Implementing diagnostic testing to verify an asthma diagnosis in the United States could save more than $56 billion over 20 years, according to the results of a recent study published in the Journal of Allergy and Clinical Immunology.
A decision tree-based diagnostic approach was applied to simulated US adults with diagnosed asthma. Using numbers from previously reported studies, it was determined that 15% of patients would have their asthma confirmed through a positive spirometry test result, and 48% of the remaining patients would have their asthma confirmed through a positive methacholine challenge test (MCT) result. Cost savings of applying the diagnostic criteria — called the diagnostic verification scenario — were then determined.
The model was applied to a simulated cohort of 10,000 adults with diagnosed asthma. Of these 10,000 simulated patients, 3366 were expected to have their diagnosis reversed. Additional costs of spirometry testing and an MCT in the diagnostic verification scenario would be $2.48 million and $3.77 million, respectively. The total savings in medication costs would be $49.85 million. However, there would be an extra 3314 patient-years with uncontrolled asthma compared with under the status quo scenario, and as a result there would be 1595 more exacerbations.
When extrapolating this to the entire US population over the course of 20 years, diagnosis of asthma would be reversed in 70.29 million individuals, the total undiscounted cost savings would be $56.48 billion, and there would be a cumulative gain in quality-adjusted life years of 6.14 million.
“Our results indicate that secondary diagnostic verification of asthma during routine clinical encounters among adults with a self-reported asthma diagnosis may be cost-saving and may improve patients’ quality of life,” the researchers wrote. “The overall conclusions made in this study about the merits of such diagnostic verification remained robust against changes in assumptions and parameter values.”
Yaghoubi M, Adibi A, Zafari Z, et al. Cost-effectiveness of implementing objective diagnostic verification of asthma in the United States. J Allergy Clin Immunol. 2020;145(5):1367-1377.