Long Term Effects of Continuous Positive Airway Pressure in Obstructive Sleep Apnea Patients: Apnea-Hypopnea Index and Blood Pressure Changes

Abstract

Background and Objective Obstructive sleep apnea (OSA) is characterized by repetitive episodes of complete or partial upper airway obstruction during sleep. Although, optimal treatment of OSA with continuous positive airway pressure (CPAP) reduce the number of respiratory events during sleep, and thus improve daytime sleepiness, quality of life, and cardiovascular risk, there are few studies that address the long term effects of CPAP treatment. This study aims to determine the long term effects of positive airway pressure (PAP) in compliant OSA patients. Methods Forty OSA patients naïve to PAP treatment were included. Polysomnography for apnea-hypopnea index, sleep structure, and desaturation index, blood pressure, Epworth Sleepiness Scale (ESS) for excessive daytime sleepiness, and Beck Depression Inventory (BDI) for depressive mood were initially administered before the PAP treatment and after the long term PAP treatment. We have excluded immediate pneumatic effects of the PAP treatment, by administrating a follow up study after 7 days of PAP treatment withdrawal. Results A total of 40 (male: 92.5%, mean age: 54.4 ± 10.4 yr) patients were enrolled. The duration of PAP treatment was 3.4 ± 1.4 years. The initial apnea-hypopnea index (AHI) was 50.8 ± 22.6/hr which decreased to 34.4 ± 19.1/hr (p ≤ 0.001). These significant reductions in AHI were seen without Body Mass Index changes (p = 0.707). The sleep architecture revealed no significant changes between the initial and follow up study. The systolic and diastolic blood pressure (DBP) decreased significantly after the long term CPAP treatment (systolic blood pressure pre: 138.5 ± 18.1, post: 122.3 ± 13.7, p ≤ 0.001, DBP pre: 88.7 ± 13.6, post: 78.5 ± 11.1, p ≤ 0.001). ESS and BDI decreased significantly after years of PAP treatment compared to the baseline study (ESS pre: 11.5 ± 5.3, post: 8.3 ± 4.7, p ≤ 0.001, BDI pre: 12.7 ± 11.6, post: 6.3 ± 7.0, p = 0.019). Conclusions This study confirmed that after years of faithful PAP treatment for OSA, the severity of OSA significantly improved. In addition, blood pressure, daytime sleepiness, and depression levels also decreased significantly.

Keywords

• OSA
• CPAP
• Body weight
• Blood
• Pressure