Editor's Note: Commentary based on Shear TC, Balachandran JS, Mokhlesi B, et al. Risk of sleep apnea in hospitalized older patients. J Clin Sleep Med 2014;10:1061-6.

Background

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder that affects one in four adults in the U.S. The association of sleep apnea with multiple comorbidities (hypertension, diabetes, heart failure, arrhythmias) that lead to hospitalizations is well established. Sleep architecture disruption has been described in the elderly. The incidence of OSA among elderly general medicine inpatients, and OSA correlation with in-hospital sleep patterns have not been systematically studied. Since under-diagnosis of sleep apnea is a frequent issue, studying physician awareness is critical.

Methods

In this prospective cohort study at a tertiary care center conducted over 36 months, general medicine inpatients over 50 years of age with intact cognition were invited to participate. Exclusion criteria included prior history of sleep apnea, non-ambulatory patients, non-English-speaking patients, and those who were critically ill or frequently hospitalized. OSA risk was estimated using the Berlin questionnaire. The Epworth Sleepiness Scale, Karolinska Sleep Log, and Pittsburgh Sleep Quality Index tools were used to ascertain subjective sleep quality while the patients were hospitalized. Sleep quality was objectively measured by wristwatch-like activity monitors (actigraphy) that were worn by patients throughout their hospital stay. Demographic information and hospital stay details were obtained from chart surveys. A sample of internal medicine resident physicians was surveyed for their knowledge and practice patterns in screening inpatients for OSA.

Results

Of the 800 patients who met eligibility criteria, 424 patients (53%) consented to participate. In this cohort, there were 72% African Americans, and 57% women. The mean age was 65 years, with median length of enrollment being two days (median hospital stay four days). The average sleep duration and sleep efficiency were five hours, and 70% respectively. One-month follow-up information was available for 63% of patients, of whom 26% reported acute care visits.

Two out of five patients met high-risk criteria for OSA on the Berlin questionnaire. This high-risk group had a higher body mass index (30.9 kg/m² high risk vs. 26.1 kg/m² low risk, χ² = 7.43, p = 0.006) and were less likely to be older than 74 years (χ² = 7.52, p = 0.006). There was no association with male sex, prior hospitalization, or higher Charlson comorbidity score. Based on the actigraphy data, this cohort slept 40 minutes less and had lower sleep efficiency compared to the remainder of patients. Subjectively, the high-risk cohort reported higher rates of daytime sleepiness (50.8% >9 Epworth Sleepiness scale high risk vs. 27.4% low risk, p <0.001), and worse sleep quality (83.3% ≥5 PSQI high risk vs. 69.1% low risk, p = 0.001). They were also three times as likely to receive pharmacologic sleep aids (15.5% of high risk vs. 5.1% of low risk, p <0.001). There was no correlation of high-risk OSA with length of stay or acute care visits on follow-up.

Of the 26 physicians surveyed, 19% reported knowledge on OSA screening with 0% routinely doing so. Half of this group felt that it was their responsibility as providers to screen patients for this disorder.

Conclusion

In summary, approximately 40% of hospitalized adults ≥50 years old met high-risk criteria for OSA. This cohort had worse in-hospital sleep duration, lower sleep efficiency, poorer self-reported sleep quality and were more likely to receive pharmacologic sleep aids. Although low physician awareness was noted, over 50% providers felt that they should address this issue. This study highlights the high prevalence of OSA in the elderly hospitalized patients.

Commentary

This is a well conducted cohort study at a tertiary care center, and reports a relatively high incidence of OSA in the elderly inpatients. Whether their rates are higher owing to the elderly patients or the complexity of medical conditions remains to be known. The authors have reported correlation with subjective measures like sleepiness, and sleep efficiency. A similar study in patients with heart failure showed higher mortality on three-year follow-up.¹ It is surprising to note that this cohort does not have worse in-hospital outcomes or recurrent visits on follow-up. Either a larger sample size or a longer follow-up could have possibly unmasked the differences in recurrent admissions for this study.

One pressing concern is whether the frequent monitoring of vital signs during the night shift could have further disturbed sleep patterns, and led to an overestimation of sleep disorders. Another possible confounder is that the medical diagnoses for admission could have impacted outcomes, and are not detailed. For instance, patients with acute cardiac conditions report worse breathing patterns, which could have placed them in the higher risk cohort.²

A major issue with inpatient sleep testing is the loss of follow-up in the outpatient setting. Although under-diagnosis of sleep apnea is a major concern, non-compliance and lack of patient understanding to use continuous positive pressure therapies are large impediments to curtailing this illness.³ Inpatient screening of patients is a good starting point if combined with an infrastructure for outpatient formal testing and close follow-up.⁴

This study brings to attention the lack of house staff awareness and the scope to improve instruction in this area. A recent study dismally concluded that patients had to see over multiple providers with a lag period exceeding 22 months before being diagnosed with a sleep disorder.⁵ Given the complex interactions of sleep apnea with hypertension, diabetes, and cardiac and cerebrovascular systems, this disease entity needs prompt recognition and an emphasis on education.⁶

References

1. Khayat R, Jarjoura D, Porter K, et al. Sleep disordered breathing and post-discharge mortality in patients with acute heart failure. Eur Heart J 2015 Jan 29. [Epub ahead of print]
2. Oza NM, Baveja S, Khayat R, Houmsse M. Obstructive sleep apnea and atrial fibrillation: understanding the connection. Expert Rev Cardiovasc Ther 2014;12:613-21.
3. Wozniak D, Lasserson T, Smith I. Educational, supportive and behavioral interventions to improve usage of continuous positive airway pressure machines in adults with obstructive sleep apnea. Cochrane Database Syst Rev 2014;1:CD007736.
4. Stevens J. Behavioural economics strategies for promoting adherence to sleep interventions. Sleep Med Rev 2014;23C:20-7.
5. Carter L, Acebo C, Kim A. Patient's journeys to a narcolepsy diagnosis: a physician survey and retrospective chart review. Postgrad Med 2014;126:216-24.
6. Gonzaga C, Bertolami A, Bertolami M, Amodeo C, Calhoun D. Obstructive sleep apnea, hypertension and cardiovascular diseases. J Hum Hypertension 2015 March 12. [Epub ahead of print]

Keywords: Actigraphy, Adult, African Americans, Aged, Arrhythmias, Cardiac, Attention, Berlin, Body Mass Index, Cognition, Cohort Studies, Comorbidity, Critical Illness, Diabetes Mellitus, Female, Follow-Up Studies, Heart Failure, Humans, Hypertension, Incidence, Inpatients, Internal Medicine, Internship and Residency, Length of Stay, Male, Outpatients, Polysomnography, Prevalence, Prospective Studies, Sample Size, Self Report, Sleep Apnea Syndromes, Sleep Apnea, Obstructive, Sleep Wake Disorders, Tertiary Care Centers, Wrist

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