By Lisa Rapaport

(Reuters Health) – People with sleep apnea, a common nighttime breathing disorder, are more likely to stick with treatment that keeps their airways open at night when they use a built-in humidifier, a Swedish study suggests.

Apnea that isn’t properly treated has been linked with excessive daytime sleepiness, heart attacks, heart failure and an increased risk of premature death. Often, patients are prescribed treatment with masks connected to a machine that provides continuous positive airway pressure (CPAP) that splints the airway open with an airstream so the upper airway can’t collapse during sleep.

To see what factors might influence whether patients stick with this cumbersome treatment, researchers followed 16,425 people who were prescribed CPAP between 2010 and 2017.

Within one year of starting treatment, 1,527 patients, or about 9 percent, had stopped using their machines, and another 2,395 people, or almost 15 percent, were only using it an average of 2.5 hours a night instead of all night as prescribed.

Patients who used CPAP machines with built-in humidifiers from the start, however, were 43 percent less likely to discontinue treatment, researchers report in Sleep Medicine.

“Upper-airway symptoms, such as nasal congestion, (runny nose) and mouth dryness are common in patients with sleep apnea on CPAP and are associated with CPAP failure,” said lead study author Dr. Andreas Palm of Uppsala University.

“Humidifiers reduce these symptoms and makes the CPAP treatment more comfortable,” Palm said by email.

While CPAP machines with integrated humidifiers are now common, doctors don’t always prescribe them right away, Palm noted. The study results should encourage more physicians to offer CPAP machines with humidifiers to patients right at the start of treatment, Palm said.

This is already happening more often. The proportion of patients getting humidifiers at the start of CPAP treatment increased from 30 percent at the start of the study to 72 percent by the end.

Anything that helps patients continue to use their CPAP machines might be a way to lower their risk of premature death, the study also suggests.

After that one-year checkup to see if patients were still using CPAP all night, researchers followed most participants for at least another 2.4 years. During this period, 378 patients died.

People who stuck with CPAP were 26 percent less likely to die than patients who discontinued treatment, the study found.

In general, patients were more likely to stick with CPAP when they were older, had more severe apnea, or were overweight and obese but not severely obese. Women and patients with high blood pressure, on the other hand, were more likely to abandon treatment.

The study wasn’t designed to prove whether or how humidifiers or other factors might directly influence patients to abandon treatment or stick with it.

“Although it is tempting to interpret this as meaning that CPAP reduces the risk of death, we must be very careful in interpreting this finding,” said Dr. Ken Kunisaki of the Minneapolis VA Health Care System and the University of Minnesota.

“Many studies in all sorts of diseases have shown that people who stick with their treatment live longer, and this includes sticking with placebo/sugar-pill treatments,” Kunisaki, who wasn’t involved in the study, said by email.

There are also a variety of reasons that people may discontinue CPAP, and many aren’t issues that could be addressed by a humidifier, said Kristen Knutson, a researcher at Northwestern University Feinberg School of Medicine in Chicago.

“Some people find it uncomfortable or claustrophobic, for example, while others perceive no benefit,” Knutson, who wasn’t involved in the study, said by email.

SOURCE: Sleep Medicine, online July 16, 2018.