Effects of nasal CPAP treatment on insulin resistance, lipid profile, and plasma leptin in sleep apnea.
BACKGROUND
Obstructive sleep apnea has been linked with metabolic syndrome characterized by dyslipidemia, dyscoagulation, hypertension, and diabetes mellitus type 2 and their cardiovascular consequences. This study was designed to determine the effects of 8 weeks of therapy with continuous positive airway pressure (CPAP) on insulin resistance, glucose, and lipid profile, and the relationship between leptin and insulin-resistance parameters in patients with moderate-to-severe obstructive sleep apnea.


METHODS
In 44 patients, serum cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, very low-density lipoprotein, leptin, and insulin parameters were measured at baseline and after 8 weeks of CPAP. Insulin resistance index was based on the homeostasis model assessment (HOMA-IR) method. Insulin sensitivity (HOMA-S) and insulin secretion capacity (HOMA-beta) also were calculated. Thirteen patients were excluded from statistical analyses due to noncompliant CPAP usage (<4 h night(-1)).


RESULTS
In 31 patients who used CPAP for > or =4 h night(-1), CPAP therapy reduced total cholesterol (P < 0.05), low-density lipoprotein (P < 0.05), and leptin (P < 0.05). Circulating leptin levels showed significant correlation with both HOMA-S and HOMA-IR at baseline and follow-up (P = 0.03 for all). In addition, there was no correlation between HOMA-IR and the severity of sleep apnea, which was shown by apnea-hypopnea index.


CONCLUSIONS
In patients with moderate-to-severe obstructive sleep apnea, compliant CPAP usage may improve insulin secretion capacity, reduce leptin, total cholesterol, and low-density lipoprotein levels. Leptin showed significant relationship with insulin resistance, and this relationship remained after 8 weeks of CPAP therapy.
Cuhadaroğlu
Cağlar
C
Department of Chest Diseases, Istanbul Faculty of Medicine, Istanbul University, Göğüs Hastaliklari Anabilim Dali, Istanbul, Turkey. cuhad@turk.net
Utkusavaş
Ayfer
A
Oztürk
Levent
L
Salman
Serpil
S
Ece
Turhan
T
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D020738:Leptin / Q000097:blood*; D008055:Lipids / Q000097:blood*; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D008875:Middle Aged; D010349:Patient Compliance; D012720:Severity of Illness Index; D012891:Sleep Apnea Syndromes / Q000097:blood / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome
D015415:Biomarkers; D001786:Blood Glucose; D007328:Insulin; D020738:Leptin; D008055:Lipids