Characteristics and Predictors of Obstructive Sleep Apnea in Patients With Systemic Hypertension

Hypertension Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, São Paulo, Brazil.
The American journal of cardiology (Impact Factor: 3.28). 04/2010; 105(8):1135-9. DOI: 10.1016/j.amjcard.2009.12.017
Source: PubMed


Obstructive sleep apnea (OSA) is a secondary cause of hypertension and independently associated with target-organ damage in hypertensive patients. However, OSA remains largely underdiagnosed and undertreated. The aim of the present study was to evaluate the characteristics and clinical predictors of OSA in a consecutive series of patients followed up in a hypertension unit. A total of 99 patients (age 46 + or - 11 years, body mass index 28.8 kg/m(2), range 25.1 to 32.9) underwent polysomnography. The clinical parameters included age, gender, obesity, daytime sleepiness, snoring, Berlin Questionnaire, resistant hypertension, and metabolic syndrome. Of the 99 patients, 55 (56%) had OSA (apnea-hypopnea index >5 events/hour). Patients with OSA were older and more obese, had greater levels of blood pressure, and presented with more diabetes, dyslipidemia, resistant hypertension, and metabolic syndrome than the patients without OSA. Of the patients with OSA, 51% had no excessive daytime sleepiness. The Berlin Questionnaire and patient age revealed a high sensitivity (0.93 and 0.91, respectively) but low specificity (0.59 and 0.48, respectively), and obesity and resistant hypertension revealed a low sensitivity (0.58 and 0.44, respectively) but high specificity (0.75 and 0.91, respectively) for OSA. Metabolic syndrome was associated with high sensitivity and specificity for OSA (0.86 and 0.85, respectively). Multiple regression analysis showed that age of 40 to 70 years (odds ratio 1.09, 95% confidence interval 1.03 to 1.16), a high risk of OSA on the Berlin Questionnaire (odds ratio 8.36, 95% confidence interval 1.67 to 41.85), and metabolic syndrome (odds ratio 19.04, 95% confidence interval 5.25 to 69.03) were independent variables associated with OSA. In conclusion, more important than the typical clinical features that characterize OSA, including snoring and excessive daytime sleepiness, the presence of the metabolic syndrome is as an important marker of OSA among patients with hypertension.

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    • "In a previous study, patients who have hypertension or OSA were reported to have higher prevalence of diabetes mellitus, metabolic syndrome, and dyslipidemia (including low level of high density lipoprotein and high level of triglyceride).8,9,10,11 They also had distinguishing physical characteristics such as increased body mass index (BMI), neck circumference, and abdominal circumference compared to control.4 In another study, age, sex, BMI, and family history of hypertension were representatively different between OSA patients with hypertension and OSA patients having normal blood pressure.12 "
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