Effectiveness of home single-channel nasal pressure for sleep apnea diagnosis

Abstract

Home single-channel nasal pressure (HNP) may be an alternative to polysomnography (PSG) for obstructive sleep apnea (OSA) diagnosis but no cost studies have been carried out. Automatic scoring is simpler but less effective than manual scoring. However, there have been no studies comparing the efficacy and cost of PSG with HNP with manual scoring, automatic scoring or sequential protocol (automatic and then manual scoring for undiagnosed subjects). To determine the diagnostic efficacy and cost of two HNP protocols, manual and sequential, compared with in-hospital PSG. We included suspected OSA patients in a multicentric study. They were assigned to home and hospital protocols at random. We constructed Receiver Operating Characteristic (ROC) curves for manual and automatic scorings. Diagnostic efficacy was explored for several HNP apnea-hypopnea index cut-off points and costs were calculated for equally effective alternatives. Of 787 randomized patients, 752 underwent HNP. Manual scoring produced better ROC curves than automatic scoring. 67% of the patients who underwent HNP were correctly classified (OSA or not) with manual scoring, as were 61% with sequential protocol. The costs of PSG were more than double those of the manual HNP and sequential HNP protocols, with minimal differences between them. HNP is a significantly cheaper alternative for diagnosis in patients with suspected OSA. The costs of the sequential protocol (automatic scoring and then manual scoring for invalid automatic recording) were lower than automatic scoring and similar to manual scoring, for the same diagnostic efficacy as PSG. Instituto de Salud Carlos III (Fondo de Investigaciones Sanitarias, Ministerio de Sanidad y Consumo) PI050402, Spanish Respiratory Foundation 2005 (FEPAR) and Departamento de Sanidad del Gobierno Vasco (2005111010) and Caja Vital (2005).