Limitations of questioning asthma to assess asthma control in general practice

Longitudinal validation of a tool for asthma self-monitoring

OBJECTIVES

To establish longitudinal validation of a new tool, the Asthma Symptom Tracker (AST). AST combines weekly use of the Asthma Control Test with a color-coded graph for visual trending.

METHODS

Prospective cohort study of children age 2 to 18 years admitted for asthma. Parents or children (n = 210) completed baseline AST assessments during hospitalization, then over 6 months after discharge. Concurrent with the first 5 AST assessments, the Asthma Control Questionnaire (ACQ) was administered for comparison.

RESULTS

Test-retest reliability (intraclass correlation) was moderate, with a small longitudinal variation of AST measurements within subjects during follow-ups. Internal consistency was strong at baseline (Cronbach's α 0.70) and during follow-ups (Cronbach's α 0.82-0.90). Criterion validity demonstrated a significant correlation between AST and ACQ scores at baseline (r = -0.80, P < .01) and during follow-ups (r = -0.64, -0.72, -0.63, and -0.69). The AST was responsive to change over time; an increased ACQ score by 1 point was associated with a decreased AST score by 2.65 points (P < .01) at baseline and 3.11 points (P < .01) during follow-ups. Discriminant validity demonstrated a strong association between decreased AST scores and increased oral corticosteroid use (odds ratio 1.13, 95% confidence interval, 1.10-1.16, P < .01) and increased unscheduled acute asthma visits (odds ratio 1.23, 95% confidence interval, 1.18-1.28, P < .01).

CONCLUSIONS

The AST is reliable, valid, and responsive to change over time, and can facilitate ongoing monitoring of asthma control and proactive medical decision-making in children.

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.

Association of the asthma control questionnaire with exercise-induced bronchoconstriction

INTRODUCTION

Asthma is a common chronic disease in childhood which features bronchial hyperresponsiveness to exercise (EIB). In daily clinical practice, the report of EIB is used to assess the level of control of asthma. The asthma control questionnaire (ACQ) is a tool to evaluate the control of asthma in children. The aim of this study was to evaluate the relationship between the ACQ and EIB.

MATERIALS AND METHODS

Two hundred children, aged 12.5 ± 2.5 years, with a pediatrician-diagnosed mild-to-moderate asthma filled out an ACQ and performed an exercise provocation test in cold air. EIB was defined as a fall in FEV(1) of 15%.

RESULTS

Eighty six of the 200 children had a positive exercise challenge. There was no relationship between the categorical ACQ and the occurrence of EIB (p = .39). There was no difference in the occurrence of EIB between genders (p = .12). The positive predictive value of the ACQ for EIB was 51% and the negative predictive value for EIB was 59%. In comparison to the girls, the boys carried an odds ratio (OR) of 0.48 for having an indifferent control of asthma (p = .04; confidence interval (CI): 0.23-0.96), and an OR of 0.46 for having a not well-controlled asthma (p = .03; CI: 0.23-0.93).

CONCLUSION

This study shows that the ACQ is not related to EIB in children with asthma. Remarkable is the percentage (41%) of children who, despite well-controlled asthma according to the ACQ, had EIB, which implies that their asthma is not well-controlled. Boys were more likely to report well-controlled asthma, although boys and girls were equally likely to have EIB.