Japanese researchers found that nasal continuous positive airway pressure (CPAP) in patients with obstructive sleep apnea (OSA) decreases the levels of inflammatory marker C-reactive protein (CRP).
The role of OSA versus obesity in sleep apnea has been somewhat controversial, told investigator Dr. Masahiko Kato. These data, showing that effective treatment of OSA lowers CRP, are suggestive of OSA itself being a factor in increasing CRP.
Dr Kato of Tottori University and team reported that there is a strong association between the degree of sleep-disordered breathing and serum levels of CRP. To further investigate the effect of nasal CPAP on these findings, the researchers examined 55 patients with newly diagnosed OSA who were prescribed CPAP treatment.
They found that there was a significant reduction from baseline in CRP levels at 6 months. The researchers divided the participants into good and poor compliance groups and found that this difference was no longer significant in the poor compliance group.
When they were further divided into patients with and without high CRP levels at baseline, there was a significant reduction apparent only in good compliance patients with initially elevated CRP.
The researchers reported that this may have cardiovascular implications. However, Dr. Kato concluded that whether CRP is important in raising the cardiovascular risk associated with OSA, and whether reducing CRP by treating OSA reduces that risk, remains to be determined.