Prevalence of obstructive sleep apnea (OSA) in patients with hypertension outnumbers the prevalence reported in general population. Concurrently, majority of patients remain undiagnosed. Given the fact that untreated OSA contributes to an ineffective hypotensive treatment, and higher rate of complications ascribed to hypertension, early OSA-diagnosis and its elimination constitutes one of the key clinical goals. Polysomnography comprises a golden standard in sleep apnea diagnosis, however, it is a time-consuming and expensive procedure which requires hospitalization. Therefore we assessed the utility of simplified polygraphic (PG) studies in the OSA-screening of patients with hypertension requiring regular tertiary-care.Design and method:
Study was conducted in Outpatient Tertiary Care Clinic of the Medical University Hospital of Gdansk. We enrolled patients both randomly selected regardless the presence of OSA symptoms (Random-group), as well as patients with OSA-suspicion (Symptomatic-group). A total of 322 patients (38.5 % females) were subjected to ambulatory, one-night polygraphic studies (ApneaLink™). Following signals were recorded: airflow (pressure cannula), respiratory movements, and pulse + oximetry. Additionally, anthropometrics, Epworth Sleepiness Scale (ESS), selected clinical symptoms and drug-regime were recorded.Results:
312 (97%) patients completed the study (10 drop-outs due to PG-study failure). Selective clinical characteristic was as follows: 57.2 ± 11.6 years old; BMI = 29.9 ± 5.0 kg/m2. Cohort consisted of Random-group n = 247 and Symptomatic-group n = 75. ESS = 5.8 ± 4.6 (4.5 ± 3.6 vs. 7.0 ± 5.2 for Random vs. Symptomatic-group, respectively). 65.7% of all patients scored AHI> = 5 (62.9% in Random-group, and 74.7% in Symptomatic-group, P = NS). 27.2% of patients were diagnosed with AHI> = 15 (23.2% in Random-group and 40.0% in Symptomatic-group). Patients with AHI> = 30 had nocturia 1.8 vs. 0.9 for AHI < 5 group; P < 0.05.Results:
54.1% required 3 or more blood-lowering drugs. The distribution of hypotensive drugs in different AHI-groups equaled: 2.3 ± 0.1; 2.7 ± 0.1; 3.0 ± 0.2; 3.1 ± 0.2 for AHI < 5, AHI 5–15, AHI 15–30, and AHI> = 30-groups, respectively (ANOVA, P < 0.01).Conclusions:
Our results justify routine polygraphic screening of hypertensive patients requiring tertiary care.