Patient Preference and Adherence (Mar 2016)
Development and validation of a predictive model of failed stepping-down of inhaled corticosteroids in adult asthmatics
Abstract
Akira Yamasaki,1 Katsuyuki Tomita,2 Kazuhiro Kato,3 Kouji Fukutani,3 Hiroyuki Sano,4 Yuji Tohda,4 Eiji Shimizu1 1Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, Faculty of Medicine, Tottori University, Tottori, 2Department of Respiratory Medicine, Yonago Medical Centre, Tottori, 3Department of Respiratory Medicine, Sanin Rosai Hospital, Tottori, 4Department of Respiratory Medicine and Allergology, Faculty of Medicine, Kinki University, Osaka, Japan Background: Asthma guidelines suggest stepping-down of inhaled corticosteroids (ICSs) when asthma is stable. Objective: To determine outcomes of stepping-down and prediction of outcome after stepping-down of ICSs in controlled adult asthma. Methods: We performed a retrospective study on 21–81 year-old hospital-based outpatients with asthma in Japan. Protocol for stepping-down of ICSs was performed according to the GINA guideline. Failure/success of stepping-down is judged as occurring exacerbation or not for stepping-down of ICSs. Multiple logistic regression analysis was used to develop a prediction model for failed stepping-down, and then was validated by the leave-one-out cross-validation method. Our model of prediction score was calculated using receiver-operating characteristic area under the curve (AUC) analysis. The Nelson–Aalen curve demonstrated time to failure of stepping-down of ICSs. Results: A total of 126 patients with asthma attempted the stepping-down of ICSs according to the guideline. Of patients with follow-up, 97 (77.0%) of stepping-down attempts were successful. Using multivariate logistic regression analysis, comorbidity with rhinitis/rhinosinusitis and phlegm grade were independent predictors of failed stepping-down of ICSs, with odds ratios of 3.8 (95% confidence interval, 1.04–13.3; P=0.04) and 1.3 (95% confidence interval, 1.01–11.5; P=0.04), respectively. These variables were then used to build a prediction score in terms of the prediction of failed stepping-down events. When the two variables were added to form the prediction score, the discriminative power of scores calculated by the prediction model using the AUC was 0.75 (range: 0.62–0.88) for naïve prediction and 0.72 (range: 0.60–0.86) after cross-validation. In the time-to-failure models, cumulative hazard ratio of failed stepping-down have fixed 1 year after stepping-down. Conclusion: Our results suggest that comorbidity with rhinitis/rhinosinusitis and phlegm grade are imperative to predict failed stepping-down of ICSs in controlled patients with adult asthma. Keywords: asthma, ICSs, stepping-down
