Probability of sufficient CPAP daily compliance. CPAP compliance is commonly referred to as sufficient if the patient is able to use the CPAP on average of 4 hours/day or more. Kaplan-Meier estimate shows the probability of good compliance over the course of time in patients within the IAP group and controls. Patients in the IAP group not only used their device longer daily average hours but also the probability to stay compliant within the course of time was remarkably higher.