Figure 3.

Kaplan–Meir curves of time to achieve Medicare-defined adherence to positive airway pressure (PAP) therapy device are shown for various income quartiles. Note that individuals from higher income neighborhoods are more likely to become adherent by Medicare-defined criteria sooner in time and also a greater proportion of individuals from a higher income neighborhood are likely to be adherent to PAP therapy (Log Rank test, p < 0.0001). The inset reveals a distinct pattern of emergent differences at the 90-day and again at the 120-day timepoints suggesting an effect of the 90-day Medicare rule that threatens to discontinue benefits in individuals who are nonadherent at that point in time (difference-in-difference analysis; p < 0.0001).