Socioeconomic Inequities in Adherence to Positive Airway Pressure Therapy in Population-Level Analysis

Abstract

(a) Background: In patients with sleep apnea, poor adherence to positive airway pressure (PAP) therapy has been associated with mortality. Regional studies have suggested that lower socioeconomic status is associated with worse PAP adherence but population-level data is lacking. (b) Methods: De-identified data from a nationally representative database of PAP devices was geo-linked to sociodemographic information. (c) Results: In 170,641 patients, those in the lowest quartile of median household income had lower PAP adherence (4.1 + 2.6 hrs/night; 39.6% adherent by Medicare criteria) than those in neighborhoods with highest quartile median household income (4.5 + 2.5 hrs/night; 47% adherent by Medicare criteria; p < 0.0001). In multivariate regression, individuals in neighborhoods with the highest income quartile were more adherent to PAP therapy than those in the lowest income quartile after adjusting for various confounders (adjusted Odds Ratio (adjOR) 1.18; 95% confidence interval (CI) 1.14, 1.21; p < 0.0001). Over the past decade, PAP adherence improved over time (adjOR 1.96; 95%CI 1.94, 2.01), but health inequities in PAP adherence remained even after the Affordable Care Act was passed. (d) Conclusion: In a nationally representative population, disparities in PAP adherence persist despite Medicaid expansion. Interventions aimed at promoting health equity in sleep apnea need to be undertaken.

Keywords: adherence; big data; health disparities; health equity; health policy; positive airway pressure therapy; sleep apnea.

Figure 1

Geo-linked representation of individual patients who are adherent (blue symbols) or nonadherent to their positive airway pressure (PAP) therapy device. The data for 170,641 individuals (63.7%) of our available database with valid ZIP codes are shown. Note that more than half the symbols are red denoting a greater proportion of nonadherent individuals in this database.

Figure 2

Number of patients who are adherent (red column) or nonadherent (blue columns) to positive airway pressure therapy by Medicare standards are shown by median household income quartile ranging from the lowest to the highest income levels. Note that the number of patients who are PAP adherent progressively increases as the median household income increases (χ² < 0.0001). In our dataset, the lowest income group (Quartile 1) had a median ZIP code household income less than $40,834 with progressively greater ZIP code-based household income in Quartile 2 ($40,834–50,366), Quartile 3 ($50,376–65,143), and Quartile 4 ($65,150–223,106).

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).

Figure 4

Raw unadjusted adherence to positive airway pressure (PAP) device (with 95% confidence intervals) is shown for various income quartiles as a function of year of set-up or initiation of the PAP device. Notice that there is a clear trend for improvement in adherence as a function of time, but disappointingly the health inequities remain even after 2014 when the Affordable Care Act and Medicaid expansion occurred.

Figure 5

(a) The upper panel shows Kaplan–Meir curves that reveal differences in the temporal pattern of adherence to positive airway pressure (PAP) therapy (by Medicare-defined criteria) based upon the year of set-up or PAP initiation. Note that progressively after 2010 there is a greater proportion of individuals who are adherent by Medicare standards and they accomplish such adherence earlier in time after their device is set-up (Log Rank; p < 0.0001). The lower panels reveal similar graphs for the (b) lowest and (c) highest income groups.