abnormalities. Arriving at a diagnosis includes taking into consideration the symptomatology, triggers, atopic features, family history, absence of red flags and therapeutic trial, where indicated.

Automated chart review for asthma cohort identification using natural language processing: an exploratory study

BACKGROUND

A significant proportion of children with asthma have delayed diagnosis of asthma by health care providers. Manual chart review according to established criteria is more accurate than directly using diagnosis codes, which tend to under-identify asthmatics, but chart reviews are more costly and less timely.

OBJECTIVE

To evaluate the accuracy of a computational approach to asthma ascertainment, characterizing its utility and feasibility toward large-scale deployment in electronic medical records.

METHODS

A natural language processing (NLP) system was developed for extracting predetermined criteria for asthma from unstructured text in electronic medical records and then inferring asthma status based on these criteria. Using manual chart reviews as a gold standard, asthma status (yes vs no) and identification date (first date of a "yes" asthma status) were determined by the NLP system.

RESULTS

Patients were a group of children (n = 112, 84% Caucasian, 49% girls) younger than 4 years (mean 2.0 years, standard deviation 1.03 years) who participated in previous studies. The NLP approach to asthma ascertainment showed sensitivity, specificity, positive predictive value, negative predictive value, and median delay in diagnosis of 84.6%, 96.5%, 88.0%, 95.4%, and 0 months, respectively; this compared favorably with diagnosis codes, at 30.8%, 93.2%, 57.1%, 82.2%, and 2.3 months, respectively.

CONCLUSION

Automated asthma ascertainment from electronic medical records using NLP is feasible and more accurate than traditional approaches such as diagnosis codes. Considering the difficulty of labor-intensive manual record review, NLP approaches for asthma ascertainment should be considered for improving clinical care and research, especially in large-scale efforts.

Serum 25-hydroxyvitamin D concentrations and waning pneumococcal antibody titers among individuals with atopy

Serum 25-hydroxyvitamin D (25[OH]D) concentrations are positively associated with pneumococcal antibody titers (PATs) in subjects with atopy or asthma. Little is known about the association of serum 25(OH)D concentrations and the waning of PATs over time in subjects with or without atopy. This study was designed to determine whether serum 25(OH)D concentrations are associated with waning of PATs and if such relationship is modified by atopic conditions. The study was designed as a prospective cohort study, which followed 20 asthmatic patients and 19 individuals without asthma for an average of 12 months. We measured PATs and serum 25(OH)D concentrations at baseline and at a subsequent follow-up visit. Asthma was ascertained by predetermined criteria. The association between serum 25(OH)D concentrations and PATs was determined by Pearson's correlation coefficient and a least square model. Of the 39 children and adults, 21(53%) were male subjects, all were white, and 6 (15%) were children. There was an overall negative correlation between serum 25(OH)D concentrations and the decrease of PATs during follow-up (r = -0.47; p = 0.004), suggesting that higher 25(OH)D concentrations were associated with a reduction in waning of PATs over time. Controlling for follow-up duration and pneumococcal colonization, these trends were significant among asthmatic patients but not in individuals without asthma. Similar trends were observed for individuals with or without other atopic conditions. Serum 25(OH)D concentrations are inversely associated with the waning of PATs over time, especially individuals with asthma and other atopy conditions. These study findings deserve further investigation.

Characteristics of children with asthma who achieved remission of asthma

OBJECTIVE

To characterize two groups of asthmatics who had achieved remission and those who had not achieved remission of asthma.

METHODS

The study was a retrospective cohort study based on 117 asthmatic children who participated in a previous study. We categorized the children into two groups: asthmatics with remission versus asthmatics without remission. We defined remission of asthma as lack of symptoms/signs of asthma or asthma-related medications or health care services for at least three consecutive years. Long-term remission was defined by no relapse of asthma after achieving remission. We characterized these groups.

RESULTS

Of the 117 subjects, 70 (60%) were male, 91 (78%) were Caucasians, and the mean age at index date of asthma was 8.1 years. A total of 59 asthmatic children (50%) achieved remission and 28 asthmatics (24%) achieved long-term remission. Asthmatics with remission were more likely to be Caucasian (87%) compared to those without (69%) (p = .039) There were no differences in the frequency of visits for viral (0.3 vs. 0.4 per person-years, p = .29) or bacterial infections (0.7 vs. 0.5 per person-years, p = .49) between asthmatics with and without remission. Gender, socioeconomic status, smoking exposure, family history of asthma or atopy, breastfeeding history, peak flow meter availability, asthma action plan, and influenza vaccinations were not associated with remission.

CONCLUSIONS

Only half of asthmatic children accomplished remission of asthma ever and 24% of asthmatic children had long-term remission. Ethnicity may affect remission of asthma but microbial infections may not influence the likelihood of remission of asthma and vice versa.

Exposure to farming environments in childhood and asthma and wheeze in rural populations: a systematic review with meta-analysis

Asthma is a chronic respiratory disorder that has become substantially more common over the past decades. One environmental factor for which particularly strong associations with asthma and allergic diseases have been described is exposure to farming environments in childhood. The aim of this systematic review was to update and extend existing narrative reviews, test for heterogeneity of effect across studies, and conduct a meta-analysis to report a summary effect measure. Published relevant literature was searched through PubMed including all articles added to PubMed before September 1, 2011. Articles were included if they reported an epidemiological study on the exposure to a farming environment in childhood and subsequent wheeze or asthma. Heterogeneity of effect measures across studies was evaluated using Cochran's Q and I(2). Random-effects meta-analysis was performed to summarize effect measures for various outcome definitions. In total, 357 retrieved abstracts revealed 52 original articles from 39 studies with data considered for the meta-analysis. Most studies were conducted among children or on childhood onset of disease. Most data were published on doctor-diagnosed asthma or current wheeze. The meta-analysis showed substantial heterogeneity across studies with similar outcome definitions. Nonetheless, the combined effects were statistically significant and showed an approximate 25% lower asthma prevalence among exposed subjects compared with unexposed subjects. The protective 'farm-effect' on asthma was reported in numerous studies. Its underlying factors ought to be studied, and promising efforts have been already made. However, the heterogeneity of the effect across studies should also be investigated because whatever causes it is a potential threat to valid synthesis of evidence and to the detection of specific protective factors.

Impact of delay in asthma diagnosis on chest X-ray and antibiotic utilization by clinicians

OBJECTIVE

To evaluate the effect of the timeliness of asthma diagnosis on chest X-ray (CXR) and antibiotic utilization in children.

PATIENTS AND METHODS

This was a retrospective cohort study of 276 asthmatic children aged 5-12 years from Rochester, Minnesota. From the time when children met our predetermined asthma criteria, the frequency of CXR and antibiotic utilizations for respiratory illnesses were collected from medical records until age 18 years. Using a Poisson regression model, the frequency of CXR and antibiotic utilizations were compared in children with timely, delayed, or no clinician diagnosis of asthma.

RESULTS

Of the 276 asthmatic patients, 97 (35%) had a timely diagnosis, 122 (44%) had a delayed diagnosis, while 57 patients (21%) had no clinician diagnosis of asthma. There was no significant difference in CXR or antibiotic utilization for respiratory illness between these groups. In addition, this was true for the comparison between the timely diagnosed group and the delayed diagnosed group combining both the group with a delay in asthma diagnosis and the group who never had asthma diagnosis.

CONCLUSIONS

A delay in the diagnosis of asthma in children is common and overall it may not influence antibiotic and CXR utilization for respiratory symptoms by clinicians. However, its impact on access to asthma-related therapies and other healthcare utilizations could be possible and was not assessed in this study. Given the limitations of our study, a larger prospective study needs to be considered.

An increasing trend of the delay in asthma diagnosis after the discontinuation of a population-based intervention

BACKGROUND

We have previously analyzed the delay in asthma diagnosis in children from the cohort of Asthma Prevention Program in Lodz Province, Poland. That community-based intervention focused mainly on the improvement in access to specialists. The aim of this study was reevaluation of the timelines of all recent asthma diagnoses (N = 500) in children referred to our clinic after the discontinuation of the program, that is, in the time span from 2004 to 2009.

METHODS

Subjects with no previous diagnosis of asthma but a positive asthma predictive index were labeled as having undiagnosed asthma. The time from the first medical appointment when asthma could have been diagnosed the earliest until the final diagnosis of asthma was calculated for each subject and defined as the duration of undiagnosed asthma (years). All data were obtained from children's medical documentation and through phone interviews.

RESULTS

During the intervention program, the duration of undiagnosed asthma significantly decreased. However, it showed a significant upward trend after the discontinuation of the program. After 6 years since the program was abandoned, the average undiagnosed asthma duration returned to its initial length from before the intervention. The independent statistical predictors of the delayed asthma diagnosis were the absence of atopy and suboptimal initial antiasthma therapy.

CONCLUSION

Our results revealed the following: first, general practitioners do not follow the recommended guidelines for early detection of asthma in children; and second, a greater accessibility of specialists could enhance chances of early asthma diagnosis, especially in nonatopic children.

Prenatal or early-life exposure to antibiotics and risk of childhood asthma: a systematic review

CONTEXT

The increasing prevalence of childhood asthma has been associated with low microbial exposure as described by the hygiene hypothesis.

OBJECTIVE

We sought to evaluate the evidence of association between antibiotic exposure during pregnancy or in the first year of life and risk of childhood asthma.

METHODS

PubMed was systematically searched for studies published between 1950 and July 1, 2010. Those that assessed associations between antibiotic exposure during pregnancy or in the first year of life and asthma at ages 0 to 18 years (for pregnancy exposures) or ages 3 to 18 years (for first-year-of-life exposures) were included. Validity was assessed according to study design, age at asthma diagnosis, adjustment for respiratory infections, and consultation rates.

RESULTS

For exposure in the first year of life, the pooled odds ratio (OR) for all studies (N = 20) was 1.52 (95% confidence interval [CI]: 1.30-1.77). Retrospective studies had the highest pooled risk estimate for asthma (OR: 2.04 [95% CI: 1.83-2.27]; n = 8) compared with database and prospective studies (OR: 1.25 [95% CI: 1.08-1.45]; n = 12). Risk estimates for studies that adjusted for respiratory infections (pooled OR: 1.16 [95% CI: 1.08-1.25]; n = 5) or later asthma onset (pooled OR for asthma at or after 2 years: OR: 1.16 [95% CI: 1.06-1.25]; n = 3) were weaker but remained significant. For exposure during pregnancy (n = 3 studies), the pooled OR was 1.24 (95% CI: 1.02-1.50).

CONCLUSIONS

Antibiotics seem to slightly increase the risk of childhood asthma. Reverse causality and protopathic bias seem to be possible confounders for this relationship.

Inflammatory bowel disease and asthma: a population-based, case-control study

BACKGROUND

A few cross-sectional studies reported an increased risk of inflammatory bowel disease (IBD) among asthmatics. We conducted a population-based, case-control study that applied predetermined criteria for asthma and IBD to determine whether asthma, as a T-helper 2 (Th2) condition, reduces the risk of IBD, a Th1 condition.

METHODS

This was a population-based, case-control study using criteria-based ascertainment for IBD and asthma. Subjects were all Rochester, Minnesota, residents who had developed IBD between 1964 and 1983 and their age- and gender-matched controls, using 1:1 matching. Controls were randomly selected from the community using the Rochester Epidemiology Project database and confirmed not to have IBD. All cases and controls were merged with the database comprising all Rochester residents with or without asthma between 1964 and 1983.

RESULTS

Of the 231 IBD cases, 55% had ulcerative colitis and the remainder had Crohn's disease. Of these, 50.4% were male and 98.1% were Caucasians. The mean age at the time of IBD diagnosis was 33.8 years. Four cases (1.7%) had asthma prior to the index date of IBD, whereas two controls (0.9%) had asthma (unadjusted odds ratio [OR]: 3.0, 95% confidence interval [CI]: 0.31-28.84, P = 0.34). Similarly, 16 IBD cases (6.9%) had asthma ever while 12 controls (5.2%) had asthma ever (unadjusted OR: 1.4, 95% CI: 0.62-3.38, P = 0.40).

CONCLUSIONS

Asthma as a Th2 condition does not reduce the risk of IBD as a Th1 condition. Because of the limitations of our study and others, the association between asthma and IBD needs to be further studied.

Impact of delay in asthma diagnosis on health care service use

Delays in diagnosing asthma in children are common and are known to delay asthma-specific treatment. Few studies have investigated whether a delay in asthma diagnosis impacts the use of health care services. This study was designed to assess whether a delay in diagnosis of asthma influences the use of health care services. This was a retrospective cohort study with subjects elicited from a convenience sample of 839 healthy children. The criteria for asthma was met in 276 (33%) subjects; of these subjects 179 (65%) had a delay in the diagnosis of asthma and 97 (35%) had a timely diagnosis. Data on health care services (e.g., flu shot, availability of a peak flow meter, hospitalizations, and urgent care or emergency department visits) and the frequency of systemic steroid treatments were collected from medical records during the first 18 years of life. The frequencies of health service and use of systemic steroids were compared using Poisson and logistic regression models in asthmatic children with and without a delay in asthma diagnosis. Children with a delay in asthma diagnosis were more likely to visit urgent care centers at least once (40.8% versus 21.6%; p < 0.001), compared with those with a timely diagnosis. There were no significant differences in other health care service or systemic steroid use. A delay in the diagnosis of asthma was associated with an increase in urgent care visits suggesting suboptimal care. Clinicians should be aware that a delay in the diagnosis of asthma in children may result in the use of suboptimal health care services.

An update on exercise-induced bronchoconstriction with and without asthma

Exercise-induced bronchoconstriction (EIB) is defined as transient, reversible bronchoconstriction that develops after strenuous exercise. It is a heterogeneous syndrome made up of a spectrum of phenotypes ranging from the asymptomatic military recruit whose condition is detected by diagnostic exercise challenge to the athlete with known asthma to the elite athlete for whom EIB represents an overuse or injury syndrome. If exercise is the only identified trigger for bronchoconstriction, it is called EIB. However, when it is associated with known asthma, then it is defined as EIB with asthma. This review discusses the pathogenesis, presentation, diagnosis, and management of EIB and EIB with asthma.