Background and aims:Obstructive Sleep Apnea Syndrome (OSAS) isassociated with increased prevalence of type 2 diabetes (T2DM) and non-alcoholic fatty liver disease (NAFLD). While it is known that after bar-iatric surgery OSAS, T2DM and NAFLD all improve, the link betweenliver enzymes and OSAS in morbid obesity has not been examined.Materials and methods:We studied 164 morbidly obese men and wom-en (116 with normal glucose tolerance and 48 with T2DM) undergoingRoux-en-Y-gastric bypass (RYGB) surgery. Before the operation, all sub-jects received a 3-hour OGTT, from which insulin sensitivity was estimat-ed as the OGIS index. OSAS was diagnosed by polysomnography (usingthe Apnea-Hypopnea Index (AHI) = mild 5-15, moderate 15-30, severe>30). Six months after surgery, a subgroup of subjects (33 NGT and 11T2DM) was re-evaluated for all parameters.Results:Age and BMI were significantly higher in the OSAS group(n=83, p=0.001) and the prevalence of T2DM was 73% compared to38% in non-OSAS group (n=81, p<0.0001). Both fasting plasma glucose(111±48 vs 92±25 mg/dL) and HbA1c (7.3±4.5 vs 5.9±1%) were higher inOSAS group regardless of AHI, while insulin sensitivity was lower (346±71 vs 390±69, p=0.03). Before surgery, the OSAS group had higherserum ALT (33 [18] vs 19 [20] U/L, median [IQR]) andγGT levels (36[30] vs 21 [16]) than the non-OSAS group. In multivariate logistic analysis,HbA1c (p=0.015), BMI (p=0.026) andγGT (p=0.033) were independentlyassociated with the presence of OSAS. In a similar model, the severity ofOSAS and HbA1c were explanatory variables ofγGT concentrations. Sixmonths after surgery, BMI and HbA1cdecreased similarly in both groups,while fasting glycaemia declined more in OSAS than non-OSAS subjects.Furthermore, AST, ALT andγGT decreased in a greater degree in theformer than the latter (AST -21% vs 0.6%, ALT -60% vs -16% andγGT-53% vs -45%, p=0.03, p=0.01 and p=0.018, respectively). In logisticregression, surgery-induced changes inγGT were positively associatedwith baseline HbA1c (p=0.026)and presence of OSAS (p=0.05).Conclusion:In morbidly obese subjects, the presence of OSAS is asso-ciated with higherγGT concentrations independently of obesity andHbA1c. After surgery, however, serumγGT concentrations improve toa greater extent in patients with OSAS at baseline.

gamma-Glutamyltransferase concentrations and obstructive sleep apnea syndrome: effect of bariatric surgery

Guarino, D;Bonanni, E;Taddei, S;Ferrannini, E;Nannipieri, M
2016-01-01

Abstract

Background and aims:Obstructive Sleep Apnea Syndrome (OSAS) isassociated with increased prevalence of type 2 diabetes (T2DM) and non-alcoholic fatty liver disease (NAFLD). While it is known that after bar-iatric surgery OSAS, T2DM and NAFLD all improve, the link betweenliver enzymes and OSAS in morbid obesity has not been examined.Materials and methods:We studied 164 morbidly obese men and wom-en (116 with normal glucose tolerance and 48 with T2DM) undergoingRoux-en-Y-gastric bypass (RYGB) surgery. Before the operation, all sub-jects received a 3-hour OGTT, from which insulin sensitivity was estimat-ed as the OGIS index. OSAS was diagnosed by polysomnography (usingthe Apnea-Hypopnea Index (AHI) = mild 5-15, moderate 15-30, severe>30). Six months after surgery, a subgroup of subjects (33 NGT and 11T2DM) was re-evaluated for all parameters.Results:Age and BMI were significantly higher in the OSAS group(n=83, p=0.001) and the prevalence of T2DM was 73% compared to38% in non-OSAS group (n=81, p<0.0001). Both fasting plasma glucose(111±48 vs 92±25 mg/dL) and HbA1c (7.3±4.5 vs 5.9±1%) were higher inOSAS group regardless of AHI, while insulin sensitivity was lower (346±71 vs 390±69, p=0.03). Before surgery, the OSAS group had higherserum ALT (33 [18] vs 19 [20] U/L, median [IQR]) andγGT levels (36[30] vs 21 [16]) than the non-OSAS group. In multivariate logistic analysis,HbA1c (p=0.015), BMI (p=0.026) andγGT (p=0.033) were independentlyassociated with the presence of OSAS. In a similar model, the severity ofOSAS and HbA1c were explanatory variables ofγGT concentrations. Sixmonths after surgery, BMI and HbA1cdecreased similarly in both groups,while fasting glycaemia declined more in OSAS than non-OSAS subjects.Furthermore, AST, ALT andγGT decreased in a greater degree in theformer than the latter (AST -21% vs 0.6%, ALT -60% vs -16% andγGT-53% vs -45%, p=0.03, p=0.01 and p=0.018, respectively). In logisticregression, surgery-induced changes inγGT were positively associatedwith baseline HbA1c (p=0.026)and presence of OSAS (p=0.05).Conclusion:In morbidly obese subjects, the presence of OSAS is asso-ciated with higherγGT concentrations independently of obesity andHbA1c. After surgery, however, serumγGT concentrations improve toa greater extent in patients with OSAS at baseline.
2016
https://link.springer.com/article/10.1007/s00125-016-4046-9
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/955026
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