Figure 2.

Adjusted probability of initial CPAP use ≥4 h, by lipid-adherence subgroup (n = 117). Medication adherence is measured as the PDC, calculated as the number of d with medication available from the Veterans Affairs pharmacy divided by the total number of d exposed in the year before CPAP therapy. Estimates are adjusted for age, race, BMI, Epworth Sleepiness Scale, apnea-hypopnea index, in-laboratory vs unattended sleep study, Charlson Index, and CPAP use on first night vs subsequent nights. PDC = proportion of days covered. See Figure 1 for expansion of other abbreviation.