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

Nimesh Patel, Afshin Sam, Alexandra Valentin, Stuart F Quan, Sairam Parthasarathy

Research output: Contribution to journalArticle

6 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)169-175
Number of pages7
JournalJournal of Clinical Sleep Medicine
Issue number2
Publication statusPublished - Apr 15 2012



  • Adherence
  • Adult
  • Artificial respiration
  • Compliance
  • Continuous positive airway pressure
  • Obstructive sleep apnea
  • Sleep apnea

ASJC Scopus subject areas

  • Clinical Neurology
  • Pulmonary and Respiratory Medicine
  • Neurology

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