Patients with obstructive sleep apnea who develop central sleep apnea (CSA) were more compliant on therapy after they switched from CPAP to adaptive servo-ventilation (ASV) therapy, according to research announced and sponsored by ResMed Inc.

The study analyzed anonymous, aggregated data from the devices of 198,890 telemonitored patients in the United States who were receiving positive airway pressure therapy for their sleep apnea. It showed that those with treatment-emergent CSA who switched from CPAP to ASV used their therapy longer and had significantly fewer apneas (breathing stoppages or reductions) during sleep, according to a ResMed press release.

Specifically, patients were 62.7% compliant on CPAP, but after they switched to ASV those same patients were 76.6% compliant, according to ResMed. (The study used the U.S. Medicare definition of compliance: device usage for more than four hours per night on 70% of nights during a consecutive 30-day period anytime during the first three months of initial use.)

Three groups of patients were analyzed for compliance, device usage, and measures of disease severity: Those patients that started and stayed on CPAP (the “CPAP-only” group), patients that started and stayed on ASV (the “ASV-only” group), and patients that started on CPAP and switched to ASV (the “Switch” group). All patients in the analysis received CPAP via ResMed’s AirSense 10 or ASV via ResMed’s AirCurve 10 devices.In the “Switch” group, patients beginning on CPAP had the lowest initial compliance rate at 62.7%, but improved to 76.6% after switching to ASV. The low initial compliance seen in the Switch patients is possibly due to untreated CSA, based on their overall higher AHI – specifically their central apnea index (CAI) – during week one of therapy compared to the CPAP-only group.The 90-day compliance rates seen for the CPAP-only and ASV-only groups were 73.8% and 73.2%, respectively. In the Switch group, average residual AHI also decreased significantly (reduction from 17.2±0.9/h to 4.4±0.3/h) after the switch, indicating that ASV reduced both obstructive and central events.

“Achieving compliance through proper therapy usage is a well-recognized clinical goal in sleep apnea management, and one that is often hard to achieve, particularly in difficult-to-treat patients who may have untreated central sleep apnea,” said Carlos Nunez, MD, ResMed’s chief medical officer. “These findings underscore the importance of continuously monitoring central sleep apnea and rethinking the conventional wisdom on therapeutic options based on each patient’s disease severity.”

The study results were presented in an abstract at The European Respiratory Society and European Society of Sleep Research 2017 Sleep and Breathing conference in Marseilles, France.