Prevalence of airflow limitation in outpatients with cardiovascular diseases in Japan.

BACKGROUND AND OBJECTIVES: Cardiovascular disease (CVD) and chronic obstructive pulmonary disease (COPD) commonly coexist and share common risk factors. The prevalence of COPD in outpatients with a smoking history and CVD in Japan is unknown. The aim of this study was to determine the proportion of Japanese patients with a smoking history being treated for CVD who have concurrent airflow limitation compatible with COPD. A secondary objective was to test whether the usage of lung function tests performed in the clinic influenced the diagnosis rate of COPD in the patients identified with airflow limitation. METHODS: In a multicenter observational prospective study conducted at 17 centers across Japan, the prevalence of airflow limitation compatible with COPD (defined as forced expiratory volume (FEV)1/FEV6 <0.73, by handheld spirometry) was investigated in cardiac outpatients ≥40 years old with a smoking history who routinely visited the clinic for their CVD. Each patient completed the COPD Assessment Test prior to spirometry testing. RESULTS: Data were available for 995 patients with a mean age of 66.6±10.0 years, of whom 95.5% were male. The prevalence of airflow limitation compatible with COPD was 27.0% (n=269), and 87.7% of those patients (n=236) did not have a prior diagnosis of COPD. The prevalence of previously diagnosed airflow limitation was higher in sites with higher usage of lung function testing (14.0%, 15.2% respectively) compared against sites where it is performed seldom (11.1%), but was still low. CONCLUSION: The prevalence of airflow limitation in this study indicates that a quarter of outpatients with CVD have COPD, almost all of whom are undiagnosed. This suggests that it is important to look routinely for COPD in CVD outpatients.

The natural history of community-acquired pneumonia in COPD patients: a population database analysis.

BACKGROUND: Patients with Chronic Obstructive Pulmonary Disease (COPD) are at higher risk of developing Community-Acquired Pneumonia (CAP) than patients in the general population. However, no studies have been performed in general practice assessing longitudinal incidence rates for CAP in COPD patients or risk factors for pneumonia onset. METHODS: A cohort of COPD patients aged ≥ 45 years, was identified in the General Research Practice Database (GPRD) between 1996 and 2005, and annual and 10-year incidence rates of CAP evaluated. A nested case-control analysis was performed, comparing descriptors in COPD patients with and without CAP using conditional logistic regression generating odds ratios (OR) and 95% confidence intervals (CI). RESULTS: The COPD cohort consisted of 40,414 adults. During the observation period, 3149 patients (8%) experienced CAP, producing an incidence rate of 22.4 (95% CI 21.7-23.2) per 1000 person years. 92% of patients with pneumonia diagnosis had suffered only one episode. Multivariate modelling of pneumonia descriptors in COPD indicate that age over 65 years was significantly associated with increased risk of CAP. Other independent risk factors associated with CAP were co-morbidities including congestive heart failure (OR 1.4, 95% CI 1.2-1.6), and dementia (OR 2.6, 95%CI 1.9-3.). Prior severe COPD exacerbations requiring hospitalization (OR 2.7, 95% CI 2.3-3.2) and severe COPD requiring home oxygen or nebulised therapy (OR 1.4, 95% CI 1.1-1.6) were also significantly associated with risk of CAP. CONCLUSION: COPD patients presenting in general practice with specific co-morbidities, severe COPD, and age >65 years are at increased risk of CAP.

Prevalence of airflow obstruction in patients attending a rapid access chest pain clinic.

BACKGROUND: Many UK hospitals have set-up specialised chest pain clinics to deal promptly and efficiently with cases of possible cardiac chest pain. It is possible that a proportion of patients attending these clinics will have a respiratory cause for their chest pain, or respiratory disease in addition to their cardiac pain. This study aimed to determine the prevalence of airflow obstruction, ischaemic heart disease and dual pathology in such patients. METHODS: Spirometry was performed on patients referred to a rapid access chest pain clinic over a 12-month period (target population of 400 patients). The main outcome measure was the prevalence of airflow obstruction (defined using spirometry), ischaemic heart disease and dual pathology. RESULTS: 405 subjects participated in the study. Abnormal spirometry was detected in 21% of patients (n=85). Airflow obstruction was the predominant lung function abnormality and was detected in 60 patients. Ischaemic heart disease was diagnosed in 21% of patients (n=85). Dual pathology was found in 4% of patients (n=17). CONCLUSIONS: Previous studies have reported a link between impaired lung function and future cardiovascular morbidity and mortality. This study suggests that airflow obstruction is an important alternative differential diagnosis in patients referred to a rapid access chest pain clinic. The identification of abnormal spirometry may help to better risk-stratify patients for future cardiovascular events and allow interventions to be instituted.

Use of plasma biomarkers at exacerbation of chronic obstructive pulmonary disease.

IMPACT: This study explores the use of measuring plasma biomarkers at exacerbation of chronic obstructive pulmonary disease (COPD), providing insight into the underlying pathogenesis of these important events. RATIONALE: The use of measuring C-reactive protein (CRP) to confirm exacerbation, or to assess exacerbation severity, in COPD is unclear. Furthermore, it is not known whether there may be more useful systemic biomarkers. OBJECTIVE: To assess the use of plasma biomarkers in confirming exacerbation and predicting exacerbation severity. METHODS: We assessed 36 biomarkers in 90 paired baseline and exacerbation plasma samples from 90 patients with COPD. The diagnosis of exacerbation fulfilled both health care use and symptom-based criteria. Biomarker concentrations were related to clinical indices of exacerbation severity. Interrelationships between biomarkers were examined to gain information on mechanisms of systemic inflammation at exacerbation of COPD. MEASUREMENTS AND MAIN RESULTS: To confirm the diagnosis of exacerbation, the most selective biomarker was CRP. However, this was neither sufficiently sensitive nor specific alone (area under the receiver operating characteristic curve [AUC], 0.73; 95% confidence interval, 0.66-0.80). The combination of CRP with any one increased major exacerbation symptom recorded by the patient on that day (dyspnea, sputum volume, or sputum purulence) significantly increased the AUC to 0.88 (95% confidence interval, 0.82-0.93; p<0.0001). There were no significant relationships between biomarker concentrations and clinical indices of exacerbation severity. Interrelationships between biomarkers suggest that the acute-phase response is related, separately, to monocytic and lymphocytic-neutrophilic pathways. CONCLUSIONS: Plasma CRP concentration, in the presence of a major exacerbation symptom, is useful in the confirmation of COPD exacerbation. Systemic biomarkers were not helpful in predicting exacerbation severity. The acute-phase response at exacerbation was most strongly related to indices of monocyte function.