A recent study in Sleep and Breathing Journal,"Adherence to CPAP therapy improves quality of life and reduces symptoms among obstructive sleep apnea syndrome patients"showed significant improvement in patients who used CPAP for 6 months.
A more careful look at the study also shows the major problem with CPAP.
This study looked at 50 patients, 41 men and 9 women who were "compliant" with CPAP usage. This means that they wore CPAP an average of 4-5 hours/night. It is well established that 7-7.5 hours/night is ideal CPAP usage. Standardized tests showed subjective improvement in quality of life but a large group of patients still reported "excessive fatigue" (54.5%), and "decreased energy" (55.3%).
The real danger to using CPAP for 4-5 hours a night is the risk of cardiovascular events including heart attack and stroke. Patients with untreated sleep apnea have an enormous and dangerous increased risk of myocardial infarction and cerebral vascular accidents in the early morning hours, usually between 3 and 5 AM. Patient who wear CPAP for only 4-5 hours are no longer utilizing it during the hours of greatest risk!
The danger of unacceptably low CPAP use (4-5 hours /night) was well documented by an article in Sleep (2011 Jan 1;34(1):105-10.) "Reliable calculation of the efficacy of non-surgical and surgical treatment of obstructive sleep apnea revisited."
The article concludes "Using a mean AHI in CPAP therapy is more realistic than using arbitrary compliance rates, which, in fact, hide insufficient reductions in AHI." Clearly stating 4-5 hour compliance is a poor measure of success.
Compare this information to a recent article in Chest (2011 Jun 2) "Efficacy of An Adjustable Oral Appliance and Comparison to Continuous Positive Airway Pressure For the Treatment of Obstructive Sleep Apnea Syndrome." Where they found high effectiveness of Oral Appliances. Oral Appliances are utilized by most patients for the entire night.
Sleep Breath. 2011 Jun 11. [Epub ahead of print]
Adherence to CPAP therapy improves quality of life and reduces symptoms among obstructive sleep apnea syndrome patients.
Avlonitou E, Kapsimalis F, Varouchakis G, Vardavas CI, Behrakis P.
Sleep Laboratory, Henry Dunant Hospital, Athens, Greece.
The aim of the study was to asses quality of life and symptoms of obstructive sleep apnea syndrome (OSAS) patients after adhering to 6 months of continuous positive airway pressure (CPAP) treatment.
A group of 50 patients (41 men and 9 women) were diagnosed by polysomnography and treated with CPAP therapy for 6 months. Their symptoms and health-related quality of life were assessed by administering a validated and translated version of the sleep apnea quality of life index (SAQLI). Sleepiness was measured using the Epworth Sleepiness Scale (ESS) and through electronic monitoring of CPAP usage per night of sleep.
Mean CPAP usage was 4.5 ± 0.5 h per night. Comparisons between quality of life indexes before and after CPAP treatment showed an improvement in the total SAQLI score (3.8 ± 0.9 vs. 5.8 ± 0.8 after CPAP, p < 0.01), in daily functioning (4.2 ± 1.4 vs. 6.0 ± 0.9, p < 0.01), social interactions (4.8 ± 1.3 vs.6.3 ± 0.7, p < 0.01), emotional functioning (4.4 ± 1.4 vs. 5.7 ± 1.0, p < 0.01), symptoms (1.6 ± 0.8 vs. 5.8 ± 1.2, p < 0.01), and in the ESS (13.7 ± 6.5 vs. 3.9 ± 3.8, p < 0.01). Regarding the patients' symptoms, improvement was noticed for "sleepiness while watching a spectacle" (96%), "reading" (95%), "carrying on a conversation" (95%), "driving" (92.9%), "restless sleep" (87.8%), and "urinating more than once per night" (84.8%). Smaller improvements were observed for the reported "dry mouth-throat upon awakening" (36.1%),"excessive fatigue" (54.5%), and "decreased energy" (55.3%).
We conclude that OSAS patients who adhere to nighttime CPAP therapy show significant improvement of their quality of life, daytime sleepiness, and other symptoms after 6 months of treatment with CPAP. The article explains mathematically the problems of considering 4-5 hours as "success. "The more severe the AHI, the more percentage of total sleep time (TST) CPAP must be used to significantly reduce the AHI. Patients with moderate OSA reduce the AHI by 33.3% to 48.3% when using CPAP 4 h/ night (AHI 0-5, respectively). The required nightly percentage use rises as one reduces the AHI target to < 5. CPAP must be used 66.67% to 83.33% per night to reduce the AHI below 5 (AHI of 0 while using CPAP). By using these definitions most CPAP usage of 4-5 hours a night is actually only partial treatment leaving the patient at risk.
Sleep. 2011 Jan 1;34(1):105-10.
Reliable calculation of the efficacy of non-surgical and surgical treatment of obstructive sleep apnea revisited.
Ravesloot MJ, de Vries N.
Sint Lucas Andreas Ziekenhuis, Department of Otolaryngology/Head Neck Surgery, Amsterdam, the Netherlands. firstname.lastname@example.org
Various treatment methods exist to treat obstructive sleep apnea (OSA); continuous positive airway pressure (CPAP) is considered the gold standard. It is however a clinical reality that the use of CPAP is often cumbersome. CPAP treatment is considered compliant when used ≥ 4 h per night as an average over all nights observed. Surgery, on the other hand, is regarded as successful when the apnea hypopnea index (AHI) drops at least 50% and is reduced below 20/h postoperatively in patients whose preoperative AHI was > 20/h. The effectiveness of CPAP compliance criteria can be questioned, just as the effectiveness of surgical success criteria has often been questioned.
The aim of the study was to compare non optimal use of optimal therapy (CPAP) with the continuous effect (100%) of often non optimal therapy (surgery).
Using mathematical function formulas, the effect on the AHI of various treatment modalities and their respective compliance and success criteria were calculated.
The more severe the AHI, the more percentage of total sleep time (TST) CPAP must be used to significantly reduce the AHI. Patients with moderate OSA reduce the AHI by 33.3% to 48.3% when using CPAP 4 h/ night (AHI 0-5, respectively). The required nightly percentage use rises as one reduces the AHI target to < 5. CPAP must be used 66.67% to 83.33% per night to reduce the AHI below 5 (AHI of 0 while using CPAP).
Using a mean AHI in CPAP therapy is more realistic than using arbitrary compliance rates, which, in fact, hide insufficient reductions in AHI.
[PubMed - indexed for MEDLINE]
[Available on 2011/7/1]
Chest. 2011 Jun 2. [Epub ahead of print]
Efficacy of An Adjustable Oral Appliance and Comparison to Continuous Positive Airway Pressure For the Treatment of Obstructive Sleep Apnea Syndrome.
Holley AB, Lettieri CJ, Shah AA.
Pulmonary, Critical Care, and Sleep Medicine, Walter Reed Army Medical Center.
We sought to establish the efficacy of an adjustable oral appliance (aOA) in the largest patient population studied to date, and provide a comparison to CPAP.
Retrospective analysis of patients prescribed an aOA. Results of overnight, PSG with aOA titration were evaluated and compared to CPAP. Predictors of a successful aOA titration were determined using a multivariate logistic regression model.
A total of 497 patients were prescribed an aOA during the specified time period. The aOA reduced the mean AHI to 8.4±11.4, and 70.3%, 47.6%, and 41.4% of patients with mild, moderate, and severe disease achieved an AHI<5, respectively. Patients using an aOA decreased their mean Epworth Sleepiness Score (ESS) by 2.71 (95% CI: 2.3-3.2; p<0.001) at follow-up. CPAP improved the AHI by - 3.43 (95% CI: 1.88-4.99; p<0.001) when compared to an aOA, but when adjusted for severity of disease, this difference only reached significance for patients with severe disease (-5.88 (95% CI: -8.95 - -2.82; p<0.001)). However, 70.1% of all patients achieved an AHI < 5using CPAP, compared to 51.6% for the aOA (p<0.001). On multivariate analysis, baseline AHI was a significant predictor of achieving an AHI < 5 on aOA titration, and age showed a trend toward significance.
In comparison to past reports, more patients in our study achieved an AHI < 5 using an aOA. The aOA is comparable to CPAP for patients with mild disease, while CPAP is superior for patients with moderate to severe disease. A lower AHI was the only predictor of a successful aOA titration.