Refill rates of accessories for positive airway pressure therapy as a surrogate measure of long-term adherence

J Clin Sleep Med. 2012 Apr 15;8(2):169-75. doi: 10.5664/jcsm.1772.


Study objectives: To identify and validate a surrogate measure of long-term adherence to positive airway pressure (PAP) therapy in patients with obstructive sleep apnea (OSA).

Design: Retrospective cohort study.

Setting: Academic center.

Participants: 220 consecutive patients with OSA.

Interventions: N/A.

Measurements: In patients with OSA who were receiving PAP therapy (for > 1 year), PAP adherence measured by device-download and defined by Medicare criteria was compared to refill rates for mask and other PAP therapy accessories. First, receiver operating characteristic (ROC) curves were constructed to identify a threshold value of refills per year that discriminated best between PAP adherent and non-adherent patients (derivation set; n = 100). Then the predictive accuracy of the threshold value of refills per year was tested in an additional 120 consecutive patients (validation set).

Results: From the derivation set, ROC curve with good discriminant characteristics (ROC 0.83; 95% confidence intervals [CI], 0.75, 0.91, p < 0.0001) was used to identify a threshold value of refills (0.7 refills/year) for distinguishing PAP adherent and non-adherent patients. Subsequently, when the threshold was applied to the validation set, the likelihood ratio for a positive test (weighted for prevalence) predicting adherence to PAP therapy was 7.3 (95%CI, 3.8, 14), and likelihood ratio for a negative test was 0.6 (95%CI; 0.4, 0.8).

Conclusion: Refill rate of PAP accessories exhibited good test characteristics for predicting long-term PAP adherence. Such a surrogate measure based upon insurance claims data can be a powerful epidemiological tool in bioinformatics-aided comparative-effectiveness research and to monitor clinical performance of health systems.

Keywords: Adherence; adherence; adult; artificial respiration; compliance; continuous positive airway pressure; obstructive sleep apnea; sleep apnea.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Continuous Positive Airway Pressure / instrumentation
  • Continuous Positive Airway Pressure / psychology*
  • Continuous Positive Airway Pressure / statistics & numerical data
  • Female
  • Humans
  • Likelihood Functions
  • Male
  • Middle Aged
  • Patient Compliance* / psychology
  • Patient Compliance* / statistics & numerical data
  • ROC Curve
  • Retrospective Studies
  • Sleep Apnea, Obstructive / psychology
  • Sleep Apnea, Obstructive / therapy*
  • Time Factors