After 6 months of D supply , there was a significant intergroup difference in the change in HbA ( c ) levels ( relative change [ mean standard deviation ] +2.9 % 1.5 % in the D group vs +6.9 % 2.1 % the in placebo group , p = 0.041 ) as HOMA-IR decreased by 12.8 % 5.6 % in the D group and increased by 10 % 5.4 % in the placebo group ( intergroup difference , p = 0.032 ) .