The overall glucose response was reduced ( treatment difference : -1,276.9 [ mg/dl ] min [ 95 % confidence interval , -2,392.4 to -161.5 ] ; P = 0.03 ) and insulin sensitivity was improved ( treatment difference : 0.77 [ mU/L ] ( -1 ) min ( -1 ) [ 95 % confidence interval , 0.03-1 .52 ] ; P = 0.04 ) with CPAP as compared with placebo .