Predicting Poor Asthma Control, Exacerbations in Adults Using Percent Recovery Index

Using a percent recovery index (PRI) to predict poor asthma control and exacerbations in adults may be an effective tool in navigating treatment options and management of the disease, a study finds.

The authors noted that effective treatment of asthma can reduce PRI, demonstrating the index’s value for evaluating curative effects of therapy, making this the first study to examine the influence of treatment on PRI. Findings were published in the Journal of Asthma and Allergy.

PRI is a metric produced from the methacholine bronchial provocation test (MBPT) and is the percentage increase from the maximally reduced forced expiratory volume per 1 second (FEV₁) after bronchodilator inhalation. However, there is little research on the effects of PRI in predicting poor asthma control and exacerbations. In the current study, the researchers aimed to examine whether PRI can be used to predict poor asthma control and exacerbations in adults, while also evaluating the impact of treatment on PRI.

The study included a total of 61 adults aged 18 to 60 years with a diagnosis of asthma based on a history of wheezing or coughing, as well as at least 1 of the following characteristics: FEV₁ reversibility greater than 12%, positive bronchial challenge tests, average daily diurnal peak expiratory flow (PEF) variability greater than 10%, or PEF weekly variation rate greater than 20%.

Additionally, the researchers defined an asthma exacerbation as the use of systemic corticosteroids for at least 3 consecutive days or asthma-specific emergency visits or hospitalizations. A history of previous exacerbations during 1 year prior to enrollment was also recorded.

Baseline characteristics obtained at enrollment included MBPT, lung function, asthma exacerbation, Asthma Control Test, Mini Asthma Quality of Life Questionnaire, and inflammation factors: fractional exhaled nitric oxide (FENO), blood eosinophil count, and alveolar NO (CaNO). These characteristics were also measured at a 3-month follow up. Additionally, covariates such as age, sex, body mass index, previous exacerbation, smoking status, and lung function were obtained for each patient at the start of the trial.

At follow up, the researchers discovered a significant association between PRI and asthma exacerbation (P = .023), poor asthma control (P = .014), decreased quality of life (P = .010), and a cumulative number of emergency visits or hospitalizations (P = .039).

However, no association was observed between baseline values for FENO, CaNO, or blood eosinophil count and follow-up.

Furthermore, PRI dramatically decreased after 3 months of standard treatment.

The researchers acknowledge some limitations to the study. First, the comparison between PRI and bronchodilator reversibility was not included in the study, in which the researchers believe more studies need to be done on this distinction. Additionally, the researchers believe PRI may reflect the inherent property of airway smooth muscle (ASM), suggesting a different direction for future research.

Despite limitations, the researchers believe this study shows how PRI can be used as a valuable tool in predicting poor asthma control, exacerbations, and decreased quality of life in adults.

“PRI may be also valuable to the evaluation of curative effect in asthma,” wrote the researchers. “Finally, we proposed that predicting ability of PRI may be based on the inherent property of ASM.”

Reference

Kuang L, Ren C, Liao X, Zhang X, Zhou X. Percent recovery index predicts poor asthma control and exacerbation in adults. J Asthma Allergy. 2023;16:711-722. doi:10.2147/jaa.s414164