Severe obstructive sleep apnea heightens risk for various hospitalizations
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Key takeaways:
- Those with vs. without severe obstructive sleep apnea faced an 87% greater risk for being hospitalized with pneumonia.
- This risk was also high among those with a hypoxic burden greater than 5%.
Severe obstructive sleep apnea raised the risk for hospital admittance with pneumonia and any infections compared with individuals who have normal breathing during sleep, according to results published in CHEST.
“Severe obstructive sleep apnea and hypoxemia were independently associated with increased risk of hospitalization with pneumonia in a community-based sample of older adults,” Pamela L. Lutsey, MPH, PhD, professor in the division of epidemiology and community health at University of Minnesota, and colleagues wrote. “Findings for respiratory infection and hospitalization with any infection followed a similar pattern, though effect sizes were modestly lower.”
In a prospective cohort study, Lutsey and colleagues analyzed 1,586 individuals (mean age, 62.7 years; 52.8% women) from the Atherosclerosis Risk in Communities study to see if there is a relationship between OSA and risk for hospitalization with pneumonia, respiratory infections or any infections.
Using results from polysomnography taken between 1996 and 1998, researchers divided individuals according to their apnea-hypopnea index to determine the severity of OSA and found that 6% of individuals had 30 or more events per hour (severe OSA), 12.7% had 15 to 29 events per hour (moderate OSA), 30% had five to 14 events per hour and 51.3% had less than five events per hour (normal breathing).
The median follow-up period in this study cohort was 20.4 years, during which researchers reported 253 hospitalizations for pneumonia, 330 hospitalizations for respiratory infections and 589 hospitalizations for any infection.
In a model that accounted for age, sex, center, education, sports index, drinking status and smoking status, the risk for hospital admittance for pneumonia increased by 87% (adjusted HR = 1.87; 95% CI, 1.19-2.95) among those with severe OSA vs. normal breathing. Researchers further accounted for BMI, as well as prevalent asthma and COPD and observed a slightly lower, but still elevated, risk for this type of hospitalization when comparing those with severe OSA to those with normal breathing (aHR = 1.62; 95% CI, 0.99-2.63).
The risk for hospital admittance with pneumonia did not differ between patients with mild/moderate OSA and patients with normal breathing during sleep.
When evaluating the risk for a respiratory infection hospitalization in the demographic and behavior adjusted model, researchers observed a 47% (aHR = 1.47; 95% CI, 0.96-2.25) greater risk among those with severe OSA vs. normal breathing. Adjusting for additional variables led to a lower risk among those with severe OSA.
The elevated risk found for hospital admittance with a respiratory infection among patients with severe OSA was comparable to the risk for hospitalization with any infection (aHR = 1.48; 95% CI, 1.07-2.04). Increasing the number of variables in the model also reduced this risk among patients with severe OSA, according to researchers.
During analysis of the risk for hospitalization with pneumonia and respiratory infections, researchers did not find any significant interactions by age, sex or BMI; however, an increased risk for hospitalization with any infection was found in those with severe OSA aged 62 years or younger (aHR = 2.11; 95% CI, 1.26-3.54) compared with those older than 62 years (aHR = 0.89; 95% CI, 0.56-1.4; P = .03) in the model adjusted for age, sex, center, education, sports index, drinking status, smoking status and BMI.
Researchers also compared those with a hypoxic burden greater than 5% with those with a burden less than 1% in the adjusted model outlined above and found that individuals with a higher burden faced a 59% (95% CI, 1.12-2.24) increased risk for pneumonia hospitalization, a 53% (95% CI, 1.12-2.08) increased risk for respiratory infection hospitalization and a 25% (95% CI, 0.98-1.59) increased risk for hospitalization with any infection.
“Given this emerging evidence, more research is needed to determine whether screening for OSA and treating severe OSA in the primary care setting will lower the risk of hospitalization resulting from pneumonia and other infectious diseases, including COVID-19,” Lutsey and colleagues wrote.
Perspective
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I think these findings are interesting in that the authors found an association between severe OSA and a significantly increased risk for hospitalization with pneumonia; the data suggested an essentially “dose-dependent” relationship between the degree of OSA, as measured by apnea-hypopnea index, and risk for hospitalization with pneumonia. In my clinical practice, I have noticed a trend among patients with severe, untreated OSA to generally be sicker and have poorer long-term health outcomes.
I think the results of this study can be used as additional ammunition to motivate patients to take their sleep apnea seriously. Not infrequently, patients may ignore the symptoms of sleep apnea such as chronic snoring and daytime sleepiness, but the risk for developing medical comorbidities — such as high blood pressure, dementia and, in this case, pneumonia — can often tip patients over to take action and start treatment.
The big question in my mind after reviewing this paper is whether treatment with CPAP helped to mitigate the risk for pneumonia in this group. There is no mention of whether the patients were being treated. Further, investigating whether there is a causal relationship between severe OSA and pneumonia and not just an association is the logical next step in research. And a fascinating question is, if there is a causal relationship, what might the mechanism be?
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