Effects of nondipping pattern on systemic inflammation in obstructive sleep apnea

Obstructive sleep apnea syndrome (OSAS) is a highly prevalent chronic systemic disease in the general population with high morbidity and mortality. Nondipping pattern-failure to drop blood pressure levels in nighttime-is also seen in OSAS patients. We aim to investigate dipping and nondipping patterns of OSAS patients and to compare inflammatory markers.

Patients with the confirmed diagnosis of OSAS with polysomnography underwent ambulatory blood pressure monitoring. During monitoring, patients with decreased nighttime mean systolic blood pressures 10 % or more were defined as dippers, and the patients without this amount of decrease were defined as nondippers. Peripheral venous blood samples were collected for the analysis of IL-2, IL-6, IL-8, IL-10, IL-12, and TNF-α. Results were compared with convenient statistical tests.

According to monitoring results, 34 of 62 OSAS patients were dipper and 28 of 62 patients were nondipper. Demographic characteristics, OSAS severity, and Apnea Hypopnea Index were similar in both groups. When inflammatory markers were compared between two groups, IL-2 levels were found to be significantly different (p = 0.014).

In conclusion, nondipping pattern appears to be associated with increased serum IL-2 levels indicating the increased inflammatory response independently from OSAS severity, and this pattern should be evaluated carefully for possible cardiovascular complications.