[Relationship between serum substance P levels and excessive daytime sleepiness in patients with obstructive sleep apnea-hypopnea syndrome].

OBJECTIVE

To investigate the relationship between serum Substance P levels and excessive daytime sleepiness (EDS) in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS).

METHODS

A total of 120 adult habitual snorers treated by respiratory physicians in First Hospital of Quanzhou Affiliated to Fujian Medical University were selected for this study. The patients were grouped as simple snorers and OSAHS by the results of polysomnography test. Thirty patients were in the simple snorer group, among whom 24 were male and 6 were female. Their average age was (48 ± 15) years and average AHI was (2.8 ± 1.6) events/hour. Ninety patients were in the OSAHS group, among whom 78 were male and 12 were female. Their average age was (49 ± 12) years and average AHI was (37.1 ± 23.7) events/hour. EDS was assessed using the Epworth sleepiness scale (ESS). Substance P levels were analyzed with a radioimmunoassay.

RESULTS

There was no significant difference in gender, age, and body mass index between the 2 groups. The ESS score for patients with OSAHS was (13 ± 5), higher than that for patients in the simple snorer group (F = 10.299, P < 0.05). With increasing severity of OSAHS, the score increased. The serum Substance P level for OSAHS group was (132 ± 27) ng/L, which was lower than that in the control (F = 3.048, P = 0.031), and decrease in Substance P level was most significant in patients with severe OSAHS. Pearson correlation analysis showed that Substance P levels in OSAHS patients were negatively correlated with ESS scores (r = -0.238, P < 0.05).

CONCLUSIONS

Substance P levels were lower in OSAHS patients with higher degree of daytime sleepiness. Daytime sleepiness and Substance P level were interrelated in patients with OSAHS.