The RAD score: a simple acute asthma severity score compares favorably to more complex scores

Acute asthma severity scores facilitate assessment and implementation of timely and appropriate therapy for pediatric patients but are complex and challenging for clinicians to use at the bedside.

To assess whether a simple, bedside acute asthma severity score comprising 3 standard clinical measures performs as well as more comprehensive asthma scores.

We prospectively enrolled participants 5 to 17 years of age with acute asthma exacerbations. We recorded 3 asthma scores at baseline and after 2 hours of treatment: the Pediatric Asthma Severity Score (PASS), the Pediatric Respiratory Assessment Measure (PRAM), and the RAD score (Respiratory rate; Accessory muscle use; Decreased breath sounds). We assessed each score for criterion validity in predicting baseline percent forced expiratory volume in 1 second (%FEV(1)) and for responsiveness in predicting change of %FEV(1) after 2 hours of treatment using multiple linear regression models adjusted for age, race, sex, and Global Initiative for Asthma chronic control.

Of 536 participants included for analyses, median age was 8.8 years, 60% were male, and 58% were African American. The 3 acute asthma scores demonstrated similar criterion validity to explain variation of baseline %FEV(1) (R(2): 0.434 [PASS]; 0.462 [PRAM]; 0.426 [RAD]), but none demonstrated clinically significant responsiveness to change in %FEV(1) (R(2): 0.109 [PASS]; 0.106 [PRAM]; 0.139 [RAD]).

The RAD score, comprising 3 routinely measured bedside clinical parameters, is a simple and easily used instrument for assessing the severity of an acute asthma exacerbation and has comparable criterion validity and improved responsiveness when compared with 2 more complex acute asthma scores.