Epidemiology of COPD: Why Is the Disease So Poorly Recognized?

Participant Selection from the General Japanese Population for Pulmonary Function Tests Using a Questionnaire on Symptoms and Smoking Habits during Annual Health Checkups: The Yamagata-Takahata Study

Objective Pulmonary function tests are essential for diagnosing respiratory diseases, such as chronic obstructive pulmonary disease (COPD), but are typically not performed in Japan during annual health checkups, which hinders the early diagnosis of respiratory diseases. Methods Individuals who agreed to participate in the Yamagata-Takahata study during medical checkups in Takahata (Yamagata Prefecture, Japan) in 2011 were examined. We interviewed 669 participants (49.0% men; mean age, 67.7 years old) regarding their respiratory symptoms and smoking habits and performed pulmonary function tests during the study. Results Based on pulmonary function test results, 141 participants had pulmonary dysfunction, and 115 had obstructive pulmonary dysfunction. The risk of respiratory dysfunction, particularly obstructive respiratory dysfunction, was examined by referring to a questionnaire tool for an early COPD diagnosis. The associations between age, the smoking history, respiratory symptoms, and obstructive respiratory dysfunction were evaluated. Obstructive respiratory dysfunction was found in 17.6% of participants ≥50 years old and 19.5% ≥60 years old, 30.3% had a smoking history, and 32.8% had respiratory symptoms. Furthermore, the participants with multiple factors had a higher probability of obstructive respiratory dysfunction. Conclusion Subjects with obstructive pulmonary dysfunction are expected to be efficiently identified by extracting individuals by age and smoking habit and through a respiratory symptom questionnaire, although pulmonary function tests cannot be performed for all individuals during health checkups.

[Assessment of the respiratory muscles strength at patients with chronic obstructive pulmonary disease with various forms of comorbidity]

The respiratory muscles (RM) strength is the main indicator of their functional state. However, RM strength is not used as criteria for chronic obstructive pulmonary disease (COPD) stratification.

AIM

To evaluate the RM power of COPD patients with various variants of comorbidity and to determine the role of comorbidity in the development of respiratory muscle dysfunction.

MATERIALS AND METHODS

RM strength of 64 men with exacerbation of COPD was studied. The severity of comorbidity was assessed by the Charlson index. Depending on the prevalence of comorbidity, patients were divided into 3 groups: cardiovascular, cerebrovascular and metabolic. Maximum inspiratory (MIP) and expiratory (MEP) pressures in the oral cavity, maximum rate of pressure development (MRPD), sniff nasal inspiratory pressure (SNIP), MEP/MIP and SNIP/MIP indexes were determined with MicroRPM device (UK). Measured values of MIP, MEP and SNIP were compared with the proper ones. The most noticeable decrease of RM strength was defined in the group of patients with severe comorbidity.

RESULTS

In case of a mild comorbidity MEP and SNIP values were 68 and 78% of the predicted values and MIP value corresponded to the personified standard. RM strength of patients with COPD depended on the clinical variant of comorbidity. Thus, in the group of patients with cardiovascular variant of comorbidity auxiliary inspiratory muscles strength decreased. In the group of patients with cerebrovascular variant of comorbidity the expiratory muscles dysfunction predominated. In the group of patients with metabolic variant of comorbidity diaphragm dysfunction predominated.

CONCLUSION

The pathogenetic significance of various factors of COPD comorbidity in the development of RM dysfunction was confirmed by the results of the correlation analysis.