Validation of Ramathibodi's acute asthma predictive score.

BACKGROUND: The authors have recently developed Ramathibodi's acute asthma predictive score to help the attending physician decide on a safe discharge of an acute asthmatic patient from the emergency room (ER). However the authors did not validate it in the previous study. OBJECTIVE: To validate the predictive score with a new different population. MATERIAL AND METHOD: The authors conducted a study on acute asthmatic patients, in continuation from our previous study, between September 2005 and September 2007 in the ER of Ramathibodi Hospital. Vital signs, oxygen saturation, and severity factors were recorded. All patients were treated with nebulized salbutamol initially and repeatedly if the peak expiratory flow rates were < 70% predicted or if unfavorable physical signs were seen. The patients who had any of the severity factors were given systemic steroids. Patients were assessed for admission if further treatments were needed after the fourth nebulization. An unfavorable outcome was defined as either hospital admission or relapse within 48 hours of the ER discharge. Then, the authors' predictive score was calculated to give a total score for each patient. Using a cutoff score of 2, the authors calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). The area under the receiver operating characteristic (ROC) curve (AUC) was also calculated and compared with that of the development cohort. RESULTS: There were 863 visits from 546 patients and 66.6% had a score of < or = 1 while 33.4% had a score of > or = 2. Using a cutoff score of 2, the acute asthma score exhibited a sensitivity of 60.0%, a specificity of 67.4%, a PPV of 5.7%, and a NPV of 98.1%. The validation group's AUC did not differ from that of the development group. CONCLUSION: Ramathibodi's acute asthma predictive score was found as a valid useful tool for a proper ER discharge of acute asthmatic patients.