Scientific Investigations
Refill Rates of Accessories for Positive Airway Pressure Therapy as a Surrogate Measure of Long-Term Adherence
http://dx.doi.org/10.5664/jcsm.1772
Nimesh Patel, D.O.1,2; Afshin Sam, M.D.1,2; Alexandra Valentin, RRT1,3; Stuart F. Quan, M.D.2,3,4; Sairam Parthasarathy, M.D.1,2,3
1Southern Arizona Veterans Administration Healthcare System, Tucson, AZ; 2Department of Medicine; 3Arizona Respiratory Center, University of Arizona, Tucson, AZ; 4Division of Sleep Medicine, Harvard Medical School, Boston, MA
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.
Participants:
220 consecutive patients with OSA.
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.
Citation:
Patel N; Sam A; Valentin A; Quan SF; Parthasarathy S. Refill rates of accessories for positive airway pressure therapy as a surrogate measure of long-term adherence. J Clin Sleep Med 2012;8(2):169-175.
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