Sleep apnea in end-stage renal disease patients: Impact on cardiovascular and neurological outcomes.

INTRODUCTION: Sleep apnea (SA) is an important comorbidity in end-stage renal disease (ESRD) patients. The association between SA and cardiac and neurological disease is known. This study investigates the relationship between SA and cardiovascular and cerebrovascular outcomes in the ESRD population. METHODS: In a retrospective cohort study, the United States Renal Data System was queried to identify ESRD patients aged 18-100 years in whom hemodialysis had been initiated between 2005 and 2013. Diagnoses of SA and clinical comorbidities were determined from International Classification of Disease-9 codes. Demographic variables were obtained from Centers for Medicare and Medicaid Services Form-2728. Logistic regression was used to examine the association of SA with myocardial infarction (MI) or with stroke, controlling for demographic and clinical variables. RESULTS: Of 858,131 subjects meeting the inclusion criteria, 587 had central SA, and 22,724 had obstructive SA. The SA cohort was younger, more likely to be male and Caucasian compared to the non-SA cohort. Patients with SA also had more tobacco and alcohol use, hypertension, heart failure, and diabetes. Central SA (aRR = 1.69, 95% CI = 1.28-2.23) and obstructive SA (aRR = 1.15, 95% CI = 1.09-1.21) were associated with an increased risk of stroke but not MI. CONCLUSION: In the ESRD population, a diagnosis of central SA or obstructive SA increased the risk of stroke, but not MI. Early identification and treatment of SA in the ESRD population may help reduce the risk of stroke in these patients.

Assessment of exercise tolerance in chronic bronchitis and interstitial lung disease.

Cardiopulmonary exercise testing has a definitive place in objective evaluation of the subjective sensation of breathlessness. In the present study 21 patients with COPD, 10 with ILD and 17 normals were subjected to stage 1 exercise testing and correlations were sought between Vo2 and work, FVC, FeV1, Ve, respiratory rate and tidal volume and between VCO2 and work. In COPD and ILD the Vo2 correlated with work, Fev1, Fvc and Ve whereas in normals it correlated with the VE but not with the FeV1 and FVC. In COPD VO2 correlated with TV though this was not the case in ILD. Thus stage 1 exercise testing can be a useful additional method to assess the disability in COPD and ILD although differentiation between these two respiratory diseases on basis of exercise testing alone may not be possible.