Consequences of non-compliance
CPAP treatment has been proven efficacious, but adherence to therapy can be challenging. Lack of compliance is recognised as the key factor that significantly compromises the potential benefits of treatment. Until recently, it has been unclear exactly how many hours of CPAP use are required to gain benefits. Increasingly, research is now showing that while any CPAP usage is better than none, the greatest improvements are correlated with the most hours of use.
The literature relating to fatal and non-fatal cardiovascular events is scarce. However, current knowledge indicates that even as little as 1 hour CPAP usage can improve outcomes, with more significant improvements being seen in over 4 and 6 hours usage.1
Reductions in blood pressure have been studied more frequently, with literature from 6 studies concluding that patients need to use CPAP for at least 4 hours per night to see improvements, while higher usage of more than five and a half hours leads to more pronounced blood pressure drops.2-6
Excessive daytime sleepiness appears to improve with as little as 2.5 hours per night, with multiple studies supporting a linear dose-response relationship of higher CPAP use leading to greater improvements7-10. Studies show that cognitive functions including memory, functional outcomes of sleepiness and executive function may require at least 6 hours use per night before improvements are seen.11,12
Techniques to Improve Compliance
CPAP usage can be accurately determined using data stored in the CPAP device.13 If patient adherence to therapy is poor the following techniques may be used to improve compliance:
- Increasing patient education about both sleep apnoea and CPAP treatment through use of printed materials, videos, websites and discussions. 14
- Using positive peer support groups, buddy systems and ensuring spousal support.15
- Increasing support from care providers, including more face-to face physician time, nurse time, phone calls and follow up appointments.15,16,17,18
- Using telemonitoring services to remotely monitor patients can be used to identify and intervene when patients are non-adherent.18
- Psychological interventions such as cognitive behavioral therapy, and relaxation therapy may assist patients overcoming anxieties associated with wearing a mask.15
- Improving mask comfort and reducing mask obstructiveness by trying different mask types and sizes.
- Overcoming side effects from the equipment. Common complaints include dryness of the nose and mouth, nasal symptoms, and intolerance of high pressures. These can often be overcome by adding heated humidification to the system; using an Auto adjusting (AutoSet) device to keep median pressures lower; or adding EPR to reduce pressure on each exhalation.
- ResMed provides sleep therapy devices that combine a number of additional features that support better PAP usage, including a smart humidification system with heated tube, tailored algorithms and reduced noise.
Barbe F, Duran-Cantolla J, Sanchez-de-la-Torre M, et al. Effect of continuous positive airway pressure on the incidence of hypertension and cardiovascular events in nonsleepy patients with obstructive sleep apnea: a randomized controlled trial. JAMA 2012;307:2161-8.
Montesi SB, Edwards BA, Malhotra A, Bakker JP. The effect of continuous positive airway pressure treatment on blood pressure: a systematic review and meta-analysis of randomized controlled trials. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine 2012;8:587-96.
Duran-Cantolla J, Aizpuru F, Montserrat JM, et al. Continuous positive airway pressure as treatment for systemic hypertension in people with obstructive sleep apnoea: randomised controlled trial. BMJ 2010;341:c5991.
Barbe F, Duran-Cantolla J, Capote F, et al. Long-term effect of continuous positive airway pressure in hypertensive patients with sleep apnea. American journal of respiratory and critical care medicine 2010;181:718-26.
Barnes M, Houston D, Worsnop CJ, et al. A randomized controlled trial of continuous positive airway pressure in mild obstructive sleep apnea. American journal of respiratory and critical care medicine 2002;165:773-80.
Engleman HM, Kingshott RN, Wraith PK, Mackay TW, Deary IJ, Douglas NJ. Randomized placebo-controlled crossover trial of continuous positive airway pressure for mild sleep Apnea/Hypopnea syndrome. American journal of respiratory and critical care medicine 1999;159:461-7.
Antic NA, Catcheside P, Buchan C, et al. The effect of CPAP in normalizing daytime sleepiness, quality of life, and neurocognitive function in patients with moderate to severe OSA. Sleep 2011;34:111-9.
Zimmerman ME, Arnedt JT, Stanchina M, Millman RP, Aloia MS. Normalization of memory performance and positive airway pressure adherence in memory-impaired patients with obstructive sleep apnea. Chest 2006;130:1772-8.
Schwab RJ, Badr SM, Epstein LJ, et al. An Official American Thoracic Society Statement: Continuous Positive Airway Pressure Adherence Tracking Systems. The Optimal Monitoring Strategies and Outcome Measures in Adults. American Journal of Respiratory and Critical Care Medicine 2013;188:613-20.
Smith I, Nadig V, Lasserson TJ. Educational, supportive and behavioural interventions to improve usage of continuous positive airway pressure machines for adults with obstructive sleep apnoea. Cochrane Database Syst Rev 2009:CD007736.
Hoy CJ, Vennelle M, Kingshott RN, Engleman HM, Douglas NJ. Can intensive support improve continuous positive airway pressure use in patients with the sleep apnea/hypopnea syndrome? American journal of respiratory and critical care medicine 1999;159:1096-100.
Coma-Del-Corral MJ, Alonso-Alvarez ML, Allende M, et al. Reliability of telemedicine in the diagnosis and treatment of sleep apnea syndrome. Telemedicine journal and e-health : the official journal of the American Telemedicine Association 2013;19:7-12.