Risk assessment for CPAP nonadherence in adults with newly diagnosed obstructive sleep apnea: preliminary testing of the Index for Nonadherence to PAP (I-NAP).

Purpose: Identification of risk for continuous positive airway pressure therapy (CPAP) nonadherence prior to home treatment is an opportunity to deliver targeted adherence interventions. Study objectives included the following: (1) test a risk screening questionnaire to prospectively identify CPAP nonadherence risk among adults with newly diagnosed obstructive sleep apnea (OSA), (2) reduce the questionnaire to a minimum item set that effectively identifies 1-month CPAP nonadherence, and (3) examine the diagnostic utility of the screening index.

Methods: A prospective, longitudinal study at two clinical sleep centers in the USA included adults with newly diagnosed OSA (n=97; AHI≥5 events/h) by polysomnogram (PSG) consecutively recruited to participate. After baseline participant and OSA characteristics were collected, a risk screening questionnaire was administered immediately following CPAP titration polysomnogram. One-month objective CPAP use was collected.

Results: Predominantly, white (87%), males (55%), and females (45%) with obesity (BMI 38.3 kg/m2; SD 9.3) and severe OSA (AHI 36.8; SD 19.7) were included. One-month CPAP use was 4.25 h/night (SD 2.35). Nineteen questionnaire items (I-NAP) reliably identified nonadherers defined at <4 h/night CPAP use (Wald X2[8]=34.67, p<0.0001) with ROC AUC 0.83 (95% CI 0.74-0.91). Optimal score cut point for the I-NAP screening questionnaire were determined to maximize sensitivity (87%) while maintaining specificity>60% (63%).

Conclusion: A risk screening questionnaire employed immediately after titration PSG may reliably identify CPAP nonadherers and permit the delivery of targeted interventions to prevent or reduce nonadherence. This novel approach may enhance cost-effectiveness of care and permit appropriate allocation of resources for CPAP adherence.