Asthma control and its direct healthcare costs: findings using a derived Asthma Control TestTM score in eight Asia-Pacific areas

Asthma control is associated with economic outcomes, work productivity and health-related quality of life in patients with asthma

Background

The objective of this analysis was to examine the association between asthma control (based on Asthma Control Test (ACT) responses) and healthcare resource utilisation (HRU), work productivity and health-related quality of life (HRQoL) among a nationwide sample of US adults with a self-reported diagnosis of asthma and without comorbid chronic obstructive pulmonary disease.

Methods

Data were obtained from the 2015 and 2016 self-administered, internet-based National Health and Wellness Surveys. Patients were grouped by ACT score (≤15: poorly controlled; 16–19: partly controlled; 20–25: well-controlled asthma). Study outcomes included HRU (patient-reported healthcare provider visits, emergency department visits and hospitalisations during the previous 6 months); work productivity, measured using the Work Productivity and Activity Impairment-General Health Scale; HRU-associated costs and work productivity loss and HRQoL, measured using EuroQoL-5 Dimensions-5 Levels (EQ-5D-5L) and the Short Form Health Survey-36V.2 (SF-36V.2). Incremental differences in outcomes between groups were assessed using generalised linear models adjusted for covariates.

Results

Of 7820 eligible adults, 17.4% had poorly controlled, 20.1% partly controlled and 62.5% well-controlled asthma. Well-controlled asthma was associated with significantly lower HRU (p<0.001) and lower mean direct costs ($6012 vs $8554 and $15 262, respectively; p<0.001); well-controlled asthma was also associated with significantly lower mean scores for work absenteeism, work presenteeism, overall work impairment and activity impairment (all p<0.001), and lower mean indirect costs ($6353 vs $10 448 and $14 764, respectively; p<0.001). Clinically meaningful differences favouring well-controlled asthma were seen for all HRQoL measures, with statistically significantly higher adjusted mean EQ-5D-5L index and SF-6D Health Utilities Index scores (derived from SF-36V.2) for patients with well-controlled asthma compared with partly controlled or poorly controlled asthma (p<0.001).

Conclusions

The study demonstrates a clear relationship between asthma control and its impact on HRU, costs, work productivity and HRQoL. This will allow for better identification and management of patients with poorly controlled asthma.

Relationship between the Asthma Control Test (ACT) and other outcomes: a targeted literature review

BACKGROUND

The Asthma Control Test (ACT) has been used to assess asthma control in both clinical trials and clinical practice. However, the relationships between ACT score and other measures of asthma impact are not fully understood. Here, we evaluate how ACT scores relate to other clinical, patient-reported, or economic asthma outcomes.

METHODS

A targeted literature search of online databases and conference abstracts was performed. Data were extracted from articles reporting ACT score alongside one or more of: Asthma Control Questionnaire (ACQ) score; rescue medication use; exacerbations; lung function; health-/asthma-related quality of life (QoL); sleep quality; work and productivity; and healthcare resource use (HRU) and costs.

RESULTS

A total of 1653 publications were identified, 74 of which were included in the final analysis. Of these, 69 studies found that improvement in ACT score was related to improvement in outcome(s), either as correlation or by association. The level of evidence for each relationship differed widely between outcomes: substantial evidence was identified for relationships between ACT score and ACQ score, lung function, and asthma-related QoL; moderate evidence was obtained for relationships between ACT score and rescue medication use, exacerbations, sleep quality, and work and productivity; limited evidence was identified for relationships between ACT score and general health-related QoL, HRU, and healthcare costs.

CONCLUSIONS

Findings of this review suggest that the ACT is an appropriate measure for overall asthma impact and support its use in clinical trial settings. GlaxoSmithKline plc. study number HO-17-18170.

A review of psychological dysfunction in asthma: affective, behavioral and cognitive factors

BACKGROUND

The research on psychological dysfunction in asthma is extensive but heterogeneous. We undertook a narrative review about the effects of psychological dysfunction on asthma.

METHODS

Electronic searches of MEDLINE, EMBASE, CINAHL and the Cochrane Library were conducted, supplemented by hand-searching bibliographies and seeking expert opinion.

RESULTS

The impact of psychological factors on asthma can be classified according to dysfunction in the domains of affect, behavior and cognition. Affective or emotional disturbance may lead to poor asthma control by directly modulating disease activity. Maladaptive behaviors may occur in asthma patients. These include maladaptive breathing behaviors, such as impaired voluntary drive to breathe and dysfunctional breathing, as well as impaired asthma health behaviors, that is, a coordinated range of activities performed to maintain good disease control. Dysfunctional cognitions (thoughts and beliefs) about asthma and impaired cognitive processing of the perception of dyspnea are associated with poorly controlled disease and asthma deaths, respectively. The three domains of psychological dysfunction are often closely intertwined, leading to vicious circles.

CONCLUSIONS

We have conceptualized psychological dysfunction in asthma using a framework consisting of affect, behavior and cognition. Their influences are intertwined and complex. Future research should focus on the formulation of a psychological assessment tool based on this framework and evaluating its efficacy in improving asthma outcomes.