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Volume 14 No. 02
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Accepted Papers

Scientific Investigations

Clinical Trial Enrollment Enrichment in Resource-Constrained Research Environments: Multivariable Apnea Prediction (MAP) Index in SCIP-PA Trial

Hyunju Yang, PhD, RN1; Alexa Watach, PhD, RN1,2; Miranda Varrasse, PhD, RN2,3; Tonya S. King, PhD4; Amy M. Sawyer, PhD, RN1,3
1Penn State University College of Nursing, University Park, Pennsylvania; 2University of Pennsylvania Perelman School of Medicine, Center for Sleep & Circadian Neurobiology, Philadelphia, Pennsylvania; 3University of Pennsylvania School of Nursing, Philadelphia, Pennsylvania; 4Penn State University College of Medicine, Department of Public Health Sciences, Hershey, Pennsylvania

Study Objectives:

Determine the Multivariable Apnea Prediction (MAP) index predictive utility for enrollment enrichment in a clinical trial wherein enrollment was prior to obstructive sleep apnea diagnosis.


Secondary analysis of screening data (n = 264) from randomized, double-blind, pilot trial. Clinical sleep center patients with complete screening and polysomnography data were included. To determine diagnostic test accuracy of the MAP index using apnea-hypopnea index criterion ≥ 10 events/h (primary) and ≥ 5, ≥ 15, and ≥ 30 events/h (secondary), sensitivity, specificity, negative and positive predictive values, likelihood positive and negative ratios, and receiver operating characteristic curves were calculated. Predictive utility was examined by characteristic variables.


Middle-aged, overweight or obese, men and women were included. Employing a MAP index threshold ≥ 0.5, sensitivity for obstructive sleep apnea (apnea-hypopnea index ≥ 10 events/h) was 83.6%; specificity was 46.4%; area under the curve = 0.74. Sensitivity was higher in males than females (95.3%, 68.7%, respectively); specificity was lower in males than females (30.4%, 57.6%, respectively) with similar area under the curve (0.74 versus 0.72, respectively). MAP accuracy was higher in younger versus older adults (younger than 50 years, or 50 years or older; area under the curve 0.82 versus 0.63, respectively). Varied apnea-hypopnea index criteria produced stable accuracy estimates.


Recruitment/enrollment is a high-cost endeavor. Screening procedures may confer resource savings but careful evaluation prior to study implementation assures effectiveness and efficiency.

Clinical Trial Registration:

The secondary analysis reports data from the SCIP-PA Trial (NCT 01454830); study information available at:


Yang H, Watach A, Varrasse M, King TS, Sawyer AM. Clinical trial enrollment enrichment in resource-constrained research environments: Multivariable Apnea Prediction (MAP) index in SCIP-PA Trial. J Clin Sleep Med. 2018;14(2):173–181.

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