Mar et al have recently put out a commentary in the Journal of Clinical Sleep Medicine that discusses an important consideration for our patients on CPAP: compliance.
Not every patient uses their CPAP each night, and not every patient uses their CPAP all night. Our position is that CPAP should be used all night, every night, however this isn’t always going to be realistic.
Looking at compliance through the clinical lens, we want to understand the targets for compliance and where these targets come from. We also need to consider two key outcomes of CPAP therapy; improved sleepiness and improvement/ dampening comorbidity risk (eg memory function, blood pressure and cardiac mortality).
The percentage of nights with CPAP being used for greater than 4hrs is a common metric used to measure compliance. Mar et al discuss the origins of this metric and gives some insights to support this measure, and some evidence to support expanding these to better reflect the dose response benefit of CPAP therapy.
One point we wanted to highlight for consideration:
“Adherence is simply defined as hours of CPAP use per night, which does not integrate the total sleep time duration. Four hours of CPAP use on 5 hours of sleep time may have a different clinical effect than on 10 hours of sleep duration.”
While not mentioned directly, this concept has been explored by Boyd et al in 2016 when they coined the term “Effective AHI”. Let’s say someone has very severe OSA with an AHI of 60 events per hour and they only use therapy for 4 out of 8 hours. They would technically be compliant. However when you consider this patients night as a whole, they would still be categorised as having severe OSA with an “Effective AHI” of 30 events per hour. Their risk of comorbidities would remain high as would the likelihood of them experiencing some residual sleepiness.
We won’t list the rest of the nice insights this commentary brings, so we went ahead and included the link below. It’s not an overly difficult commentary to read and we encourage you to have a look for yourself.
Ultimately we want to help our patients and their primary care physicians understand that the better their CPAP compliance is, the better their outcomes will likely be too.
You can read the commentary for yourself here:
https://doi.org/10.5664/jcsm.9918
Citations:
1) Paz y Mar, H., & Castriotta, R. (2022). Duration of positive airway pressure adherence: how much PAP is enough?Commentary on Pascoe M, Bena J, Andrews ND, et al. Dose-response relationship between positive airway pressure therapy and excessive daytime sleepiness: the HomePAP study. <i>J Clin Sleep Med</i> . 2022;18(4):1027–1034. doi: 10.5664/jcsm.9792. Journal Of Clinical Sleep Medicine, 18(4), 969-970. doi: 10.5664/jcsm.9918
2) Boyd SB, Upender R, Walters AS, et al. Effective Apnea-Hypopnea Index (“Effective AHI”): A New Measure of Effectiveness for Positive Airway Pressure Therapy. Sleep. 2016;39(11):1961-1972. Published 2016 Nov 1. doi:10.5665/sleep.6224
