A1C decreased by 1.9 % ( 21 mmol/mol ) with IDegLira and by 0.9 % ( 10 mmol/mol ) with IDeg ( estimated treatment difference -1.1 % [ 95 % CI -1.3 , -0.8 ] , -12 mmol/mol [ 95 % CI -14 , -9 ; P < 0.0001 ) .