Asthma control and severe exacerbations in patients with moderate or severe asthma in Jilin Province, China: a multicenter cross-sectional survey

Asthma is a common disease of airway inflammation with a high prevalence worldwide [1]. Asthma control refers to coming to a steady state after treatment. It has been reported that asthma has not been well-controlled in a large number of asthma patients, as defined by international guidelines [2‐4]. A multicenter study of 10 large developed cities in China has reported that 28.7 % and 45.0 % of asthmatic patients achieve full and partial control, respectively, according to the guidelines of the Global Initiative for Asthma (GINA) [5]. However, the data is not sufficient for evaluating the asthma control in China, because China is a large country in which the socioeconomic status, medical insurance coverage, climate and living environments vary considerably between different regions. All of these factors might influence asthma control. Therefore, additional studies on asthma control in different regions of China are needed.

Jilin Province is located in the northeast region of China and characterized by a cold climate, relatively low gross domestic product (GDP) and slow economic development. Until recently, there is few data on asthma control and risk factors for severe asthma exacerbations in Jilin Province. This study aimed to provide useful information in this field. In addition to asthma control test (ACT) questionnaire, we also investigated frequencies of asthma exacerbations. Because there is rare data on risk factors of asthma in China, the study also analyzed the effect of adherence, application of asthma medicine, severity and socioeconomic status on asthma control in Jilin Province so as to further explore the risk factors of asthma in China. This survey will provide useful guidelines for preventing and managing asthma in Jilin Province, China.

It was the first multicenter hospital-based cross-sectional study to comprehensively investigate status of asthma control and risk factors for severe asthma exacerbations in patients with moderate or severe asthma in Jilin Province in northeast China. Based on the ACT scores, the current study found good asthma control in 31.61 % of the patients with moderate or severe asthma; partial asthma control in 40.27 %; and poor asthma control in 28.12 %. The percentage of the patients with severe asthma exacerbations during the follow-up period was 54.89 %. These findings suggest unsatisfactory asthma control. Moreover, the study found that the ACT scores were negatively correlated with the frequency of severe asthma exacerbations during the follow-up period, and ACT scores ≤ 15 was identified as an important risk factor for severe asthma exacerbations. The finding was in accordance with the data presented by Haselkorn T [11]. The differences between ACT scores and frequency of severe asthma exacerbations were that ACT scores were often required from the patient's subjective feeling, and revealed four recent weeks of asthma control rather than one year.

Poor adherence was shown in our study. Only 38.4 % of the patients continued their medication for more than 3 months after discharge, and only 8.66 % of the patients were reviewed regularly by physicians, which is lower than the data found in a study conducted in USA [12]. The study also showed that within one year after discharge, severe asthma, rural and poor patients tended to have lower ACT scores and higher frequencies of severe asthma exacerbations.

Asthma control assessments contain symptom control assessment and risk factor assessment. It has been reported that overestimating asthma control based on ACT scores will result in inadequate treatment or even termination of medication [13‐15]. Thus, we not only studied ACT scores, but also investigated the frequency and risk factors of severe asthma exacerbations in the patients in the current study. The use of ICS/(ICS + LABA)/(ICS + LAMA) ≤ 3 months was found to be the greatest risk factor for severe asthma exacerbations, which was in line with previous findings [16‐19]. In addition to ICS/(ICS + LABA)/(ICS + LAMA) ≤ 3 months, the study found that ACT scores ≤15, asthma severity, a junior high school and lower educational level, an income level lower than PCDI, hospital days ≥15 days, rural residence and FEV1 ≤ 50 % predicted were also risk factors for severe asthma exacerbations. Previous studies have reported that FEV1 < 60 % predicted is a risk factor for exacerbations [20, 21]. However, the study found that FEV1 < 50 % predicted was a more significant criterion than FEV1 < 60 % predicted for severe asthma exacerbations. This difference might be attributed to the fact that the pulmonary function testing has primarily been conducted in convalescence, immediately following an acute exacerbation, when pulmonary function is not totally recovered. In the study, 71.48 % of the patients who did not take the ICS/(ICS + LABA)/(ICS + LAMA) for more than 3 months complained that the medicines were too expensive (300–600 RMB per month). Our study revealed that lower income and education, and medical insurance with low reimbursement ratio were main risk factors for poor adherence of asthma treatment, and 71.48 % of patients stopped the therapy of ICS/(ICS + LABA)/(ICS + LAMA) ahead of schedule, due to expensive price of medicines. So reduced out-of-pocket expenses [22] or free drugs may improve medication adherence from the government level. Otherwise, 45.89 % of asthma patients used other drugs to instead of ICS/(ICS + LABA)/(ICS + LAMA), for example theophylline, which has been recently shown to have antiinflammatory effects in asthma at lower concentrations, is used commonly in China for cheaper price [23]. Meanwhile, some traditional Chinese medicine had been used irregularly. So a multi-center, cross-sectional study about certain cheaper drugs for asthma control to improve adherence to self-administered medications should be designed well in further.

These findings suggested that lower socioeconomic and educational levels and limited reimbursement from insurance were the primary obstacles to regularly using their asthma medicine. These were in accordance with previous data showing that socioeconomic problems are major risk factors for asthma-related deaths [24]. One explanation is that government revenue, education and medical expenditures of Jilin Province are relatively low in China [6]. Furthermore, a low household income and low educational level were shown to not only decrease the adherence of asthma medication but also independently increase the risk of severe asthma exacerbations in the present study. Similarly, it has been shown that the risk of severe life threatening asthma (SLTA) increases with the lack of formal income [25]. This indicated that higher household income, increased education and medical expenditures, and higher reimbursement from insurance might aid in prevention of severe asthma exacerbations and contribute to asthma control improvement.

Atopic status and infection are both important factors for acute attack of asthma. We found 36.67 % of patients had atopic status in our study, but atopic status of patients was not risk factor for severe asthma exacerbations in the follow-up period. The comorbidity of pneumonia, which reflected partly infection in lung, was not associated with severe asthma exacerbations in the follow-up period.

Smoking has been reported to be a risk factor for poorly controlled asthma and an impaired corticosteroid response [26]. In contrast, smoking was not a significant risk factor for severe asthma exacerbations in our survey, which might be due to the lower percentage (9.96 %) of asthma patients who were currently smoking compared with other studies. The percentage of former smoker was 39.78 %. This suggested that many patients might quit smoking after diagnosis of asthma. Another reason might be difference patient resources.

The study has some limitations. There may be a selection bias because the asthma patients were enrolled only from five first-class hospitals in Jilin Province. Another limitation is the high dropout rate that 889 of 1546 patients provided a complete follow-up questionnaire. Furthermore, it is difficult to evaluate the effect of season and airway infection on severe asthma exacerbation each time, because we collected the data of severe asthma exacerbations of patients in follow up visit per three months retrospectively, but not immediately when the acute exacerbations happened. And some information in detail was not complete because the hospitalization and emergency department visit of patients were not in original hospitals sometimes. Otherwise, it is difficult to evaluate the infection situation each time, due to the partly abuse of antibiotics in China. Thus, increasing the frequency of follow-up visits and establishing the network of hospitals with different grades would be solutions. Finally, follow-up studies after discharge might increase the understanding and condition of asthma control. Further large-scale studies are warranted to validate the findings of this study.

Collectively, this study found unsatisfactory asthma control and a high frequency of severe asthma exacerbation in Jilin Province, which were mainly due to poor adherence to asthma medication, poor asthma symptom control, low income, a low educational level and a low proportion of reimbursements from insurance companies. Our results provide basic data for improving asthma control in Jilin Province and will help physicians instruct patients on how to avoid the risk factors associated with asthma exacerbation.