Correspondence: Sean Hesselbacher(Hesselse@evms.edu)
aEastern Virginia Medical School, Norfolk
bHampton Veterans Affairs Medical Center, Virginia
Author contributions
All authors approved the final manuscript. Conceptualization, methodology, visualization: Hesselbacher, Nye. Investigation, writing original draft: Nye. Data curation, formal analysis, writing review & editing, supervision: Hesselbacher.
Author disclosures
The authors report no actual or potential conflicts of interest or outside sources of funding with regard to this article.
Disclaimer
The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the US Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review the complete prescribing information for specific drugs or drug combinations—including indications, contraindications, warnings, and adverse effects—before administering pharmacologic therapy to patients.
Ethics and consent
This study was determined to be exempt by the Hampton Veterans Affairs Medical Center Institutional Review Board (protocol #20-01).
Seventeen patients (55%) met the minimum adherence criteria of ≥ 4 hours of usage for ≥ 70% of the nights. There were no significant differences in age, BMI, sex, race, comorbidities, medications, or ESS when comparing patients who were adherent to ASC and those who were not (Table 1). The date of diagnostic sleep testing and sleep architecture, including sleep latency, total sleep time, sleep efficiency, wake after sleep onset, arousal index, and percentage of rapid eye movement stage sleep were similar between the adherent patients and nonadherent patients (Table 2).
The overall AHI mean (SD) on diagnostic PSG were also similar between the adherent group (52.3 [24.8] events/h) and nonadherent group (45.1 [27.0] events/h) (P = .47). The mean (SD) for obstructive AHI (obstructive apneas, mixed apneas, obstructive hypopneas, and undifferentiated hypopneas per hour of sleep) were higher in the adherent group as a percentage of the total AHI: 81.5% (27.9) in the adherent group vs 46.7% (38.4%) in the nonadherent group; P = .02) (Figure 1).
This difference was primarily driven by a difference in mean (SD) HI: 29.7 (16.5) in the adherent group vs. 15.3 (12.1) in the nonadherent group (P = .04).
There were no significant differences between the proportions of patients on ASV with set EPAP or the titrated EPAP and IPAP. The median (IQR) residual AHI was lower in the adherent group compared with the nonadherent group, both in absolute values (1.7 [0.9-3.2] events/h vs 4.7 [2.4-10.3] events/h, respectively [P = .004]), and as a percentage of the pretreatment AHI (3.1% [2.5-6.0] vs 10.2% [5.3-34.4], respectively; P = .002) (Figure 2).
Primarily Obstructive Sleep Apnea
Sleep apnea was a mixed picture of obstructive and central events in many patients. Only 3 patients had “pure” CSA. Thus, we were unable to define discrete comparison groups based on the sleep-disordered breathing phenotype. We identified 19 patients with primarily OSA (ie, initially diagnosed with OSA, OSA with TECSA, or complex sleep apnea). The mean (SD) age was 66.1 (12.8) years, BMI was 36.2 (4.7), and ESS was 11.4 (5.6). The mean (SD) baseline AHI was 46.9 (29.5), obstructive AHI was 40.5 (30.4), and central AHI was 0.4 (1.2); the median (IQR) SpO2 nadir was 81% (78%-84%). The mean (SD) titrated EPAP was 10.2 (3.5) cm H2O, and the 90th/95th percentile IPAP was 17.9 (3.5) cm H2O. The mean (SD) usage of ASV was 7.9 (5.3) hours with 11 patients (58%) meeting the minimum standard for adherence to ASV therapy.
No significant differences were seen between the adherent and nonadherent groups in clinical or demographic characteristics or date of diagnostic sleep testing (eAppendix, available online at doi:10.12788/fp.0374). In baseline sleep studies the mean (SD) HI was 32.3 (15.8) in the adherent group compared with 14.7 (8.8) in the nonadherent group (P = .049). In contrast, obstructive AHI was not significantly lower in the adherent group: 51.9 (30.9) in the adherent group compared with 22.2 (20.6) in the nonadherent group (P = .09). The median (IQR) residual AHI on ASV as a percentage of the pretreatment AHI was 3.0% (2.4%-6.5%) in the adherent group compared with 11.3% (5.4%-89.1%) in the nonadherent group, a statistically significant difference (P = .01). No other significant differences were seen between the groups.
