Survey of COPD Management among the Primary Care Physicians in Korea

Prescription patterns and effectiveness of medications for chronic obstructive pulmonary disease: A retrospective study of real-world settings

This study aimed to define real-world prescription patterns in Korea and compare the effectiveness of chronic obstructive pulmonary disease (COPD) medications. We used national claims data provided by the Health Insurance Review and Assessment Service in Korea and examined patients who were first diagnosed with COPD and started treatment between May 1, 2017, and April 30, 2018, with no change in drug regimen. Among 30,784 patients with COPD, long-acting β2 agonist (LABA) combined with long-acting muscarinic antagonist (LAMA) (32.7%), inhaled corticosteroid-LABA (ICS-LABA) (25.6%), LAMA (18.3%), ICS (5.8%), or LABA (4.6%) were prescribed as the first-choice inhalers. The use of LABA-LAMA (hazard ratio [HR], 0.248-0.584), LAMA (HR, 0.320-0.641), ICS-LABA (HR, 0.325-0.643), and xanthine (HR, 0.563-0.828) significantly reduced the total and severe exacerbation rates compared with no use of each medication. However, the use of ICS or LABA individually did not yield such effects. The continued use of LABA-LAMA, LAMA, and ICS-LABA showed a significant effect on exacerbation rate, whereas the long-term use of ICS, LABA, and xanthine did not. Moreover, some high doses of ICS-LABA did not show significant effects. This real-world study revealed that LAMA and/or LABA could be the first choice of therapy, as recommended by recent guidelines. However, ICS, xanthine, and high-dose ICS-LABA are still being prescribed frequently as first-line drugs in Korea.

Cut-off value of FEV1/FEV6 to determine airflow limitation using handheld spirometry in subjects with risk of chronic obstructive pulmonary disease

BACKGROUND/AIMS

Postbronchodilator forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) less than 0.7 using spirometry is the golden standard to diagnose airf low limitation of chronic obstructive pulmonary disease (COPD). Recently, measuring FEV6 has been suggested as an alternative to measure FVC. Studies about the cut-off value for FEV1/FEV6 to diagnose airflow limitation have shown variable results, with values between 0.7 and 0.8. The purpose of this study was to determine the best cut-off value of FEV1/FEV6 to detect airflow limitation using handheld spirometry.

METHODS

We recruited subjects over 40 years of age with smoking history over 10 pack-years. Participants underwent measurements with both handheld spirometry and conventional spirometry. We calculated the sensitivity and specificity of the value of FEV1/FEV6 using receiver-operating characteristic (ROC) curve analysis to obtain the diagnostic accuracy of handheld spirometry to detect airflow limitation.

RESULTS

A total of 290 subjects were enrolled. Their mean age and smoking amount were 63.1 years and 31.6 pack-years, respectively. According to our ROC curve analysis, when FEV1/FEV6 ratio was 73%, sensitivity and specificity were the maximum and the area under the ROC curve was 0.93, showing an excellent diagnostic accuracy. Sensitivity, specificity, positive predictive value, and negative predictive value were 86.7%, 89.7%, 88.0%, and 88.5%, respectively. Participants with FEV1/FEV6 ≤ 73% had lower FEV1 predicted value compared to those with FEV1/FEV6 > 73% (65.4% vs. 86.5%, p < 0.001).

CONCLUSION

In summary, we demonstrate that the value of 73% in FEV1/FEV6 using handheld spirometry has the best sensitivity and specificity to detect airflow limitation in subjects with risk of COPD.

Patterns and determinants of COPD-related healthcare utilization by severity of airway obstruction in Korea

Background

We investigated patients with chronic obstructive pulmonary disease (COPD) to analyze patterns and identify determinants of healthcare use, according to the severity of airflow obstruction. We used retrospective cohort data from a combination of the 4^th Korea National Health and Nutritional Examination Survey (KNHANES) and Korean National Health Insurance (NHI) claims.

Methods

Demographic and medical claims data were retrospectively analyzed from the 4^th KNHANES along with NHI claims. Eligible patients were aged ≥40 years, who underwent complete pulmonary function tests (PFTs), and had at least one inpatient or outpatient claim coded as COPD between January 1, 2007 and December 31, 2010.

Results

Among 6,663 eligible participants, 897 (13.5%) had airway obstruction. Self-reported physician-diagnosed COPD comprised only 3%, and there were 870 undiagnosed COPD patients (97%). Self-reported physician-diagnosed asthma made up 3.7%. Of the 897 respondents, 244 (27.2%) used COPD-related healthcare services. The frequency of healthcare visits increased with increasing severity of airway obstruction. After a 3-year follow-up period, 646 (74.2% of those initially undiagnosed) remained undiagnosed and only 224 (25.8%) were diagnosed and treated for COPD. Only 27.5% of the 244 participants with airway obstruction who used COPD-related healthcare underwent PFTs during the study period. The percentage of prescribed medications associated with COPD increased in accordance with the severity of the COPD. Inhaled long-acting anticholinergics were prescribed for 10.9% of patients with moderate airway obstruction and for 52.4% of patients with severe obstruction. Inhaled long-acting β-agonists combined with corticosteroids were prescribed for 50% of patients with severe airway obstruction. Conversely, 44.6% of healthcare users were prescribed oral theophylline for COPD treatment, and 21.7% were also prescribed an oral corticosteroid. The determinants of COPD-associated healthcare use in respondents with obstructive lung disease were advanced age, severe airflow limitation, presence of comorbidities, and self-reported physician diagnosis of COPD.

Conclusions

This study ascertained marked underdiagnosed COPD. Although the percentage of prescribed medication used to treat COPD increased with the severity of the COPD, medications primarily prescribed such as oral theophylline or oral corticosteroids are inappropriate for first-line COPD treatment.

A Validation Study for the Korean Version of Chronic Obstructive Pulmonary Disease Assessment Test (CAT)

BACKGROUND

Health status measure is not only important for clinical research studies but also for clinical practices of chronic obstructive pulmonary disease (COPD) patients. The objective of this study is to evaluate the validity of the Korean Version of COPD Assessment Test (CAT) in primary care clinics as well as in referral hospitals.

METHODS

Smokers or ex-smokers, aged 40 years or older, with a smoking history of >10 pack-years; and a COPD diagnosis in the past 6 months or more, were recruited from 4 primary care clinics and 2 referral hospitals. Demographic, medical, and spirometry data was collected from patients who completed the CAT and St. George Respiratory Questionnaire (SGRQ), and had their dyspnea been assessed. The primary endpoint was the correlation between of the Korean version of CAT with SGRQ in patients with COPD.

RESULTS

A total 100 patients were enrolled. The mean age and smoking amounts were 69.2±8.4 years and 40.6±22.3 pack-years, respectively. Sixty-seven percent of the patients reported at least one exacerbation in the past year. The mean CAT score was 16.9±8.0. The internal consistency assessed by Cronbach's alpha was 0.85. The CAT score was positively correlated with the SGRQ score (r=0.76, p<0.0001) and each component of SGRQ: symptoms, activity and impacts; r=0.68, r=0.61, and r=0.72, respectively (all p<0.0001). These positive correlations were preserved in the different groups (r=0.86, p<0.0001 in primary care clinic group; r=0.69, p<0.0001 in hospital group). The CAT score was also positively correlated to the Medical Research Council dyspnoea scale (r=0.46, p<0.0001).

CONCLUSION

The Korean version of CAT had good internal consistency and showed good correlations with SGRQ. It can be used for assessing the impacts of COPD on the patient's health including primary care setting.

Customized Asthma Control Test with reflection on sociocultural differences

We evaluated the utility and feasibility of customizing Asthma Control Test (ACT) items to generate a Korean Asthma Control Test (KACT) specific for Korean patients. We surveyed 392 asthma patients with 19 items, selected to reflect the Korean sociocultural context. Guideline ratings were integrated with the evaluations of specialists (i.e., using both guide base rating together with specialist's rating), and items with the greatest discriminating validity were identified. Stepwise regression methods were used to select items. KACT scale scores showed significant differences between the asthma control ratings generated by integrating ratings (r=0.77, P<0.001), by specialist's evaluations (r=0.54, P<0.001), or by FEV(1) percent predicted (r=0.39, P<0.001). Specialist's and guideline ratings detected 56% and 48.6% of patients with well-controlled asthma, respectively. However, the integrated ratings indicated that only 34.3% of the patients in the test sample were well controlled. The overall agreement between KACT and the integrated rating ranged from 45% to 78%, depending on the cut-off points used. It is possible to formulate a valid, useful country-specific diagnostic tool for the assessment of asthma patients based on the original ACT that reflect differences in sociocultural context.