Treatments for Obstructive Sleep Apnea

Improved CPAP Treatment

As stated previously, CPAP pneumatically splints the upper airway, thus preventing it from collapsing during sleep. However, CPAP is not well-tolerated. Modifications to standard CPAP to increase adherence have been met with disappointing results. Humidification with heated tubing delivering heated moistened air did not increase compliance compared to standard CPAP [19]. CPAP was also compared with auto-adjusting CPAP (APAP), where respiration is monitored and the minimum pressure of air is applied to splint the upper airway open. In a meta-analysis, APAP only had very small effect on compliance [20]. Lastly, reduction in pressure during expiration was investigated, and a meta-analysis showed no effect [21,22]. However, recent advances in CPAP delivery give hope to increasing compliance. The S9CPAP machine (Resmed, San Diego, CA), which combines a humidification system and an APAP, showed increased compliance compared to standard CPAP. Compliance increased by an average of 30 minutes per night, and variance of daily usage decreased (eg, patients used it more day-to-day) [23]. However, a randomized blinded study needs to be conducted to corroborate these results.

Promoting CPAP Adherence Through Patient Interventions

Educational, supportive, and behavioral interventions have been used to increase CPAP adherence and have been thoroughly reviewed via meta-analysis [24]. Briefly, 30 studies of various interventions were included and demonstrated that educational, supportive, or behavioral interventions increased CPAP usage in OSA-naive patients. Behavioral interventions increased CPAP usage by over an hour, but the evidence was of “low-quality.” Educational and supportive interventions also increased CPAP usage, with the former having “moderate-quality” evidence [24]. However, whether increased CPAP usage had an effect on symptoms and quality of life was statistically unclear, and the authors recommended further assessment [24]. Three more studies on interventions to increase CPAP usage have been conducted since the aforementioned review. In a randomized controlled study, investigators had OSA patients participate in a 30-minute group social cognitive therapy session (eg, increasing perceived self-efficacy, outcome expectations, and social support) to increase CPAP adherence. Compared to a social interaction control group, there was no increase in adherence rates [25]. In another smaller randomized controlled study that used a social cognition model of behavioral therapy, there were small increases of CPAP usage. At 3 months, the social cognitive intervention increased CPAP usage by an average of 23 minutes per night, increased the number of individuals using their CPAP machine for more than 4 hours compared to standard care group, and decreased symptom of sleepiness [26]. And lastly, a preliminary study looked at increasing adherence rates by utilizing easily accessible alternative care providers, such as nurses and respiratory therapists, for the management of OSA [27]. Though this study had no control group, it did show that good adherence and a decrease in symptoms of sleepiness could be achieved with non-physician management of OSA [27]. A randomized controlled study will be needed to validate the use of alternative care providers.

Interventions have shown some success in increasing adherence rates, but the question remains on who should receive those interventions. Predicting which OSA patients are in most need of an intervention has been studied. A recent study used a 19-question assessment tool called the Index of Nonadherence to PAP to screen for nonadherers (OSA patients who used CPAP for less than 4 hours a night, after 1 month of OSA diagnosis). The assessment tool was 87% sensitive and 63% specific at determining those OSA patients who would not adhere to CPAP treatment [28]. Another study investigated the reliability and validity of a self-rating scale measuring the side effects of CPAP and their consequences on adherence [15]. The investigators showed that the scale was able to reliably discriminate between those who adhered to CPAP treatment and those that did not [15]. Both of these scales can be used to screen OSA patients that need interventions to increase CPAP adherence. Lastly, a recent systematic review showed that a user’s CPAP experience was not defined by the user but by the user’s health care provider, who framed CPAP as “problematic” [29]. The authors argue that users of CPAP are “primed” to reflect negatively on their CPAP experience [29]. Interventions can be used to change the way OSA patients think or feel about their CPAP machines.

When OSA Patients Do Not Adhere to CPAP Treatment

With adherence rates as low as 50% [16–18], those who fail to tolerate CPAP are unlikely to be referred for additional treatment [30]. Those who do tolerate treatment dislike the side effects of CPAP and show an interest in other treatment options [14]. Other treatment options have been shown to decrease the severity of OSA.

Weight Loss and Exercise

OSA prevalence is correlated with body mass index (BMI), and the increasing rates of OSA has been attributed to the increasing rates of obesity in the United States [2]. A meta-analysis of 3 randomized controlled studies of weight loss induced by dieting or lifestyle change showed that weight loss decreased OSA severity. The effect was the greatest for OSA patients who lost more than 10 kg or had severe OSA at baseline [31]. A recent randomized controlled study involving OSA patients with type 2 diabetes investigated if either a weight loss intervention or a diabetes support and education intervention would be able to decrease OSA severity [32]. The weight loss intervention significantly decreased OSA severity, which was largely but not entirely attributed to weight loss. The participants regained 50% of their weight 4 years after the intervention and still had significantly less severe OSA compared to control intervention group. The downside to this intervention is the intensity of the regimen to which the subjects had to adapt: portion-controlled diets with liquid meals and snack bars for the first 4 months and moderate-intensity physical activity for a minimum of 3 hours a week for the first year. After that, patients were still required to follow through with the intervention for 3 years, which included one on-site visit per month and a second contact by phone, mail, or email [32]. One study looked at weight loss and sleep position (supine vs. lateral). The study showed a decrease in AHI in OSA patients that lost weight, and the biggest decrease was in AHI in the lateral sleeping position [33]. Another study looked at the more invasive procedure of bariatric surgery to decrease weight and OSA. At the 1-year follow-up, patients had significantly decreased their BMI and AHI [34]. Two more randomized controlled studies investigated if exercise or fitness level might be beneficial to OSA patients independent of weight loss. Exercise improved AHI even though there was not a significant decrease in weight between the exercise and stretching control group [35]. However, an increase in fitness level did not have any additive effect on the decrease of AHI when weight change was taken into account [36]. The difference in results might be attributed to the latter study using older type 2 diabetic patients and moderate physical activity, while the former studied incorporated moderate-intensity aerobic activity and resistance training for younger patients [35,36]. There is evidence that a sedentary lifestyle increases diurnal leg fluid volume that can shift to the neck during sleep and might play a role in pathogenesis of OSA [37]. Decreasing a sedentary lifestyle by exercising might therefore be beneficial to OSA patients. Given the increasing rates of obesity [2], implementing weight loss as a solution to OSA is viable, especially considering that OSA is not the only comorbid disease of obesity [38].