More science links CHF & OSA

Wednesday, April 30, 2003

MURRYSVILLE, Penn. — A sleep study published in the March 27 issue of The New England Journal of Medicine has found that heart function can be significantly improved in patients with CHF and OSA by CPAP treatment.

The study tested 24 patients with CHF and OSA who were taking medication for heart failure. For one month, 12 of those patients were treated with CPAP treatment; the other 12 were left untreated. The study found that patients on CPAP:

- reduced their OSA episodes by 80%.

- increased by 35% the amount of blood their hearts could pump when compared to where they were prior to the start of CPAP therapy.

- realized a 6% decrease in heart size.

- reduced their blood pressure by 10-mm, while the blood pressure of the control group remained the same.

- reduced their heart rate from 68 to 64 beats per second while the heart rate of the control group remained the same.

The NEJM study’s strengthens the case for a link between hypertension and sleep disordered breathing made in a ResMed-sponsored study published in Circulation in January. That study also found that effective CPAP therapy could reduce blood pressure by 10-mm of mercury.

Another January study, published in CHEST, found the link to be less well-established. If a definitive link is found, and educational outreach succeeds among cardiologists and primary care physicians, the market for sleep therapy products would grow substantially.

About one of every three patients with CHF also have obstructive sleep apnea, according to Respironics, a sponsor of the study.

Although the NEJM study took in only 24 patients, John Frank, vice president of marketing at Respironics, said it has achieved the highest level of statistical significance. While randomized drug trials take in hundreds and thousands of patients, he doubts trials for a medical device such as CPAP would ever take in as many participants.

“There’s always this question in mind for the physicians — ‘Is it ethical to not treat a patient with OSA?’” said Frank. “’Should I withhold CPAP from a patient from for two months to determine whether there is any benefit?’ That’s always going to be a challenge.” HME