Objective: To investigate the relationship between Leptin-insulin resistance and pulmonary function in patients with chronic obstructive pulmonary disease (COPD) with acute exacerbation.
Methods: Fifty-six patients with COPD with acute exacerbation were divided into two groups according to the fasting plasma glucose level [the hyperglycemia group: fasting blood glucose (FBG)> or =6.2 mmol/L, n=42. the hypoglycemia group: FBG 3.1-6.2 mmol/L, n=14], and 20 normal healthy controls [the control group, FBG (5.49+/-1.06) mmol/L)] were also included in the study. All patients had complete data of FBG, C-reactive protein (CRP), albumin (ALB), Leptin, fasting serum insulin (FISN), counting insulin sensitivity index (ISI), and pulmonary function tests [forced expiratory volume in one second (FEV1), FEV1 in percentage of forced vital capacity (FEV1/FVC), peak expiratory flow (PEF), maximal mid-expiratory flow (MMEF), total respiratory impedance (Zrs), airway resistance at 5, 20 Hz (R5, R20), airway resistance of capacitance and inertance at 5, 20 Hz (X5, X20), core resistance (Rc), periphery resistance (Rp), frequency resonant (Fres)].
Results: The FBG, FISN, CRP were significantly higher and body mass index (BMI), ALB, ISI were significantly lower in the hyperglycemia group compared with control group (all P<0.01), but there was no difference in Leptin level (P>0.05). However, BMI, ALB, Leptin, ISI were significantly decreased and CRP, FISN were significantly increased in hypoglycemia group compared with the control group (P<0.05 or P<0.01). FBG, FISN, Leptin, CRP were significantly higher and ISI was significantly lower in hyperglycemia group compared with the hypoglycemia group (all P<0.01), but there was no significant difference in BMI and ALB (both P>0.05). The serum levels of Leptin was significantly positively correlated with Zrs, R5, R20, Rc, BMI (all P<0.01), and with significantly negative correlations with FEV1, X20 (P<0.01 and P<0.05), but had no correlation with FEV1/FVC, PEF, MMEF, X5, Rp, Fres (all P>0.05). ISI had significant positive correlations with FEV1/FVC, FEV1, PEF, MMEF (P<0.05 or P<0.01), but it had significant negative correlations with Zrs, R5, R20, X5, Rc, Rp, X20, BMI (P<0.05 or P<0.01), and no correlation with Fres. Multiple organ failure (MOF) was found in 6 cases (14%) in hyperglycemia group, one case (7%) was found in the second group, the incidence of MOF in hyperglycemia group was significantly higher compared with the hypoglycemia group (P<0.01). The length of hospital stay was prolonged in hyperglycemia group, compared with hypoglycemia group [(25.00+/-0.13) days vs. (17.93+/-0.22) days, P<0.01].
Conclusion: High glucose and Leptin-insulin resistance may aggravate the impairment of pulmonary function, prolong the length of hospital stay in the patient with COPD.