The Accuracy of Portable Monitoring in Diagnosing Significant Sleep Disordered Breathing in Hospitalized Patients

Abstract

Background: Polysomnograms are not always feasible when sleep disordered breathing (SDB) is suspected in hospitalized patients. Portable monitoring is a practical alternative; however, it has not been recommended in patients with comorbidities.

Objective: We evaluated the accuracy of portable monitoring in hospitalized patients suspected of having SDB.

Design: Prospective observational study.

Setting: Large, public, urban, teaching hospital in the United States.

Participants: Hospitalized patients suspected of having SDB.

Methods: Patients underwent portable monitoring combined with actigraphy during the hospitalization and then polysomnography after discharge. We determined the accuracy of portable monitoring in predicting moderate to severe SDB and the agreement between the apnea hypopnea index measured by portable monitor (AHIPM) and by polysomnogram (AHIPSG).

Results: Seventy-one symptomatic patients completed both tests. The median time between the two tests was 97 days (IQR 25-75: 24-109). Forty-five percent were hospitalized for cardiovascular disease. Mean age was 52±10 years, 41% were women, and the majority had symptoms of SDB. Based on AHIPSG, SDB was moderate in 9 patients and severe in 39. The area under the receiver operator characteristics curve for AHIPM was 0.8, and increased to 0.86 in patients without central sleep apnea; it was 0.88 in the 31 patients with hypercapnia. For predicting moderate to severe SDB, an AHIPM of 14 had a sensitivity of 90%, and an AHIPM of 36 had a specificity of 87%. The mean±SD difference between AHIPM and AHIPSG was 2±29 event/hr.

Conclusion: In hospitalized, symptomatic patients, portable monitoring is reasonably accurate in detecting moderate to severe SDB.

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1. The central apnea indices on portable monitoring and polysomnography.

The central apnea index with the portable monitor (CAIPM) during the hospitalization was generally higher than on outpatient polysomnography (CAIPSG).

Fig 2. Plot versus criterion graph.

This graph plots the sensitivity and specificity with 95% confidence intervals for different cutoff values of AHIPM; the criterion was AHIPSG ≥ 15.

Fig 3. Receiver operating characteristic curve for AHIPM, Sleep Apnea Clinical Score, and neck circumference for predicting AHIPSG ≥ 15.

The areas were similar for the three predictors.

Fig 4. Receiver operating characteristic curve for AHIPM, Sleep Apnea Clinical Score, and neck circumference for predicting AHIPSG ≥ 15, excluding patients with central apnea index ≥ 5 on portable monitoring.

In these cases, AHIPM was more accurate than the Sleep Apnea Clinical Score and neck circumference.

Fig 5. Scatterplot for AHIPM and AHIPSG.

The line represents perfect agreement. The black circles represent patients with central apnea index on portable monitoring ≥ 5.

Fig 6. Modified Bland-Altman plot for AHIPM and AHIPSG.

The difference between AHIPSG and AHIPM was plotted against AHIPSG. Dark circles represent cases in which the central apnea index on portable monitoring was ≥ 5.