In multivariable analysis , upper-tertile ACR was associated with faster heart rate ( = 2.5 , 95 % CI 0.2-4 .8 , P = 0.03 ) and lower RMSSD ( = -9.5 , 95 % CI -18.2 to -0.8 , P = 0.03 ) , independent of age and HbA1c .