Asthma Severity Linked to Extent of Hospital Use, Cost of Care

Strong and graded associations were reported between asthma severity and the extent of hospital use and costs in the United Kingdom. These findings may help guide future assessments of the value of asthma management interventions.

This observational study is published in BMJ Open Respiratory Research.

“The present study provides a real-world evaluation of the excess hospital care use and costs of adults with asthma in the UK across categories of asthma severity,” wrote the researchers of the study. “Asthma clearly places a very large burden on secondary care, with severity significantly affecting the size of this burden. Understanding the scale of hospitalization use and costs is central to justifying the development and use of novel therapeutic strategies that alleviate the burden of asthma.”

The study aimed to provide an analysis of hospital care use and hospital costs of adults with asthma from the UK Biobank study, a large ongoing cohort study of 502,540 individuals ages 40 to 70 years at recruitment between 2006 and 2010.

Participants were classified according to their prescription data into mild and moderate-to-severe asthma and matched to asthma-free controls for age, sex, ethnicity, and location. Associations relating to asthma severity, the number of all-cause hospital admissions, days spent in hospital, and hospital costs were estimated over a 10-year follow up period.

The researchers identified a total of 59,998 individuals with an asthma diagnosis at the time of recruitment. Of these participants, 25,194 had a prescription of asthma medication, but 163 were excluded for missing data. After exclusion, 25,031 individuals were included in the active asthma cohort.

Of these participants, 80% had mild asthma and 20% had moderate-to-severe asthma, according to British Thoracic Society criteria. Participants with moderate-to-severe asthma were on average 2.7 years older, more likely to be current (13.7% vs 10.4%) or previous (40.2% vs 35.2%) smokers, have a higher BMI, and suffering from a variety of comorbid diseases, compared with participants with mild asthma.

Additionally, participants with mild asthma experienced on average 36% more hospital admissions (95% CI, 28-40), 48% more days in hospital (95% CI, 35-51), and 36% higher hospital costs (95% CI, 31-41) annually, compared with asthma-free individuals. Meanwhile, participants with moderate-to-severe asthma experienced 93% more hospital admissions (95% CI, 81-107), 142% more days in hospital (95% CI, 124-162), and 98% higher hospital costs (95% CI, 88-108), respectively.

After adjusting for sociodemographic and clinical characteristics, socioeconomic deprivation, smoking status, BMI, and comorbidities produced small, yet significant positive associations, graded by severity, between asthma and hospital use and costs.

However, the researchers acknowledged some limitations to the study. First, defining active asthma according to the dispense of asthma medications does not necessarily correlate with adherence to medications, in which some participants may have been misclassified. Additionally, the researchers were only able to categorize patients with asthma into 2 categories, which may have oversimplified the true complexity of asthma severity. Lastly, the researchers acknowledged their cohort was likely healthier than the wider, national population, which may have resulted in underestimated reports for overall rates and costs of hospital admissions.

Despite these limitations, the researchers believe the study shows how asthma severity is associated with hospital use and costs, which may guide strategies for cost savings through early detection and better allocation of therapies to patients who are most likely to benefit from them.

Reference

Jacobs A, Wu R, Tomini F, et al. Strong and graded associations between level of asthma severity and all-cause hospital care use and costs in the UK. BMJ Open Respir Res. 2023;10:e002003. doi:10.1136/bmjresp-2023-002003