The Apnea-Hypopnea Index Underestimates Systemic Inflammation in Women with Sleep-Disordered Breathing.

BACKGROUND

Evidence suggests that sleep-related respiratory and related metabolic compromise may vary between females and males with sleep-disordered breathing (SDB). Our purpose was to elucidate possible gender differences in sleep-associated respiratory and inflammatory parameters in patients with SDB.

MATERIALS AND METHODS

A consecutive number of SDB patients (46 females and 167 males) who underwent polysomnography were retrospectively reviewed. Fibrinogen and C-reactive protein (CRP) concentration, apnea index (ApnI), hypopnea index (HypI), apnea-hypopnea index (AHI), average and minimal SpO, duration of snoring, age, and body mass index (BMI) were compared between sexes. Spearman's ρ correlation coefficients between parameters were also calculated.

RESULTS

ApnI and AHI were significantly higher in males. Correlation analysis revealed striking gender differences: only in females, CRP concentration was highly correlated with snoring duration (r = 0.4393), BMI (r = 0.7147), minimal SpO (r = -0.4357), and average SpO (r = -0.4547); in females, HypI was more strongly correlated with AHI (r = 0.8778), average SpO (r = -0.5765), minimal SpO (r = -0.5817), and fibrinogen concentration (r = 0.4614) than in males (r = 0.4373; -0.3295; -0.2969; and 0.0887, respectively); in females, age had a much more pronounced effect on ApnI, HypI, AHI, average oxygen saturation (SaO), minimal SaO, snoring duration, and CRP and fibrinogen concentration.

CONCLUSIONS

Respiratory compromise in females with SDB is more strongly associated with systemic inflammation than in males with SDB. Although females display a pathological AHI less frequently than males, they reach quite similar pathological SaO, CRP, and fibrinogen values. Therefore, AHI may underestimate the pathophysiological systemic effects of SDB in females.