Switch Study results | ResMed
Switch Study results

Adherence to PAP therapy after switching from CPAP to ASV*

Switching from CPAP to ASV in patients with emergent or persistent CSA may improve adherence1

A second analysis was performed with a random sample representing 30% of the database population that had begun CPAP therapy or ASV therapy from 1 Jan to 2 Oct 2015 plus all who switched from CPAP to ASV over the same period. Adherence (US Medicare definition) and device usage were determined for 3 groups: started on CPAP and stayed on CPAP (CPAP only; n = 189,724), started on ASV and stayed on ASV (ASV only; n = 8,957), started on CPAP and switched to ASV (n = 209).

• Average PAP usage hours increased after ASV switch.

• Average AHI decreased after ASV switch.

Adherence to CPAP is defined as usage greater or equal to 4 hours per night on 70% of nights during a consecutive 30 days anytime during the first 3 months of initial usage.




• Adherence rate improved immediately after patients with emergent or persistent CSA switched from CPAP to ASV. (+22%)


Similar trends were observed when day-by-day values of CAI and AHI over the first 2 weeks of therapy were analysed.

These data suggest that normalisation of CSA during CPAP (transient CSA) may contribute to better long-term adherence to CPAP therapy.

However, if there is persistence of CSA after 2 weeks, then the patient fits within the trajectory of emergent or persistent CSA as shown by these data and will probably require a switch to ASV.*

These data are in line with the recent recommendations of the ERS, which state that in patients with persistent CSA and AHI ≥ 15 events per hour, ASV is the appropriate therapy.


Patients who experience emergent or persistent CSA while on CPAP therapy may benefit from a switch to ASV.

Patients who experience transient CSA with subsequent normalisation may continue on CPAP therapy.



* ASV therapy is contraindicated in patients with chronic, symptomatic heart failure (NYHA 2-4) with reduced left ventricular ejection fraction (LVEF ≤ 45%) and moderate to severe predominant central sleep apnoea.

  1. Pépin et al. Adherence to positive airway therapy after switching from CPAP to ASV: a big data analysis. J Clin Sleep Med. 2018 Jan 15;14(1):57-63