The effects of continuous positive airway pressure and mandibular advancement therapy on metabolic outcomes of patients with mild obstructive sleep apnea: a randomized controlled study

BACKGROUND

Moderate and severe obstructive sleep apnea (OSA) have been independently associated with dyslipidemia. The results of metabolic improvement with continuous positive airway pressure (CPAP) have been controversial. Less evidence exists regarding this issue in mild OSA. A current treatment for mild OSA is mandibular advancement device (MAD) therapy, but its effectiveness on the metabolic profile needs to be compared with CPAP. The purpose of this study was to compare MAD vs CPAP vs no treatment on the metabolic profile during 6 and 12 months of follow-up in patients with mild OSA.

METHODS

The inclusion criteria were patients with mild OSA, both genders, ages 18 to 65 years, and body mass index (BMI) of < 35 Kg/m². Patients were randomized in 3 groups (CPAP, MAD, and control). The evaluations included physical examination, metabolic profile, and full polysomnography at baseline, 6 months, and 12 months of follow-up.

RESULTS

Seventy-nine patients with mild OSA were randomized in three treatment groups, with mean age (± SD) of 47 ± 9 years, 54% men, and AHI 9.5 ± 2.9 events/h. MAD and CPAP reduced AHI at 6 and 12 months compared to the control group. MAD adherence was higher than CPAP at 6 and 12 months. Despite lower adherence compared to MAD, CPAP was more effective in reducing total cholesterol over 12 months (baseline 189.3 ± 60.2 mg/dl to 173.4 ± 74.3 mg/dl) and low-density lipoprotein cholesterol (LDL-c, baseline 112.8 ± 54.9 mg/dl to 94.5 ± 67.4 mg/dl).

CONCLUSIONS

After 1 year of treatment, CPAP was superior to MAD in reducing total cholesterol and LDL-c in patients with mild OSA.

Effects of positive airway pressure therapy on cardiovascular and metabolic markers in males with obstructive sleep apnea

INTRODUCTION

Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular/metabolic complications. Some analytical parameters (homocysteine, glycemic and lipidic profiles) are recognized markers of these consequences. Limited data is available on the association of these markers and OSAS's severity/response to positive airway pressure therapy (PAP).

MATERIAL AND METHODS

In this prospective study we analyzed polysomnographic and analytical data of male patients admitted to sleep laboratory. The aim was to evaluate metabolic/cardiovascular markers in snorers and OSAS patients, to relate with sleep parameters and PAP response. One-hundred and three patients were included, and 73 (71%) were OSAS patients. OSAS patients were similar to snorers except for higher body mass index (BMI) and dyslipidemia. Severe OSAS patients showed higher glycemia, HbA1c, insulin, and insulin resistance, and lower HDL cholesterol in comparison to mild-moderate (p<0.05, p<0.05, p<0.001, p<0.001, p<0.05, respectively). Glycemic profile and triglycerides were slightly correlated with OSAS severity. 46 OSAS patients were submitted to 6 months of PAP, with a statistical decrease in mean values of homocysteine, glycemia, total and LDL cholesterol (p<0.05, p<0.05, p<0.05, respectively), and in glycemia and LDL cholesterol in severe group only (p<0.05, p<0.05, respectively).

RESULTS

This study demonstrated an association between glucose metabolism parameters and triglycerides with OSAS severity underlying the complexity of the process leading to cardiovascular/metabolic complications in this disorder. Moreover, homocysteine, glycemic and lipidic profiles changed significantly after 6 months of PAP therapy in OSAS, supporting its cardiovascular and metabolic protective effect.

CONCLUSION

Our study has reinforced the importance of analytical cardiovascular/metabolic evaluation as complementary tool of diagnosis/treatment response in OSAS.

Beneficial effect of continuous positive airway pressure on lipid profiles in obstructive sleep apnea: a meta-analysis

Purpose

Dyslipidemia is considered as one mechanism causing cardiovascular sequelae in obstructive sleep apnea (OSA). Continuous positive airway pressure (CPAP) can reduce cardiovascular morbidities but its effect on lipid profiles is inconclusive. This study aimed to investigate the effects of CPAP on lipid profiles by a meta-analysis of the existing randomized controlled trials.

Methods

Studies were retrieved from MEDLINE/PubMed, EMBASE, CENTRAL, commercial websites, and article references up to August 2013 following the protocols (PROSPERO CRD42012002636). Randomized controlled trials investigating the CPAP effects on changes in lipid profiles in adult patients with OSA were included. Two independent researchers extracted relevant data in duplicate. The pooled effect was analyzed by fixed-effect generic inverse variance, and the heterogeneity was assessed using the I² statistic.

Results

Six trials with 348 patients and 351 controls were included. CPAP significantly lowered total cholesterol (mean, −6.23 mg/dl; 95% CI, −8.73 to –3.73; I², 0 %; p < 0.001), triglyceride (mean, −12.60 mg/dl; 95% CI, −18.80 to −6.41; I², 25 %; p < 0.001), and high-density lipoprotein (mean, −1.05 mg/dl; 95% CI, −1.69 to −0.40; I², 0 %; p = 0.001), but not low-density lipoprotein (mean, −1.01 mg/dl; 95% CI, −5.04 to 3.02; I², 0 %; p = 0.62). The lipid-lowering effects were homogeneous across the studies. By subgroup analysis, the reductions of lipid profiles were associated with the cross-over design, subtherapeutic CPAP as placebo, enrolled patients with moderate-to-severe OSA or daytime sleepiness, and CPAP treatment with short-term duration or good compliance.

Conclusions

This meta-analysis validates the observation that CPAP can reduce lipid profiles in patients with OSA.

Electronic supplementary material

The online version of this article (doi:10.1007/s11325-014-1082-x) contains supplementary material, which is available to authorized users.

Continuous positive airway pressure treatment: effect on serum lipids in patients with obstructive sleep apnoea

Obstructive Sleep Apnoea (OSA) is a common disorder in adults. Its hallmark is repetitive episodes of partial or complete obstruction of the upper airway during sleep associated with increasing respiratory efforts. This leads to oxyhaemoglobin desaturation, sleep fragmentation, and daytime symptoms, mainly excessive sleepiness. Accumulating evidence suggests that intermittent hypoxia and oxyhaemoglobin desaturation may, irrespective of obesity, lead to elevation of serum lipids even in non-dyslipidaemic OSA patients. Continuous Positive Airway Pressure (CPAP) is the treatment of choice for OSA, since it eliminates upper airway collapse during sleep and improves sleep fragmentation, daytime symptoms and quality of life. Moreover, it has been proposed that the amelioration of breathing disturbances during sleep can improve several markers of the lipid profile, such as total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol as well as apolipoproteins A, B and C. Indeed, some studies have reported improvements in these parameters especially in CPAP adherent patients. However, other studies failed to confirm this beneficial effect. The present article reviews the issue whether CPAP treatment exerts a beneficial effect on lipids.

Compliance to continuous positive airway pressure therapy in a group of Portuguese patients with obstructive sleep apnea syndrome

INTRODUCTION

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is an emerging public health concern. Although different treatments for OSAHS had been proposed, continuous positive airway pressure (CPAP) is the first-line treatment in moderate to serious OSAHS in which success can be achieved by increasing compliance to CPAP.

MATERIALS AND METHODS

This study analyzes long-term CPAP compliance in patients with OSAHS on CPAP therapy for at least 1 month, who began CPAP therapy between January 2004 and December 2006, followed up at a Portuguese Sleep Outpatient Clinic in Santo António Hospital. Only effective data of CPAP use had been considered. During the first year of CPAP therapy, 96 patients were enrolled and followed up, but 15 patients had discontinued CPAP treatment. CPAP was used on average 5.1 h per day and in 80.1% of the total follow-up days. When compliance is defined as the use of CPAP for a minimum of 4 h per day in at least 70% of the follow-up days, only 54% of patients were classified as compliants during the first year.

RESULTS AND CONCLUSION

No statistically significant differences were found throughout the first year (p > 0.05) in terms of the percentage of compliants, controlling for demographic and clinic variables. None of the demographic and clinical baseline variables studied were found to be significant predictor of CPAP compliance (p > 0.05). This study diagnosed a low compliance to CPAP therapy in the studied sample, warning to the need of developing further studies in this area and to the need of implementing strategies to increase CPAP compliance.

Obstructive sleep apnoea/hypopnea influences high-density lipoprotein cholesterol in the elderly

BACKGROUND AND PURPOSE

An association between obstructive sleep apnoea/hypopnea (OSAH) and cardiovascular risk factors such as dyslipidemia has been described in adults and high-risk populations.

PATIENTS AND METHODS

We examined this association in a prospective cohort (SYNAPSE study) of 846 elderly (68.5+/-1.1 years) volunteers (41.6% of men). No subject presented with recognized OSAH syndrome, heart disease, or any neurological disorder. Unattended at-home polygraphy was done by all subjects. OSAH severity was defined as moderate (apnoea/hypopnea index: AHI>15/h) or severe (AHI>30/h). High-density lipoprotein cholesterol (HDL-c) was measured by immuno-separation-based homogenous assay.

RESULTS

The prevalence of severe cases reached 21.5% (AHI mean+/-SD: 43.5+/-11.9). Using univariate linear regression analysis, AHI (R=-0.172; p<0.0001), oxyhemoglobin desaturation index (ODI) (R=-0.108; p<0.002), mean SaO(2) (R=0.125; p<0.0003) and Nadir SaO(2) (R=0.094; p<0.007) were significantly associated with HDL-c. Multiple regression analysis demonstrated that male gender, BMI, waist to hip ratio, ODI, and AHI represent independent predictors of HDL-c. Logistic regression analysis showed a significant association between severe OSAH and low HDL-c serum levels (p<0.03) after adjustment for gender, BMI, hypertension, glycaemia, waist to hip ratio, alcohol intake and treated dyslipidemia. The association appears more evident in subjects free of lipid-lowering medications and beta-blockers (p<0.007). There was no independent association of OSAH syndrome with low-density lipoprotein (LDL) cholesterol.

CONCLUSION

Unrecognized moderate to severe apnoea/hypopnea syndrome was independently associated with low HDL-c serum levels in the present cross-sectional based elderly population. This could explain the deleterious effect of OSAH syndrome on cardiovascular risk.

Effects of nasal CPAP treatment on insulin resistance, lipid profile, and plasma leptin in sleep apnea

BACKGROUND

Obstructive sleep apnea has been linked with metabolic syndrome characterized by dyslipidemia, dyscoagulation, hypertension, and diabetes mellitus type 2 and their cardiovascular consequences. This study was designed to determine the effects of 8 weeks of therapy with continuous positive airway pressure (CPAP) on insulin resistance, glucose, and lipid profile, and the relationship between leptin and insulin-resistance parameters in patients with moderate-to-severe obstructive sleep apnea.

METHODS

In 44 patients, serum cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, very low-density lipoprotein, leptin, and insulin parameters were measured at baseline and after 8 weeks of CPAP. Insulin resistance index was based on the homeostasis model assessment (HOMA-IR) method. Insulin sensitivity (HOMA-S) and insulin secretion capacity (HOMA-beta) also were calculated. Thirteen patients were excluded from statistical analyses due to noncompliant CPAP usage (<4 h night(-1)).

RESULTS

In 31 patients who used CPAP for > or =4 h night(-1), CPAP therapy reduced total cholesterol (P < 0.05), low-density lipoprotein (P < 0.05), and leptin (P < 0.05). Circulating leptin levels showed significant correlation with both HOMA-S and HOMA-IR at baseline and follow-up (P = 0.03 for all). In addition, there was no correlation between HOMA-IR and the severity of sleep apnea, which was shown by apnea-hypopnea index.

CONCLUSIONS

In patients with moderate-to-severe obstructive sleep apnea, compliant CPAP usage may improve insulin secretion capacity, reduce leptin, total cholesterol, and low-density lipoprotein levels. Leptin showed significant relationship with insulin resistance, and this relationship remained after 8 weeks of CPAP therapy.