The Effect of Asthma Clinical Guideline for Adults on Inhaled Corticosteroids PrescriptionTrend: A Quasi-Experimental Study

In order to increase inhaled corticosteroid (ICS) use and to reduce hospitalization, emergency department visits and ultimately the economic burden of asthma, "Korean Asthma Management Guideline for Adults 2007" was developed. To assess the guideline effects on physician's ICS prescription for asthma, we conducted segmented regression and multilevel logistic regression using National Health Insurance claims database of outpatient visits from 2003 to 2010. We set each quarter of a year as a time unit and compared ICS prescription between before and after guideline dissemination. A total of 624,309 quarterly visits for asthma was observed. The ICS prescription rate before and after guideline dissemination was 13.3% and 16.4% respectively (P < 0.001). In the segmented regression, there was no significant guideline effect on overall ICS prescription rate. In multilevel logistic regression analyses, the effect of guideline on overall ICS prescription was not significant (odds ratio, 1.03; 95% CI, 1.00-1.06). In subgroup analysis, ICS prescription increased in secondary care hospitals (odds ratio, 1.15; 95% CI, 1.02-1.30) and in general hospitals (odds ratio, 1.10; 95% CI, 1.04-1.16). However, in primary clinics, which covered 81.7% of asthma cases, there was no significant change (odds ratio, 0.98; 95% CI, 0.94-1.02). From the in-depth interview, we could identify that the reimbursement criteria of the Health Insurance Review and Assessment Service and patient's preference for oral drug were barriers for the ICS prescription. The domestic asthma clinical guideline have no significant effect on ICS prescription, especially in primary clinics. Graphical Abstract Keywords: Asthma, Guideline, Corticosteroid INTRODUCTION There is growing concern about the increasing prevalence, chronic morbidity, and mortality of asthma, an inflammatory disease of the lower airway system (1). Asthma also substantially impacts national economics for both industrialized and developing countries (2). Asthma-related costs represent 0.1%-0.3% of the gross domestic product (GDP) for some countries (3). In Korea in 2004, the economic burden to patients was USD 4.11 billion, which was equivalent to 0.44% of the national GDP (4). When considering the increasing trend of asthma prevalence in Korea, the socioeconomic burden for asthma may become extremely high within a few decades (5). The drug types used to control asthma can be divided into two categories: anti-inflammatory medications and bronchodilators. Among these two drug categories, anti-inflammatory medications, especially inhaled corticosteroids (ICS), are considered first-line treatments for maintenance therapy (6). In the United States, the current overall rate of anti-inflammatory medication use for asthma is 20.1%, and ICS represents a major portion of that at 72.5%. (7). In Europe, about 43% of the population has used ICS for asthma (8). However, the ICS prescription rate in Korea is much lower. In a survey conducted in 2000, which evaluated asthma control in the Asia-Pacific region, the reported ICS use was the lowest as 1.2% in Korea (9). In order to increase ICS use and reduce hospitalization, emergency department visits, and ultimately the economic burden of asthma costs, the Korean Academy of Asthma, Allergy and Clinical Immunology; the Korean Academy of Tuberculosis and Respiratory Diseases; and the Korean Academy of Medical Science cooperated to develop a clinical guideline for asthma, which was funded by the Korea Centers for Disease Control and Prevention (KCDC). This guideline was published in November 2007 and revised in March 2011 (10). Recently, a study was published that used the National Health Insurance (NHI) claims database to assess drug prescription patterns for asthma (11). The researchers observed a slightly increasing trend of ICS prescription, but the effects of the asthma guideline dissemination on this trend was not evaluated. Our aim was to evaluate the effects of the "Korean Asthma Management Guideline for Adults 2007" on physicians' ICS prescription rate.