Respiratory tract infection-induced asthma exacerbations in adults with asthma: assessing predictors and outcomes

Abstract

Objective: To evaluate clinical and economic burden associated with respiratory tract infection (RTI)-induced asthma exacerbations and to identify risk factors associated with these exacerbations. Factors associated with these exacerbations are understudied and little information is available about consequent expenditures. Methods: In this retrospective case-control study, medical records and pharmacy data in King Abdullah University Hospital in Northern Jordan were reviewed for adults with asthma aged 40 years and older, over the period 2013–2016. Cases of RTI-induced asthma exacerbations were identified, and controls were selected randomly from asthmatic adults who did not experience any RTI-induced asthma exacerbation during the same period. Independent-samples t-tests and chi-square tests were conducted to compare patient characteristics of cases and controls. Predictors of RTI-induced asthma exacerbations and the resultant complications were evaluated using multivariable logistic regression. Multivariable regression on log-transformed charges was used to predict expenditures of these exacerbations. Results: A total of 137 cases and 548 controls were identified. Using inhaled corticosteroid + long-acting beta-agonists (ICS + LABA) was significantly associated with lower odds of RTI-induced asthma exacerbations (OR = 0.4; 95% CI, 0.21–0.77; p = 0.006), and lower odds of resultant serious complications (OR = 0.23; 95% CI, 0.07–0.69; p = 0.009), compared to being untreated with any asthma maintenance treatment. Asthma severity and co-morbidities were associated with increased susceptibility to these exacerbations. The average charges of RTI-induced asthma admissions and outpatient exacerbations were 1042.9 JD ($1471.0) and 81.1 JD ($114.4), respectively. Conclusions: ICS + LABA, asthma severity and co-morbidities appeared to affect the clinical and economic burden associated with RTI-induced asthma exacerbations. Efforts to prevent these exacerbations in patients with risk factors are warranted.

Keywords:

• Asthma control
• RTI
• inpatient admission
• outpatient exacerbation
• expenditure
• ICS + LABA

Acknowledgements

Dr. Carolyn Thorpe, an associate professor in the Division of Pharmaceutical Outcomes and Policy at the UNC Eshelman School of Pharmacy, is acknowledged for copy editing the revised manuscript.

Funding

This study was supported by the Deanship of Scientific Research at Jordan University of Science and Technology (grant number 41/2017).

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.