(RxWiki News) Sleep apnea affects about a fifth of Americans and has been linked to heart disease and brain dysfunction. It's possible that this condition is associated with lung disease as well.
A recent study found that sleep apnea — a condition in which breathing pauses while sleeping — was an independent risk factor of pneumonia, a type of lung infection.
The researchers discovered that the risk of pneumonia increased as the severity of sleep apnea increased.
"Discuss the risk of pneumonia if you have sleep apnea."
The lead author of this study was Kun-Ta Chou, MD, from the Department of Chest Medicine of the Taipei Veterans General Hospital, and the Institute of Clinical Medicine in the School of Medicine at National Yang-Ming University — both in Taipei, Taiwan.
The study included 6,816 adults from Taiwan who were newly diagnosed with sleep apnea between January 1, 2000 and December 31, 2010.
All of the sleep apnea participants were 20 years old and older, with an average age of 55 years old. Thirty-seven percent were female. There was also a control group of 27,284 people who were matched for age, sex and co-occurring conditions.
None of the participants had a medical history of pulmonary infection. All of the participants were selected from the Longitudinal Health Insurance Database 2000 — a nationally representative database of insured people living in Taiwan in 2000.
The researchers conducted follow-ups after an average of five years. The findings showed that there were 2,757 total cases of pneumonia, representing 8 percent of the total study population.
There were 638 cases (9 percent) of pneumonia among the sleep apnea group and 2,119 cases (8 percent) of pneumonia among the control group.
The researchers determined that the incidence rate of pneumonia was 21 cases per 1,000 person-years (amount of people with pneumonia multiplied by number of years between diagnosis and end of study) for the sleep apnea participants versus 17 cases per 1,000 person-years for the control group.
Compared to the participants who did not have pneumonia, the participants with pneumonia were on average older and had a percentage of people with sleep apnea, diabetes, heart disease and other co-occurring conditions.
The participants with sleep apnea were 20 percent more likely to be diagnosed with pneumonia compared to the control group.
The findings also revealed that the sleep apnea participants who needed continuous positive airway pressure (CPAP) therapy had a 32 percent increased risk of pneumonia compared to the control participants. CPAP is a treatment that uses mild air pressure to keep the airways open.
The sleep apnea participants who did not need CPAP therapy were still at a 15 percent increased risk of developing pneumonia compared to the control group.
Dr. Chou and team concluded that sleep apnea was an independent risk factor for incident pneumonia.
"This is another study that demonstrates the unfortunate consequences of sleep apnea," said Robert Rosenberg, DO, of The Sleep Disorders Centers of Prescott Valley and Flagstaff in Arizona.
"We know that sleep apnea can predispose individuals to acid reflux and thus increase the potential for aspiration. We also know that people with sleep apnea demonstrate impaired immune function. Therefore, it is not entirely surprising that there is an increased incidence of pneumonia," Dr. Rosenberg said.
"What I found more bothersome as a sleep clinician is that there was a higher incidence of pneumonia even in those on CPAP (Continuous Positive Airway Pressure). This definitely merits further investigation as to cause," he told dailyRx News.
A few study limitations were mentioned by the authors. First, cases of sleep apnea and pneumonia were determined by insurance claims recorded by physicians or hospitals. Second, patient data on body mass index (height to weight ratio) and smoking history were not available in the database.
Third, the researchers used the need for CPAP therapy as an indicator of sleep apnea severity. However, the choice for CPAP therapy may not always depend solely on the severity of the condition.
This study was published on March 3 in the Canadian Medical Association Journal.