At 1 year , the composite rates of complications in the low and high groups were 28 % and 17 % ( risk difference -11 [ CI95 , -25 to 4 ] , P = 0.15 ) and mortality rates were 12 % and 9 % , respectively ( risk difference -2 [ CI95 , -14 to 9 ] , P = 0.70 ) .