A cut-point of 5 was recommended in a previous study using the English version. The reason for this Autophagy Compound Library discrepancy is not clear, but backgrounds of the study subjects may affect cut-points. In addition to the difference between Asian and Western populations, the present study is population-based while patients from general practice and specialist sites were involved in the previous report. In this study, a cut-point of 5 resulted in a lower sensitivity of 34.9% and a smaller area under the ROC curve of 0.57 compared with a cut-point of 4.
Although the use of spirometry at all levels of health care might improve diagnosis and detect COPD earlier, widespread spirometric testing for early detection without pre-selection of at-risk patients may result in wasting healthcare resources. Without bronchodilator, 11.2% of adults aged between 40 and 79 years showed an initial FEV1/FVC < 0.7, and this prevalence is in line with the previous Japanese COPD epidemiology study conducted in 2001. Finally, 6.5% had confirmed fixed AO after bronchodilator in this study, and the COPD-PS and its cut-point of 4 resulted in a positive predictive value 14.6%. The prevalence of fixed AO was lower than expected. Aging increases the prevalence of COPD. The chosen target group in our study was aged 40–79 years, and this age limit may affect the prevalence of AO. We also excluded the subjects with physician-diagnosed asthma, which contains current- and former-smokers, and thus may preclude subjects with overlap syndrome of COPD and bronchial asthma.
A PPV of 14.6% at COPD-PS cut-point 4 is lower than the previous report of a hospital/clinic-based study. However, PPV depends on the prevalence, and PPV becomes lower when the prevalence of disease is low. The hospital/clinic-based prevalence will vary by age and smoking prevalence. In contrast, we have evaluated the diagnostic cut-points of the COPD-PS in the general Japanese population. The prevalence of confirmed fixed AO was 38.4% in the previous report, and that was 6.5% in the present study. Despite this limitation, NPV was sufficiently high in this study, suggesting that COPD-PS with cut-point 4 is useful for a screening tool.
This study has limitations that should be acknowledged. Subjects over the age of 60 and have smoked more than 100 cigarettes could reach 4 point without any respiratory symptoms. This could lead to an increase in false positives. As the objective of the COPD-PS is to be a diagnostic triage for spirometry testing, it is important to capture as many true positive COPD patients as possible, while allowing false positives to a certain degree. A considerable percentage of the nonsmoker population may exhibit COPD, and future studies evaluating a secondhand smoke item and indoor pollution at home may be of interest. In addition, AO was assessed based solely on the spirometry data, and further evaluations would be needed for the diagnosis of COPD.
This study was supported in part by Nippon Boehringer Ingelheim and Pfizer Japan, by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS) (HI, 25293192), and by Health and Labour Sciences Research Grants from the Ministry of Health, Labour and Welfare of Japan. The sponsors did not have direct influence on the study design or analysis.
Japanese cedar pollinosis is an allergic disease specific to Japan with a high prevalence estimated to be 26.5%, which has increased by 10% over the past ten years. Seasonal allergic rhinitis induced by cedar pollen takes a chronic course in the majority of middle-aged patients. Remission rarely occurs, especially in the younger generation.
Sublingual immunotherapy (SLIT) is safer than conventional percutaneous antigen-specific immunotherapy, and is the only treatment which can completely cure the disease. It has been shown that SLIT is effective and safe in the treatment of cedar pollinosis by a randomized, placebo-controlled, double-blind study.