A comparison of two simple measures to evaluate the health status of asthmatics: the Asthma Bother Profile and the Airways Questionnaire 20

2021 Brazilian Thoracic Association recommendations for the management of severe asthma

Advances in the understanding that severe asthma is a complex and heterogeneous disease and in the knowledge of the pathophysiology of asthma, with the identification of different phenotypes and endotypes, have allowed new approaches for the diagnosis and characterization of the disease and have resulted in relevant changes in pharmacological management. In this context, the definition of severe asthma has been established, being differentiated from difficult-to-control asthma. These recommendations address this topic and review advances in phenotyping, use of biomarkers, and new treatments for severe asthma. Emphasis is given to topics regarding personalized management of the patient and selection of biologicals, as well as the importance of evaluating the response to treatment. These recommendations apply to adults and children with severe asthma and are targeted at physicians involved in asthma treatment. A panel of 17 Brazilian pulmonologists was invited to review recent evidence on the diagnosis and management of severe asthma, adapting it to the Brazilian reality. Each of the experts was responsible for reviewing a topic or question relevant to the topic. In a second phase, four experts discussed and structured the texts produced, and, in the last phase, all experts reviewed and approved the present manuscript and its recommendations.

Asthma outcomes: quality of life

BACKGROUND

"Asthma-related quality of life" (QOL) refers to the perceived impact that asthma has on the patient's QOL.

OBJECTIVE

National Institutes of Health institutes and other federal agencies convened an expert group to recommend standardized measures of the impact of asthma on QOL for use in future asthma clinical research.

METHODS

We reviewed published documentation regarding the development and psychometric evaluation; clinical research use since 2000; and extent to which the content of each existing QOL instrument provides a unique, reliable, and valid assessment of the intended construct. We classified instruments as core (required in future studies), supplemental (used according to the study's aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an National Institutes of Health-organized workshop convened in March 2010 and finalized in September 2011.

RESULTS

Eleven instruments for adults and 6 for children were identified for review. None qualified as core instruments because they predominantly measured indicators of asthma control (symptoms and/or functional status); failed to provide a distinct, reliable score measuring all key dimensions of the intended construct; and/or lacked adequate psychometric data.

CONCLUSIONS

In the absence of existing instruments that meet the stated criteria, currently available instruments are classified as either supplemental or emerging. Research is strongly recommended to develop and evaluate instruments that provide a distinct, reliable measure of the patient's perception of the impact of asthma on all of the key dimensions of QOL, an important outcome that is not captured in other outcome measures.

[Cultural adaptation into Spanish of the Airways Questionnaire 20, a short health-related quality-of-life questionnaire for the clinical evaluation of asthma and chronic obstructive pulmonary disease]

BACKGROUND AND OBJECTIVES

The routine use of health-related quality-of-life questionnaires in patients with chronic respiratory disease is limited due to the time required to complete them. The Airways Questionnaire 20 (AQ20) contains 20 easy-to-answer questions, making it ideal for use in routine practice. However, a Spanish version is not available. Our aim was to create a version of the AQ20 for use in Spain that would be equivalent to the original English questionnaire.

METHOD

The original questionnaire was adapted using the translation-backtranslation method. We evaluated the conceptual equivalence of the translation to the original questionnaire, classifying items as type A if they were fully equivalent, type B if they contained questionable wording, and type C if there were doubts about their equivalence. The items in categories B and C were re-examined by the researchers and translators, with input from the author of the original questionnaire and a group of patients. The final version was piloted among 30 patients.

RESULTS

Low difficulty ratings were given to both the translation (3.45) and backtranslation (3.52). Sixty-five percent of the backtranslated items were considered to be fully equivalent to the original English items (type A), 15% were classified as type B, and 20% as type C. The final Spanish version, produced after discussion of items B and C, was administered to 15 patients with asthma (66% women; mean [SD] age, 53.13 [19.6] y) and 15 patients with chronic obstructive pulmonary disease (13% women; mean age, 67.8 [8.94] y). A Cronbach alpha of 0.92 was obtained.

CONCLUSION

The adaptation process produced a Spanish questionnaire that is conceptually equivalent to the English original, easy to understand, and satisfactory in terms of internal consistency.

[Discriminative properties and validity of a health status questionnaire in obstructive airway disease patients: the Airway Questionnaire 20]

OBJECTIVE

To evaluate the discriminative properties and validity of the Airways Questionnaire 20 (AQ20) in a sample of patients with airway obstruction and to compare its properties with those of the St George's Respiratory Questionnaire (SGRQ) and the Short Form 36 (SF-36).

PATIENTS AND METHODS

A convenience sample of 47 subjects was recruited from among 61 consecutive patients referred to an outpatient clinic specialized in obstructive airway diseases. All subjects completed the AQ20, SGRQ, and SF-36. Other measures were the baseline dyspnea index (BDI), 6-minute walk test (6MWT) distance, spirometry, results of arterial blood gas analysis, and body mass index.

RESULTS

The AQ20 showed very good correlation with the SGRQ total score (rho=0.84, P< .001) and moderate correlation with all SF-36 domains (physical capacity, rho=-0.53; physical functioning, rho=-0.61; bodily pain, rho=-0.55; general health, rho=-0.59; vitality, rho=-0.55; social functioning, rho=-0.57; emotional role functioning, rho=-0.51; mental health, rho=-0.61; all P< .001). The BDI and the 6MWT distance were the best predictors of AQ20 score (r2=0.31) in the regression model. An area under the receiver operating characteristic curve of 0.91 (P< .001) indicated a high level of accuracy for the AQ20, using the SGRQ as the gold standard.

CONCLUSION

This study shows that the AQ20 is an accurate health status questionnaire in patients with moderate-to-severe airway obstruction. It could be an alternative to longer, traditional questionnaires such as the SGRQ.

Repeatability of a Rasch model of the AQ20 over five assessments

Rasch analysis is now used widely to assess the measurement properties of health status questionnaires. This study tested the stability of the AQ20 - a dichotomous-response measure of health status in asthma, using parameters estimated by a Rasch model. One hundred forty-four asthma patients completed the AQ20 on five occasions over 3 months. At visit 1, two items showed significant misfit and were deleted. At each visit, the overall mean item-person and item-trait interaction statistics from the remaining 18 items (AQ18) were very similar. The repeatability of the item calibrations was excellent (intraclass correlation coefficient 0.95), despite the patients' health having changed (repeated-measures ANOVA: FEV(1) and AQ18 score p<0.0001). Tests of differential item functioning (DIF) over time showed that one item increased in severity. This item refers to ability to garden, and changes in response patterns could be related to seasonal changes over the study period. We conclude that this study has highlighted the usefulness of multiple repeat assessments which allow items to be tested for DIF over time. This is important as inclusion of 'time-dependent' items in a questionnaire may reduce the reliability of the instrument.

Measuring disease-specific quality of life in obstructive airway disease: validation of a modified version of the airways questionnaire 20

BACKGROUND

The Airways Questionnaire 20 (AQ20) is a concise measure of health-related quality of life (HRQL) in obstructive airway disease; however, its original format may underestimate impairment due to the complete cessation of certain activities.

METHODS

We revised seven items of the original AQ20 (revised AQ20 [AQ20-R]), adding response options for inability to perform certain activities. We assessed the performance of the AQ20-R among 352 adults with various airway conditions identified through a random telephone sample. Concurrent validity of the AQ20-R was assessed relative to the Short Form-12 (SF-12) physical component summary (PCS), FEV(1), and medication use. Predictive validity was assessed relative to health-care utilization among 278 subjects studied longitudinally.

RESULTS

Twenty-one of 352 subjects were unable to perform at least one activity. These subjects demonstrated higher AQ20-R scores (p < 0.001) indicating worse HRQL. Mean (+/- SD) AQ20-R scores differed significantly (p < 0.001) among subjects with COPD (8.9 +/- 5.2), asthma (6.7 +/- 5.0), and chronic bronchitis (4.7 +/- 4.2). At baseline, the AQ20-R correlated with the SF-12 PCS (r = - 0.55, p < 0.001) and FEV(1) (r = - 0.43, p < 0.001), and was associated with the use of respiratory-specific therapies (p </= 0.001). In multivariate models, the AQ20-R was an independent predictor of outpatient visits (odds ratio, 2.2; 95% confidence interval, 1.6 to 3.1), emergency department visits (odds ratio, 2.9; 95% confidence interval, 1.9 to 4.6), hospitalization (odds ratio, 2.8; 95% confidence interval, 1.6 to 4.9), and ICU admission (odds ratio, 3.0; 95% confidence interval, 1.2 to 7.3) during the following year.

CONCLUSIONS

The AQ20-R is a valid respiratory-specific HRQL measure that accounts for activity cessation among the most impaired and can be used across various airway conditions.

Dyspnea and asthma

PURPOSE OF REVIEW

Dyspnea--the perception of respiratory discomfort--is a primary symptom of asthma. This review examines possible ways to link mechanisms, measurement and treatment that will increase our understanding of this condition.

RECENT FINDINGS

Functional neuroimaging methods have proven to be powerful tools that serve as advanced models of sensor motor brain function. Studies examining functional neuroimaging methods have revealed activation of distinct brain areas associated with increased dyspnea. Pulmonary hyperinflation has been proposed to influence the perception of dyspnea. The association of hyperinflation with minor levels of bronchoconstriction reflects the partition of the sensory effect of airway narrowing per se from that of the attendant elastic loading of the inspiratory muscles. There is evidence to suggest, however, that hyperinflation does not play an important role in the pathogenesis of exercise dyspnea as it does during induced bronchoconstriction. Decreased levels of perception of airway obstruction may be a risk factor associated with life-threatening asthma. A poor perceiver may be vulnerable to further hypoxia-induced suppression of respiratory sensation. Monitoring the response to bronchodilator therapy with formoterol and salbutamol in patients with acute or chronic asthma has resulted in significantly faster improvement in dyspnea, within 2 min.

SUMMARY

Regardless of the factors involved, much variability in dyspnea scores remains unexplained. Quantitative and qualitative assessment of the perception of dyspnea, symptom measurement and quality of life complement physiological measurements and contribute to our understanding of dyspnea in asthma.