Efficacy of home single-channel nasal pressure for recommending continuous positive airway pressure treatment in sleep apnea

Abstract

Introduction: Unlike other prevalent diseases, obstructive sleep apnea (OSA) has no simple tool for diagnosis and therapeutic decision-making in primary healthcare. Home single-channel nasal pressure (HNP) may be an alternative to polysomnography for diagnosis but its use in therapeutic decisions has yet to be explored.

Objectives: To ascertain whether an automatically scored HNP apnea-hypopnea index (AHI), used alone to recommend continuous positive airway pressure (CPAP) treatment, agrees with decisions made by a specialist using polysomnography and several clinical variables.

Methods: Patients referred by primary care physicians for OSA suspicion underwent randomized polysomnography and HNP. We analyzed the total sample and both more and less symptomatic subgroups for Bland and Altman plots to explore AHI agreement; receiver operating characteristic curves to establish area under the curve (AUC) measurements for CPAP recommendation; and therapeutic decision efficacy for several HNP AHI cutoff points.

Results: Of the 787 randomized patients, 35 (4%) were lost, 378 (48%) formed the more symptomatic and 374 (48%) the less symptomatic subgroups. AHI bias and agreement limits were 5.8 ± 39.6 for the total sample, 5.3 ± 38.7 for the more symptomatic, and 6 ± 40.2 for the less symptomatic subgroups. The AUC were 0.826 for the total sample, 0.903 for the more symptomatic, and 0.772 for the less symptomatic subgroups. In the more symptomatic subgroup, 70% of patients could be correctly treated with CPAP.

Conclusion: Automatic HNP scoring can correctly recommend CPAP treatment in most of more symptomatic patients with OSA suspicion. Our results suggest that this device may be an interesting tool in initial OSA management for primary care physicians, although future studies in a primary care setting are necessary.

Clinical trials information: Clinicaltrial.gov identifier: NCT01347398.

Keywords: Apnealink; CPAP; portable monitor; sleep apnea.

Figure 1

Flowchart of patients with automatic home single-channel nasal pressure (HNP) scoring, including performed and lost cases, valid and invalid recordings, and therapeutic decision agreements and disagreements. (A) For the total sample: of 787 randomized patients, 35 were lost without performing HNP and HNP was carried out in 752. Of these, 595 had valid automatic HNP and polysomnography (PSG) recordings and 157 had invalid recordings after 76 HNP repetitions. Of these 595 patients with valid recordings, 194 had therapeutic decision agreement and 401 therapeutic disagreements. All the 194 patients with therapeutic decision agreement were true positive results (continuous positive airway pressure [CPAP] recommendation). Of the 401 with therapeutic disagreement, there were 382 unclassified patients (without any CPAP recommendation) and 19 false positives. (B) For the more symptomatic and less symptomatic subgroups: of the 787 patients randomized, 35 were lost without performing HNP, 378 had a high clinical probability of being treated with CPAP and 374 did not. Of the 378 with a high clinical probability of being treated with CPAP, 311 had a valid automatic HNP scoring and 67 invalid scorings after 41 HNP repetitions. Of these 311, 235 had therapeutic decision agreement with PSG (189 with CPAP recommendation and 46 with non-CPAP recommendation) and 76 had therapeutic decision disagreement (53 unclassified–without any CPAP recommendation–14 false positives and nine false negatives). Of the 374 with no high clinical probability of being treated with CPAP, 284 had a valid automatic HNP scoring and 90 invalid scorings after 34 HNP repetitions. Of these 284, 56 had therapeutic decision agreement with PSG (all with CPAP recommendation) and 228 had therapeutic decision disagreement (223 unclassified– without any CPAP recommendation–and five false positives).

Figure 2

Mean AHI versus the difference in AHI between PSG and automatic HNP scorings (Bland-Altman plots). Central lines represent mean values and upper and lower lines represent agreement limits (two standard deviations). (A) entire sample, (B) more symptomatic subgroup and (C) less symptomatic subgroup. AHI, apnea-hypopnea index; HNP, home single-channel nasal airway pressure; PSG, polysomnography.

Figure 3

Receiver operating characteristic (ROC) curves for automatic HNP scorings based on CPAP recommendation (yes or no) by PSG. (A) entire sample, (B) more symptomatic subgroup, (C) less symptomatic subgroup. AHI, apnea-hypopnea index; AUC, area under the curve; CI, confidence interval; CPAP, continuous positive airway pressure; HNP, home single-channel nasal airway pressure; PSG, polysomnography.