The test diet reduction in HbA1c units of -0.47 % ( -5.15 mmol/mol ) ( 95 % CI -0.54 % to -0.40 % [ -5.92 to -4.38 mmol/mol ] ) was greater than that for the control diet ( -0.31 % [ -3.44 mmol/mol ] [ 95 % CI -0.38 % to -0.25 % ( -4.17 to -2.71 mmol/mol ) ] , P = 0.002 ) , with the greatest benefit observed in those with higher systolic blood pressure ( SBP ) .