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

INTRODUCTION: Home single-channel nasal pressure (HNP) may be an alternative to polysomnography (PSG) for obstructive sleep apnea (OSA) diagnosis, but no cost studies have yet been carried out. Automatic scoring is simpler but generally less effective than manual scoring. OBJECTIVES: To determine the diagnostic efficacy and cost of both scorings (automatic and manual) compared with PSG, taking as a polysomnographic OSA diagnosis several apnea-hypopnea index (AHI) cutoff points. METHODS: We included suspected OSA patients in a multicenter study. They were randomized to home and hospital protocols. We constructed receiver operating characteristic (ROC) curves for both scorings. Diagnostic efficacy was explored for several HNP AHI cutoff points, and costs were calculated for equally effective alternatives. RESULTS: Of 787 randomized patients, 752 underwent HNP. Manual scoring produced better ROC curves than automatic for AHI < 15; similar curves were obtained for AHI ≥ 15. A valid HNP with manual scoring would determine the presence of OSA (or otherwise) in 90% of patients with a polysomnographic AHI ≥ 5 cutoff point, in 74% of patients with a polysomnographic AHI ≥ 10 cutoff point, and in 61% of patients with a polysomnographic AHI ≥ 15 cutoff point. In the same way, a valid HNP with automatic scoring would determine the presence of OSA (or otherwise) in 73% of patients with a polysomnographic AHI ≥ 5 cutoff point, in 64% of patients with a polysomnographic AHI ≥ 10 cutoff point, and in 57% of patients with a polysomnographic AHI ≥ 15 cutoff point. The costs of either HNP approaches were 40% to 70% lower than those of PSG at the same level of diagnostic efficacy. Manual HNP had the lowest cost for low polysomnographic AHI levels (≥ 5 and ≥ 10), and manual and automatic scorings had similar costs for higher polysomnographic cutoff points (AHI ≥ 15) of diagnosis. CONCLUSION: Home single-channel nasal pressure (HNP) is a cheaper alternative than polysomnography for obstructive sleep apnea diagnosis. HNP with manual scoring seems to have better diagnostic accuracy and a lower cost than automatic scoring for patients with low apnea-hypopnea index (AHI) levels, although automatic scoring has similar diagnostic accuracy and cost as manual scoring for intermediate and high AHI levels. Therefore, automatic scoring can be appropriately used, although diagnostic efficacy could improve if we carried out manual scoring on patients with AHI < 15. CLINICAL TRIALS INFORMATION: Clinicaltrials.gov identifier: NCT01347398.

Respiratory polygraphy with actigraphy in the diagnosis of sleep apnea-hypopnea syndrome.

OBJECTIVE: To determine the utility and reliability of a respiratory polygraphy (RP) device with actigraphy (Apnoescreen II; Erich Jaeger GMBH & CoKg; Wuerzburg, Germany) in the diagnosis of sleep apnea-hypopnea syndrome (SAHS). DESIGN: A prospective randomized study with blinded analysis. PATIENTS: Sixty-two patients with suspected SAHS. MEASUREMENTS: the following two RP studies were performed: one in the sleep laboratory (sleep laboratory RP [LRP]), simultaneously with polysomnography; and the other at home (home RP [HRP]). To study the interobserver reliability of RP, two manual analyses were carried out by two different researchers. RESULTS: In LRP, when the respiratory disturbance index was calculated using the total sleep time estimated by actigraphy (RDI) as a denominator, the sensitivity ranged between 94.6% and 100%, and the specificity between 88% and 96.7% for the different cutoff points of the apnea-hypopnea indexes studied. When the respiratory disturbance index was calculated according to the total recording time (RDITRT), the sensitivity was slightly lower (91.6 to 96.9%) and the specificity was similar (92 to 96.7%). In HRP, the sensitivity of the RDI ranged between 83.8% and 95.8%, and the specificity between 92% and 100%, whereas, when the RDITRT was used, the sensitivity was between 83.8% and 87.5%, and the specificity was between 94.7% and 100%. With regard to interobserver reliability, the intraclass correlation coefficient for the RDI of the two analyses of the RP was 0.99 for both LPR and HPR. CONCLUSION: HPR is an effective and reliable technique for the diagnosis of SAHS, although it is less sensitive than LRP. Wrist actigraphy improves the results of HRP only slightly.