How to Predict Asthma Exacerbations

Data that are commonly available to clinicians may be used to predict asthma exacerbations, including blood eosinophil count, according to recent research.

A study published in the Journal of Asthma and Allergy, conducted by David Price, of the Center for Primary Care at the Institute of Applied Health Sciences at the University of Aberdeen in Scotland and colleagues, provides evidence that such data can be used as practical predictors.

Exacerbations of asthma often require hospitalization, as well as treatment with systemic corticosteroids. If exacerbations could be predicted, the clinician would be better able to create a management plan to reduce them. This study was undertaken, according to the authors, “to generate a weighted list of exacerbation predictors that would enable the physician to design an individualized management plan aimed at decreasing the patient’s exacerbation risk.”

The researchers used data from August 1990 to February 2013 of asthma patients listed in two large, anonymized databases in the UK. “The final study group consisted of patients with a physician-recorded diagnosis of asthma but no other chronic respiratory disease, at least one valid blood eosinophil count, 1 full year of data on each side of the index blood eosinophil count, and aged between 12 and 80 years at the index date,” said the researchers of participant selection.

Each patient record for the year before and the year after the date of the blood eosinophil count was examined, said the researchers, “to identify and weight the routine clinical indices that were predictive of multiple severe asthma exacerbations in the next year.” A total of 130,547 patient records were included in the study, and “approximately 7% of the patients had two or more exacerbations in either their baseline (6.9%) or outcome (6.5%) year,” said the researchers.

The researchers say, “there are three findings of particular note” in this study. The first is that the frequent exacerbation group can change; that is, the group with frequent exacerbations in the baseline year was not the same as the group that had frequent exacerbations in the outcome year. Second, the researchers report, “several novel exacerbation predictors were identified in routine medical records.” The third notable finding is that physicians can tailor the risk of exacerbation for individual patients by looking at a group of risk factors.

The researchers conclude, “More than 20 different variables significantly increased, and in some cases decreased, the likelihood that the patient would experience two or more exacerbations in the next year.” They also noted, “By identifying and quantitating all applicable risk factors, the physician is better equipped to formulate a treatment plan aimed at reducing the patient’s specific risk of frequent exacerbations.” They are working on an algorithm that may help physicians calculate risk for individual patients.