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

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