Unsuspected risk factors of frequent exacerbations requiring hospital admission in chronic obstructive pulmonary disease.

INTRODUCTION: Severe exacerbations are the leading cause of fatal events in chronic obstructive pulmonary disease (COPD). The new Global Initiative for Chronic Obstructive Lung Disease strategy included the number of exacerbations in the grading of the disease. The primary aim of this study was to evaluate the potentially modifiable precipitating factors of frequent severe exacerbations requiring hospital admission in COPD. The secondary aim was to investigate the risk factors of readmission within 2 months following an exacerbation requiring hospitalisation. METHODS: Data regarding the number of exacerbations in the previous year, current comorbidities, medications, and clinical and functional status of COPD patients were evaluated. RESULTS: We included 107 COPD patients (85% men). The mean number of severe exacerbations was 1.3 ± 1.7 (per patient/per year), and 37.4% of the patients had frequent severe exacerbations (≥ 2/year). Multivariate analysis indicated that haematocrit < 41%, angiotensin converting enzyme inhibitor or angiotensin receptor blocker use, positive gastro-oesophageal reflux disease symptoms, poor adherence to inhaled therapy/regular outpatient follow-up visits and FEV1 < 50% were independent predictors of frequent severe exacerbations. Readmission rate within 2 months after hospital discharge was 39.3%. The independent risk factors of readmission were poor adherence to inhaled therapy/regular outpatient follow-up visits, serum haematocrit < 41%, and FEV1 < 50%. CONCLUSION: Chronic obstructive pulmonary disease patients with frequent exacerbations should be carefully assessed for modifiable confounding risk factors regardless of poor lung function to decrease exacerbation frequency and related poor prognosis.

Nocturnal oxygen desaturation in coronary artery disease.

Nocturnal oxygen desaturation and sleep apnea may provoke myocardial ischemia and arrhythmias in patients with coronary artery disease (CAD). Additionally, these factors may accelerate coronary atherosclerosis in the long term and they may play a role in the progression of the disease process. On the other hand, studies related to this subject are limited. This study was conducted to investigate the nocturnal oxygen desaturation and apneas during sleep in patients with CAD and to assess the possible association of these factors with CAD. We studied 22 male patients with CAD confirmed by coronary angiography who did not have symptomatic pulmonary disease and fourteen male healthy controls without known heart disease. Patients were randomly selected from men undergoing coronary angiography. Controls were age and sex matched and selected from the population registry. The normal controls were of similar body mass index to the patients. None of them were obese. The patients and controls underwent standard polysomnography. Men with CAD and controls had a similar apnea-hypopnea index (2.3 +/- 3.8 vs. 1.2 +/- 1.7). Mean oxygen desaturation index was higher among patients than controls (2.1 vs. 0.5, p < 0.05). Patients with CAD spent 3.1% (9.7 +/- 13.6) of total sleep time desaturated, while the same proportion in controls were 0.5% (1.9 +/- 4.1)(p < 0.05). Although both groups of patients were of similar heart rates at initial, the development of bradycardia during sleep was significantly higher in patients compared with controls (43.3% vs. 25.3%, p < 0.05). The results demonstrate that sleep disordered breathing, in particular nocturnal oxygen desaturation, occurs more common in patients with CAD compared to controls. Additionally, patients are at higher risk of developing bradycardia during sleep. This findings suggest that oxygen desaturation during sleep might contribute to the progression of CAD.