What have we learned from prospective cohort studies of asthma in children?

Use of Asthma APGAR Tools in Primary Care Practices: A Cluster-Randomized Controlled Trial

PURPOSE

The purpose of this study was to assess patient and practice outcomes after introducing the Asthma APGAR (Activities, Persistent, triGGers, Asthma medications, Response to therapy) tools into primary care practices.

METHODS

We used a pragmatic cluster-randomized controlled design in 18 US family medicine and pediatric practices to compare outcomes in patients with persistent asthma aged 5 to 45 years after introduction of the Asthma APGAR tools vs usual care. Patient outcomes included asthma control, quality of life, and emergency department (ED), urgent care, and inpatient hospital visits. The practice outcome was adherence to asthma guidelines.

RESULTS

We enrolled 1,066 patients: 245 children, 174 adolescents, and 647 adults. Sixty-five percent (692 patients) completed both baseline and 12-month questionnaires, allowing analysis for patient-reported outcomes. Electronic health record data were available for 1,063 patients (99.7%) for practice outcomes. The proportion of patients reporting an asthma-related ED, urgent care, or hospital visit in the final 6 months of the study was lower in the APGAR practices vs usual care practices (10.6% vs 20.9%, P = .004). The percentage of patients with "in control" asthma increased more between baseline and 1 year in the APGAR group vs usual care group (13.5% vs 3.4%, P =.0001 vs P =.86) with a trend toward better control scores and asthma-related quality of life in the former at 1 year (P ≤.06 and P = .06, respectively). APGAR practices improved their adherence to 3 or more guideline elements compared with usual care practices (20.7% increase vs 1.9% decrease, P = .001).

CONCLUSIONS

Introduction of the Asthma APGAR tools improves rates of asthma control; reduces asthma-related ED, urgent care, and hospital visits; and increases practices' adherence to asthma management guidelines.

Association Between Bacillus Calmette-Guérin Vaccination and Childhood Asthma in the Quebec Birth Cohort on Immunity and Health

We estimated the association between bacillus Calmette-Guérin (BCG) vaccination and childhood asthma in a birth cohort using administrative databases, and we determined the impact of adjusting for potential confounders collected from a subset of the cohort members. Data were collected in 2 waves: 1) Administrative data for 76,623 individuals (stage 1) was gathered from the Quebec Birth Cohort on Immunity and Health (1974-1994), including BCG vaccination status, perinatal and sociodemographic characteristics, and use of health services for asthma; and 2) self-reported asthma risk factors were collected in 2012 by telephone interviews with 1,643 participants (stage 2) using a balanced 2-stage sampling design. We estimated odds ratios and 95% confidence intervals for asthma using logistic regression and correcting for the known sampling fractions from stage 1 to stage 2, overall and sex-stratified. In total, 35,612 (46.5%) individuals were BCG vaccinated, and 5,870 (7.7%) had asthma. The final odds ratio, integrating results from both stages of sampling, was 0.95 (95% confidence interval: 0.87, 1.04). Results did not differ according to sex (P for interaction = 0.327). To our knowledge, this is the largest study ever conducted on this topic, and using the best possible comprehensive adjustment for confounders, we found no association between BCG vaccination and asthma.

Twins' risk of childhood asthma mediated by gestational age and birthweight

BACKGROUND

Children born with low gestational age (GA) or low birthweight (BW) are at increased risk of asthma. Twins as compared to singletons are on average more likely to be born with lower GA and BW and have been hypothesized to comprise a high-risk population for asthma. Many previous studies have not accounted for potential confounders or mediators.

OBJECTIVE

To investigate the association between twinship and childhood asthma or early life wheeze and identify potential mediators, such as GA/BW.

METHODS

The study population consisted of two cohorts including all children born in Sweden from 1 January 1993 to 1 June 2001 (n = 756,363 singletons, n = 22,478 twins) and 1 July 2005 to 31 December 2009 (n = 456,239 singletons, n = 12,872 twins). Asthma was defined using validated register-based outcomes of diagnosis or medication. The data were analysed using logistic (older cohort) and Cox regression (younger cohort). Adjusted models incorporated potential confounding or mediating factors including gestational age and birthweight.

RESULTS

In the younger cohort, the crude hazard ratio (HR) of asthma medication after 1.5 years of age was 1.12 (95% CI 1.01-1.23), and fully adjusted HR was 0.80, 95% CI 0.72-0.89. Crude HR of asthma diagnosis in the same age group was 1.14 (95% CI 0.99-1.30), fully adjusted 0.78 (0.68-0.98). Adjusted analyses in the older group yielded similar results.

CONCLUSIONS

Twins were at significantly higher unadjusted risk of asthma or early life wheeze compared to singletons in the younger, but not in the older cohort. Associations attenuated following adjustment for GA/BW, suggesting that GA/BW mediates the effect of twinship on asthma risk. After adjustments, twins were at lower risk of asthma outcomes, possibly due to unmeasured confounding.

Protocol for the asthma tools study: a pragmatic practice-based research network trial

Background

Asthma is common among children, adolescents, and adults. However, management of asthma often fails to follow evidence-based guidelines. Control assessments have been developed, validated against expert opinion, and disseminated. However, in primary care, assessment of control is only one step in asthma management. To facilitate integration of the evidence-based guidelines into practice, tools should also guide the next steps in care. The Asthma APGAR tools do just that, incorporating a control assessment as well as assessment of the most common reasons for inadequate and poor control. The Asthma APGAR tool is also linked to a care algorithm based on the 2007 National Heart, Lung, and Blood Institute asthma guidelines. The objective of this study is to assess the impact of implementation of the Asthma APGAR on patient asthma outcomes in primary care practices.

Methods

A total of 1400 patients aged 5–60 years with physician-diagnosed asthma are enrolled in 20 practice-based research network (PBRN) practices randomized to intervention or usual care. The primary outcomes are changes in patient self-reported asthma control, asthma-related quality of life, and rates of exacerbations documented in medical records over the 18–24 months of enrollment. Process measures related to implementation of the Asthma APGAR system into daily care will also be assessed using review of medical records. Qualitative assessments will be used to explore barriers to and facilitators for integrating the Asthma APGAR tools into daily practice in primary care.

Discussion

Data from this pivotal pragmatic study are intended to demonstrate the importance of linking assessment of asthma and management tools to improve asthma-related patient outcomes. The study is an effectiveness trial done in real-world PBRN practices using patient-oriented outcome measures, making it generalizable to the largest possible group of asthma care providers and primary care clinics.

Validity of information on atopic disease and other illness in young children reported by parents in a prospective birth cohort study

Background

The longitudinal birth cohort study is the preferred design for studies of childhood health, particularly atopic disease. Still, prospective data collection depends on recollection of the medical history since the previous visit representing a potential recall-bias. We aimed to ascertain the quality of information on atopic disease and other health symptoms reported by parental interview in a closely monitored birth cohort study. Possible bias from symptom severity and socioeconomics were sought.

Methods

Copenhagen study on Asthma in Childhood (COPSAC) is a clinical birth cohort study of 411 children born of asthmatic mothers from 1999 to 2001. Child health is monitored at six-monthly visits with particular emphasis on atopic symptoms and infections. Data from the first three study years on 260 children was compared with records from their family practitioner as an external reference.

Results

A total of 6134 medical events were reported at the COPSAC interviews. Additional 586 medical events were recorded by family practitioners but not reported at the interview. There were no missed events related to asthma, eczema or allergy. Respiratory, infectious and skin related symptoms showed completeness above 90%, other diseases showed lower completeness around 77%. There was no meaningful influence from concurrent asthma or socioeconomics.

Conclusions

The COPSAC study exhibited full sensitivity to the main study objectives, atopic disease, and high sensitivity to respiratory, infectious and skin related illness. Our findings support the validity of parental interviews in longitudinal cohort studies investigating atopic disease and illness in childhood.