Neck circumference evolution in patients with controlled hypertension and obstructive sleep apnoea treated with CPAP for 30 months

Abstract

Introduction Neck circumference (NC) has been identified as an indicator of visceral obesity and is considered a risk factor for metabolic and cardiovascular diseases (MCD). NC is also an aggravating factor for obstructive sleep apnea (OSA). One of the factors determining NC is rostral fluid shift (RFS). Objectives To assess NC in patients with moderate-severe OSA and hypertension (HT) under long term CPAP. Methods 134 patients were screened (sleep study, APAP titration as needed). Exclusion criteria: insomnia, RLS, parasomnias, acute or incompletely controlled respiratory, MCD, noncompliance to CPAP or antiHT treatment. 7 patients were followed for 30 months by 24h ambulatory BP monitoring. Statistical analysis: SPSS17. Results 85.7% (6/7) were men, age 65.00±12.38 years, body mass index (BMI) 31.3±87.03kg/m2, waist circumference (WC) 111.7±114.62cm and buttock circumference (BC) 111.42±13.07cm, AHI=55.44±29.26/h. 30 months compliance card: percentage of use 87.7±11.9%, average number of hours of daily use 5.53±1.20h, residual AHI 3.25±2.08/h. NC decreased significantly at 30 months (from 45.14±2.41cm to 42.57±1.61cm, p=0.037). At 30 months, mean SBP/24h decreased from 147.42±20.20mmHg to 120.71±8.77mmHg (p=0.008) and mean DBP/24h dropped from 78.14±9.22mmHg to 65.71±7.78mmHg (p=0.018). BMI, WC and BC did not significantly decrease. Conclusions In absence of others anthropometrical data changes, NC decrease is attributed mainly to nocturnal RFS improvement. CPAP treatment, in patients with moderate-severe OSA and controlled HT, significantly lowers CV risk by reducing risk factors, including NC.